LoggerExporter

Export your logs to the service of your choice.

I created this library because I wanted to export logs to a different service in Heroku. There is no simple way to export your logs.

Supported exporters:

• Loki

Implement your own exporter using LoggerExporter.Exporters.Exporter behaviour.

Supported formatters:

• Basic

Implement your own formatter using LoggerExporter.Formatters.Formatter behaviour.

Installation

Add logger_exporter to your list of dependencies in mix.exs:

def deps do
  [
    {:logger_exporter, "~> 0.1.0"}
  ]
end

Configuration

By default, the timestamp sent for each log to the external service is in utc: System.os_time(:nanosecond)

• config :logger, LoggerExporter, :level. The logger level to report.
• config :logger, LoggerExporter, :formatter. Allows the selection of a formatter implementation. Defaults to LoggerExporter.Formatters.BasicFormatter
• config :logger, LoggerExporter, :metadata. Metadata to log. Defaults to []
• config :logger, LoggerExporter, :exporter. Allows selection of a exporter implementation. Defaults to LoggerExporter.Exporters.LokiExporter
• config :logger, LoggerExporter, :batch_every_ms. The time (in ms) between every batch request. Default value is 2000 (2 seconds)
• config :logger, LoggerExporter, :host. The host of the service without the path. The path is inferred by the exporter. Required
• config :logger, LoggerExporter, :app_name. The name of the app to use as label for Loki. Required if using LokiExporter
• config :logger, LoggerExporter, :environment_name. The name of the environment to use as label for Loki. Required if using LokiExporter
• config :logger, :send_to_http If set to false, the library will not make any actual API calls. This is useful for test or dev environments. Default value is true
• config :logger, LoggerExporter, :http_auth. See below

HTPP Auth

Supported authentication methods:

• Basic:

  config :logger, LoggerExporter,
    host: "https://logs-prod.grafana.net",
    http_auth: {:basic, System.fetch_env!("USER"), System.fetch_env!("PASSWORD")}
  

Usage in Phoenix

1. Add the following to deps section of your mix.exs: {:logger_exporter, "~> 0.1.0"} and then mix deps.get

2. Add LoggerExporter.Backend to your logger's backends configuration

   config :logger,
     backends: [:console, LoggerExporter.Backend]
   

3. Add config related to the exporter and other fields. ie. for LokiExporter

   config :logger, LoggerExporter,
     host: "http://localhost:3100",
     app_name: "my_app",
     environment_name: Mix.env(),
     http_auth: {:basic, System.fetch_env!("LOKI_USER"), System.fetch_env!("LOKI_PASSWORD")},
     metadata: [:request_id]
   

4. Start the LoggerExporter GenServer in the supervised children list. In application.ex add to the children list:

   children [
     ...
     LoggerExporter
   ]
   

JSON Formatter

If you want to log in JSON format, you can use the formatter of another library: logger_json

You can configure it like this:

config :logger, LoggerExporter,
  formatter: LoggerJSON.Formatters.BasicLogger

And it will work out of the box :)

Telemetry

Telemetry integration for logging and error reporting.

There is a default logger for you to attach. It logs when the status is :error

In your application.ex

:ok = LoggerExporter.Telemetry.attach_default_logger()

HTTP Post batch events

LoggerExporter emits the following events for processing each batch (sending it through http)

• [:logger_exporter, :batch, :start] -- starting to process the events
• [:logger_exporter, :batch, :stop] -- after the events is processed
• [:logger_exporter, :batch, :exception] -- after the events are processed

The following chart shows which metadata you can expect for each event:

Metadata

• :events - the list of LoggerExporter.Event processed
• :status - either :ok or :error
• :response - information of the response. Is a Finch.Response struct