v4.0 Release Notes Draft

Explorer pages

• Complete redesign with new page styles, more information, and better organization.
• Politeia Proposal(s) pages.
• Listing aggregate block information on time intervals (week, month, etc.) on Block page.
• Charts may use log or linear y axis scaling.
• Exchange rate monitoring for Decred-to-fiat conversions.
• lots...

HTTP APIs

• Added /block/.../raw and /block/.../header/raw endpoints. These return the hexadecimal encoded serialized bytes of the block or block header.
• Added /agendas and /agenda/{agendaid} endpoints.
• "hex" JSON field added to several "raw" endpoints (TODO: list endpoints here)
• "network_name" added to API Status response
• Compression is optional. Use --compress-api to enable compression in dcrdata's response handlers.
• more...

Nuts and Bolts

The following changes are of most interest to site operators and developers:

• The dcrdata module is now v4.
• New build process. Webpack via npm. See README.md and dev/build.sh to learn more.
• Support for go 1.11.5 and 1.12.1.
• Support for dcrd v1.4.0 (JSON-RPC v5.1.0).
• New config settings (see --help for details):
  • API: insight-limit-rps, max-api-addrs, compress-api
  • DB: purge-n-blocks, fast-sqlite-purge, pgtimeout, hidepgconfig, addr-cache-cap
  • Politeia: proposalsdbfile, politeiaurl
  • Exchange bot: exchange-monitor, disable-exchange, exchange-currency, ratemaster, ratecert
  • Site config: mainnet-link, testnet-link
• Removed config settings: mempool (it is required), dumpallmptix (was a debug tool)
• Updated CONTRIBUTING.md, and moved it to the docs folder.
• Information from dcrd's new getblockchaininfo RPC is used in many places.
• dcrd's notification sequence for chain reorganization events has changed with RPC v5.0.0, and dcrdata was changed to work with the new sequence. JSON-RPC server versions older than v5.0.0 are not compatible. Use the current dcrd release.
• New "gov" packages (gov/agendas and gov/politeia), and the /proposals page.
• New pubsub package, including related packages (pubsub/psclient and pubsub/types) and a demo client app (pubsub/democlient). pubsub's main types are PubSubHub and WebsocketHub. PubSubHub manages the collection and distribution of block chain and mempool data. WebsocketHub and its event loop manage all websocket client connections. psclient defines a Client type that can help writing apps that connect to a dcrdata pub-sub server.
• mempool package has expanded functionality as a central hub for mempool data. explorer and pubsub now get their mempool updates from the mempool package's MempoolMonitor type. explorerUI and PubSubHub implement the MempoolDataSaver interface.
• New exchanges package that implements an exchange rate data collection bot.
• New dcrrates package and rateserver app for running a remote exchange data bot with one ore more dcrdata instances as clients.
• New testutil/apiload package for load testing the dcrdata APIs.
• New db/cache package for caching address data. Presently used in dcrpg.
• The chainMonitor in the blockdata package replaced BlockConnectedSync with ConnectBlock. It is no longer necessary to run the BlockConnectedHandler goroutine.
• Added the ability to purge N blocks on startup to assist in recovery.
• dcrpg (dcrdata's PostgreSQL interface) changes:
  • dcrpg table versions are now 3.10.0 (dcrdata v3.1 had tables at version 3.5.5).
  • ChainDB queries have a query timeout now, and a cancelable context.Context.
  • Multiple caches added for address (db/cache) and ticket pool data.
  • When the log level is debug or verbose, the PostgreSQL server (postgres) settings are displayed in a table on dcrdata startup to assist in debugging configuration issues.
  • Time in PostgreSQL tables is now stored as TIMESTAMPTZ instead of INT64. Time fields of Go structs in api/types are changed to the new TimeDef type. Tables: addresses, vins, blocks, transactions.
  • chainwork column (TEXT) ADDED to the blocks table.
  • extra_data, merkle_root, stake_root, and final_state columns are REMOVED from the blocks table.
  • The agendas table scheme is completely new. The old table is dropped and recreated from scratch.
  • New agenda_votes table.
  • block_time column (TIMESTAMPTZ) ADDED to the votes table.
  • New testing table.
  • dcrdata sets the timezone to UTC at the beginning of each PostgreSQL session.
  • dcrpg now uses dcrjson/v2 and rpcclient/v2 modules.
• dcrsqlite changes:
  • Now exports the main SQLite interface type, WiredDB.
  • New block data cache.
  • WiredDB will request a shutdown with a provided function if the "database is locked" error is encountered on a table write operation.
  • UnconfirmedTxnsForAddress is moved from dcrsqlite to rpcutils.
  • Side chains are now tracked: hash is the new primary key. The is_mainchain and is_valid columns are added. Ability to import side chain data from dcrd also added.
  • explorer.New now takes a config struct, ExplorerConfig.
• Dependency changes:
  • Updated direct deps: asdine/storm, caarlos0/env, all dcrd modules, dcrwallet/wallet, dgraph-io/badger, didip/tollbooth, go-chi/chi, google/gops, googolleego-socket.io, mattn/go-sqlite3, rs/cors, sirupsen/logrus, golang.org/x/net,
  • Added deps: politeia, golang/protobuf, google.golang.org/grpc, jessevdk/go-flags
  • Removed deps: btcsuite/go-flags, oleide/lane