Acryl data service API

⚠️ This service is currently in /v0. Breaking changes are coming in /v1 (also possible, but not likely, within /v0 releases). Please use with caution.

This is an API aimed at retrieving data from blockchain quickly and conveniently. We support public APIs for:

• Mainnet
  • https://api.acrylplatform.com/v0/
• Testnet
  • https://apitestnet.acrylplatform.com/v0/

Visit /docs for Swagger documentation.

Data service on-premise

It is possible to create your own instance of this service. To do so, follow the guide below.

Requirements

1. PostgreSQL 10 database with a table stricture found in wavesplatform/blockchain-postgres-sync
2. Downloaded and continuously updated blockchain data in the database
3. NodeJS or Docker for either running the service directly, or in a container

Installation and start

The service uses following environment variables:

Env variable	Default	Required	Description
PORT	3000	NO	HTTP service port
PGHOST		YES	Postgres host address
PGPORT	5432	NO	Postgres port
PGDATABASE		YES	Postgres database name
PGUSER		YES	Postgres user name
PGPASSWORD		YES	Postgres password
PGPOOLSIZE	20	NO	Postgres pool size
LOG_LEVEL	info	NO	Log level ['info','warn','error']

PGPOOLSIZE is used by the pg-pool library to determine Postgres connection pool size per NodeJS process instance. A good value depends on your server and db configuration and can be found empirically. You can leave it at the default value to start with.

Set those variables to a variables.env file in the root of the project for convenience. In the next steps we will assume this file exists.

If you would like to use some other way of setting environment variables, just replace relevant commands below with custom alternatives.

Docker

1. Build a Docker image from the project root

   docker build -t acrylplatform/data-service .

2. Run the container

   docker run -p=<port>:3000 --env-file=variables.env acrylplatform/data-service

A server will start at localhost:<port> (used in the docker run command). Logs will be handled by Docker. Use any other Docker options if necessary.

When using the container in production, we recommend establishing a Docker logging and restart policy.

NodeJS

1. Install dependencies

   npm install    # or `yarn install`, if you prefer

2. Start the server

   export $(cat variables.env | xargs) && NODE_ENV=production node src/index.js

Server will start at localhost:PORT (defaults to 3000). Logs will be directed to stdout.

If you decide to use NodeJS directly (without Docker), we recommend using a process manager, such as pm2.

Daemons

To add candles and pairs functionality the following Docker daemons must be used:

• Candles — calculate candles for exchange transactions (see description)
• Pairs — calculate last pairs for 24h exchange transactions (see description)

General recommendations

• Set up a dedicated web server such as Nginx in front of data-service backends (for ssl/caching/balancing)
• Implement a caching strategy. Different endpoints may need different cache time (or no cache at all)
• Run several process instances behind a load balancer per machine. docker-compose --scale can help with that, or it can be done manually. A good rule of thumb is to use as many instances as CPU cores available.
• Use several machines in different data centers and a balancer to minimize downtime
• Experiment with PostgreSQL settings to find out what works best for your configuration. Tweaking PGPOOLSIZE also can help performance.