hasql-queue: A PostgreSQL backed queue
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- hasql-queue-1.2.0.0.tar.gz [browse] (Cabal source package)
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| Versions [RSS] | 1.0.1, 1.0.1.1, 1.2.0.0, 1.2.0.1, 1.2.0.2 |
|---|---|
| Change log | CHANGELOG.md |
| Dependencies | aeson, async, base (>=4.7 && <5), base64-bytestring, bytestring, cryptohash-sha1, exceptions, hasql, hasql-queue, here, monad-control, postgresql-libpq, postgresql-libpq-notify (>=0.2.0.0), random, resource-pool, stm, text, time, tmp-postgres, transformers [details] |
| License | BSD-3-Clause |
| Copyright | 2020 Jonathan Fischoff |
| Author | Jonathan Fischoff |
| Maintainer | jonathangfischoff@gmail.com |
| Category | Web |
| Home page | https://github.com/jfischoff/hasql-queue#readme |
| Bug tracker | https://github.com/jfischoff/hasql-queue/issues |
| Source repo | head: git clone https://github.com/jfischoff/hasql-queue |
| Uploaded | by JonathanFischoff at 2020-07-06T05:36:57Z |
| Distributions | |
| Executables | hasql-queue-tmp-db, benchmark |
| Downloads | 1081 total (20 in the last 30 days) |
| Rating | (no votes yet) [estimated by Bayesian average] |
| Your Rating | |
| Status | Docs available [build log] Last success reported on 2020-07-06 [all 1 reports] |
Readme for hasql-queue-1.2.0.0
[back to package description]
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
enqueueNotification "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
In the example above we used the Session API for enqueuing and the IO for
dequeuing.
The Session API is useful for composing larger transactions and the IO utilizes PostgreSQL notifications to avoid polling.
Installation
stack install hasql-queue