This package implements a simple wrapper over https://github.com/basho/lager.
It embeds logging calls to ExLager into a module if currently configured logging level is less or equal than severity of a call. Therefore it doesn't have any negative impact on performance of a production system when you configure error level even if you have tons of debug messages.
Information about location of a call (module, function, line, pid) is properly passed to lager for your convinience so you can easily find the source of a message. In this aspect using ExLager is equal to using parse transform shipped with basho lager.
Since ExLager depends on macro implemented in Lager module you have to require it. Then you call one of logging methods on Lager module. There are seven logging methods in order of severity:
- debug
- info
- notice
- warning
- error
- critical
- alert
- emergency
defmodule Test do
require Lager
def debug do
Lager.debug "Hi debug"
end
def info do
Lager.info "Hi error"
end
def notice do
Lager.notice "Hi notice"
end
def warning do
Lager.warning "Hi warning"
end
def error do
Lager.error "Hi error"
end
def critical do
Lager.critical "Hi critical"
end
def alert do
Lager.alert "Hi alert"
end
def emergency do
Lager.emergency "Hi emergency"
end
def test do
debug
info
notice
warning
error
critical
alert
emergency
end
end
Application.start :exlager
Test.test
It is possible to configure truncation size and compile time log level. Beign a simple wrapper ExLager doesn't attempt to configure underlying Lager. You would need to configure it yourself see to ensure that:
- lager_truncation_size >= compile_truncation_size
- lager severity level >= compile_log_level
- appropriate handlers are configured
Configuration of ExLager can be done by calling helper functions of Lager from your build system as follows:
iex(1)> Lager.compile_log_level(:info)
true
iex(2)> Lager.compile_truncation_size(512)
true
If you cannot call those function you can set compiler options:
iex(3)> Code.compiler_options exlager_level: :debug
ok
iex(4)> Code.compiler_options exlager_truncation_size: 512
ok
If you are mix user you could specify level and truncation_size in config/config.#{Mix.env}.exs as follows:
use Mix.Config
config :exlager,
level: :debug,
truncation_size: 8096