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Sync service

The Electric sync service is an Elixir application that manages active-active replication between your Postgres database and your local apps.

You can run the pre-packaged Docker images published on Docker Hub, or build and run your own Docker image, or run it directly as an Elixir service.

Configuration​

The Electric sync service is configured using environment variables. The required variables are:

Plus depending on your Write to PG mode you must either:

  • set ELECTRIC_WRITE_TO_PG_MODE=direct_writes; or
  • set LOGICAL_PUBLISHER_HOST to a hostname that the Postgres can connect to the sync service on

For example:

DATABASE_URL="postgresql://user:password@localhost:5432/electric"
ELECTRIC_WRITE_TO_PG_MODE="direct_writes"
PG_PROXY_PASSWORD="..."

See API -> Sync service for the full list of configuration options.

Docker​

Images​

Pre-packaged images are available on Docker Hub at electricsql/electric. Run using e.g.:

docker run \
    -e "DATABASE_URL=postgresql://..." \
    -e "ELECTRIC_WRITE_TO_PG_MODE=direct_writes" \
    -e "PG_PROXY_PASSWORD=..." \
    -e "AUTH_MODE=insecure" \
    -p 5133:5133 \
    -p 5433:5433 \
    -p 65432:65432 \
    -t \
    electricsql/electric

Compose​

You can deploy the sync service together with a Postgres database in a Docker Compose file. For example, save below contents to a file named compose.yaml:

version: "3.1"

volumes:
  pg_data:

services:
  pg:
    image: postgres:14-alpine
    environment:
      POSTGRES_PASSWORD: pg_password
    command:
      - -c
      - wal_level=logical
    ports:
      - 5432:5432
    restart: always
    volumes:
      - pg_data:/var/lib/postgresql/data

  electric:
    image: electricsql/electric
    depends_on:
      - pg
    environment:
      DATABASE_URL: postgresql://postgres:pg_password@pg/postgres
      DATABASE_REQUIRE_SSL: false
      ELECTRIC_WRITE_TO_PG_MODE: direct_writes
      PG_PROXY_PASSWORD: proxy_password
      AUTH_MODE: insecure
    ports:
      - 5133:5133
      - 65432:65432
    restart: always

Then start the services:

docker compose -f compose.yaml up

Build​

See the Makefile for more details but e.g.:

docker build -t electric:local-build .

Then run:

docker run \
    -e "DATABASE_URL=postgresql://..." \
    -e "ELECTRIC_WRITE_TO_PG_MODE=direct_writes" \
    -e "PG_PROXY_PASSWORD=..." \
    -e "AUTH_MODE=insecure" \
    -p 5133:5133 \
    -p 5433:5433 \
    -p 65432:65432 \
    -t \
    electric:local-build

Elixir​

See the source code and usage instructions at electric-sql/electric/components/electric.

Make sure you have Elixir 1.15 compiled with Erlang 25 installed.

Build:

mix deps.get
mix compile

Test:

mix test

Release:

MIX_ENV="prod" mix release

Run:

./_build/prod/rel/electric/bin/electric start