UniLoggerBackend

A logger backend that allows to log to processes or functions.

Installation

The package can be installed by adding uni_logger_backend to your list of dependencies in mix.exs:

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

Using a process as target

First configure the logger to use the UniLoggerBackend

# config/config.exs

config :logger, :backends, [{UniLoggerBackend, :console}]

config :logger, level: :info

Then configure the backend at runtime by giving a pid or process name as target:

Logger.configure_backend({UniLoggerBackend, :console}, target: self())

Or provive the process name in the config:

# config/config.exs
config :logger, :console, [target: :your_process]

Be aware that the process must handle two different kinds of messages. It receives a tuple with the log level, the message, a timestamp and the metadata in a tuple for all log messages and receives :flush if the logger should be flushed.

Using a function as target

Configure the logger to use the UniLoggerBackend and provide a function as target. The function can either be given as a function reference or by passing a tuple with a module and a function name.

# config/config.exs

config :logger, :backends, [{UniLoggerBackend, :console}]

config :logger, :console, [level: :info, target: {YourMod, :your_fun}]

The function can also be given at runtime:

Logger.configure_backend({UniLoggerBackend, :console}, target: some_fun/4)

Note that the arity of the function must be 4. It receives the log level, the message, a timestamp and the metadata as arguments.

Additional configuration

# config/config.exs

config :logger, :console,
  level: :info,
  formatter: {YourMod, :your_fun},
  meta: [any: "thing"]

• Log level can be set by adding the level option.
• A formatter to refine log messages before forwarding can be set with the formatter option. Can be either a tuple with a module and a function name or a function. The function must have arity 4 and receives the leve, the message, the timestam and the metadata as arguments.
• Any additional metadata can be added with the meta option. The regular metadata will be merged with the given metadata before sending or formatting.

Documentation

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/fun_logger_backend.