Macros that filter debug messages before they are generated. The filters can be changed during runtime to allow debugging of live systems. Uses the Elixir Logger.
Set require Log at the beginning of the file.
Create log messages with
Log.debug("msg")
Log.info("msg")
Log.warn("msg")
Log.error("msg")
By default debug messages will not be shown. To enable them define filters using
Log.set_filter(caller, metadata)
[1,2,3]
|> Enum.map(&(&1 * 2))
|> Log.debug("double")
|> Enum.map(&(&1 * 2))this will output the message
09:32:25.663 [debug] double: [2, 4, 6] |
while leaving the stream intact and returning [4, 8, 12].
Sometimes computing the massage might be expensive and you only want to do it if it is actually shown:
generate_message = fn() -> "I did something really complex" end
Log.debug(generate_message)
08:56:04.380 [debug] I did something really complex |