Error handling improvements (particularly in chain) (#1208)

* update error handling in chain and other modules to use error/errorkind

* sizeshift errorkind

Cargo.lock

@@ -591,6 +591,8 @@ dependencies = [
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "croaring 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "grin_core 0.2.0",
  "grin_keychain 0.2.0",
  "grin_store 0.2.0",
@@ -626,6 +628,8 @@ dependencies = [
  "blake2-rfc 0.2.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "croaring 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "grin_keychain 0.2.0",
  "grin_util 0.2.0",
  "grin_wallet 0.2.0",
@@ -729,6 +733,8 @@ dependencies = [
  "byteorder 1.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "croaring 0.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.5.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "failure_derive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "grin_core 0.2.0",
  "grin_util 0.2.0",
  "libc 0.2.42 (registry+https://github.com/rust-lang/crates.io-index)",

chain/Cargo.toml

@@ -9,6 +9,8 @@ publish = false
 bitflags = "1"
 byteorder = "1"
 lmdb-zero = "0.4.4"
+failure = "0.1"
+failure_derive = "0.1"
 croaring = "0.3"
 slog = { version = "~2.2", features = ["max_level_trace", "release_max_level_trace"] }
 serde = "1"

chain/src/chain.rs

@@ -27,13 +27,14 @@ use core::core::merkle_proof::MerkleProof;
 use core::core::target::Difficulty;
 use core::core::{Block, BlockHeader, Output, OutputIdentifier, Transaction, TxKernel};
 use core::global;
+use error::{Error, ErrorKind};
 use grin_store::Error::NotFoundErr;
 use pipe;
 use store;
 use txhashset;
-use types::{ChainAdapter, Error, Options, Tip};
+use types::{ChainAdapter, Options, Tip};
-use util::LOGGER;
 use util::secp::pedersen::{Commitment, RangeProof};
+use util::LOGGER;
 
 /// Orphan pool size is limited by MAX_ORPHAN_SIZE
 pub const MAX_ORPHAN_SIZE: usize = 200;
@@ -210,9 +211,7 @@ impl Chain {
 		b: Block,
 		opts: Options,
 	) -> Result<(Option<Tip>, Option<Block>), Error> {
-		let head = self.store
+		let head = self.store.head()?;
-			.head()
-			.map_err(|e| Error::StoreErr(e, "chain load head".to_owned()))?;
 		let mut ctx = self.ctx_from_head(head, opts)?;
 
 		let res = pipe::process_block(&b, &mut ctx);
@@ -252,7 +251,9 @@ impl Chain {
 				}
 				Ok((None, Some(b)))
 			}
-			Err(Error::Orphan) => {
+			Err(e) => {
+				match e.kind() {
+					ErrorKind::Orphan => {
 						let block_hash = b.hash();
 						let orphan = Orphan {
 							block: b,
@@ -272,9 +273,9 @@ impl Chain {
 							block_hash,
 							self.orphans.len(),
 						);
-				Err(Error::Orphan)
+						Err(ErrorKind::Orphan.into())
 					}
-			Err(Error::Unfit(ref msg)) => {
+					ErrorKind::Unfit(ref msg) => {
 						debug!(
 							LOGGER,
 							"Block {} at {} is unfit at this time: {}",
@@ -282,9 +283,9 @@ impl Chain {
 							b.header.height,
 							msg
 						);
-				Err(Error::Unfit(msg.clone()))
+						Err(ErrorKind::Unfit(msg.clone()).into())
 					}
-			Err(e) => {
+					_ => {
 						info!(
 							LOGGER,
 							"Rejected block {} at {}: {:?}",
@@ -292,7 +293,9 @@ impl Chain {
 							b.header.height,
 							e
 						);
-				Err(e)
+						Err(ErrorKind::Other(format!("{:?}", e).to_owned()).into())
+					}
+				}
 			}
 		}
 	}
@@ -409,7 +412,7 @@ impl Chain {
 		if tx.lock_height() <= height {
 			Ok(())
 		} else {
-			Err(Error::TxLockHeight)
+			Err(ErrorKind::TxLockHeight.into())
 		}
 	}
 
@@ -529,7 +532,7 @@ impl Chain {
 		let head = self.head().unwrap();
 		let header_head = self.get_header_head().unwrap();
 		if header_head.height - head.height < global::cut_through_horizon() as u64 {
-			return Err(Error::InvalidTxHashSet("not needed".to_owned()));
+			return Err(ErrorKind::InvalidTxHashSet("not needed".to_owned()).into());
 		}
 
 		let header = self.store.get_block_header(&h)?;
@@ -623,17 +626,21 @@ impl Chain {
 					batch.delete_block(&b.hash())?;
 					batch.delete_block_input_bitmap(&b.hash())?;
 				}
-				Err(NotFoundErr) => {
+				Err(NotFoundErr(_)) => {
 					break;
 				}
-				Err(e) => return Err(Error::StoreErr(e, "retrieving block to compact".to_owned())),
+				Err(e) => {
+					return Err(
+						ErrorKind::StoreErr(e, "retrieving block to compact".to_owned()).into(),
+					)
+				}
 			}
 			if current.height <= 1 {
 				break;
 			}
 			match self.store.get_block_header(&current.previous) {
 				Ok(h) => current = h,
-				Err(NotFoundErr) => break,
+				Err(NotFoundErr(_)) => break,
 				Err(e) => return Err(From::from(e)),
 			}
 		}
@@ -671,9 +678,9 @@ impl Chain {
 		let outputs = txhashset.outputs_by_insertion_index(start_index, max);
 		let rangeproofs = txhashset.rangeproofs_by_insertion_index(start_index, max);
 		if outputs.0 != rangeproofs.0 || outputs.1.len() != rangeproofs.1.len() {
-			return Err(Error::TxHashSetErr(String::from(
+			return Err(ErrorKind::TxHashSetErr(String::from(
 				"Output and rangeproof sets don't match",
-			)));
+			)).into());
 		}
 		let mut output_vec: Vec<Output> = vec![];
 		for (ref x, &y) in outputs.1.iter().zip(rangeproofs.1.iter()) {
@@ -704,9 +711,7 @@ impl Chain {
 	/// Reset header_head and sync_head to head of current body chain
 	pub fn reset_head(&self) -> Result<(), Error> {
 		let batch = self.store.batch()?;
-		batch
+		batch.reset_head()?;
-			.reset_head()
-			.map_err(|e| Error::StoreErr(e, "chain reset_head".to_owned()))?;
 		batch.commit()?;
 		Ok(())
 	}
@@ -720,28 +725,28 @@ impl Chain {
 	pub fn head_header(&self) -> Result<BlockHeader, Error> {
 		self.store
 			.head_header()
-			.map_err(|e| Error::StoreErr(e, "chain head header".to_owned()))
+			.map_err(|e| ErrorKind::StoreErr(e, "chain head header".to_owned()).into())
 	}
 
 	/// Gets a block header by hash
 	pub fn get_block(&self, h: &Hash) -> Result<Block, Error> {
 		self.store
 			.get_block(h)
-			.map_err(|e| Error::StoreErr(e, "chain get block".to_owned()))
+			.map_err(|e| ErrorKind::StoreErr(e, "chain get block".to_owned()).into())
 	}
 
 	/// Gets a block header by hash
 	pub fn get_block_header(&self, h: &Hash) -> Result<BlockHeader, Error> {
 		self.store
 			.get_block_header(h)
-			.map_err(|e| Error::StoreErr(e, "chain get header".to_owned()))
+			.map_err(|e| ErrorKind::StoreErr(e, "chain get header".to_owned()).into())
 	}
 
 	/// Gets the block header at the provided height
 	pub fn get_header_by_height(&self, height: u64) -> Result<BlockHeader, Error> {
 		self.store
 			.get_header_by_height(height)
-			.map_err(|e| Error::StoreErr(e, "chain get header by height".to_owned()))
+			.map_err(|e| ErrorKind::StoreErr(e, "chain get header by height".to_owned()).into())
 	}
 
 	/// Verifies the given block header is actually on the current chain.
@@ -750,7 +755,7 @@ impl Chain {
 	pub fn is_on_current_chain(&self, header: &BlockHeader) -> Result<(), Error> {
 		self.store
 			.is_on_current_chain(header)
-			.map_err(|e| Error::StoreErr(e, "chain is_on_current_chain".to_owned()))
+			.map_err(|e| ErrorKind::StoreErr(e, "chain is_on_current_chain".to_owned()).into())
 	}
 
 	/// Get the tip of the current "sync" header chain.
@@ -758,14 +763,14 @@ impl Chain {
 	pub fn get_sync_head(&self) -> Result<Tip, Error> {
 		self.store
 			.get_sync_head()
-			.map_err(|e| Error::StoreErr(e, "chain get sync head".to_owned()))
+			.map_err(|e| ErrorKind::StoreErr(e, "chain get sync head".to_owned()).into())
 	}
 
 	/// Get the tip of the header chain.
 	pub fn get_header_head(&self) -> Result<Tip, Error> {
 		self.store
 			.get_header_head()
-			.map_err(|e| Error::StoreErr(e, "chain get header head".to_owned()))
+			.map_err(|e| ErrorKind::StoreErr(e, "chain get header head".to_owned()).into())
 	}
 
 	/// Builds an iterator on blocks starting from the current chain head and
@@ -780,7 +785,7 @@ impl Chain {
 	pub fn block_exists(&self, h: Hash) -> Result<bool, Error> {
 		self.store
 			.block_exists(&h)
-			.map_err(|e| Error::StoreErr(e, "chain block exists".to_owned()))
+			.map_err(|e| ErrorKind::StoreErr(e, "chain block exists".to_owned()).into())
 	}
 }
 
@@ -830,7 +835,7 @@ fn setup_head(
 				}
 			}
 		}
-		Err(NotFoundErr) => {
+		Err(NotFoundErr(_)) => {
 			let tip = Tip::from_block(&genesis.header);
 			batch.save_block(&genesis)?;
 			batch.setup_height(&genesis.header, &tip)?;
@@ -844,7 +849,7 @@ fn setup_head(
 			head = tip;
 			info!(LOGGER, "chain: init: saved genesis: {:?}", genesis.hash());
 		}
-		Err(e) => return Err(Error::StoreErr(e, "chain init load head".to_owned())),
+		Err(e) => return Err(ErrorKind::StoreErr(e, "chain init load head".to_owned()))?,
 	};
 
 	// Initialize header_head and sync_head as necessary for chain init.

chain/src/error.rs

@@ -0,0 +1,248 @@
+// Copyright 2018 The Grin Developers
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Error types for chain
+use failure::{Backtrace, Context, Fail};
+use std::fmt::{self, Display};
+use std::io;
+
+use core::core::{block, committed, transaction};
+use core::ser;
+use grin_store as store;
+use keychain;
+use util::secp;
+use util::secp::pedersen::Commitment;
+
+/// Error definition
+#[derive(Debug, Fail)]
+pub struct Error {
+	inner: Context<ErrorKind>,
+}
+
+/// Chain error definitions
+#[derive(Clone, Eq, PartialEq, Debug, Fail)]
+pub enum ErrorKind {
+	/// The block doesn't fit anywhere in our chain
+	#[fail(display = "Block is unfit: {}", _0)]
+	Unfit(String),
+	/// Special case of orphan blocks
+	#[fail(display = "Orphan")]
+	Orphan,
+	/// Difficulty is too low either compared to ours or the block PoW hash
+	#[fail(display = "Difficulty is too low compared to ours or the block PoW hash")]
+	DifficultyTooLow,
+	/// Addition of difficulties on all previous block is wrong
+	#[fail(display = "Addition of difficulties on all previous blocks is wrong")]
+	WrongTotalDifficulty,
+	/// Block header sizeshift is lower than our min
+	#[fail(display = "Cuckoo Size too Low")]
+	LowSizeshift,
+	/// The proof of work is invalid
+	#[fail(display = "Invalid PoW")]
+	InvalidPow,
+	/// The block doesn't sum correctly or a tx signature is invalid
+	#[fail(display = "Invalid Block Proof")]
+	InvalidBlockProof(block::Error),
+	/// Block time is too old
+	#[fail(display = "Invalid Block Time")]
+	InvalidBlockTime,
+	/// Block height is invalid (not previous + 1)
+	#[fail(display = "Invalid Block Height")]
+	InvalidBlockHeight,
+	/// One of the root hashes in the block is invalid
+	#[fail(display = "Invalid Root")]
+	InvalidRoot,
+	/// One of the MMR sizes in the block header is invalid
+	#[fail(display = "Invalid MMR Size")]
+	InvalidMMRSize,
+	/// Error from underlying keychain impl
+	#[fail(display = "Keychain Error")]
+	Keychain(keychain::Error),
+	/// Error from underlying secp lib
+	#[fail(display = "Secp Lib Error")]
+	Secp(secp::Error),
+	/// One of the inputs in the block has already been spent
+	#[fail(display = "Already Spent: {:?}", _0)]
+	AlreadySpent(Commitment),
+	/// An output with that commitment already exists (should be unique)
+	#[fail(display = "Dupliate Commitment: {:?}", _0)]
+	DuplicateCommitment(Commitment),
+	/// Attempt to spend a coinbase output before it sufficiently matures.
+	#[fail(display = "Attempt to spend immature coinbase")]
+	ImmatureCoinbase,
+	/// Error validating a Merkle proof (coinbase output)
+	#[fail(display = "Error validating merkle proof")]
+	MerkleProof,
+	/// output not found
+	#[fail(display = "Output not found")]
+	OutputNotFound,
+	/// output spent
+	#[fail(display = "Output is spent")]
+	OutputSpent,
+	/// Invalid block version, either a mistake or outdated software
+	#[fail(display = "Invalid Block Version: {}", _0)]
+	InvalidBlockVersion(u16),
+	/// We've been provided a bad txhashset
+	#[fail(display = "Invalid TxHashSet: {}", _0)]
+	InvalidTxHashSet(String),
+	/// Internal issue when trying to save or load data from store
+	#[fail(display = "Store Error: {}", _1)]
+	StoreErr(store::Error, String),
+	/// Internal issue when trying to save or load data from append only files
+	#[fail(display = "File Read Error: {}", _0)]
+	FileReadErr(String),
+	/// Error serializing or deserializing a type
+	#[fail(display = "Serialization Error")]
+	SerErr(ser::Error),
+	/// Error with the txhashset
+	#[fail(display = "TxHashSetErr: {}", _0)]
+	TxHashSetErr(String),
+	/// Tx not valid based on lock_height.
+	#[fail(display = "Transaction Lock Height")]
+	TxLockHeight,
+	/// No chain exists and genesis block is required
+	#[fail(display = "Genesis Block Required")]
+	GenesisBlockRequired,
+	/// Error from underlying tx handling
+	#[fail(display = "Transaction Error")]
+	Transaction(transaction::Error),
+	/// Anything else
+	#[fail(display = "Other Error: {}", _0)]
+	Other(String),
+	/// Error from summing and verifying kernel sums via committed trait.
+	#[fail(display = "Committed Trait: Error summing and verifying kernel sums")]
+	Committed(committed::Error),
+}
+
+impl Display for Error {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		let cause = match self.cause() {
+			Some(c) => format!("{}", c),
+			None => String::from("Unknown"),
+		};
+		let backtrace = match self.backtrace() {
+			Some(b) => format!("{}", b),
+			None => String::from("Unknown"),
+		};
+		let output = format!(
+			"{} \n Cause: {} \n Backtrace: {}",
+			self.inner, cause, backtrace
+		);
+		Display::fmt(&output, f)
+	}
+}
+
+impl Error {
+	/// get kind
+	pub fn kind(&self) -> ErrorKind {
+		self.inner.get_context().clone()
+	}
+	/// get cause
+	pub fn cause(&self) -> Option<&Fail> {
+		self.inner.cause()
+	}
+	/// get backtrace
+	pub fn backtrace(&self) -> Option<&Backtrace> {
+		self.inner.backtrace()
+	}
+
+	/// Whether the error is due to a block that was intrinsically wrong
+	pub fn is_bad_data(&self) -> bool {
+		// shorter to match on all the "not the block's fault" errors
+		match self.kind() {
+			ErrorKind::Unfit(_)
+			| ErrorKind::Orphan
+			| ErrorKind::StoreErr(_, _)
+			| ErrorKind::SerErr(_)
+			| ErrorKind::TxHashSetErr(_)
+			| ErrorKind::GenesisBlockRequired
+			| ErrorKind::Other(_) => false,
+			_ => true,
+		}
+	}
+}
+
+impl From<ErrorKind> for Error {
+	fn from(kind: ErrorKind) -> Error {
+		Error {
+			inner: Context::new(kind),
+		}
+	}
+}
+
+impl From<Context<ErrorKind>> for Error {
+	fn from(inner: Context<ErrorKind>) -> Error {
+		Error { inner: inner }
+	}
+}
+
+impl From<block::Error> for Error {
+	fn from(error: block::Error) -> Error {
+		let ec = error.clone();
+		Error {
+			inner: error.context(ErrorKind::InvalidBlockProof(ec)),
+		}
+	}
+}
+
+impl From<store::Error> for Error {
+	fn from(error: store::Error) -> Error {
+		let ec = error.clone();
+		Error {
+			//inner: error.context();Context::new(ErrorKind::StoreErr(error.clone(),
+			// format!("{:?}", error))),
+			inner: error.context(ErrorKind::StoreErr(ec.clone(), format!("{:?}", ec))),
+		}
+	}
+}
+
+impl From<keychain::Error> for Error {
+	fn from(error: keychain::Error) -> Error {
+		Error {
+			inner: Context::new(ErrorKind::Keychain(error)),
+		}
+	}
+}
+
+impl From<transaction::Error> for Error {
+	fn from(error: transaction::Error) -> Error {
+		Error {
+			inner: Context::new(ErrorKind::Transaction(error)),
+		}
+	}
+}
+
+impl From<committed::Error> for Error {
+	fn from(error: committed::Error) -> Error {
+		Error {
+			inner: Context::new(ErrorKind::Committed(error)),
+		}
+	}
+}
+
+impl From<io::Error> for Error {
+	fn from(e: io::Error) -> Error {
+		Error {
+			inner: Context::new(ErrorKind::TxHashSetErr(e.to_string())),
+		}
+	}
+}
+
+impl From<secp::Error> for Error {
+	fn from(e: secp::Error) -> Error {
+		Error {
+			inner: Context::new(ErrorKind::Secp(e)),
+		}
+	}
+}

chain/src/lib.rs

@@ -31,7 +31,10 @@ extern crate serde;
 extern crate serde_derive;
 #[macro_use]
 extern crate slog;
+extern crate failure;
 extern crate time;
+#[macro_use]
+extern crate failure_derive;
 
 extern crate grin_core as core;
 extern crate grin_keychain as keychain;
@@ -39,6 +42,7 @@ extern crate grin_store;
 extern crate grin_util as util;
 
 mod chain;
+mod error;
 pub mod pipe;
 pub mod store;
 pub mod txhashset;
@@ -47,5 +51,6 @@ pub mod types;
 // Re-export the base interface
 
 pub use chain::{Chain, MAX_ORPHAN_SIZE};
+pub use error::{Error, ErrorKind};
 pub use store::ChainStore;
-pub use types::{ChainAdapter, Error, Options, Tip};
+pub use types::{ChainAdapter, Options, Tip};

chain/src/pipe.rs

@@ -23,12 +23,15 @@ use core::core::hash::{Hash, Hashed};
 use core::core::target::Difficulty;
 use core::core::{Block, BlockHeader};
 use core::global;
+use error::{Error, ErrorKind};
 use grin_store;
 use store;
 use txhashset;
-use types::{Error, Options, Tip};
+use types::{Options, Tip};
 use util::LOGGER;
 
+use failure::ResultExt;
+
 /// Contextual information required to process a new block and either reject or
 /// accept it.
 pub struct BlockContext {
@@ -75,10 +78,10 @@ pub fn process_block(b: &Block, ctx: &mut BlockContext) -> Result<Option<Tip>, E
 		match ctx.store.block_exists(&b.header.previous) {
 			Ok(true) => {}
 			Ok(false) => {
-				return Err(Error::Orphan);
+				return Err(ErrorKind::Orphan.into());
 			}
 			Err(e) => {
-				return Err(Error::StoreErr(e, "pipe get previous".to_owned()));
+				return Err(ErrorKind::StoreErr(e, "pipe get previous".to_owned()).into());
 			}
 		}
 	}
@@ -93,9 +96,7 @@ pub fn process_block(b: &Block, ctx: &mut BlockContext) -> Result<Option<Tip>, E
 	let mut txhashset = local_txhashset.write().unwrap();
 
 	// update head now that we're in the lock
-	ctx.head = ctx.store
+	ctx.head = ctx.store.head()?;
-		.head()
-		.map_err(|e| Error::StoreErr(e, "pipe reload head".to_owned()))?;
 
 	let mut batch = ctx.store.batch()?;
 
@@ -176,13 +177,13 @@ pub fn process_block_header(bh: &BlockHeader, ctx: &mut BlockContext) -> Result<
 fn check_header_known(bh: Hash, ctx: &mut BlockContext) -> Result<(), Error> {
 	// TODO ring buffer of the last few blocks that came through here
 	if bh == ctx.head.last_block_h || bh == ctx.head.prev_block_h {
-		return Err(Error::Unfit("already known".to_string()));
+		return Err(ErrorKind::Unfit("already known".to_string()).into());
 	}
 	if let Ok(h) = ctx.store.get_block_header(&bh) {
 		// there is a window where a block header can be saved but the chain head not
 		// updated yet, we plug that window here by re-accepting the block
 		if h.total_difficulty <= ctx.head.total_difficulty {
-			return Err(Error::Unfit("already in store".to_string()));
+			return Err(ErrorKind::Unfit("already in store".to_string()).into());
 		}
 	}
 	Ok(())
@@ -193,13 +194,13 @@ fn check_header_known(bh: Hash, ctx: &mut BlockContext) -> Result<(), Error> {
 fn check_known(bh: Hash, ctx: &mut BlockContext) -> Result<(), Error> {
 	// TODO ring buffer of the last few blocks that came through here
 	if bh == ctx.head.last_block_h || bh == ctx.head.prev_block_h {
-		return Err(Error::Unfit("already known".to_string()));
+		return Err(ErrorKind::Unfit("already known".to_string()).into());
 	}
 	if let Ok(b) = ctx.store.get_block(&bh) {
 		// there is a window where a block can be saved but the chain head not
 		// updated yet, we plug that window here by re-accepting the block
 		if b.header.total_difficulty <= ctx.head.total_difficulty {
-			return Err(Error::Unfit("already in store".to_string()));
+			return Err(ErrorKind::Unfit("already in store".to_string()).into());
 		}
 	}
 	Ok(())
@@ -216,7 +217,7 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
 			LOGGER,
 			"Invalid block header version received ({}), maybe update Grin?", header.version
 		);
-		return Err(Error::InvalidBlockVersion(header.version));
+		return Err(ErrorKind::InvalidBlockVersion(header.version).into());
 	}
 
 	// TODO: remove CI check from here somehow
@@ -226,12 +227,12 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
 	{
 		// refuse blocks more than 12 blocks intervals in future (as in bitcoin)
 		// TODO add warning in p2p code if local time is too different from peers
-		return Err(Error::InvalidBlockTime);
+		return Err(ErrorKind::InvalidBlockTime.into());
 	}
 
 	if !ctx.opts.contains(Options::SKIP_POW) {
 		if global::min_sizeshift() > header.pow.cuckoo_sizeshift {
-			return Err(Error::LowSizeshift);
+			return Err(ErrorKind::LowSizeshift.into());
 		}
 		if !(ctx.pow_verifier)(header, header.pow.cuckoo_sizeshift) {
 			error!(
@@ -239,31 +240,32 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
 				"pipe: validate_header failed for cuckoo shift size {}",
 				header.pow.cuckoo_sizeshift,
 			);
-			return Err(Error::InvalidPow);
+			return Err(ErrorKind::InvalidPow.into());
 		}
 	}
 
 	// first I/O cost, better as late as possible
 	let prev = match ctx.store.get_block_header(&header.previous) {
-		Ok(prev) => Ok(prev),
+		Ok(prev) => prev,
-		Err(grin_store::Error::NotFoundErr) => Err(Error::Orphan),
+		Err(grin_store::Error::NotFoundErr(_)) => return Err(ErrorKind::Orphan.into()),
-		Err(e) => Err(Error::StoreErr(
+		Err(e) => {
-			e,
+			return Err(
-			format!("previous header {}", header.previous),
+				ErrorKind::StoreErr(e, format!("previous header {}", header.previous)).into(),
-		)),
+			)
-	}?;
+		}
+	};
 
 	// make sure this header has a height exactly one higher than the previous
 	// header
 	if header.height != prev.height + 1 {
-		return Err(Error::InvalidBlockHeight);
+		return Err(ErrorKind::InvalidBlockHeight.into());
 	}
 
 	// TODO - get rid of the automated testing mode check here somehow
 	if header.timestamp <= prev.timestamp && !global::is_automated_testing_mode() {
 		// prevent time warp attacks and some timestamp manipulations by forcing strict
 		// time progression (but not in CI mode)
-		return Err(Error::InvalidBlockTime);
+		return Err(ErrorKind::InvalidBlockTime.into());
 	}
 
 	// verify the proof of work and related parameters
@@ -274,27 +276,27 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
 	// as the target difficulty
 	if !ctx.opts.contains(Options::SKIP_POW) {
 		if header.total_difficulty.clone() <= prev.total_difficulty.clone() {
-			return Err(Error::DifficultyTooLow);
+			return Err(ErrorKind::DifficultyTooLow.into());
 		}
 
 		let target_difficulty = header.total_difficulty.clone() - prev.total_difficulty.clone();
 
 		if header.pow.to_difficulty() < target_difficulty {
-			return Err(Error::DifficultyTooLow);
+			return Err(ErrorKind::DifficultyTooLow.into());
 		}
 
 		// explicit check to ensure we are not below the minimum difficulty
 		// we will also check difficulty based on next_difficulty later on
 		if target_difficulty < Difficulty::one() {
-			return Err(Error::DifficultyTooLow);
+			return Err(ErrorKind::DifficultyTooLow.into());
 		}
 
 		// explicit check to ensure total_difficulty has increased by exactly
 		// the _network_ difficulty of the previous block
 		// (during testnet1 we use _block_ difficulty here)
 		let diff_iter = store::DifficultyIter::from(header.previous, ctx.store.clone());
-		let network_difficulty =
+		let network_difficulty = consensus::next_difficulty(diff_iter)
-			consensus::next_difficulty(diff_iter).map_err(|e| Error::Other(e.to_string()))?;
+			.context(ErrorKind::Other("network difficulty".to_owned()))?;
 		if target_difficulty != network_difficulty.clone() {
 			error!(
 				LOGGER,
@@ -302,7 +304,7 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
 				target_difficulty.to_num(),
 				prev.total_difficulty.to_num() + network_difficulty.to_num()
 			);
-			return Err(Error::WrongTotalDifficulty);
+			return Err(ErrorKind::WrongTotalDifficulty.into());
 		}
 	}
 
@@ -312,7 +314,7 @@ fn validate_header(header: &BlockHeader, ctx: &mut BlockContext) -> Result<(), E
 fn validate_block(b: &Block, ctx: &mut BlockContext) -> Result<(), Error> {
 	let prev = ctx.store.get_block_header(&b.header.previous)?;
 	b.validate(&prev.total_kernel_offset, &prev.total_kernel_sum)
-		.map_err(&Error::InvalidBlockProof)?;
+		.map_err(|e| ErrorKind::InvalidBlockProof(e))?;
 	Ok(())
 }
 
@@ -329,7 +331,8 @@ fn validate_block_via_txhashset(b: &Block, ext: &mut txhashset::Extension) -> Re
 	ext.apply_block(&b)?;
 
 	let roots = ext.roots();
-	if roots.output_root != b.header.output_root || roots.rproof_root != b.header.range_proof_root
+	if roots.output_root != b.header.output_root
+		|| roots.rproof_root != b.header.range_proof_root
 		|| roots.kernel_root != b.header.kernel_root
 	{
 		ext.dump(false);
@@ -353,11 +356,11 @@ fn validate_block_via_txhashset(b: &Block, ext: &mut txhashset::Extension) -> Re
 			b.header.kernel_root,
 		);
 
-		return Err(Error::InvalidRoot);
+		return Err(ErrorKind::InvalidRoot.into());
 	}
 	let sizes = ext.sizes();
 	if b.header.output_mmr_size != sizes.0 || b.header.kernel_mmr_size != sizes.2 {
-		return Err(Error::InvalidMMRSize);
+		return Err(ErrorKind::InvalidMMRSize.into());
 	}
 
 	Ok(())
@@ -371,7 +374,7 @@ fn add_block(
 ) -> Result<(), Error> {
 	batch
 		.save_block(b)
-		.map_err(|e| Error::StoreErr(e, "pipe save block".to_owned()))?;
+		.map_err(|e| ErrorKind::StoreErr(e, "pipe save block".to_owned()))?;
 	let bitmap = store.build_and_cache_block_input_bitmap(&b)?;
 	batch.save_block_input_bitmap(&b.hash(), &bitmap)?;
 	Ok(())
@@ -381,7 +384,7 @@ fn add_block(
 fn add_block_header(bh: &BlockHeader, batch: &mut store::Batch) -> Result<(), Error> {
 	batch
 		.save_block_header(bh)
-		.map_err(|e| Error::StoreErr(e, "pipe save header".to_owned()))
+		.map_err(|e| ErrorKind::StoreErr(e, "pipe save header".to_owned()).into())
 }
 
 /// Directly updates the head if we've just appended a new block to it or handle
@@ -394,7 +397,7 @@ fn update_head(b: &Block, ctx: &BlockContext, batch: &store::Batch) -> Result<Op
 		// update the block height index
 		batch
 			.setup_height(&b.header, &ctx.head)
-			.map_err(|e| Error::StoreErr(e, "pipe setup height".to_owned()))?;
+			.map_err(|e| ErrorKind::StoreErr(e, "pipe setup height".to_owned()))?;
 
 		// in sync mode, only update the "body chain", otherwise update both the
 		// "header chain" and "body chain", updating the header chain in sync resets
@@ -403,11 +406,11 @@ fn update_head(b: &Block, ctx: &BlockContext, batch: &store::Batch) -> Result<Op
 		if ctx.opts.contains(Options::SYNC) {
 			batch
 				.save_body_head(&tip)
-				.map_err(|e| Error::StoreErr(e, "pipe save body".to_owned()))?;
+				.map_err(|e| ErrorKind::StoreErr(e, "pipe save body".to_owned()))?;
 		} else {
 			batch
 				.save_head(&tip)
-				.map_err(|e| Error::StoreErr(e, "pipe save head".to_owned()))?;
+				.map_err(|e| ErrorKind::StoreErr(e, "pipe save head".to_owned()))?;
 		}
 		debug!(
 			LOGGER,
@@ -436,7 +439,7 @@ fn update_sync_head(
 	let tip = Tip::from_block(bh);
 	batch
 		.save_sync_head(&tip)
-		.map_err(|e| Error::StoreErr(e, "pipe save sync head".to_owned()))?;
+		.map_err(|e| ErrorKind::StoreErr(e, "pipe save sync head".to_owned()))?;
 	ctx.head = tip.clone();
 	debug!(LOGGER, "sync head {} @ {}", bh.hash(), bh.height);
 	Ok(Some(tip))
@@ -451,7 +454,7 @@ fn update_header_head(
 	if tip.total_difficulty > ctx.head.total_difficulty {
 		batch
 			.save_header_head(&tip)
-			.map_err(|e| Error::StoreErr(e, "pipe save header head".to_owned()))?;
+			.map_err(|e| ErrorKind::StoreErr(e, "pipe save header head".to_owned()))?;
 		ctx.head = tip.clone();
 		debug!(LOGGER, "header head {} @ {}", bh.hash(), bh.height);
 		Ok(Some(tip))
@@ -509,7 +512,7 @@ pub fn rewind_and_apply_fork(
 	for (_, h) in fork_hashes {
 		let fb = store
 			.get_block(&h)
-			.map_err(|e| Error::StoreErr(e, format!("getting forked blocks")))?;
+			.map_err(|e| ErrorKind::StoreErr(e, format!("getting forked blocks")))?;
 		ext.apply_block(&fb)?;
 	}
 	Ok(())

chain/src/store.rs

@@ -27,7 +27,7 @@ use core::core::hash::{Hash, Hashed};
 use core::core::target::Difficulty;
 use core::core::{Block, BlockHeader};
 use grin_store as store;
-use grin_store::{option_to_not_found, to_key, Error, u64_to_key};
+use grin_store::{option_to_not_found, to_key, u64_to_key, Error};
 use types::Tip;
 
 const STORE_SUBPATH: &'static str = "chain";
@@ -63,7 +63,7 @@ impl ChainStore {
 #[allow(missing_docs)]
 impl ChainStore {
 	pub fn head(&self) -> Result<Tip, Error> {
-		option_to_not_found(self.db.get_ser(&vec![HEAD_PREFIX]))
+		option_to_not_found(self.db.get_ser(&vec![HEAD_PREFIX]), "HEAD")
 	}
 
 	pub fn head_header(&self) -> Result<BlockHeader, Error> {
@@ -71,15 +71,18 @@ impl ChainStore {
 	}
 
 	pub fn get_header_head(&self) -> Result<Tip, Error> {
-		option_to_not_found(self.db.get_ser(&vec![HEADER_HEAD_PREFIX]))
+		option_to_not_found(self.db.get_ser(&vec![HEADER_HEAD_PREFIX]), "HEADER_HEAD")
 	}
 
 	pub fn get_sync_head(&self) -> Result<Tip, Error> {
-		option_to_not_found(self.db.get_ser(&vec![SYNC_HEAD_PREFIX]))
+		option_to_not_found(self.db.get_ser(&vec![SYNC_HEAD_PREFIX]), "SYNC_HEAD")
 	}
 
 	pub fn get_block(&self, h: &Hash) -> Result<Block, Error> {
-		option_to_not_found(self.db.get_ser(&to_key(BLOCK_PREFIX, &mut h.to_vec())))
+		option_to_not_found(
+			self.db.get_ser(&to_key(BLOCK_PREFIX, &mut h.to_vec())),
+			&format!("BLOCK: {} ", h),
+		)
 	}
 
 	pub fn block_exists(&self, h: &Hash) -> Result<bool, Error> {
@@ -99,6 +102,7 @@ impl ChainStore {
 		let header: Result<BlockHeader, Error> = option_to_not_found(
 			self.db
 				.get_ser(&to_key(BLOCK_HEADER_PREFIX, &mut h.to_vec())),
+			&format!("BLOCK HEADER: {}", h),
 		);
 
 		// cache miss - so adding to the cache for next time
@@ -121,26 +125,33 @@ impl ChainStore {
 
 		// check we are not out ahead of the current head
 		if header.height > head.height {
-			return Err(Error::NotFoundErr);
+			return Err(Error::NotFoundErr(String::from(
+				"header.height > head.height",
+			)));
 		}
 
 		let header_at_height = self.get_header_by_height(header.height)?;
 		if header.hash() == header_at_height.hash() {
 			Ok(())
 		} else {
-			Err(Error::NotFoundErr)
+			Err(Error::NotFoundErr(String::from(
+				"header.hash == header_at_height.hash",
+			)))
 		}
 	}
 
 	pub fn get_header_by_height(&self, height: u64) -> Result<BlockHeader, Error> {
-		option_to_not_found(self.db.get_ser(&u64_to_key(HEADER_HEIGHT_PREFIX, height)))
+		option_to_not_found(
-			.and_then(|hash| self.get_block_header(&hash))
+			self.db.get_ser(&u64_to_key(HEADER_HEIGHT_PREFIX, height)),
+			&format!("Header at height: {}", height),
+		).and_then(|hash| self.get_block_header(&hash))
 	}
 
 	pub fn get_output_pos(&self, commit: &Commitment) -> Result<u64, Error> {
 		option_to_not_found(
 			self.db
 				.get_ser(&to_key(COMMIT_POS_PREFIX, &mut commit.as_ref().to_vec())),
+			&format!("Output position for: {:?}", commit),
 		)
 	}
 
@@ -239,7 +250,7 @@ impl<'a> Batch<'a> {
 	pub fn init_sync_head(&self, t: &Tip) -> Result<(), Error> {
 		let header_tip = match self.store.get_header_head() {
 			Ok(hh) => hh,
-			Err(store::Error::NotFoundErr) => {
+			Err(store::Error::NotFoundErr(_)) => {
 				self.save_header_head(t)?;
 				t.clone()
 			}
@@ -257,7 +268,10 @@ impl<'a> Batch<'a> {
 
 	/// get block
 	pub fn get_block(&self, h: &Hash) -> Result<Block, Error> {
-		option_to_not_found(self.db.get_ser(&to_key(BLOCK_PREFIX, &mut h.to_vec())))
+		option_to_not_found(
+			self.db.get_ser(&to_key(BLOCK_PREFIX, &mut h.to_vec())),
+			&format!("Block with hash: {}", h),
+		)
 	}
 
 	/// Save the block and its header
@@ -303,6 +317,7 @@ impl<'a> Batch<'a> {
 		option_to_not_found(
 			self.db
 				.get_ser(&to_key(COMMIT_POS_PREFIX, &mut commit.as_ref().to_vec())),
+			&format!("Output position for commit: {:?}", commit),
 		)
 	}
 
@@ -315,6 +330,7 @@ impl<'a> Batch<'a> {
 		option_to_not_found(
 			self.db
 				.get_ser(&to_key(BLOCK_HEADER_PREFIX, &mut h.to_vec())),
+			&format!("Block header for block: {}", h),
 		)
 	}
 

chain/src/txhashset.rs

@@ -31,16 +31,18 @@ use core::core::hash::{Hash, Hashed};
 use core::core::merkle_proof::MerkleProof;
 use core::core::pmmr;
 use core::core::pmmr::PMMR;
-use core::core::{Block, BlockHeader, Input, Output, OutputFeatures, OutputIdentifier, Transaction,
+use core::core::{
-                 TxKernel};
+	Block, BlockHeader, Input, Output, OutputFeatures, OutputIdentifier, Transaction, TxKernel,
+};
 use core::global;
 use core::ser::{PMMRIndexHashable, PMMRable};
 
+use error::{Error, ErrorKind};
 use grin_store;
 use grin_store::pmmr::PMMRBackend;
 use grin_store::types::prune_noop;
 use store::{Batch, ChainStore};
-use types::{Error, TxHashSetRoots};
+use types::TxHashSetRoots;
 use util::{secp_static, zip, LOGGER};
 
 const TXHASHSET_SUBDIR: &'static str = "txhashset";
@@ -138,14 +140,14 @@ impl TxHashSet {
 					if hash == output_id.hash_with_index(pos - 1) {
 						Ok(hash)
 					} else {
-						Err(Error::TxHashSetErr(format!("txhashset hash mismatch")))
+						Err(ErrorKind::TxHashSetErr(format!("txhashset hash mismatch")).into())
 					}
 				} else {
-					Err(Error::OutputNotFound)
+					Err(ErrorKind::OutputNotFound.into())
 				}
 			}
-			Err(grin_store::Error::NotFoundErr) => Err(Error::OutputNotFound),
+			Err(grin_store::Error::NotFoundErr(_)) => Err(ErrorKind::OutputNotFound.into()),
-			Err(e) => Err(Error::StoreErr(e, format!("txhashset unspent check"))),
+			Err(e) => Err(ErrorKind::StoreErr(e, format!("txhashset unspent check")).into()),
 		}
 	}
 
@@ -338,7 +340,7 @@ where
 		Err(e) => {
 			debug!(
 				LOGGER,
-				"Error returned, discarding txhashset extension: {:?}", e
+				"Error returned, discarding txhashset extension: {}", e
 			);
 			trees.output_pmmr_h.backend.discard();
 			trees.rproof_pmmr_h.backend.discard();
@@ -577,7 +579,7 @@ impl<'a> Extension<'a> {
 			// If we have not yet reached 1,000 blocks then
 			// we can fail immediately as coinbase cannot be mature.
 			if height < global::coinbase_maturity() {
-				return Err(Error::ImmatureCoinbase);
+				return Err(ErrorKind::ImmatureCoinbase.into());
 			}
 
 			// Find the "cutoff" pos in the output MMR based on the
@@ -586,11 +588,10 @@ impl<'a> Extension<'a> {
 			let cutoff_header = self.commit_index.get_header_by_height(cutoff_height)?;
 			let cutoff_pos = cutoff_header.output_mmr_size;
 
-
 			// If any output pos exceeed the cutoff_pos
 			// we know they have not yet sufficiently matured.
 			if pos > cutoff_pos {
-				return Err(Error::ImmatureCoinbase);
+				return Err(ErrorKind::ImmatureCoinbase.into());
 			}
 		}
 
@@ -641,7 +642,9 @@ impl<'a> Extension<'a> {
 					.expect("no output at pos")
 					.hash_with_index(pos - 1);
 				if output_id_hash != read_hash || output_id_hash != read_elem_hash {
-					return Err(Error::TxHashSetErr(format!("output pmmr hash mismatch")));
+					return Err(
+						ErrorKind::TxHashSetErr(format!("output pmmr hash mismatch")).into(),
+					);
 				}
 			}
 
@@ -652,13 +655,13 @@ impl<'a> Extension<'a> {
 				Ok(true) => {
 					self.rproof_pmmr
 						.prune(pos)
-						.map_err(|s| Error::TxHashSetErr(s))?;
+						.map_err(|s| ErrorKind::TxHashSetErr(s))?;
 				}
-				Ok(false) => return Err(Error::AlreadySpent(commit)),
+				Ok(false) => return Err(ErrorKind::AlreadySpent(commit).into()),
-				Err(s) => return Err(Error::TxHashSetErr(s)),
+				Err(s) => return Err(ErrorKind::TxHashSetErr(s).into()),
 			}
 		} else {
-			return Err(Error::AlreadySpent(commit));
+			return Err(ErrorKind::AlreadySpent(commit).into());
 		}
 		Ok(())
 	}
@@ -677,21 +680,21 @@ impl<'a> Extension<'a> {
 				// We may be on a fork which may result in the entry at that pos being
 				// different to the one we expect.
 				if hash == OutputIdentifier::from_output(out).hash_with_index(pos - 1) {
-					return Err(Error::DuplicateCommitment(commit));
+					return Err(ErrorKind::DuplicateCommitment(commit).into());
 				}
 			}
 		}
 		// push new outputs in their MMR and save them in the index
 		let pos = self.output_pmmr
 			.push(OutputIdentifier::from_output(out))
-			.map_err(&Error::TxHashSetErr)?;
+			.map_err(&ErrorKind::TxHashSetErr)?;
 		self.batch.save_output_pos(&out.commitment(), pos)?;
 		self.new_output_commits.insert(out.commitment(), pos);
 
 		// push range proofs in their MMR and file
 		self.rproof_pmmr
 			.push(out.proof)
-			.map_err(&Error::TxHashSetErr)?;
+			.map_err(&ErrorKind::TxHashSetErr)?;
 		Ok(())
 	}
 
@@ -699,7 +702,7 @@ impl<'a> Extension<'a> {
 		// push kernels in their MMR and file
 		self.kernel_pmmr
 			.push(kernel.clone())
-			.map_err(&Error::TxHashSetErr)?;
+			.map_err(&ErrorKind::TxHashSetErr)?;
 
 		Ok(())
 	}
@@ -729,7 +732,7 @@ impl<'a> Extension<'a> {
 		let pos = self.batch.get_output_pos(&output.commit)?;
 		let merkle_proof = self.output_pmmr
 			.merkle_proof(pos)
-			.map_err(&Error::TxHashSetErr)?;
+			.map_err(&ErrorKind::TxHashSetErr)?;
 
 		Ok(merkle_proof)
 	}
@@ -742,10 +745,10 @@ impl<'a> Extension<'a> {
 	pub fn snapshot(&mut self, header: &BlockHeader) -> Result<(), Error> {
 		self.output_pmmr
 			.snapshot(header)
-			.map_err(|e| Error::Other(e))?;
+			.map_err(|e| ErrorKind::Other(e))?;
 		self.rproof_pmmr
 			.snapshot(header)
-			.map_err(|e| Error::Other(e))?;
+			.map_err(|e| ErrorKind::Other(e))?;
 		Ok(())
 	}
 
@@ -820,17 +823,17 @@ impl<'a> Extension<'a> {
 		if rewind_utxo {
 			self.output_pmmr
 				.rewind(output_pos, rewind_add_pos, rewind_rm_pos)
-				.map_err(&Error::TxHashSetErr)?;
+				.map_err(&ErrorKind::TxHashSetErr)?;
 		}
 		if rewind_rproof {
 			self.rproof_pmmr
 				.rewind(output_pos, rewind_add_pos, rewind_rm_pos)
-				.map_err(&Error::TxHashSetErr)?;
+				.map_err(&ErrorKind::TxHashSetErr)?;
 		}
 		if rewind_kernel {
 			self.kernel_pmmr
 				.rewind(kernel_pos, rewind_add_pos, rewind_rm_pos)
-				.map_err(&Error::TxHashSetErr)?;
+				.map_err(&ErrorKind::TxHashSetErr)?;
 		}
 
 		Ok(())
@@ -863,10 +866,11 @@ impl<'a> Extension<'a> {
 		}
 
 		let roots = self.roots();
-		if roots.output_root != header.output_root || roots.rproof_root != header.range_proof_root
+		if roots.output_root != header.output_root
+			|| roots.rproof_root != header.range_proof_root
 			|| roots.kernel_root != header.kernel_root
 		{
-			return Err(Error::InvalidRoot);
+			return Err(ErrorKind::InvalidRoot.into());
 		}
 		Ok(())
 	}
@@ -876,13 +880,13 @@ impl<'a> Extension<'a> {
 
 		// validate all hashes and sums within the trees
 		if let Err(e) = self.output_pmmr.validate() {
-			return Err(Error::InvalidTxHashSet(e));
+			return Err(ErrorKind::InvalidTxHashSet(e).into());
 		}
 		if let Err(e) = self.rproof_pmmr.validate() {
-			return Err(Error::InvalidTxHashSet(e));
+			return Err(ErrorKind::InvalidTxHashSet(e).into());
 		}
 		if let Err(e) = self.kernel_pmmr.validate() {
-			return Err(Error::InvalidTxHashSet(e));
+			return Err(ErrorKind::InvalidTxHashSet(e).into());
 		}
 
 		debug!(
@@ -1017,7 +1021,7 @@ impl<'a> Extension<'a> {
 						out.into_output(rp).verify_proof()?;
 					} else {
 						// TODO - rangeproof not found
-						return Err(Error::OutputNotFound);
+						return Err(ErrorKind::OutputNotFound.into());
 					}
 					proof_count += 1;
 
@@ -1056,10 +1060,10 @@ impl<'a> Extension<'a> {
 			// rewinding further and further back
 			self.rewind(&current, &head_header, false, true, false)?;
 			if self.kernel_pmmr.root() != current.kernel_root {
-				return Err(Error::InvalidTxHashSet(format!(
+				return Err(ErrorKind::InvalidTxHashSet(format!(
 					"Kernel root at {} does not match",
 					current.height
-				)));
+				)).into());
 			}
 		}
 		Ok(())
@@ -1075,7 +1079,7 @@ pub fn zip_read(root_dir: String) -> Result<File, Error> {
 	// create the zip archive
 	{
 		zip::compress(&txhashset_path, &File::create(zip_path.clone())?)
-			.map_err(|ze| Error::Other(ze.to_string()))?;
+			.map_err(|ze| ErrorKind::Other(ze.to_string()))?;
 	}
 
 	// open it again to read it back
@@ -1089,7 +1093,8 @@ pub fn zip_write(root_dir: String, txhashset_data: File) -> Result<(), Error> {
 	let txhashset_path = Path::new(&root_dir).join(TXHASHSET_SUBDIR);
 
 	fs::create_dir_all(txhashset_path.clone())?;
-	zip::decompress(txhashset_data, &txhashset_path).map_err(|ze| Error::Other(ze.to_string()))
+	zip::decompress(txhashset_data, &txhashset_path)
+		.map_err(|ze| ErrorKind::Other(ze.to_string()).into())
 }
 
 /// Given a block header to rewind to and the block header at the

chain/src/types.rs

@@ -14,18 +14,10 @@
 
 //! Base types that the block chain pipeline requires.
 
-use std::{error, fmt, io};
-
-use util::secp;
-use util::secp::pedersen::Commitment;
-
-use core::core::committed;
 use core::core::hash::{Hash, Hashed};
 use core::core::target::Difficulty;
-use core::core::{block, transaction, Block, BlockHeader};
+use core::core::{Block, BlockHeader};
 use core::ser;
-use grin_store as store;
-use keychain;
 
 bitflags! {
 /// Options for block validation
@@ -53,146 +45,6 @@ pub struct TxHashSetRoots {
 	pub kernel_root: Hash,
 }
 
-/// Errors
-#[derive(Debug)]
-pub enum Error {
-	/// The block doesn't fit anywhere in our chain
-	Unfit(String),
-	/// Special case of orphan blocks
-	Orphan,
-	/// Difficulty is too low either compared to ours or the block PoW hash
-	DifficultyTooLow,
-	/// Addition of difficulties on all previous block is wrong
-	WrongTotalDifficulty,
-	/// Block header sizeshift is lower than our min
-	LowSizeshift,
-	/// The proof of work is invalid
-	InvalidPow,
-	/// The block doesn't sum correctly or a tx signature is invalid
-	InvalidBlockProof(block::Error),
-	/// Block time is too old
-	InvalidBlockTime,
-	/// Block height is invalid (not previous + 1)
-	InvalidBlockHeight,
-	/// One of the root hashes in the block is invalid
-	InvalidRoot,
-	/// One of the MMR sizes in the block header is invalid
-	InvalidMMRSize,
-	/// Error from underlying keychain impl
-	Keychain(keychain::Error),
-	/// Error from underlying secp lib
-	Secp(secp::Error),
-	/// One of the inputs in the block has already been spent
-	AlreadySpent(Commitment),
-	/// An output with that commitment already exists (should be unique)
-	DuplicateCommitment(Commitment),
-	/// Attempt to spend a coinbase output before it sufficiently matures.
-	ImmatureCoinbase,
-	/// Error validating a Merkle proof (coinbase output)
-	MerkleProof,
-	/// output not found
-	OutputNotFound,
-	/// output spent
-	OutputSpent,
-	/// Invalid block version, either a mistake or outdated software
-	InvalidBlockVersion(u16),
-	/// We've been provided a bad txhashset
-	InvalidTxHashSet(String),
-	/// Internal issue when trying to save or load data from store
-	StoreErr(store::Error, String),
-	/// Internal issue when trying to save or load data from append only files
-	FileReadErr(String),
-	/// Error serializing or deserializing a type
-	SerErr(ser::Error),
-	/// Error with the txhashset
-	TxHashSetErr(String),
-	/// Tx not valid based on lock_height.
-	TxLockHeight,
-	/// No chain exists and genesis block is required
-	GenesisBlockRequired,
-	/// Error from underlying tx handling
-	Transaction(transaction::Error),
-	/// Anything else
-	Other(String),
-	/// Error from summing and verifying kernel sums via committed trait.
-	Committed(committed::Error),
-}
-
-impl error::Error for Error {
-	fn description(&self) -> &str {
-		match *self {
-			_ => "some kind of chain error",
-		}
-	}
-}
-
-impl fmt::Display for Error {
-	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-		match *self {
-			_ => write!(f, "some kind of chain error"),
-		}
-	}
-}
-
-impl From<store::Error> for Error {
-	fn from(e: store::Error) -> Error {
-		Error::StoreErr(e, "wrapped".to_owned())
-	}
-}
-
-impl From<ser::Error> for Error {
-	fn from(e: ser::Error) -> Error {
-		Error::SerErr(e)
-	}
-}
-
-impl From<io::Error> for Error {
-	fn from(e: io::Error) -> Error {
-		Error::TxHashSetErr(e.to_string())
-	}
-}
-
-impl From<keychain::Error> for Error {
-	fn from(e: keychain::Error) -> Error {
-		Error::Keychain(e)
-	}
-}
-
-impl From<secp::Error> for Error {
-	fn from(e: secp::Error) -> Error {
-		Error::Secp(e)
-	}
-}
-
-impl From<committed::Error> for Error {
-	fn from(e: committed::Error) -> Error {
-		Error::Committed(e)
-	}
-}
-
-impl Error {
-	/// Whether the error is due to a block that was intrinsically wrong
-	pub fn is_bad_data(&self) -> bool {
-		// shorter to match on all the "not the block's fault" errors
-		match *self {
-			Error::Unfit(_)
-			| Error::Orphan
-			| Error::StoreErr(_, _)
-			| Error::SerErr(_)
-			| Error::TxHashSetErr(_)
-			| Error::GenesisBlockRequired
-			| Error::Other(_) => false,
-			_ => true,
-		}
-	}
-}
-
-impl From<transaction::Error> for Error {
-	fn from(e: transaction::Error) -> Error {
-		Error::Transaction(e)
-	}
-}
-
 /// The tip of a fork. A handle to the fork ancestry from its leaf in the
 /// blockchain tree. References the max height and the latest and previous
 /// blocks

chain/tests/test_coinbase_maturity.rs

@@ -24,7 +24,8 @@ extern crate time;
 use std::fs;
 use std::sync::Arc;
 
-use chain::types::{Error, NoopAdapter};
+use chain::types::NoopAdapter;
+use chain::{Error, ErrorKind};
 use core::core::target::Difficulty;
 use core::core::{transaction, OutputIdentifier};
 use core::global::{self, ChainTypes};
@@ -126,8 +127,11 @@ fn test_coinbase_maturity() {
 	// Confirm the tx attempting to spend the coinbase output
 	// is not valid at the current block height given the current chain state.
 	match chain.verify_coinbase_maturity(&coinbase_txn) {
-		Err(Error::ImmatureCoinbase) => {}
+		Ok(_) => {}
+		Err(e) => match e.kind() {
+			ErrorKind::ImmatureCoinbase => {}
 			_ => panic!("Expected transaction error with immature coinbase."),
+		},
 	}
 
 	pow::pow_size(

core/Cargo.toml

@@ -10,6 +10,8 @@ bitflags = "1"
 blake2-rfc = "0.2"
 byteorder = "1"
 croaring = "0.3"
+failure = "0.1"
+failure_derive = "0.1"
 lazy_static = "1"
 num-bigint = "0.2"
 rand = "0.3"

core/src/consensus.rs

@@ -103,7 +103,8 @@ pub const MAX_TX_KERNELS: u64 = 2048;
 
 /// Whether a block exceeds the maximum acceptable weight
 pub fn exceeds_weight(input_len: usize, output_len: usize, kernel_len: usize) -> bool {
-	input_len * BLOCK_INPUT_WEIGHT + output_len * BLOCK_OUTPUT_WEIGHT
+	input_len * BLOCK_INPUT_WEIGHT
+		+ output_len * BLOCK_OUTPUT_WEIGHT
 		+ kernel_len * BLOCK_KERNEL_WEIGHT > MAX_BLOCK_WEIGHT || input_len > MAX_BLOCK_INPUTS
 }
 
@@ -159,14 +160,20 @@ pub const DAMP_FACTOR: u64 = 3;
 pub const INITIAL_DIFFICULTY: u64 = 1_000_000;
 
 /// Consensus errors
-#[derive(Clone, Debug, Eq, PartialEq)]
+#[derive(Clone, Debug, Eq, PartialEq, Fail)]
 pub enum Error {
 	/// Inputs/outputs/kernels must be sorted lexicographically.
 	SortError,
 }
 
+impl fmt::Display for Error {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		write!(f, "Sort Error")
+	}
+}
+
 /// Error when computing the next difficulty adjustment.
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, Fail)]
 pub struct TargetError(pub String);
 
 impl fmt::Display for TargetError {

core/src/core/block.rs

@@ -16,6 +16,7 @@
 
 use rand::{thread_rng, Rng};
 use std::collections::HashSet;
+use std::fmt;
 use std::iter::FromIterator;
 use time;
 
@@ -24,15 +25,17 @@ use core::committed::{self, Committed};
 use core::hash::{Hash, HashWriter, Hashed, ZERO_HASH};
 use core::id::ShortIdentifiable;
 use core::target::Difficulty;
-use core::{transaction, Commitment, Input, KernelFeatures, Output, OutputFeatures, Proof, ShortId,
+use core::{
-           Transaction, TxKernel};
+	transaction, Commitment, Input, KernelFeatures, Output, OutputFeatures, Proof, ShortId,
+	Transaction, TxKernel,
+};
 use global;
 use keychain::{self, BlindingFactor};
 use ser::{self, read_and_verify_sorted, Readable, Reader, Writeable, WriteableSorted, Writer};
 use util::{secp, secp_static, static_secp_instance, LOGGER};
 
 /// Errors thrown by Block validation
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone, Eq, PartialEq, Fail)]
 pub enum Error {
 	/// The sum of output minus input commitments does not
 	/// match the sum of kernel commitments
@@ -95,6 +98,12 @@ impl From<consensus::Error> for Error {
 	}
 }
 
+impl fmt::Display for Error {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		write!(f, "Block Error (display needs implementation")
+	}
+}
+
 /// Block header, fairly standard compared to other blockchains.
 #[derive(Clone, Debug, PartialEq)]
 pub struct BlockHeader {

core/src/core/id.rs

@@ -14,8 +14,8 @@
 
 //! short ids for compact blocks
 
-use std::cmp::Ordering;
 use std::cmp::min;
+use std::cmp::Ordering;
 
 use byteorder::{ByteOrder, LittleEndian};
 use siphasher::sip::SipHasher24;

core/src/core/pmmr.rs

@@ -39,9 +39,9 @@ use std::marker;
 
 use croaring::Bitmap;
 
-use core::BlockHeader;
 use core::hash::Hash;
 use core::merkle_proof::MerkleProof;
+use core::BlockHeader;
 use ser::{PMMRIndexHashable, PMMRable};
 use util::LOGGER;
 

core/src/core/transaction.rs

@@ -14,8 +14,8 @@
 
 //! Transactions
 
-use std::cmp::Ordering;
 use std::cmp::max;
+use std::cmp::Ordering;
 use std::collections::HashSet;
 use std::{error, fmt};
 
@@ -27,8 +27,9 @@ use consensus::{self, VerifySortOrder};
 use core::hash::Hashed;
 use core::{committed, Committed};
 use keychain::{self, BlindingFactor};
-use ser::{self, read_and_verify_sorted, PMMRable, Readable, Reader, Writeable,
+use ser::{
-          WriteableSorted, Writer};
+	self, read_and_verify_sorted, PMMRable, Readable, Reader, Writeable, WriteableSorted, Writer,
+};
 use util;
 
 bitflags! {
@@ -250,7 +251,9 @@ pub struct Transaction {
 /// PartialEq
 impl PartialEq for Transaction {
 	fn eq(&self, tx: &Transaction) -> bool {
-		self.inputs == tx.inputs && self.outputs == tx.outputs && self.kernels == tx.kernels
+		self.inputs == tx.inputs
+			&& self.outputs == tx.outputs
+			&& self.kernels == tx.kernels
 			&& self.offset == tx.offset
 	}
 }
@@ -290,7 +293,8 @@ impl Readable for Transaction {
 		let (input_len, output_len, kernel_len) =
 			ser_multiread!(reader, read_u64, read_u64, read_u64);
 
-		if input_len > consensus::MAX_TX_INPUTS || output_len > consensus::MAX_TX_OUTPUTS
+		if input_len > consensus::MAX_TX_INPUTS
+			|| output_len > consensus::MAX_TX_OUTPUTS
 			|| kernel_len > consensus::MAX_TX_KERNELS
 		{
 			return Err(ser::Error::CorruptedData);
@@ -436,16 +440,12 @@ impl Transaction {
 
 	/// Calculate transaction weight
 	pub fn tx_weight(&self) -> u32 {
-		Transaction::weight(
+		Transaction::weight(self.inputs.len(), self.outputs.len())
-			self.inputs.len(),
-			self.outputs.len(),
-		)
 	}
 
 	/// Calculate transaction weight from transaction details
 	pub fn weight(input_len: usize, output_len: usize) -> u32 {
-		let mut tx_weight =
+		let mut tx_weight = -1 * (input_len as i32) + (4 * output_len as i32) + 1;
-			-1 * (input_len as i32) + (4 * output_len as i32) + 1;
 		if tx_weight < 1 {
 			tx_weight = 1;
 		}
@@ -669,14 +669,8 @@ impl Readable for Input {
 impl Input {
 	/// Build a new input from the data required to identify and verify an
 	/// output being spent.
-	pub fn new(
+	pub fn new(features: OutputFeatures, commit: Commitment) -> Input {
-		features: OutputFeatures,
+		Input { features, commit }
-		commit: Commitment,
-	) -> Input {
-		Input {
-			features,
-			commit,
-		}
 	}
 
 	/// The input commitment which _partially_ identifies the output being

core/src/global.rs

@@ -17,9 +17,11 @@
 //! should be used sparingly.
 
 use consensus::TargetError;
-use consensus::{BLOCK_TIME_SEC, COINBASE_MATURITY, CUT_THROUGH_HORIZON, DEFAULT_MIN_SIZESHIFT,
+use consensus::{
+	BLOCK_TIME_SEC, COINBASE_MATURITY, CUT_THROUGH_HORIZON, DEFAULT_MIN_SIZESHIFT,
 	DIFFICULTY_ADJUST_WINDOW, INITIAL_DIFFICULTY, MEDIAN_TIME_WINDOW, PROOFSIZE,
-                REFERENCE_SIZESHIFT};
+	REFERENCE_SIZESHIFT,
+};
 use core::target::Difficulty;
 /// An enum collecting sets of parameters used throughout the
 /// code wherever mining is needed. This should allow for
@@ -184,7 +186,8 @@ pub fn is_user_testing_mode() -> bool {
 /// Are we in production mode (a live public network)?
 pub fn is_production_mode() -> bool {
 	let param_ref = CHAIN_TYPE.read().unwrap();
-	ChainTypes::Testnet1 == *param_ref || ChainTypes::Testnet2 == *param_ref
+	ChainTypes::Testnet1 == *param_ref
+		|| ChainTypes::Testnet2 == *param_ref
 		|| ChainTypes::Mainnet == *param_ref
 }
 

core/src/lib.rs

@@ -38,7 +38,10 @@ extern crate serde_derive;
 extern crate siphasher;
 #[macro_use]
 extern crate slog;
+extern crate failure;
 extern crate time;
+#[macro_use]
+extern crate failure_derive;
 
 #[macro_use]
 pub mod macros;

core/src/pow/cuckoo.rs

@@ -171,7 +171,13 @@ impl Miner {
 		let size = 1 << sizeshift;
 		let graph = vec![0; size + 1];
 		let easiness = (ease as u64) * (size as u64) / 100;
-		Miner{easiness, cuckoo, graph, proof_size, sizeshift}
+		Miner {
+			easiness,
+			cuckoo,
+			graph,
+			proof_size,
+			sizeshift,
+		}
 	}
 
 	/// Searches for a solution
@@ -298,8 +304,13 @@ impl Miner {
 
 /// Utility to transform a 8 bytes of a byte array into a u64.
 fn u8_to_u64(p: &[u8], i: usize) -> u64 {
-	(p[i] as u64) | (p[i + 1] as u64) << 8 | (p[i + 2] as u64) << 16 | (p[i + 3] as u64) << 24
+	(p[i] as u64)
-		| (p[i + 4] as u64) << 32 | (p[i + 5] as u64) << 40 | (p[i + 6] as u64) << 48
+		| (p[i + 1] as u64) << 8
+		| (p[i + 2] as u64) << 16
+		| (p[i + 3] as u64) << 24
+		| (p[i + 4] as u64) << 32
+		| (p[i + 5] as u64) << 40
+		| (p[i + 6] as u64) << 48
 		| (p[i + 7] as u64) << 56
 }
 
@@ -400,7 +411,9 @@ mod test {
 	#[test]
 	fn validate_fail() {
 		// edge checks
-		assert!(!Cuckoo::from_hash(blake2(&[49]).as_bytes(), 20).verify(&Proof::new(vec![0; 42]), 75));
+		assert!(
+			!Cuckoo::from_hash(blake2(&[49]).as_bytes(), 20).verify(&Proof::new(vec![0; 42]), 75)
+		);
 		assert!(!Cuckoo::from_hash(blake2(&[49]).as_bytes(), 20)
 			.verify(&Proof::new(vec![0xffff; 42]), 75));
 		// wrong data for proof

core/src/ser.rs

@@ -25,16 +25,17 @@ use core::hash::{Hash, Hashed};
 use keychain::{BlindingFactor, Identifier, IDENTIFIER_SIZE};
 use std::io::{self, Read, Write};
 use std::{cmp, error, fmt, mem};
-use util::secp::Signature;
+use util::secp::constants::{
-use util::secp::constants::{AGG_SIGNATURE_SIZE, MAX_PROOF_SIZE, PEDERSEN_COMMITMENT_SIZE,
+	AGG_SIGNATURE_SIZE, MAX_PROOF_SIZE, PEDERSEN_COMMITMENT_SIZE, SECRET_KEY_SIZE,
-                            SECRET_KEY_SIZE};
+};
 use util::secp::pedersen::{Commitment, RangeProof};
+use util::secp::Signature;
 
 /// Possible errors deriving from serializing or deserializing.
-#[derive(Debug)]
+#[derive(Clone, Eq, PartialEq, Debug)]
 pub enum Error {
 	/// Wraps an io error produced when reading or writing
-	IOErr(io::Error),
+	IOErr(String, io::ErrorKind),
 	/// Expected a given value that wasn't found
 	UnexpectedData {
 		/// What we wanted
@@ -54,7 +55,7 @@ pub enum Error {
 
 impl From<io::Error> for Error {
 	fn from(e: io::Error) -> Error {
-		Error::IOErr(e)
+		Error::IOErr(format!("{}", e), e.kind())
 	}
 }
 
@@ -67,7 +68,7 @@ impl From<consensus::Error> for Error {
 impl fmt::Display for Error {
 	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
 		match *self {
-			Error::IOErr(ref e) => write!(f, "{}", e),
+			Error::IOErr(ref e, ref _k) => write!(f, "{}", e),
 			Error::UnexpectedData {
 				expected: ref e,
 				received: ref r,
@@ -83,14 +84,14 @@ impl fmt::Display for Error {
 impl error::Error for Error {
 	fn cause(&self) -> Option<&error::Error> {
 		match *self {
-			Error::IOErr(ref e) => Some(e),
+			Error::IOErr(ref _e, ref _k) => Some(self),
 			_ => None,
 		}
 	}
 
 	fn description(&self) -> &str {
 		match *self {
-			Error::IOErr(ref e) => error::Error::description(e),
+			Error::IOErr(ref e, _) => e,
 			Error::UnexpectedData {
 				expected: _,
 				received: _,
@@ -265,26 +266,30 @@ struct BinReader<'a> {
 	source: &'a mut Read,
 }
 
+fn map_io_err(err: io::Error) -> Error {
+	Error::IOErr(format!("{}", err), err.kind())
+}
+
 /// Utility wrapper for an underlying byte Reader. Defines higher level methods
 /// to read numbers, byte vectors, hashes, etc.
 impl<'a> Reader for BinReader<'a> {
 	fn read_u8(&mut self) -> Result<u8, Error> {
-		self.source.read_u8().map_err(Error::IOErr)
+		self.source.read_u8().map_err(map_io_err)
 	}
 	fn read_u16(&mut self) -> Result<u16, Error> {
-		self.source.read_u16::<BigEndian>().map_err(Error::IOErr)
+		self.source.read_u16::<BigEndian>().map_err(map_io_err)
 	}
 	fn read_u32(&mut self) -> Result<u32, Error> {
-		self.source.read_u32::<BigEndian>().map_err(Error::IOErr)
+		self.source.read_u32::<BigEndian>().map_err(map_io_err)
 	}
 	fn read_i32(&mut self) -> Result<i32, Error> {
-		self.source.read_i32::<BigEndian>().map_err(Error::IOErr)
+		self.source.read_i32::<BigEndian>().map_err(map_io_err)
 	}
 	fn read_u64(&mut self) -> Result<u64, Error> {
-		self.source.read_u64::<BigEndian>().map_err(Error::IOErr)
+		self.source.read_u64::<BigEndian>().map_err(map_io_err)
 	}
 	fn read_i64(&mut self) -> Result<i64, Error> {
-		self.source.read_i64::<BigEndian>().map_err(Error::IOErr)
+		self.source.read_i64::<BigEndian>().map_err(map_io_err)
 	}
 	/// Read a variable size vector from the underlying Read. Expects a usize
 	fn read_vec(&mut self) -> Result<Vec<u8>, Error> {
@@ -306,7 +311,7 @@ impl<'a> Reader for BinReader<'a> {
 		self.source
 			.read_exact(&mut buf)
 			.map(move |_| buf)
-			.map_err(Error::IOErr)
+			.map_err(map_io_err)
 	}
 
 	fn expect_u8(&mut self, val: u8) -> Result<u8, Error> {
@@ -459,7 +464,7 @@ where
 			let elem = T::read(reader);
 			match elem {
 				Ok(e) => buf.push(e),
-				Err(Error::IOErr(ref ioerr)) if ioerr.kind() == io::ErrorKind::UnexpectedEof => {
+				Err(Error::IOErr(ref _d, ref kind)) if *kind == io::ErrorKind::UnexpectedEof => {
 					break
 				}
 				Err(e) => return Err(e),

p2p/src/store.rs

@@ -118,7 +118,10 @@ impl PeerStore {
 	}
 
 	pub fn get_peer(&self, peer_addr: SocketAddr) -> Result<PeerData, Error> {
-		option_to_not_found(self.db.get_ser(&peer_key(peer_addr)[..]))
+		option_to_not_found(
+			self.db.get_ser(&peer_key(peer_addr)[..]),
+			&format!("Peer at address: {}", peer_addr),
+		)
 	}
 
 	pub fn exists_peer(&self, peer_addr: SocketAddr) -> Result<bool, Error> {

servers/src/common/adapters.rs

@@ -216,7 +216,9 @@ impl p2p::ChainAdapter for NetToChainAdapter {
 				Ok(_) => {
 					added_hs.push(bh.hash());
 				}
-				Err(chain::Error::Unfit(s)) => {
+				Err(e) => {
+					match e.kind() {
+						chain::ErrorKind::Unfit(s) => {
 							info!(
 								LOGGER,
 								"Received unfit block header {} at {}: {}.",
@@ -225,7 +227,7 @@ impl p2p::ChainAdapter for NetToChainAdapter {
 								s
 							);
 						}
-				Err(chain::Error::StoreErr(e, explanation)) => {
+						chain::ErrorKind::StoreErr(e, explanation) => {
 							error!(
 								LOGGER,
 								"Store error processing block header {}: in {} {:?}",
@@ -235,12 +237,14 @@ impl p2p::ChainAdapter for NetToChainAdapter {
 							);
 							return;
 						}
-				Err(e) => {
+						_ => {
 							info!(LOGGER, "Invalid block header {}: {:?}.", bh.hash(), e);
 							// TODO penalize peer somehow
 						}
 					}
 				}
+			}
+		}
 
 		let header_head = w(&self.chain).get_header_head().unwrap();
 		info!(
@@ -269,11 +273,13 @@ impl p2p::ChainAdapter for NetToChainAdapter {
 			let header = w(&self.chain).get_header_by_height(h);
 			match header {
 				Ok(head) => headers.push(head),
-				Err(chain::Error::StoreErr(store::Error::NotFoundErr, _)) => break,
+				Err(e) => match e.kind() {
-				Err(e) => {
+					chain::ErrorKind::StoreErr(store::Error::NotFoundErr(_), _) => break,
+					_ => {
 						error!(LOGGER, "Could not build header locator: {:?}", e);
 						return vec![];
 					}
+				},
 			}
 		}
 
@@ -331,7 +337,7 @@ impl p2p::ChainAdapter for NetToChainAdapter {
 		if let Err(e) =
 			w(&self.chain).txhashset_write(h, rewind_to_output, rewind_to_kernel, txhashset_data)
 		{
-			error!(LOGGER, "Failed to save txhashset archive: {:?}", e);
+			error!(LOGGER, "Failed to save txhashset archive: {}", e);
 			!e.is_bad_data()
 		} else {
 			info!(LOGGER, "Received valid txhashset data for {}.", h);
@@ -391,13 +397,15 @@ impl NetToChainAdapter {
 					self.find_common_header(locator[1..].to_vec())
 				}
 			}
-			Err(chain::Error::StoreErr(store::Error::NotFoundErr, _)) => {
+			Err(e) => match e.kind() {
+				chain::ErrorKind::StoreErr(store::Error::NotFoundErr(_), _) => {
 					self.find_common_header(locator[1..].to_vec())
 				}
-			Err(e) => {
+				_ => {
 					error!(LOGGER, "Could not build header locator: {:?}", e);
 					None
 				}
+			},
 		}
 	}
 
@@ -413,14 +421,6 @@ impl NetToChainAdapter {
 				self.check_compact(tip);
 				true
 			}
-			Err(chain::Error::Orphan) => {
-				// make sure we did not miss the parent block
-				if !chain.is_orphan(&prev_hash) && !self.currently_syncing.load(Ordering::Relaxed) {
-					debug!(LOGGER, "adapter: process_block: received an orphan block, checking the parent: {:}", prev_hash);
-					self.request_block_by_hash(prev_hash, &addr)
-				}
-				true
-			}
 			Err(ref e) if e.is_bad_data() => {
 				debug!(
 					LOGGER,
@@ -435,6 +435,18 @@ impl NetToChainAdapter {
 				false
 			}
 			Err(e) => {
+				match e.kind() {
+					chain::ErrorKind::Orphan => {
+						// make sure we did not miss the parent block
+						if !chain.is_orphan(&prev_hash)
+							&& !self.currently_syncing.load(Ordering::Relaxed)
+						{
+							debug!(LOGGER, "adapter: process_block: received an orphan block, checking the parent: {:}", prev_hash);
+							self.request_block_by_hash(prev_hash, &addr)
+						}
+						true
+					}
+					_ => {
 						debug!(
 							LOGGER,
 							"adapter: process_block: block {} refused by chain: {:?}", bhash, e
@@ -443,6 +455,8 @@ impl NetToChainAdapter {
 					}
 				}
 			}
+		}
+	}
 
 	fn validate_chain(&self, bhash: Hash) {
 		// If we are running in "validate the full chain every block" then
@@ -451,7 +465,8 @@ impl NetToChainAdapter {
 		// down as soon as possible.
 		// Skip this if we are currently syncing (too slow).
 		let chain = w(&self.chain);
-		if chain.head().unwrap().height > 0 && !self.currently_syncing.load(Ordering::Relaxed)
+		if chain.head().unwrap().height > 0
+			&& !self.currently_syncing.load(Ordering::Relaxed)
 			&& self.config.chain_validation_mode == ChainValidationMode::EveryBlock
 		{
 			let now = Instant::now();

servers/src/mining/mine_block.rs

@@ -92,12 +92,17 @@ pub fn get_block(
 	);
 	while let Err(e) = result {
 		match e {
-			self::Error::Chain(chain::Error::DuplicateCommitment(_)) => {
+			self::Error::Chain(c) => match c.kind() {
+				chain::ErrorKind::DuplicateCommitment(_) => {
 					debug!(
 						LOGGER,
 						"Duplicate commit for potential coinbase detected. Trying next derivation."
 					);
 				}
+				_ => {
+					error!(LOGGER, "Chain Error: {}", c);
+				}
+			},
 			self::Error::Wallet(_) => {
 				error!(
 					LOGGER,
@@ -187,17 +192,23 @@ fn build_block(
 		// If it's a duplicate commitment, it's likely trying to use
 		// a key that's already been derived but not in the wallet
 		// for some reason, allow caller to retry
-		Err(chain::Error::DuplicateCommitment(e)) => {
+		Err(e) => {
-			Err(Error::Chain(chain::Error::DuplicateCommitment(e)))
+			match e.kind() {
-		}
+				chain::ErrorKind::DuplicateCommitment(e) => Err(Error::Chain(
+					chain::ErrorKind::DuplicateCommitment(e).into(),
+				)),
 
 				//Some other issue, possibly duplicate kernel
-		Err(e) => {
+				_ => {
 					error!(
 						LOGGER,
 						"Error setting txhashset root to build a block: {:?}", e
 					);
-			Err(Error::Chain(chain::Error::Other(format!("{:?}", e))))
+					Err(Error::Chain(
+						chain::ErrorKind::Other(format!("{:?}", e)).into(),
+					))
+				}
+			}
 		}
 	}
 }

store/Cargo.toml

@@ -10,6 +10,8 @@ byteorder = "1"
 croaring = "0.3"
 env_logger = "0.5"
 libc = "0.2"
+failure = "0.1"
+failure_derive = "0.1"
 lmdb-zero = "0.4.4"
 memmap = { git = "https://github.com/danburkert/memmap-rs", tag = "0.6.2" }
 serde = "1"

store/src/leaf_set.rs

@@ -21,9 +21,9 @@ use std::path::Path;
 
 use croaring::Bitmap;
 
-use core::core::BlockHeader;
 use core::core::hash::Hashed;
 use core::core::pmmr;
+use core::core::BlockHeader;
 use prune_list::PruneList;
 use util::LOGGER;
 

store/src/lib.rs

@@ -29,6 +29,9 @@ extern crate memmap;
 extern crate serde;
 #[macro_use]
 extern crate slog;
+extern crate failure;
+#[macro_use]
+extern crate failure_derive;
 
 #[macro_use]
 extern crate grin_core as core;

store/src/lmdb.rs

@@ -19,21 +19,24 @@ use std::marker;
 use std::sync::Arc;
 
 use lmdb_zero as lmdb;
-use lmdb_zero::LmdbResultExt;
 use lmdb_zero::traits::CreateCursor;
+use lmdb_zero::LmdbResultExt;
 
 use core::ser;
 
 /// Main error type for this lmdb
-#[derive(Debug)]
+#[derive(Clone, Eq, PartialEq, Debug, Fail)]
 pub enum Error {
 	/// Couldn't find what we were looking for
-	NotFoundErr,
+	#[fail(display = "DB Not Found Error: {}", _0)]
+	NotFoundErr(String),
 	/// Wraps an error originating from RocksDB (which unfortunately returns
 	/// string errors).
+	#[fail(display = "LMDB error")]
 	LmdbErr(lmdb::error::Error),
 	/// Wraps a serialization error for Writeable or Readable
-	SerErr(ser::Error),
+	#[fail(display = "Serialization Error")]
+	SerErr(String),
 }
 
 impl From<lmdb::error::Error> for Error {
@@ -43,9 +46,9 @@ impl From<lmdb::error::Error> for Error {
 }
 
 /// unwraps the inner option by converting the none case to a not found error
-pub fn option_to_not_found<T>(res: Result<Option<T>, Error>) -> Result<T, Error> {
+pub fn option_to_not_found<T>(res: Result<Option<T>, Error>, field_name: &str) -> Result<T, Error> {
 	match res {
-		Ok(None) => Err(Error::NotFoundErr),
+		Ok(None) => Err(Error::NotFoundErr(field_name.to_owned())),
 		Ok(Some(o)) => Ok(o),
 		Err(e) => Err(e),
 	}
@@ -117,9 +120,9 @@ impl Store {
 	) -> Result<Option<T>, Error> {
 		let res: lmdb::error::Result<&[u8]> = access.get(&self.db, key);
 		match res.to_opt() {
-			Ok(Some(mut res)) => match ser::deserialize(&mut res).map_err(Error::SerErr) {
+			Ok(Some(mut res)) => match ser::deserialize(&mut res) {
 				Ok(res) => Ok(Some(res)),
-				Err(e) => Err(From::from(e)),
+				Err(e) => Err(Error::SerErr(format!("{}", e))),
 			},
 			Ok(None) => Ok(None),
 			Err(e) => Err(From::from(e)),
@@ -179,7 +182,7 @@ impl<'a> Batch<'a> {
 		let ser_value = ser::ser_vec(value);
 		match ser_value {
 			Ok(data) => self.put(key, data),
-			Err(err) => Err(Error::SerErr(err)),
+			Err(err) => Err(Error::SerErr(format!("{}", err))),
 		}
 	}
 

wallet/src/lmdb_wallet.rs

@@ -96,7 +96,7 @@ where
 
 	fn get(&self, id: &Identifier) -> Result<OutputData, Error> {
 		let key = to_key(OUTPUT_PREFIX, &mut id.to_bytes().to_vec());
-		option_to_not_found(self.db.get_ser(&key)).map_err(|e| e.into())
+		option_to_not_found(self.db.get_ser(&key), &format!("Key Id: {}", id)).map_err(|e| e.into())
 	}
 
 	fn iter<'a>(&'a self) -> Box<Iterator<Item = OutputData> + 'a> {
@@ -166,7 +166,10 @@ impl<'a, K> WalletOutputBatch for Batch<'a, K> {
 
 	fn get(&self, id: &Identifier) -> Result<OutputData, Error> {
 		let key = to_key(OUTPUT_PREFIX, &mut id.to_bytes().to_vec());
-		option_to_not_found(self.db.borrow().as_ref().unwrap().get_ser(&key)).map_err(|e| e.into())
+		option_to_not_found(
+			self.db.borrow().as_ref().unwrap().get_ser(&key),
+			&format!("Key ID: {}", id),
+		).map_err(|e| e.into())
 	}
 
 	fn iter<'b>(&'b self) -> Box<Iterator<Item = OutputData> + 'b> {