dcrdata

The dcrdata repository is a collection of golang packages and apps for Decred datacollection, storage, and presentation.

Repository overview

../dcrdata              The dcrdata daemon.
├── blockdata           Package blockdata.
├── cmd
│   ├── rebuilddb       rebuilddb utility.
│   └── scanblocks      scanblocks utility.
├── dcrdataapi          Package dcrdataapi for golang API clients.
├── dcrsqlite           Package dcrsqlite providing SQLite backend.
├── public              Public resources for web UI (css, js, etc.).
├── mempool             Package mempool.
├── rpcutils            Package rpcutils.
├── semver              Package semver.
├── stakedb             Package stakedb, for tracking tickets.
├── txhelpers           Package txhelpers.
└── views               HTML temlates for web UI.

dcrdata daemon

The root of the repository is the main package for the dcrdata app, which has several components including:

1. Blockchain monitoring and data collection.
2. Mempool monitoring and reporting.
3. Data storage in durable database (sqlite presently).
4. RESTful JSON API over HTTP(S).
5. Basic web interface.

JSON REST API

The API serves JSON data over HTTP(S). After dcrdata syncs with the blockchain server, by default it will begin listening on http://0.0.0.0:7777/. This means it starts a web server listening on all network interfaces on port 7777. All API endpoints are currently prefixed with /api (e.g. http://localhost:7777/api/stake), but this may be configurable in the future.

Endpoint List

Best block
Summary	/block/best
Stake info	/block/best/pos
Header	/block/best/header
Hash	/block/best/hash
Height	/block/best/height
Size	/block/best/size
Transactions	/block/best/tx
Transactions Count	/block/best/tx/count
Verbose block result	/block/best/verbose

Block X (block index)
Summary	/block/X
Stake info	/block/X/pos
Header	/block/X/header
Hash	/block/X/hash
Size	/block/X/size
Transactions	/block/X/tx
Transactions Count	/block/X/tx/count
Verbose block result	/block/X/verbose

Block H (block hash)
Summary	/block/hash/H
Stake info	/block/hash/H/pos
Header	/block/hash/H/header
Height	/block/hash/H/height
Size	/block/hash/H/size
Transactions	/block/hash/H/tx
Transactions Count	/block/hash/H/tx/count
Verbose block result	/block/hash/H/verbose

Block range (X < Y)
Summary array for blocks on [X,Y]	/block/range/X/Y
Summary array with block index step S	/block/range/X/Y/S
Size (bytes) array	/block/range/X/Y/size
Size array with step S	/block/range/X/Y/S/size

Transaction T (transaction id)
Transaction Details	/tx/T
Inputs	/tx/T/in
Details for input at index X	/tx/T/in/X
Outputs	/tx/T/out
Details for output at index X	/tx/T/out/X

Address A
Summary of last 10 transactions	/address/A
Verbose transaction result for last 10 transactions	/address/A/raw
Summary of last N transactions	/address/A/count/N
Verbose transaction result for last N transactions	/address/A/count/N/raw

Stake Difficulty (Ticket Price)
Current sdiff and estimates	/stake/diff
Sdiff for block X	/stake/diff/b/X
Sdiff for block range [X,Y] (X <= Y)	/stake/diff/r/X/Y
Current sdiff separately	/stake/diff/current
Estimates separately	/stake/diff/estimates

Ticket Pool
Current pool info (size, total value, and average price)	/stake/pool
Pool info for block X	/stake/pool/b/X
Pool info for block range [X,Y] (X <= Y)	/stake/pool/r/X/Y?arrays=[true|false] *

^*For the pool info block range endpoint that accepts the arrays url query, a value of true will put all pool values and pool sizes into separate arrays, rather than having a single array of pool info JSON objects. This may make parsing more efficient for the client.

Mempool
Ticket fee rate summary	/mempool/sstx
Ticket fee rate list (all)	/mempool/sstx/fees
Ticket fee rate list (N highest)	/mempool/sstx/fees/N
Detailed ticket list (fee, hash, size, age, etc.)	/mempool/sstx/details
Detailed ticket list (N highest fee rates)	/mempool/sstx/details/N

Other
Status	/status
Endpoint list (always indented)	/list
Directory	/directory

All JSON endpoints accept the URL query indent=[true|false]. For example, /stake/diff?indent=true. By default, indentation is off. The characters to use for indentation may be specified with the indentjson string configuration option.

Web Interface

In addition to the API that is accessible via paths beginning with /api, an HTML interface is served on the root path (/).

Important Note About Mempool

Although there is mempool data collection and serving, it is very important to keep in mind that the mempool in your node (dcrd) is not likely to be the same as other nodes' mempool. Also, your mempool is cleared out when you shutdown dcrd. So, if you have recently (e.g. after the start of the current ticket price window) started dcrd, your mempool will be missing transactions that other nodes have.

Command Line Utilities

rebuilddb

rebuilddb is a CLI app that performs a full blockchain scan that fills past block data into a SQLite database. This functionality is included in the startup of the dcrdata daemon, but may be called alone with rebuilddb.

scanblocks

scanblocks is a CLI app to scan the blockchain and save data into a JSON file. More details are in its own README. The repository also includes a shell script, jsonarray2csv.sh, to convert the result into a comma-separated value (CSV) file.

Helper packages

package dcrdataapi defines the data types, with json tags, used by the JSON API. This facilitates authoring of robust golang clients of the API.

package rpcutils includes helper functions for interacting with a dcrrpcclient.Client.

package stakedb defines the StakeDatabase and ChainMonitor types for efficiently tracking live tickets, with the primary purpose of computing ticket pool value quickly. It uses the database.DB type from github.com/decred/dcrd/database with an ffldb storage backend from github.com/decred/dcrd/database/ffldb. It also makes use of the stake.Node type from github.com/decred/dcrd/blockchain/stake. The ChainMonitor type handles connecting new blocks and chain reorganiation in response to notifications from dcrd.

package txhelpers includes helper functions for working with the common types dcrutil.Tx, dcrutil.Block, chainhash.Hash, and others.

Internal-use packages

Packages blockdata and dcrsqlite are currenly designed only for internal use by other dcrdata packages, but they may be of general value in the future.

blockdata defines:

• The chainMonitor type and its BlockConnectedHandler() method that handles block-connected notifications and triggers data collection and storage.
• The BlockData type and methods for converting to API types.
• The blockDataCollector type and its Collect() and CollectHash() methods that are called by the chain monitor when a new block is detected.
• The BlockDataSaver interface required by chainMonitor for storage of collected data.

dcrsqlite defines:

• A sql.DB wrapper type (DB) with the necessary SQLite queries for storage and retrieval of block and stake data.
• The wiredDB type, intended to satisfy the APIDataSource interface used by the dcrdata app's API. The block header is not stored in the DB, so a RPC client is used by wiredDB to get it on demand. wiredDB also includes methods to resync the database file.

package mempool defines a mempoolMonitor type that can monitor a node's mempool using the OnTxAccepted notification handler to send newly received transaction hashes via a designated channel. Ticket purchases (SSTx) are triggers for mempool data collection, which is handled by the mempoolDataCollector class, and data storage, which is handled by any number of objects implementing the MempoolDataSaver interface.

Plans

See the GitHub issue tracker and the project milestones.

Requirements

• Go 1.7 or newer.
• Running dcrd (>=0.6.1) synchronized to the current best block on the network.

Installation

Build from Source

The following instructions assume a Unix-like shell (e.g. bash).

• Install Go

• Verify Go installation:

    go env GOROOT GOPATH
  

• Ensure $GOPATH/bin is on your $PATH

• Install glide

    go get -u -v github.com/Masterminds/glide
  

• Clone dcrdata repo

    git clone https://github.com/dcrdata/dcrdata $GOPATH/src/github.com/dcrdata/dcrdata
  

• Glide install, and build executable

    cd $GOPATH/src/github.com/dcrdata/dcrdata
    glide install
    go build # or go install $(glide nv)
  

The sqlite driver uses cgo, which requires gcc to compile the C sources. On Windows this is easily handled with MSYS2 (download and install MinGW-w64 gcc packages).

If you receive other build errors, it may be due to "vendor" directories left by glide builds of dependencies such as dcrwallet. You may safely delete vendor folders.

Updating

First, update the repository (assuming you have master checked out):

cd $GOPATH/src/github.com/dcrdata/dcrdata
git pull origin master
glide install
go build

Look carefully for errors with git pull, and reset changed files if necessary.

Getting Started

Create configuration file.

cp ./sample-dcrdata.conf ./dcrdata.conf

Then edit dcrdata.conf with your dcrd RPC settings.

Finally, launch the daemon and allow the databases to sync. This takes about an hour on the first time. On subsequent launches, only new blocks need to be scanned.

./dcrdata

Contributing

Yes, please!

1. Fork the repo.
2. Create a branch for your work (git branch -b cool-stuff).
3. Code something great.
4. Commit and push to your repo.
5. Create a pull request.

License

This project is licensed under the ISC License. See the LICENSE file for details.