One of the distinguishing features of ecto_job is that the API encourages transactional job processing through Ecto.Multi. Job handlers are passed an Ecto.Multi parameter that must be passed to Repo.transaction to complete the job.
def perform(multi = %Ecto.Multi{}, job = %{}) do
multi
|> do_first_thing(job["customer_id"])
|> do_second_thing(job["product_id"])
|> MyApp.Repo.transaction()
end
Similarly, there are helpers to encourage transactional job creation by adding to an Ecto.Multi
Jobs are processed using a GenStage producer and ConsumerSupervisor that will execute jobs concurrently up to a configurable max_demand.
Postgrex.Notifications is used to trigger job processors as soon as the transaction that adds a job is committed.
Job workers can be run on a separate node, without requiring any beam clustering, just PostgreSQL listen/notify.
Job completion is also signalled using listen/notify enabling websocket or chunked HTTP responses (on another node) to be triggered once a job completes.
Sounds like an interesting library! Did you design the library to work on Heroku? It seems like relying on listen/notify instead of clustering is partially to fit Heroku’s constraints.
Not quite. I noticed that most of the Exq jobs in our system were enqueued along with changes to the database, and workers updated the database also.
To guarantee that jobs are enqueued consistently and worked idempotently requires bookkeeping that all goes away if you let a db transaction take care of it
Hi, thanks for great library, I am currently testing it inside my new project.
My only question is: is there a way or at least a plan to implement priorities in message job queue?
It’s important for SaaS app to make sure come clients are not waiting for someone else pushing loads of requests to server.
Thank you to everyone that contributed to this version!
I’d also like to invite any users of EctoJob to please raise issues on the GitHub page for any features you’d like to see added or would be willing to work on (admin UI, Telemetry, Pre/Post job hooks, etc..)
The library is very good and works fine for my delayed email sending functionality. But I am facing a problem, when I add the child worker in supervisor tree, like this
def start(_type, _args) do
# List all child processes to be supervised
children = [
# Start the Ecto repository
MyApp.Repo,
# Start the Endpoint (http/https)
MyAppWeb.Endpoint,
{MyApp.JobQueue, repo: MyApp.Repo, max_demand: 100},
{Task.Supervisor, [name: MyApp.TaskSupervisor]}
]
I am unable to run any tests. Getting the error like this
I am getting the error
** (DBConnection.OwnershipError) cannot find ownership process for pid<0.847.0>.
When using ownership, you must manage connections in one
of the four ways:
By explicitly checking out a connection
By explicitly allowing a spawned process
By running the pool in shared mode
By using :caller option with allowed process
The first two options require every new process to explicitly
check a connection out or be allowed by calling checkout or
allow respectively.
The third option requires a {:shared, pid} mode to be set.
If using shared mode in tests, make sure your tests are not
async.
The fourth option requires [caller: pid] to be used when
checking out a connection from the pool. The caller process
should already be allowed on a connection.
If you are reading this error, it means you have not done one
of the steps above or that the owner process has crashed.
See Ecto.Adapters.SQL.Sandbox docs for more information.
(ecto_sql 3.3.3) lib/ecto/adapters/sql.ex:609: Ecto.Adapters.SQL.raise_sql_call_error/1
(ecto_sql 3.3.3) lib/ecto/adapters/sql.ex:545: Ecto.Adapters.SQL.execute/5
(ecto 3.3.2) lib/ecto/repo/queryable.ex:192: Ecto.Repo.Queryable.execute/4
(ecto_job 3.0.0) lib/ecto_job/producer.ex:184: EctoJob.Producer.dispatch_jobs/2
(gen_stage 0.14.3) lib/gen_stage.ex:2103: GenStage.noreply_callback/3
(stdlib 3.11.1) gen_server.erl:637: :gen_server.try_dispatch/4
(stdlib 3.11.1) gen_server.erl:711: :gen_server.handle_msg/6
(stdlib 3.11.1) proc_lib.erl:249: :proc_lib.init_p_do_apply/3
Last message: {:DOWN, reference<0.1630123645.3685482498.192412>, :process, pid<0.847.0>, {%DBConnection.OwnershipError{message: “cannot find ownership process for pid<0.847.0>.\n\nWhen using ownership, you must manage connections in one\nof the four ways:\n\n* By explicitly checking out a connection\n* By explicitly allowing a spawned process\n* By running the pool in shared mode\n* By using :caller option with allowed process\n\nThe first two options require every new process to explicitly\ncheck a connection out or be allowed by calling checkout or\nallow respectively.\n\nThe third option requires a {:shared, pid} mode to be set.\nIf using shared mode in tests, make sure your tests are not\nasync.\n\nThe fourth option requires [caller: pid] to be used when\nchecking out a connection from the pool. The caller process\nshould already be allowed on a connection.\n\nIf you are reading this error, it means you have not done one\nof the steps above or that the owner process has crashed.\n\nSee Ecto.Adapters.SQL.Sandbox docs for more information.”}, [{Ecto.Adapters.SQL, :raise_sql_call_error, 1, [file: ‘lib/ecto/adapters/sql.ex’, line: 609]}, {Ecto.Adapters.SQL, :execute, 5, [file: ‘lib/ecto/adapters/sql.ex’, line: 545]}, {Ecto.Repo.Queryable, :execute, 4, [file: ‘lib/ecto/repo/queryable.ex’, line: 192]}, {EctoJob.Producer, :dispatch_jobs, 2, [file: ‘lib/ecto_job/producer.ex’, line: 184]}, {GenStage, :noreply_callback, 3, [file: ‘lib/gen_stage.ex’, line: 2103]}, {:gen_server, :try_dispatch, 4, [file: ‘gen_server.erl’, line: 637]}, {:gen_server, :handle_msg, 6, [file: ‘gen_server.erl’, line: 711]}, {:proc_lib, :init_p_do_apply, 3, [file: ‘proc_lib.erl’, line: 249]}]}}
I have tried many ways to resolve this, but unable to succeed.
It was accidentally jobs table is deleted from my local database. I am unable to re-run the migration.
It always gives the error
execute “CREATE FUNCTION fn_notify_inserted()\n RETURNS trigger AS $$\nDECLARE\nBEGIN\n PERFORM pg_notify(TG_TABLE_NAME, ‘’);\n RETURN NEW;\nEND;\n$$ LANGUAGE plpgsql\n”
** (Postgrex.Error) ERROR 42723 (duplicate_function) function “fn_notify_inserted” already exists with same argument types.
@santoshbt use the postgresql drop function command to remove the function before running the migration.
the CASCADE option will also remove any triggers that depend on that function.
Version 3.1.0 adds support for MySQL 8 and storing job params as an Elixir/Erlang term.
You can insert any arbitrary Elixir/Erlang term into the queue:
Is it expected that each queue creates a new DB connection independent of the connection pool maintained by Ecto? It is how I see EctoJob behave in our production and it seems very weird to me. So in effect there is pool_size + number_of_queues connections.
