Oban Web uses Telemetry to provide instrumentation and to power logging of dashboard activity. See the [Telemetry][tel] guide for a breakdown of emitted events and how to use the default logger.


Action Events

An action event is emitted whenever a user performs a write operation with the dashboard, e.g. pausing a queue, cancelling a job, etc.

The dashboard emits the following events:

  • [:oban_web, :action, :start]
  • [:oban_web, :action, :stop]
  • [:oban_web, :action, :exception]

Action events include the action name, Oban config, the user that performed the action (if available), and relevant metadata. In addition, failed actions provide the error type, the error itself, and the stacktrace.

The following chart shows the base metadata for each event:

:start:system_time:action, :config, :user
:stop:duration:action, :config, :user
:exception:duration:action, :config, :user, :kind, :error, :stacktrace

For :exception events the metadata includes details about what caused the failure. The :kind value is determined by how an error occurred.

This chart breaks down the possible actions and their specific metadata:

:scale_queue:queue, :limit


Action Logging

The Oban.Web.Telemetry module ships with a default handler that logs structured JSON for :stop and :exception events. To attach the logger, call attach_default_logger/1 as your application starts:

def start(_type, _args) do
  children = [
    {Oban, oban_opts()}


  Supervisor.start_link(children, [strategy: :one_for_one, name: MyApp.Supervisor])

Here is an example of the JSON output for an action:stop event:


Event metadata is passed through directly along with these constant fields:

  • duration — Action duration, recorded in native units and logged as microseconds
  • source — Always "oban_web", which is useful for log filtering
  • user — If the dashboard was mounted with a resolver that implements resolve_user/1 this is the user's id, otherwise null
  • oban_name — The instance that the dashboard is linked to, typically this is "Oban" unless an application is using multiple Oban instances.