chaind

README

chaind

chaind is a process that reads information from an Ethereum 2 beacon node and stores it in a database for reporting and analysis.

Table of Contents

• Install
  • Binaries
  • Docker
  • Source
• Usage
• Maintainers
• Contribute
• License

Install

Binaries

Binaries for the latest version of chaind can be obtained from the releases page.

Docker

You can obtain the latest version of chaind using docker with:

docker pull wealdtech/chaind

Source

chaind is a standard Go binary which can be installed with:

GO111MODULE=on go get github.com/wealdtech/chaind

Usage

Data gathers four pieces of information from the beacon node, broken down by the modules that obtain the information:

• Proposer duties The proposer duties module provides information on the validator expected to propose a beacon block at a given slot;
• Beacon committees The beacon committees module provides information on the validators expected to attest to a beacon block at a given slot;
• Validators The validators module provides information on the current statue of validators. It can also obtain information on the validators' balances and effective balances at a given epoch;
• Blocks The blocks module provides information on blocks proposed for each slot. This includes:
  • the block structure
  • attestations
  • proposer slashings
  • attester slashings
  • deposits
  • voluntary exits; and
• Ethereum 1 deposits The Ethereum 1 deposits module provides information on deposits made on the Ethereum 1 network;
• Finalizer The finalizer module augments the information present in the database from finalized states. This includes:
  • the canonical state of blocks.

In addition, the summarizer module takes the finalized information and generates summary statistics at the validator, block and epoch level.

Requirements to run chaind

Database

At current the only supported backend is PostgreSQL. Once you have a PostgreSQL instance you will need to create a user and database that chaind can use, for example run the following commands as the PostgreSQL superuser (postgres on most linux installations):

# This command creates a user named 'chain' and will prompt for a password.
createuser chain -P
# This command creates a database named 'chain' owned by the 'chain' user.
createdb -E UTF8 --owner=chain chain

You can also run chaind using the example docker-compose file, it setups the Postgres database automatically a container.

Beacon node

chaind supports Teku and Lighthouse beacon nodes. The current state of obtaining data from beacon nodes is as follows:

• Teku: must be run in archive mode to allow chaind to obtain historical data
• Lighthouse: Make sure to run with --slots-per-restore-point 64 --reconstruct-historic-states --genesis-backfill, else fetching historical information will be very slow. For more information on the trade off between Freezer DB size and fetching performance, please refer to Database Configuration in the Lighthouse Book.

At current Prysm is not supported due to its lack of Altair-related information in its gRPC and HTTP APIs. We expect to be able to support Prysm again soon.

chaind supports all execution nodes. The current state of obtaining data from execution nodes is as follows:

• geth: must run with --txlookuplimit 0 to ensure that all deposit transactions can be obtained

Example

To start a Teku node suitable for chaind download Teku and run the following command:

teku --rest-api-enabled --data-storage-mode=archive

Once Teku has finished syncing, run:

chaind --eth2client-address=http://localhost:5051/

Or if you prefer using docker-compose:

CHAIND_ETH2CLIENT_ADDRESS=http://localhost:5051/ docker-compose up -d

You can modify the configuration in chaind.config.docker-compose.yml file. The postgres server is exposed at 127.0.0.1:5432.

Managing the database size

Two tables take up the majority of the database size. These are:

• t_validator_balances the balance and effective balance of each validator at each epoch
• t_validator_epoch_summaries the expected and actual actions undertaken by each validator each epoch

These tables, along with their indices, take over 90% of the space required for the database on mainnet and goerli. The t_validator_day_summaries table contains the same information but aggregated per day (a day being 00:00 to 00:00 UTC). If the information in this table is sufficient for your needs you can prune old data from the larger tables, keeping their size down and hence managing the overall space requirement for chaind.

Pruning data removes data older than a certain age from the two database tables mentioned above. Pruning is set for each table individually and so it is possible to prune either or both of the tables, and to have different retentions for each. For example, the following configuration:

summarizer:
  validators:
    balance-retention: "P6M"
    epoch-retention: "P1Y"

This will store 6 month's worth of balances, and 1 year's worth of epoch summaries. Retention periods are ISO 8601 durations. Note that if it is not desired to retain any balance or epoch summary data then the retention can be set to "PT0s".

Upgrading chaind

chaind should upgrade automatically from earlier versions. Note that the upgrade process can take a long time to complete, especially where data needs to be refetched or recalculated. chaind should be left to complete the upgrade, to avoid the situation where additional fields are not fully populated. If chaind is ever stopped or crashes while upgrading and this situation does happen, one should rerun chaind with the options --blocks.start-slot=0 --blocks.refetch=true to force chaind to refetch all blocks.

Querying chaind

chaind attempts to lay its data out in a standard fashion for a SQL database, mirroring the data structures that are present in Ethereum 2. There are some places where the structure or data deviates from the specification, commonly to provide additional information or to make the data easier to query with SQL. It is recommended that the notes on the tables are read before attempting to write any complicated queries.

Configuring chaind

The minimal requirements for chaind are references to the database and beacon node, for example:

chaind --chaindb.url=postgres://chain:secret@localhost:5432 --eth2client.address=localhost:5051

Here, chaindb.url is the URL of a local PostgreSQL database with password 'secret' and 'eth2client.address' is the address of a supported beacon client node (gRPC for Prysm, HTTP for Teku and Lighthouse).

chaind allows additional configuration for itself and its modules. It takes configuration from the command line, environment variables or a configuration file, but for the purposes of explaining the configuration options the configuration file is used. This should be in the home directory and called .chaind.yml. Alternatively, the configuration file can be placed in a different directory and referenced by --base-dir, for example --base-dir=/home/user/config/chaind; in this case the file should be called chaind.yml (without the leading period).

# log-level is the base log level of the process.
# 'info' should be a suitable log level, unless detailed information is
# required in which case 'debug' or 'trace' can be used.
log-level: info
# log-file specifies that log output should go to a file.  If this is not
# present log output will be to stderr.
log-file: /var/log/chaind.log
chaindb:
  # url is the URL of the PostgreSQL database.
  url: postgres://chain:secret@localhost:5432
  max-connections: 16
# eth2client contains configuration for the Ethereum 2 client.
eth2client:
  # log-level is the log level of the specific module.  If not present the base log
  # level will be used.
  log-level: debug
  # address is the address of the beacon node.
  address: localhost:5051
# eth1client contains configuration for the Ethereum 1 client.
eth1client:
  # address is the address of the Ethereum 1 node.
  address: localhost:8545
# blocks contains configuration for obtaining block-related information.
blocks:
  # enable states if this module will be operational.
  enable: true
  # address is a separate connection for this module.  If not present then
  # chaind will use the eth2client connection.
  address: localhost:5051
  # start-slot is the slot from which to start.  chaind should keep track of this itself,
  # however if you wish to start from a later slot this can be set.
  # start-slot: 2000
  # refetch will refetch block data from a beacon node even if it has already has a block
  # in its database.
  # refetch: false
# validators contains configuration for obtaining validator-related information.
validators:
  enable: true
  # balances contains configuration for obtaining validator balances.  This is
  # a separate configuration flag for two reasons.  First, it can take a long
  # time to retrieve this information.  Second, the information can be
  # derived from the data obtained by the other modules.
  balances:
    enable: false
# beacon-committees contains configuration for obtaining beacon committee-related
# information.
beacon-committees:
  enable: true
# proposer-duties contains configuration for obtaining proposer duty-related
# information.
proposer-duties:
  enable: true
# finalizer updates tables with information available for finalized states.
finalizer:
  enable: true
# eth1deposits contains information about transactions made to the deposit contract
# on the Ethereum 1 network.
eth1deposits:
  enable: false
  # start-block is the block from which to start fetching deposits.  chaind should
  # keep track of this itself, however if you wish to start from a different block this
  # can be set.
  # start-block: 500

Support

We gratefully acknowledge the Ethereum Foundation for supporting chaind through their grant FY21-0360, which allowed collection of Ethereum 1 deposits.

Maintainers

Jim McDonald: @mcdee.

Contribute

Contributions welcome. Please check out the issues.

License

Apache-2.0 © 2020 Weald Technology Trading.