slack_log

SlackLog View Source

SlackLog is a library that borrows heavily from logger_file_backend to allow for custom logging to defined Slack channels.

Installation

If available in Hex, the package can be installed by adding slack_log to your list of dependencies in mix.exs:

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

Configuration

SlackLog is a custom backend for elixir's :logger application. To configure logging to a Slack channel, you need to define the backend in the :logger configuration.

Example config.exs:

config :logger,
    backends: [{SlackLog, :error_log}]
    
# Configure the error logger
# slack_url is the url you receive from Slack when setting up your webhook
config :logger, :error_log,
    slack_url: "https://url_for_slack_hook",
    level: :error,
    metadata: [:file, :line, :function]

This configuration - apart from slack_url - follows the same syntax as logger_file_backend, so it is possible to use one configuration for both backends. (e. g. when you want to log levels to different files, but also want to log errors to Slack.

The slack_url is defined in every backend configuration, so that different metadata filters or log levels can be posted to different channels.

It supports the following configuration values:

  • slack_url the url to the custom Slack Webhook to send the messages to
  • level the minimum log level to send
  • metadata a list of atoms for the metadata to include in messages
  • metadata_filter a keyword list with metadata and value to filter out which messages to log

Example metadata_filter:

config :logger, :user_activity_log,
    level: :debug,
    metadata_filter: [area: :user, action: [:login, :sign_up]]

In the example above, it would only send out log events that have area: :user and the metadata :action is one of :login or :sign_up. If one of these conditions do not match, the event will not be sent to your specified channel.

Defining custom headers

SlackLog allows to configure custom headers (including icons) for different Log levels.

Example config.exs:

config :slack_log, :headers,
  emergency: ":skull: New Emergency!!!",
  alert: ":skull: New Alert!!!",
  critical: ":x: New Critical Error!!!",
  error: ":x: New Error",
  warning: ":x: New Warning",
  notice: ":information_source: New Notice",
  info: ":information_source: New Info",
  debug: ":information_source: New Debug Message"