master	develop

Algorand Indexer

The Indexer is a standalone service that reads committed blocks from the Algorand blockchain and maintains a database of transactions and accounts that are searchable and indexed.

Tested Requirements Versions

• go 1.16
• Postgres 13

Quickstart

We prepared a docker compose file to bring up indexer and Postgres preloaded with some data. From the root directory run:

~$ docker-compose up

Once running, here are a few commands to try out:

~$ curl "localhost:8980/v2/assets?name=bogo"
~$ curl "localhost:8980/v2/transactions?limit=1"
~$ curl "localhost:8980/v2/transactions?round=10"
~$ curl "localhost:8980/v2/transactions?tx-type=acfg"
~$ curl "localhost:8980/v2/accounts?asset-id=9"
~$ curl "localhost:8980/v2/accounts/ZBBRQD73JH5KZ7XRED6GALJYJUXOMBBP3X2Z2XFA4LATV3MUJKKMKG7SHA?round=15"
~$ curl "localhost:8980/v2/assets/9/balances"
~$ curl "localhost:8980/health"

Features

• Search and filter accounts, transactions, assets, and asset balances with many different parameters:
  • Round
  • Date
  • Address (Sender|Receiver)
  • Balances
  • Signature type
  • Transaction type
  • Asset holdings
  • Asset name
  • More
• Lookup historic account data for a particular round.
• Result paging
• Enriched transaction and account data:
  • Confirmation round (block containing the transaction)
  • Confirmation time
  • Signature type
  • Asset ID
  • Close amount when applicable
  • Rewards
• Human readable field names instead of the space optimized protocol level names.

There are a number of technical features as well:

• Abstracted database layer. We want to support many different backend databases.
• Optimized Postgres DB backend.
• User defined API token.

Contributing

Contributions welcome! Please refer to our CONTRIBUTING document.

Usage

The most common usage of the Indexer is expecting to be getting validated blocks from a local algod Algorand node, adding them to a PostgreSQL database, and serving an API to make available a variety of prepared queries. Some users may wish to directly write SQL queries of the database.

Indexer works by fetching blocks one at a time, processing the block data, and loading it into a traditional database. There is a database abstraction layer to support different database implementations. In normal operation, the service will run as a daemon and always requires access to a database.

As of the end of July 2021, storing all the raw blocks in MainNet is about 609 GB and the PostgreSQL database of transactions and accounts is about 495 GB. Much of that size difference is the Indexer ignoring cryptographic signature data; relying on algod to validate blocks. Dropping that, the Indexer can focus on the 'what happened' details of transactions and accounts.

There are two primary modes of operation:

• Database updater
• Read only

Database updater

In this mode, the database will be populated with data fetched from an Algorand archival node. Because every block must be fetched to bootstrap the database, the initial import for a ledger with a long history will take a while. If the daemon is terminated, it will resume processing wherever it left off.

Keeping the indexer daemon as close as possible to the database helps minimize latency. For example, if using AWS EC2 and RDS, we suggest putting EC2 in the same VPC, Region, and even Availability Zone.

You should use a process manager, like systemd, to ensure the daemon is always running. Indexer will continue to update the database as new blocks are created.

To start indexer as a daemon in update mode, provide the required fields:

~$ algorand-indexer daemon --algod-net yournode.com:1234 --algod-token token --genesis ~/path/to/genesis.json  --postgres "user=readonly password=YourPasswordHere {other connection string options for your database}"

Alternatively if indexer is running on the same host as the archival node, a simplified command may be used:

~$ algorand-indexer daemon --algod-net yournode.com:1234 -d /path/to/algod/data/dir --postgres "user=readonly password=YourPasswordHere {other connection string options for your database}"

Read only

It is possible to set up one daemon as a writer and one or more readers. The Indexer pulling new data from algod can be started as above. Starting the indexer daemon without $ALGORAND_DATA or -d/--algod/--algod-net/--algod-token will start it without writing new data to the database. For further isolation, a readonly user can be created for the database.

~$ algorand-indexer daemon --no-algod --postgres "user=readonly password=YourPasswordHere {other connection string options for your database}"

The Postgres backend does specifically note the username "readonly" and changes behavior to avoid writing to the database. But the primary benefit is that Postgres can enforce restricted access to this user. This can be configured with:

CREATE USER readonly LOGIN PASSWORD 'YourPasswordHere';
REVOKE ALL ON ALL TABLES IN SCHEMA public FROM readonly;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO readonly;

Authorization

When --token your-token is provided, an authentication header is required. For example:

~$ curl localhost:8980/transactions -H "X-Indexer-API-Token: your-token"

Metrics

The /metrics endpoint is configured with the --metrics-mode option and configures if and how Prometheus formatted metrics are generated.

There are different settings:

Setting	Description
ON	Metrics for each REST endpoint in addition to application metrics.
OFF	No metrics endpoint.
VERBOSE	Separate metrics for each combination of query parameters. This option should be used with caution, there are many combinations of query parameters which could cause extra memory load depending on usage patterns.

Settings

Settings can be provided from the command line, a configuration file, or an environment variable

Command Line Flag (long)	(short)	Config File	Environment Variable
postgres	P	postgres-connection-string	INDEXER_POSTGRES_CONNECTION_STRING
pidfile		pidfile	INDEXER_PIDFILE
algod	d	algod-data-dir	INDEXER_ALGOD_DATA_DIR
algod-net		algod-address	INDEXER_ALGOD_ADDRESS
algod-token		algod-token	INDEXER_ALGOD_TOKEN
genesis	g	genesis	INDEXER_GENESIS
server	S	server-address	INDEXER_SERVER_ADDRESS
no-algod		no-algod	INDEXER_NO_ALGOD
token	t	api-token	INDEXER_API_TOKEN
dev-mode		dev-mode	INDEXER_DEV_MODE
metrics-mode		metrics-mode	INDEXER_METRICS_MODE

Command line

The command line arguments always take priority over the config file and environment variables.

~$ ./algorand-indexer daemon --pidfile /var/lib/algorand/algorand-indexer.pid --algod /var/lib/algorand --postgres "host=mydb.mycloud.com user=postgres password=password dbname=mainnet"`

Configuration file

Default values are placed in the configuration file. They can be overridden with environment variables and command line arguments.

The configuration file must named indexer, indexer.yml, or indexer.yaml. It must also be in the correct location. Only one configuration file is loaded, the path is searched in the following order:

• ./ (current working directory)
• $HOME
• $HOME/.algorand-indexer
• $HOME/.config/algorand-indexer
• /etc/algorand-indexer/

Here is an example indexer.yml file:

postgres-connection-string: "host=mydb.mycloud.com user=postgres password=password dbname=mainnet"
pidfile: "/var/lib/algorand/algorand-indexer.pid"
algod-data-dir: "/var/lib/algorand"

If it is in the current working directory along with the indexer command we can start the indexer daemon with:

~$ ./algorand-indexer daemon

Example environment variable

Environment variables are also available to configure indexer. Environment variables override settings in the config file and are overridden by command line arguments.

The same indexer configuration from earlier can be made in bash with the following:

~$ export INDEXER_POSTGRES_CONNECTION_STRING="host=mydb.mycloud.com user=postgres password=password dbname=mainnet"
~$ export INDEXER_PIDFILE="/var/lib/algorand/algorand-indexer.pid"
~$ export INDEXER_ALGOD_DATA_DIR="/var/lib/algorand"
~$ ./algorand-indexer daemon

Systemd

/lib/systemd/system/algorand-indexer.service can be partially overridden by creating /etc/systemd/system/algorand-indexer.service.d/local.conf. The most common things to override will be the command line and pidfile. The overriding local.conf file might be this:

[Service]
ExecStart=
ExecStart=/usr/bin/algorand-indexer daemon --pidfile /var/lib/algorand/algorand-indexer.pid --algod /var/lib/algorand --postgres "host=mydb.mycloud.com user=postgres password=password dbname=mainnet"
PIDFile=/var/lib/algorand/algorand-indexer.pid

The systemd unit file can be found in source at misc/systemd/algorand-indexer.service

Note that the service assumes an algorand group and user. If the Algorand package has already been installed on the same machine, this group and user has already been created. However, if the Indexer is running stand-alone, the group and user will need to be created before starting the daemon:

adduser --system --group --home /var/lib/algorand --no-create-home algorand

Once configured, turn on your daemon with:

sudo systemctl enable algorand-indexer
sudo systemctl start algorand-indexer

If you wish to run multiple indexers on one server under systemd, see the comments in /lib/systemd/system/algorand-indexer@.service or misc/systemd/algorand-indexer@.service

Unique Database Configurations

Load balancing: If indexer is deployed with a clustered database using multiple readers behind a load balancer, query discrepancies are possible due to database replication lag. Users should check the current-round response field and be prepared to retry queries when stale data is detected.

Migrating from Indexer v1

Indexer v1 was built into the algod v1 REST API. It has been removed with the algod v2 REST API, all of the old functionality is now part of this project. The API endpoints, parameters, and response objects have all been modified and extended. Any projects depending on the old endpoints will need to be updated accordingly.

Building

Indexer is built using an in-house task framework called mule (it has since been open-sourced).

Please refer to the build docs in the mule/ directory.