defmodule Oban.Telemetry do
@moduledoc """
Telemetry integration for event metrics, logging and error reporting.
### Initialization Events
Oban emits the following telemetry event when an Oban supervisor is started:
* `[:oban, :supervisor, :init]` - when the Oban supervisor is started this will execute
The initialization event contains the following measurements:
* `:system_time` - The system's time when Oban was started
The initialization event contains the following metadata:
* `:conf` - The configuration used for the Oban supervisor instance
* `:pid` - The PID of the supervisor instance
### Job Events
Oban emits the following telemetry events for each job:
* `[:oban, :job, :start]` — at the point a job is fetched from the database and will execute
* `[:oban, :job, :stop]` — after a job succeeds and the success is recorded in the database
* `[:oban, :job, :exception]` — after a job fails and the failure is recorded in the database
All job events share the same details about the job that was executed. In addition, failed jobs
provide the error type, the error itself, and the stacktrace. The following chart shows which
metadata you can expect for each event:
| event | measures | metadata |
| ------------ | -------------------------- | ------------------------------------------------- |
| `:start` | `:system_time` | `:job, :conf, :state` |
| `:stop` | `:duration`, `:queue_time` | `:job, :conf, :state, :result` |
| `:exception` | `:duration`, `:queue_time` | `:job, :conf, :state, :kind, :reason, :stacktrace` |
Metadata
* `:conf` — the config of the Oban supervised producer
* `:job` — the executing `Oban.Job`
* `:state` — one of `:success`, `:discard` or `:snoozed`
* `:result` — the `perform/1` return value, only included when the state is `:success`
For `:exception` events the metadata includes details about what caused the failure. The `:kind`
value is determined by how an error occurred. Here are the possible kinds:
* `:error` — from an `{:error, error}` return value. Some Erlang functions may also throw an
`:error` tuple, which will be reported as `:error`.
* `:exit` — from a caught process exit
* `:throw` — from a caught value, this doesn't necessarily mean that an error occurred and the
error value is unpredictable
### Producer Events
Oban emits the following telemetry span events for each queue's producer:
* `[:oban, :producer, :start | :stop | :exception]` — when a producer dispatches new jobs
| event | measures | metadata |
| ------------ | -------------- | --------------------------------------------- |
| `:start` | `:system_time` | `:queue, :conf` |
| `:stop` | `:duration` | `:queue, :conf, :dispatched_count` |
| `:exception` | `:duration` | `:queue, :conf`, :kind, :reason, :stacktrace |
Metadata
* `:queue` — the name of the queue as a string, e.g. "default" or "mailers"
* `:conf` — the config of the Oban supervised producer
* `:dispatched_count` — the number of jobs fetched and started by the producer
### Engine Events
Oban emits telemetry span events for the following Engine operations:
* `[:oban, :engine, :init, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------ |
| `:start` | `:system_time` | `:conf`, `engine` |
| `:stop` | `:duration` | `:conf`, `engine` |
| `:exception` | `:duration` | `:conf`, `engine` |
* `[:oban, :engine, :refresh, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------ |
| `:start` | `:system_time` | `:conf`, `engine` |
| `:stop` | `:duration` | `:conf`, `engine` |
| `:exception` | `:duration` | `:conf`, `engine` |
* `[:oban, :engine, :put_meta, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------ |
| `:start` | `:system_time` | `:conf`, `engine` |
| `:stop` | `:duration` | `:conf`, `engine` |
| `:exception` | `:duration` | `:conf`, `engine` |
* `[:oban, :engine, :fetch_jobs, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------ |
| `:start` | `:system_time` | `:conf`, `engine` |
| `:stop` | `:duration` | `:conf`, `engine` |
| `:exception` | `:duration` | `:conf`, `engine` |
* `[:oban, :engine, :complete_job, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------------------------------------------- |
| `:start` | `:system_time` | `:conf`, `engine`, `job` |
| `:stop` | `:duration` | `:conf`, `engine`, `job` |
| `:exception` | `:duration` | `:conf`, `engine`, `job`, `kind`, `reason`, `stacktrace` |
* `[:oban, :engine, :discard_job, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------------------------------------------- |
| `:start` | `:system_time` | `:conf`, `engine`, `job` |
| `:stop` | `:duration` | `:conf`, `engine`, `job` |
| `:exception` | `:duration` | `:conf`, `engine`, `job`, `kind`, `reason`, `stacktrace` |
* `[:oban, :engine, :error_job, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------------------------------------------- |
| `:start` | `:system_time` | `:conf`, `engine`, `job` |
| `:stop` | `:duration` | `:conf`, `engine`, `job` |
| `:exception` | `:duration` | `:conf`, `engine`, `job`, `kind`, `reason`, `stacktrace` |
* `[:oban, :engine, :snooze_job, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------------------------------------------- |
| `:start` | `:system_time` | `:conf`, `engine`, `job` |
| `:stop` | `:duration` | `:conf`, `engine`, `job` |
| `:exception` | `:duration` | `:conf`, `engine`, `job`, `kind`, `reason`, `stacktrace` |
* `[:oban, :engine, :cancel_job, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------------------------------------------- |
| `:start` | `:system_time` | `:conf`, `engine`, `job` |
| `:stop` | `:duration` | `:conf`, `engine`, `job` |
| `:exception` | `:duration` | `:conf`, `engine`, `job`, `kind`, `reason`, `stacktrace` |
* `[:oban, :engine, :cancel_all_jobs, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | ------------------------------------------------- |
| `:start` | `:system_time` | `:conf`, `engine` |
| `:stop` | `:duration` | `:conf`, `engine` |
| `:exception` | `:duration` | `:conf`, `engine`, `kind`, `reason`, `stacktrace` |
Metadata
* `:conf` — the config of the Oban supervised producer
* `:engine` — the module of the engine used
* `:job` - the `Oban.Job` in question
### Notifier Events
Oban emits telemetry a span event each time the Notifier is triggered:
* `[:oban, :notifier, :notify, :start | :stop | :exception]`
| event | measures | metadata |
| ------------ | -------------- | -------------------------------------------------------------- |
| `:start` | `:system_time` | `:conf`, `channel`, `payload` |
| `:stop` | `:duration` | `:conf`, `channel`, `payload` |
| `:exception` | `:duration` | `:conf`, `channel`, `payload`, `kind`, `reason`, `stacktrace` |
* `:conf` — the config of the Oban supervised producer
* `:channel` — the channel on which the notification was sent
* `:payload` - the payload that was sent
* `kind`, `reason`, `stacktrace`, see the explanation above.
### Circuit Events
All processes that interact with the database have circuit breakers to prevent errors from
crashing the entire supervision tree. Processes emit a `[:oban, :circuit, :trip]` event when a
circuit is tripped and `[:oban, :circuit, :open]` when the breaker is subsequently opened again.
| event | measures | metadata |
| -------------------------- | -------- | ----------------------------------------------------- |
| `[:oban, :circuit, :trip]` | | `:kind, :reason, :message, :name, :stacktrace, :conf` |
| `[:oban, :circuit, :open]` | | `:name, :conf` |
Metadata
* `:kind` — the kind of error (see the explanation above)
* `:reason` — the error that tripped the circuit, see the error kinds breakdown above
* `:name` — the registered name of the process that tripped a circuit, i.e. `Oban.Notifier`
* `:message` — a formatted error message describing what went wrong
* `:stacktrace` — exception stacktrace, when available
* `:conf` — the config of the Oban supervisor that the producer is for
### Plugin Events
All the Oban plugins emit telemetry events under the `[:oban, :plugin, *]` pattern (where `*` is
either `:start`, `:stop`, or `:exception`). You can filter out for plugin events by looking into
the metadata of the event and checking the value of `:plugin`. The `:plugin` key will contain the
module name of the plugin module that emitted the event. For example, to get `Oban.Plugins.Cron`
specific events, you can filter for telemetry events with a metadata key/value of
`plugin: Oban.Plugins.Cron`.
Oban emits the following telemetry event whenever a plugin executes (be sure to check the
documentation for each plugin as each plugin can also add additional metadata specific to
the plugin):
* `[:oban, :plugin, :start]` — when the plugin beings performing its work
* `[:oban, :plugin, :stop]` — after the plugin completes its work
* `[:oban, :plugin, :exception]` — when the plugin encounters an error
The following chart shows which metadata you can expect for each event:
| event | measures | metadata |
| ------------ | ---------------| --------------------------------------------- |
| `:start` | `:system_time` | `:conf, :plugin` |
| `:stop` | `:duration` | `:conf, :plugin` |
| `:exception` | `:duration` | `:kind, :reason, :stacktrace, :conf, :plugin` |
## Default Logger
A default log handler that emits structured JSON is provided, see `attach_default_logger/0` for
usage. Otherwise, if you would prefer more control over logging or would like to instrument
events you can write your own handler.
Here is an example of the JSON output for the `job:stop` event:
```json
{
"args":{"action":"OK","ref":1},
"duration":4327295,
"event":"job:stop",
"queue":"alpha",
"queue_time":3127905,
"source":"oban",
"worker":"Oban.Integration.Worker"
}
```
All timing measurements are recorded as native time units but logged in microseconds.
## Examples
A handler that only logs a few details about failed jobs:
```elixir
defmodule MicroLogger do
require Logger
def handle_event([:oban, :job, :exception], %{duration: duration}, meta, nil) do
Logger.warn("[#\{meta.queue}] #\{meta.worker} failed in #\{duration}")
end
end
:telemetry.attach("oban-logger", [:oban, :job, :exception], &MicroLogger.handle_event/4, nil)
```
Another great use of execution data is error reporting. Here is an example of integrating with
[Honeybadger][honey], but only reporting jobs that have failed 3 times or more:
```elixir
defmodule ErrorReporter do
def handle_event([:oban, :job, :exception], _, %{attempt: attempt} = meta, _) do
if attempt >= 3 do
context = Map.take(meta, [:id, :args, :queue, :worker])
Honeybadger.notify(meta.reason, context, meta.stacktrace)
end
end
end
:telemetry.attach("oban-errors", [:oban, :job, :exception], &ErrorReporter.handle_event/4, [])
```
[honey]: https://honeybadger.io
"""
@moduledoc since: "0.4.0"
require Logger
@doc """
Attaches a default structured JSON Telemetry handler for logging.
This function attaches a handler that outputs logs with the following fields:
* `args` — a map of the job's raw arguments
* `duration` — the job's runtime duration, in the native time unit
* `event` — either `:success` or `:failure` depending on whether the job succeeded or errored
* `queue` — the job's queue
* `source` — always "oban"
* `system_time` — when the job started, in microseconds
* `worker` — the job's worker module
## Examples
Attach a logger at the default `:info` level:
:ok = Oban.Telemetry.attach_default_logger()
Attach a logger at the `:debug` level:
:ok = Oban.Telemetry.attach_default_logger(:debug)
"""
@doc since: "0.4.0"
@spec attach_default_logger(Logger.level()) :: :ok | {:error, :already_exists}
def attach_default_logger(level \\ :info) do
events = [
[:oban, :job, :start],
[:oban, :job, :stop],
[:oban, :job, :exception],
[:oban, :circuit, :trip],
[:oban, :circuit, :open]
]
:telemetry.attach_many("oban-default-logger", events, &__MODULE__.handle_event/4, level)
end
@deprecated "Use the official :telemetry.span/3 instead"
@spec span(name :: atom(), fun :: (() -> term()), meta :: map()) :: term()
def span(name, fun, meta \\ %{}) when is_atom(name) and is_function(fun, 0) do
start_time = System.system_time()
start_mono = System.monotonic_time()
execute([:oban, name, :start], %{system_time: start_time}, meta)
try do
result = fun.()
execute([:oban, name, :stop], %{duration: duration(start_mono)}, meta)
result
catch
kind, reason ->
execute(
[:oban, name, :exception],
%{duration: duration(start_mono)},
Map.merge(meta, %{kind: kind, reason: reason, stacktrace: __STACKTRACE__})
)
:erlang.raise(kind, reason, __STACKTRACE__)
end
end
defp duration(start_mono), do: System.monotonic_time() - start_mono
@doc false
def execute(event_name, measurements, meta) do
:telemetry.execute(event_name, measurements, normalize_meta(meta))
end
defp normalize_meta(%{name: {:via, Registry, {Oban.Registry, {_pid, name}}}} = meta) do
name =
with {role, name} <- name do
Module.concat([
Oban.Queue,
Macro.camelize(to_string(name)),
Macro.camelize(to_string(role))
])
end
%{meta | name: name}
end
defp normalize_meta(meta), do: meta
@doc false
@spec handle_event([atom()], map(), map(), Logger.level()) :: :ok
def handle_event([:oban, :job, event], measure, meta, level) do
meta
|> Map.take([:args, :worker, :queue])
|> Map.merge(converted_measurements(measure))
|> log_message("job:#{event}", level)
end
def handle_event([:oban, :circuit, event], _measure, meta, level) do
meta
|> Map.take([:message, :name])
|> log_message("circuit:#{event}", level)
end
defp converted_measurements(measure) do
for {key, val} <- measure, key in [:duration, :queue_time], into: %{} do
{key, System.convert_time_unit(val, :native, :microsecond)}
end
end
defp log_message(message, event, level) do
Logger.log(level, fn ->
message
|> Map.put(:event, event)
|> Map.put(:source, "oban")
|> Jason.encode_to_iodata!()
end)
end
end
