This commit is the first stage of several that are planned to convert
the blockchain package into a concurrent safe package that will
ultimately allow support for multi-peer download and concurrent chain
processing. The goal is to update btcd proper after each step so it can
take advantage of the enhancements as they are developed.
In addition to the aforementioned benefit, this staged approach has been
chosen since it is absolutely critical to maintain consensus.
Separating the changes into several stages makes it easier for reviewers
to logically follow what is happening and therefore helps prevent
consensus bugs. Naturally there are significant automated tests to help
prevent consensus issues as well.
The main focus of this stage is to convert the blockchain package to use
the new database interface and implement the chain-related functionality
which it no longer handles. It also aims to improve efficiency in
various areas by making use of the new database and chain capabilities.
The following is an overview of the chain changes:
- Update to use the new database interface
- Add chain-related functionality that the old database used to handle
- Main chain structure and state
- Transaction spend tracking
- Implement a new pruned unspent transaction output (utxo) set
- Provides efficient direct access to the unspent transaction outputs
- Uses a domain specific compression algorithm that understands the
standard transaction scripts in order to significantly compress them
- Removes reliance on the transaction index and paves the way toward
eventually enabling block pruning
- Modify the New function to accept a Config struct instead of
inidividual parameters
- Replace the old TxStore type with a new UtxoViewpoint type that makes
use of the new pruned utxo set
- Convert code to treat the new UtxoViewpoint as a rolling view that is
used between connects and disconnects to improve efficiency
- Make best chain state always set when the chain instance is created
- Remove now unnecessary logic for dealing with unset best state
- Make all exported functions concurrent safe
- Currently using a single chain state lock as it provides a straight
forward and easy to review path forward however this can be improved
with more fine grained locking
- Optimize various cases where full blocks were being loaded when only
the header is needed to help reduce the I/O load
- Add the ability for callers to get a snapshot of the current best
chain stats in a concurrent safe fashion
- Does not block callers while new blocks are being processed
- Make error messages that reference transaction outputs consistently
use <transaction hash>:<output index>
- Introduce a new AssertError type an convert internal consistency
checks to use it
- Update tests and examples to reflect the changes
- Add a full suite of tests to ensure correct functionality of the new
code
The following is an overview of the btcd changes:
- Update to use the new database and chain interfaces
- Temporarily remove all code related to the transaction index
- Temporarily remove all code related to the address index
- Convert all code that uses transaction stores to use the new utxo
view
- Rework several calls that required the block manager for safe
concurrency to use the chain package directly now that it is
concurrent safe
- Change all calls to obtain the best hash to use the new best state
snapshot capability from the chain package
- Remove workaround for limits on fetching height ranges since the new
database interface no longer imposes them
- Correct the gettxout RPC handler to return the best chain hash as
opposed the hash the txout was found in
- Optimize various RPC handlers:
- Change several of the RPC handlers to use the new chain snapshot
capability to avoid needlessly loading data
- Update several handlers to use new functionality to avoid accessing
the block manager so they are able to return the data without
blocking when the server is busy processing blocks
- Update non-verbose getblock to avoid deserialization and
serialization overhead
- Update getblockheader to request the block height directly from
chain and only load the header
- Update getdifficulty to use the new cached data from chain
- Update getmininginfo to use the new cached data from chain
- Update non-verbose getrawtransaction to avoid deserialization and
serialization overhead
- Update gettxout to use the new utxo store versus loading
full transactions using the transaction index
The following is an overview of the utility changes:
- Update addblock to use the new database and chain interfaces
- Update findcheckpoint to use the new database and chain interfaces
- Remove the dropafter utility which is no longer supported
NOTE: The transaction index and address index will be reimplemented in
another commit.
This commit converts all block height references to int32 instead of
int64. The current target block production rate is 10 mins per block
which means it will take roughly 40,800 years to reach the maximum
height an int32 affords. Even if the target rate were lowered to one
block per minute, it would still take roughly another 4,080 years to
reach the maximum.
In the mean time, there is no reason to use a larger type which results
in higher memory and disk space usage. However, for now, in order to
avoid having to reserialize a bunch of database information, the heights
are still serialized to the database as 8-byte uint64s.
This is being mainly being done in preparation for further upcoming
infrastructure changes which will use the smaller and more efficient
4-byte serialization in the database as well.
This commit modifies the createTxRawResult code path along with callers
to work with block headers as opposed to btcutil.Blocks. This in turn
allows the code in handleGetRawTransaction and
handleSearchRawTransactions to perform a much cheaper block header load
as opposed to a full block load.
While here, also very slightly optimize the createVinList function to
avoid creating a util.Tx wrapper and to take advantage of the
btcutil.Amount type added after the function was originally written
This allows clients watching for both to know when all mined
transaction notifications for the block have been received.
Otherwise, clients would be aware that there is a new block, see the
exact same block hash/height in the next tx notifications, but never
know when all txs from the block have been received and processed.
This fixes a synchronization issue in btcwallet where the wallet would
mark itself synced to some block height before any of those blocks'
transactions were processed. If the RPC connection is lost between
sending the blockconnected notification and receiving the last
transaction notification, the wallet would not know of this and
continue with missing transactions.
The limited user is specified with the --rpclimituser and
--rpclimitpass options (or the equivalent in the config file).
The config struct and loadConfig() are updated to take the
new options into account. The limited user can have neither
the same username nor the same password as the admin user.
The package-level rpcLimit map in rpcserver.go specifies
the RPC commands accessible by limited users. This map
includes both HTTP/S and websocket commands.
The checkAuth function gets a new return parameter to
signify whether the user is authorized to change server
state. The result is passed to the jsonRPCRead function and
to the WebsocketHandler function in rpcwebsocket.go.
The wsClient struct is updated with an "isAdmin" field
signifying that the client is authorized to change server
state, written by WebsocketHandler and handleMessage.
The handleMessage function also checks the field to
allow or disallow an RPC call.
The following documentation files are updated:
- doc.go
- sample-btcd.conf
- docs/README.md
- docs/json_rpc_api.md
- docs/configure_rpc_server_listen_interfaces.md
This commit converts the RPC server over to use the new features available
in the latest version of btcjson and improve a few things along the way.
This following summarizes the changes:
- All btcjson imports have been updated to the latest package version
- The help has been significantly improved
- Invoking help with no command specified now provides an alphabetized
list of all supported commands along with one-line usage
- The help for each command is automatically generated and provides much
more explicit information such as the type of each parameter, whether
or not it's optional or required, etc
- The websocket-specific commands are now provided when accessing the
help when connected via websockets
- Help has been added for all websocket-specific commands and is only
accessible when connected via websockets
- The error returns and handling of both the standard and websocket
handlers has been made consistent
- All RPC errors have been converted to the new RPCError type
- Various variables have been renamed for consistency
- Several RPC errors have been improved
- The commands that are marked as unimplemented have been moved into the
separate map where they belong
- Several comments have been improved
- An unnecessary check has been removed from the createrawtransaction
handler
- The command parsing has been restructured a bit to pave the way for
JSON-RPC 2.0 batching support
This commit reorders the RPC server code to more closely match the
ordering used by the rest of the code base such that functions are
typically defined before they are used and near their call site.
This changes the behavior of the rescan RPC to automatically set the
client up for transaction notifications for transactions paying to any
rescanned address and spending outputs in the final rescan UTXO set
after a rescanned is performed through the best block in the chain.
The notification queue used for websocket client notifications had a
bug which caused the next queued item in some situations to not be
sent, but instead send a previously sent item. This change fixes this
by setting the 'next' variable to the next item which must be
dequeued, if the queue length is non-zero.
This bug did not always manifest itself as if the receiving goroutine
was ready, a queued item could be sent directly to it rather than
waiting in the queue to be sent at a later time.
This commit modifies the RPC server such that all handlers now receive a
channel which will be notified when a client disconnects. This
notification can then be used to stop long-running operations early when a
client disconnects.
This capability was already present for websocket clients, but this commit
exposes it to standard HTTP clients as well.
Also, since the new websoscket package allows the message type to be set
independently from the type of the variable, remove the casts between
strings and []byte in the websocket read/write paths. This avoids extra
copies thereby reducing the garbage generated.
Closes#134.
This change modifies the params struct to embed a *btcnet.Params,
removing the old parameter fields that are handled by the btcnet
package.
Hardcoded network checks have also been removed in favor of modifying
behavior based on the current active net's parameters.
Not all library packages, notable btcutil and btcchain, have been
updated to use btcnet yet, but with this change, each package can be
updated one at a time since the active net's btcnet.Params are
available at each callsite.
ok @davecgh
