@hackage / hasql-queue

A PostgreSQL backed queue

Latest1.2.0.2

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  • Last updated , by JonathanFischoff
  • License BSD-3-Clause
  • Categories Web Development

  • Maintained by: jonathangfischoff@gmail.com

  • Lottery factor: 0

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Installation

Tested Compilers

  1. 8.8.1

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hasql-queue

This module utilizes PostgreSQL to implement a durable queue for efficently processing payloads.

Typically a producer would enqueue a new payload as part of larger database transaction

createAccount userRecord = transaction Serializable Write $ do
  createUser userRecord
  enqueue "queue_channel" emailEncoder [makeVerificationEmail userRecord]

In another thread or process the consumer would drain the queue.

  -- Wait for a single new record and try to send the email 5 times for giving
  -- up and marking the payload as failed.
  forever $ withDequeue "queue_channel" conn emailDecoder 5 1 $
    mapM_ sendEmail