Logs & Process Crashes

Elixir and Erlang automatically log process crashes. To capture these errors in Sentry, you'll want to enable the Elixir SDK's built-in :logger handler. The most common way to do this is by adding the handler in your application's configuration, and then calling Logger.add_handlers/1 in the Application.start/2 callback of your application.

First, add the Sentry handler to your application's configuration. (You can use any handler identifier instead of :my_sentry_handler. ):

config :my_app, :logger, [
  {:handler, :my_sentry_handler, Sentry.LoggerHandler, %{
    config: %{
      metadata: [:file, :line],
      rate_limiting: [max_events: 10, interval: _1_second = 1_000],
      capture_log_messages: true
    }
  }}
]

Next, add the handler to the logger in your application's Application.start/2 callback:

@impl Application
def start(_type, _args) do
  children = [
    # ...
  ]

  Logger.add_handlers(:my_app)
end

Capturing Logged Messages

If you also want to capture logged messages above a specific log level (and not just process crashes), you'll need to set :capture_log_messages. Then you can use the :level option in the handler configuration:

config :my_app, :logger, [
  {:handler, :my_sentry_handler, Sentry.LoggerHandler, %{
    config: %{capture_log_messages: true, level: :error}
  }}
]

Now messages will be reported to Sentry even if logged with Logger.error/1, for example:

Logger.error("This will be reported to Sentry")

Logger Handler Configuration

You can configure the :logger handler under the :config key, as shown above. The configuration options are shown below.

capture_log_messages

This is set to false by default and will only send crash reports (which are messages with metadata that look like an exit reason and a stacktrace). When set to true, the handler will report all logged messages to Sentry (provided they're not filtered by :excluded_domains and :level).

level

This is the minimum Logger level to send events for and is set to :error by default. You can lower it to :warning, for example, to also report Logger.warning/1 calls.

metadata

Use this to include non-Sentry logger metadata in reports. It's set to to [] by default. If it's a list of keys, metadata in those keys will be added in the :extra context under the :logger_metadata key. If it's set to :all, all metadata will be included.

excluded_domains

This configuration option makes it so that messages with a domain in the configured list will not be sent. It's set to [:cowboy] by default to avoid double-reporting events from Sentry.PlugCapture.

rate_limiting

This configures rate-limiting for reported logged messages to Sentry and is disabled by default. It can help limit the number of messages being reported in a short period of time.