MIT licensed by Freckle Engineering
Maintained by [email protected]
This version can be pinned in stack with:faktory-,8916
# faktory\_worker\_haskell


Haskell client and worker process for the Faktory background job server.

Architecture overview from [Ruby client README](

| |
| Faktory |
| Server |
+---------->>>>| +>>>>--------+
| | | |
| | | |
| +--------------------+ |
+-----------------+ +-------------------+
| | | |
| Client | | Worker |
| pushes | | pulls |
| jobs | | jobs |
| | | |
| | | |
+-----------------+ +-------------------+

- Client - an API any process can use to push jobs to the Faktory server.
- Worker - a process that pulls jobs from Faktory and executes them.
- Server - the Faktory daemon which stores background jobs in queues to be
processed by Workers.

This package contains only the client and worker parts. The server part is

## Installation

- Hackage:
- Stackage: *Coming soon*

## Faktory Documentation

See the [wiki](// for more

## Usage

import Data.Aeson
import Prelude
import Faktory.Producer
import Faktory.Job
import Faktory.Worker
import GHC.Generics
import Text.Markdown.Unlit ()

{- Don't actually run anything -}
main :: IO ()
main = if True then pure () else (workerMain >> producerMain)
workerMain :: IO ()
producerMain :: IO ()

### Job

Any value can be a "Job" that is pushed and pulled to and from Faktory via its
`ToJSON` and `FromJSON` instances:

newtype MyJob = MyJob
{ myJobMessage :: String
deriving stock Generic
deriving anyclass (ToJSON, FromJSON)

### Worker

workerMain = runWorkerEnv $ \job ->
-- Process your Job here
putStrLn $ myJobMessage job

-- If any exception is thrown, the job will be marked as Failed in Faktory
-- and retried. Note: you will not otherwise hear about any such exceptions,
-- unless you catch-and-rethrow them yourself.

### Producer

`Producer` wraps `Client` for push-only usage.

producerMain = do
producer <- newProducerEnv

jobId <- perform mempty producer $ MyJob "Hello world"

print jobId

closeProducer producer

### Configuration

When using `envSettings`, the following variables will be used:

- `FAKTORY_PROVIDER`: the name of another environment variable where the
connection string can be found. Defaults to `FAKTORY_URL`.
- `FAKTORY_URL` (or whatever you named in `FAKTORY_PROVIDER`): connection string
to the Faktory server. Format is
`tcp(+tls)://(:password@)host:port(/namespace)`. Defaults to
`tcp://localhost:4719`. `namespace` is prependend to queue names on job
submission and worker consumption.

When using `envWorkerSettings`, the following variables are also used:

- `FAKTORY_QUEUE`: the name of the queue to consume from. Default is "default".
- `FAKTORY_WORKER_ID`: the Id to use for this Worker. Default is to assign a
random one.

## Examples

See the [examples](./examples). To run them:

1. Run a local Faktory server

docker run --rm \
--publish 7419:7419 \
--publish 7420:7420 \

1. Run the consumer example

% stack exec faktory-example-consumer
Starting consumer loop

(Assumes you've built the project.)

1. Submit a Job through the producer example

% stack exec faktory-example-producer hello world
Pushed job: "ljcjlbexbgun"

*NOTE*: if you submit "BOOM" as a Job, the processing loop will raise an
exception, so you can see how a Failed Job looks in Faktory.

1. See that your Job was processed back in the consumer

% stack exec faktory-example-consumer
Starting consumer loop
hello world

## Development & Tests

stack build --dependencies-only --test --no-run-tests
stack build --pedantic --test --no-run-tests
stack build --pedantic --test

- `FactorySpec` requires a local Faktory server is running, and it will flush
all Jobs from this server as part of running the tests.
- The tests for `BATCH` require testing against an Enterprise Faktory image







  • Export lower-level BATCH functions


  • Support for TRACK (Enterprise only)


  • Remove dependencies upper bounds


  • Relax dependencies upper bounds


  • Fix bug in at parsing of consumed Job payloads


  • Partial BATCH support (Enterprise only)
  • Support for custom field in Job payloads
  • Lower-level buildJob and commandByteString functions


  • Relax dependencies upper bounds


  • Maintain version bounds


  • Various CI and dependency bounds changes


  • Add support for queue namespacing


  • Fix internal handling of invalid Server Replies


  • Include non-OK reply in commandOK error
  • Build with GHC-8.8


  • Upgrade to megaparsec-7


Initial release.