dramatiq-pg − Postgres Broker for Dramatiq

Dramatiq is a simple task queue implementation for Python3. dramatiq-pg provides a Postgres-based implementation of a dramatiq broker.

Features

• Super simple deployment.
• Uses plain psycopg2. No ORM.
• Stores message payload and results as native JSONb.
• Stores all messages in a single table, in a dedicated schema.
• Uses LISTEN/NOTIFY to keep worker sync. No polling.
• Requeue of failed tasks.
• Delayed task.
• Reliable thanks to Postgres MVCC.
• Self-healing. Old messages are purge from time to time.
• Utility CLI for maintainance : flush, purge, stats, etc.

Note that dramatiq assumes tasks are idempotent. This broker makes the same assumptions for recovering after a crash.

Installation

• Install dramatiq-pg package from PyPI:

  $ pip install dramatiq-pg psycopg2-binary
  

  Ensure you have either psycopg2 or psycopg2-binary installed.
• Apply dramatiq_pg/schema.sql file in your database:

  $ psql -f dramatiq_pg/schema.sql
  

• Before importing actors, define global broker with a connection pool:

  import dramatiq
  import psycopg2.pool
  from dramatiq_pg import PostgresBroker
  
  dramatiq.set_broker(PostgresBroker(i))
  
  @dramatiq.actor
  def myactor():
      ...
  

Now declare/import actors and manage worker just like any dramatiq setup. An example script is available, tested on CI.

The CLI tool dramatiq-pg allows you to requeue messages, purge old messages and show stats on the queue. See --help for details.

Dramatiq-pg documentation is hosted on GitLab and give you more details on deployment and operation of Postgres as a Dramatiq broker.

Support

If you encounter a bug or miss a feature, please open an issue on GitLab with as much information as possible.

dramatiq_pg is available under the PostgreSQL licence.