WORK IN PROGRESS, DO NOT USE YET

Backy

Simple background job backed by PostgreSQL for Elixir.

Installation

If available in Hex, the package can be installed as:

  1. Add backy to your list of dependencies in mix.exs:

    def deps do [{:backy, "~> 0.0.1"}] end

  2. Ensure backy is started before your application:

    def application do [applications: [:backy]] end

Configuration

Database configuration

In your config.exs:

# Default configuration

config :backy, :db,

  database: "backy"

The :db hash is passed directly to Postgrex.start_link/1 ( https://hexdocs.pm/postgrex/Postgrex.html#start_link/1 ). You can specify any supported option

Backy configuration

# Default configuration

config :backy,

  table_name: "jobs", # The postgresql table name

  retry_count: 3, # The number of retry for a job before marking it as failed

  retry_delay: fn (retry) -> :math.pow(retry, 3) + 100 end, # Retry delay

  poll_interval: 1000, # Polling interval for the job poller

  # If false, jobs will be marked as finished, otherwise they are deleted

  # If false, you are responsible for purging the jobs table

  delete_finished_jobs: true

Writing a worker

defmodule TestWorker do

  use Backy.Worker,

      # If the job `perform` takes more than 20 sec, kill it

      # default to 1000 (1sec)

      max_runtime: 20000,

      # Max concurrency, default to `:unlimited`

      max_concurrency: 2,

      # When a job is stuck (for example, beam crashed), wait 10 sec before

      # queuing it again, default to 10000 (10sec)

      requeue_delay: 20000





  # The following example runs for 30 sec while the max runtime is 20 sec

  def perform(%Backy.Job{} = job, name: name) do

    IO.puts("Job started for #{name}")

    :timer.sleep(10000) # Simulate work for 10 sec

    # We have still work to do, max runtime is 20sec, avoid a timeout

    Backy.touch(job)

    :timer.sleep(10000) # Simulate work for 10 sec

    # We have still work to do, max runtime is 20sec, avoid a timeout

    Backy.touch(job)

    :timer.sleep(10000) # Simulate work for 10 sec

    IO.puts("Job finished")

  end



end

Enqueuing jobs

job = Backy.enqueue(TestWorker, name: "foo bar")

Contributors

Copyright ©2016 Nicolas Goy

This library is loosely inspired by:

License

MIT