LoggerJsonFileBackend

LoggerJsonFileBackend is elixir logger backend that writes json logs to a file.

Configuration

This logger backend provides follow options:

name	description
path	log file path. this option is "MUST"
level	minimum logging level. default is :info
metadata	included metadata keys list. detault is empty list
metadata_filter	metadata terms which must be present in order to log, for example: [status: 404]. detault is empty list
metadata_triming	if false, ignoring previous metadata options and all metadata are output. default is true. It is recommended true in production environment.
json_encoder	using json encoder. default jason
uuid	If true, add uuid field to record. Default is false.

You need to add logger backend setting

config :logger,
  backends: [{LoggerJSONFileBackend, :log_name}]

config :logger, :log_name,
  path: "/var/log/my_app/app.log",
  level: :info,
  metadata: [:request_id, :user_id, :method, :path, :req_params],
  metadata_filter: [status: 404],
  json_encoder: Poison, # default is Jason
  uuid: true

Use case

This module is assumed to be used with a custom plug logger.

Example 1:

Logger.info("request", [
  method:     conn.method,
  path:       conn.request_path,
  req_params: conn.params,
])

Example 2:

Logger.error("not found", [
  method:     conn.method,
  path:       conn.request_path,
  req_params: conn.params,
  status:     404
])