This will allow the worker goroutine to return even if one of the
other workers has already errored, preventing these goroutines from
lingering forever blocking on a channel send.
When detaching the tail end of a slice of blocks or transactions and
appending the newly inserted middle block, and the previous tail, the
capacity of the slice head must be limited to prevent overwriting the
newly inserted block/tx in the same memory as the tail slice.
Bug discovered by @mably while working on the peercoin port of
btcwallet and reported on IRC.
This commit is the result of several big changes being made to the
wallet. In particular, the "handshake" (initial sync to the chain
server) was quite racy and required proper synchronization. To make
fixing this race easier, several other changes were made to the
internal wallet data structures and much of the RPC server ended up
being rewritten.
First, all account support has been removed. The previous Account
struct has been replaced with a Wallet structure, which includes a
keystore for saving keys, and a txstore for storing relevant
transactions. This decision has been made since it is the opinion of
myself and other developers that bitcoind accounts are fundamentally
broken (as accounts implemented by bitcoind support both arbitrary
address groupings as well as moving balances between accounts -- these
are fundamentally incompatible features), and since a BIP0032 keystore
is soon planned to be implemented (at which point, "accounts" can
return as HD extended keys). With the keystore handling the grouping
of related keys, there is no reason have many different Account
structs, and the AccountManager has been removed as well. All RPC
handlers that take an account option will only work with "" (the
default account) or "*" if the RPC allows specifying all accounts.
Second, much of the RPC server has been cleaned up. The global
variables for the RPC server and chain server client have been moved
to part of the rpcServer struct, and the handlers for each RPC method
that are looked up change depending on which components have been set.
Passthrough requests are also no longer handled specially, but when
the chain server is set, a handler to perform the passthrough will be
returned if the method is not otherwise a wallet RPC. The
notification system for websocket clients has also been rewritten so
wallet components can send notifications through channels, rather than
requiring direct access to the RPC server itself, or worse still,
sending directly to a websocket client's send channel. In the future,
this will enable proper registration of notifications, rather than
unsolicited broadcasts to every connected websocket client (see
issue #84).
Finally, and the main reason why much of this cleanup was necessary,
the races during intial sync with the chain server have been fixed.
Previously, when the 'Handshake' was run, a rescan would occur which
would perform modifications to Account data structures as
notifications were received. Synchronization was provided with a
single binary semaphore which serialized all access to wallet and
account data. However, the Handshake itself was not able to run with
this lock (or else notifications would block), and many data races
would occur as both notifications were being handled. If GOMAXPROCS
was ever increased beyond 1, btcwallet would always immediately crash
due to invalid addresses caused by the data races on startup. To fix
this, the single lock for all wallet access has been replaced with
mutexes for both the keystore and txstore. Handling of btcd
notifications and client requests may now occur simultaneously.
GOMAXPROCS has also been set to the number of logical CPUs at the
beginning of main, since with the data races fixed, there's no reason
to prevent the extra parallelism gained by increasing it.
Closes#78.
Closes#101.
Closes#110.
The lockunspent RPC is volatile, that is, it only locks unspent
transaction outputs from being used as inputs for the duration of the
wallet process, or until the UTXO is unlocked with a later call to
lockunspent. Therefore, remove the serialization of the lockedness
when writing txstore Credits.
The space which used to contain the locked flag is now unused and may
be used for other flags in the future.
The info log level (default) will produce output about confirmed and
unconfirmed transactions being inserted into the store, as well as
unconfirmed transactions which have been mined into blocks. By
enabling the debug log level (-d TXST=debug), additional information
about transaction inputs and outputs is logged. This includes the
total amount of previously-unspent outputs which have been marked
spent by the inserted transaction, and the output indexes and amounts
for each spendable output. Additionally, the debug log level will log
whenever transactions are removed due to being a double spend of
another inserted transaction.
If a transaction is added that debits from previous transaction
outputs, and those outputs are still unconfirmed, it is possible that
if the credits were not already known (as is the case with
transactions notified after a sendrawtransaction), only mined unspent
transaction outputs would be searched and the unconfirmed unspent
credits would be missed. This results in spent outputs still being
marked unspent.
This change fixes the above by also searching through unconfirmed
transactions when the previous credits must be lookup up, rather than
being pass from an AddDebits call.
Fixes issue #91.
This commit is the result of inspecting the results of both cpu and
memory profiling, to improve areas where wallet can be more efficient
on transaction inserts.
One problem that's very evident by profiling is how much waiting there
is for file (txstore, wallet) writes. This commit does not attempt to
fix this yet, but focuses on the easier-to-fix memory allocation
issues which can slow down the rest of wallet due to excessive garbage
collection scanning.
While here, fix a race where a closure run as a goroutine was closing
over a range iterator.
The Credit and Debits structures are simple wrappers around an
embedded *txstore.TxRecord, as well as an output index in the case of
Credit. This means that a Credit is at most two words, while a Debits
struct is just one. To avoid the unnecessary garbage of creating
Credit and Debits structures on the heap (where the underlying
TxRecord likely already is), simply pass around everywhere as
non-pointer types, and modify the receivers for all Credit and Debits
methods to non-pointer receivers since none of them ever modify the
value.
This change "reverses" the mapping used by the transaction store to
reference and lookup unspent credits. Rather than mapping slice
indexes of a block, and then another block map for slice indexes of
transactions with unspent credits, and requiring a lookup through each
credit for whether it is spent or unspent, keep a simple map of
outpoints to a lookup key to find the transaction in a block.
This has a positive effect on performance when searching for previous
transaction outputs that have been spent by a newly-inserted
transaction. Rather than iterating through every block with an
unspent credit, and then every transaction with unspent credits, a
simple map lookup can be done to check whether a transaction input's
previous outpoint is marked as unspent by wallet, and then access the
transaction record itself by the lookup key. While transactions
created by wallet with the sendfrom/many RPCs may mark debits with the
previous credits already known, the previous outputs may still not be
known if a debiting transaction was added by rescan, or notified as a
result of a create+sendrawtransaction.
If a JSON array result was successfully calculated, but the
slice/array is empty, the result must be marshaled as '[]' rather than
the JSON null value. To do this in go, the RPC handlers should never
return nil slices for non-error returns, but return a non-nil slice
header with 0 length.
For example, an empty listtransactions result should be returned as
[]btcjson.ListTransactionsResult{}, rather than nil.
The gettransaction handler was attempting to lookup the "sent-to"
address of an outgoing transaction from the transaction store (as a
wallet credit). This is the incorrect address when sending to an
address controlled by another wallet, and panics when there are no
credits (for example, sending to another wallet without any change
address). Instead, use the first non-change output address is used as
the address of the "send" result.
This fixes the panic reported when debugging issue #91.
While here, fix the category strings used for wallet credits to
support immature and generate (the categories for coinbase outputs).
This change is the result of using the errcheck tool
(https://github.com/kisielk/errcheck) to find all unchecked errors,
both unassigned and those assigned to the blank identifier.
Every returned error is now handled in some manner. These include:
- Logging errors that would otherwise be missed
- Returning errors to the caller for further processing
- Checking error values to determine what to do next
- Panicking for truely exceptional "impossible" errors
On the subject of panics, they are a sharp tool and should be used
sparingly. That being said, I have added them to check errors that
were previously explicitly ignored, because they were expected to
always return without failure. This could be due to fake error paths
(i.e. writing to a bytes.Buffer panics for OOM and should never return
an error) or previous logic asserts that an error case is impossible.
Rather than leaving these unhandled and letting code fail later,
either with incorrect results or a nil pointer dereference, it now
produces a stack trace at the error emit site, which I find far more
useful when debugging.
While here, a bunch of dead code was removed, including code to move
pre-0.1.1 uxto and transaction history account files to the new
directory (as they would be unreadable anyways) and a big chunk of
commented out rpcclient code.
This is an intial pass at converting the btcwallet and deps codebases
to pass a network by their parameters, rather than by a magic number
to identify the network. The parameters in params.go have been
updated to embed a *btcnet.Params, and all previous uses of cfg.Net()
have been replaced with activeNet.{Params,Net} (where activeNet is
the global var for the active network).
Although dependancy packages have not yet been updated from using
btcwire.BitcoinNet to btcnet.Params, the parameters are now accessible
at all callsites, and individual packages can be updated to use btcnet
without requiring updates in each external btc* package at once.
While here, the exported API for btcwallet internal library packages
(txstore and wallet) have been updated to pass full network parameters
rather than the btcwire definition of a network.
