NAME Log::ger::App - An easy way to use Log::ger in applications VERSION version 0.024 SYNOPSIS In your script: use Log::ger::App; use Your::App::Module; # your module which uses Log::ger to do its logging If you also do logging in your script: use Log::ger::App; use Log::ger; log_warn("Some log ..."); DESCRIPTION This module basically loads Log::ger::Output::Composite with some sensible defaults and allows customizing some aspects via environment variable. Default outputs Code Screen File Syslog ------------------------------ ------ ---- ------ One-liner (-e) y - - Script running as normal user y ~/PROGNAME.log - Script running as root y /var/log/PROGNAME.log - Daemon - /var/log/PROGNAME.log y Determining if script is a daemon Log::ger::App assumes your script is a daemon if some daemon-related modules are loaded, e.g. App::Daemon, HTTP::Daemon, Net::Daemon, etc (see the source code for the complete list). Alternatively, you can also set $main::IS_DAEMON to 1 (0) to specifically state that your script is (not) a daemon. Or, you can set it via import argument (see "import"). Setting general log level Via import argument 'level'. You can set general log level via import argument "level" (see "import") but users of your script will not be able to customize it: use Log::ger::App level => 'debug'; # hard-coded to debug, not recommended Via environment variables. You can also set general log level from environment using "LOG_LEVEL" (e.g. "LOG_LEVEL=trace" to set level to trace or "LOG_LEVEL=0" to turn off logging). Alternatively, you can set to "trace" using "TRACE=1", or "debug" with "DEBUG=1", "info" with "VERBOSE=1", "error" with "QUIET=1". Via import argument 'default_level'. If the environment variables does not provide a value, next the import argument "default_level" is consulted. This is the preferred method of setting default level: use Log::ger::App default_level => 'info'; # be verbose by default. unless changed by env vars Via main package variable $main::Default_Log_Level. The next value to be consulted is the main package variable $main::Default_Log_Level. The name of the variable can be customized using the import argument "default_level_var_name". Note that you need to set the variable's value before loading Log::ger::App, so this does not work: use Log::ger::App; our $Default_Log_Level = 'info'; this does not also: our $Default_Log_Level = 'info'; use Log::ger::App; but this does: BEGIN { our $Default_Log_Level = 'info' } use Log::ger::App; Fallback value "warn". The fallback level is warn, if all the above does not provide a value. Setting per-output log level Via environment variables. You can set level for each output using *OUTPUT_NAME*_{"LOG_LEVEL|TRACE|DEBUG|VERBOSE|QUIET"} environment variables. For example, "SCREEN_DEBUG=1" to set screen level to "debug" or "FILE_LOG_LEVEL=off" to turn off file logging. General level. If the environment variables do not provide a value, the general level (see "Setting general log level") will be used. Showing timestamp Timestamps are shown in log files. On the screen, timestamps are not shown by default. To show timestamps on the screen, set "LOG_ADD_TIMESTAMP" to true. For example, when timestamps are not shown: myprog: First log message myprog: Doing task 1 ... myprog: Doing task 2 ... When timestamps are shown: myprog: [2018-08-30T15:14:50] First log message myprog: [2018-08-30T15:14:50] Doing task 1 ... myprog: [2018-08-30T15:15:01] Doing task 2 ... FUNCTIONS import Usage: $pkg->import(%args) Arguments: * level str|num. Explicitly set a hard-coded level. Not recommended because of lack of flexibility. See instead: "default_level". * default_level str|num. Instead of hard-coding level with "level", you can set a default level. Environment variables will be consulted first (as described in "DESCRIPTION") before falling back to this level. * default_level_var_name str. Optional. Name of scalar variable (without the sigil) to be consulted for the default level (after the "default_level" import argument). If the name of the variable does not contain package name, it will be assumed to be in the "main" package. The default value is "main::Default_Log_Level". * name str. Explicitly set program name. Otherwise, default will be taken from $0 (after path and '.pl' suffix is removed) or set to "prog". Program name will be shown on the screen, e.g.: myprog: First log message myprog: Doing task 1 ... myprog: Doing task 2 ... myprog: Exiting ... * file_name str. Explicitly set log filename. By default, filename will be set to *name*.log. * file_dir str. Explicitly set log file's directory. By default, it is user's home (if not running as root), or /var/log (if running as root). * daemon bool. Explicitly tell Log::ger::App that your application is a daemon or not. Otherwise, Log::ger::App will try some heuristics to guess whether your application is a daemon: from the value of $main::IS_DAEMON and from the presence of modules like HTTP::Daemon, Proc::Daemon, etc. * outputs hash. Specify extra outputs. Will be added to Log::ger::Output::Composite's "outputs" configuration. Example: outputs => { DirWriteRotate => { conf => {dir=>'/home/ujang/log', max_size=>10_000}, level => 'off', category_level => {Dump => 'info'}, }, }, * extra_conf Hash. Specify extra configuration, will be added to Log::ger::Output::Composite's configuration. Example: extra_conf => { category_level => {Dump => 'off'}, }, VARIABLES $DEBUG Default is false. If set to true, will show more details about how log level, etc is set. @IMPORT_ARGS Will be set with the last aguments passed to import(), for informational purposes. ENVIRONMENT LOG_GER_APP_DEBUG Used to set the default for $DEBUG. LOG_ADD_LOCATION Boolean. Default to false. If set to true, will add location to the log: [file /some/path.pm:123] LOG_ADD_STACK_TRACE Boolean. Default to false. If set to true, will add stack trace to the log: [stack ...] LOG_ADD_TIMESTAMP Boolean. Default to false. If set to true, will add timestamps to the screen log. Normally, timestamps will only be added to the file log. LOG_ADD_MEMORY_INFO Boolean. Default to false. If set to true, will add memory info to log (see %_{vmtime} pattern in Log::ger::Layout::Pattern). LOG_LEVEL String. Can be set to "off" or numeric/string log level. TRACE Bool. DEBUG Bool. VERBOSE Bool. QUIET Bool. SCREEN_LOG_LEVEL SCREEN_TRACE SCREEN_DEBUG SCREEN_VERBOSE SCREEN_QUIET FILE_LOG_LEVEL FILE_TRACE FILE_DEBUG FILE_VERBOSE FILE_QUIET SYSLOG_LOG_LEVEL SYSLOG_TRACE SYSLOG_DEBUG SYSLOG_VERBOSE SYSLOG_QUIET FAQS How do I turn off file logging? By default, file logging is on unless running as a Perl one-liner (under "perl"'s "-e"). To explicitly turn file logging off, you can set *FILE_LEVEL* environment variable to "off", for example: BEGIN { $ENV{FILE_LEVEL} //= "off" } use Log::ger::App; How do I turn off screen logging? By default, screen logging is on unless script is a daemon. To explicitly turn screen logging off, you can set *SCREEN_LEVEL* environment variable to "off", for example: BEGIN { $ENV{SCREEN_LEVEL} //= "off" } use Log::ger::App; How do I turn off syslog logging? By default, syslog logging is on if script is a daemon. To explicitly turn syslog logging off, you can set *SYSLOG_LEVEL* environment variable to "off", for example: BEGIN { $ENV{SYSLOG_LEVEL} //= "off" } use Log::ger::App; Why doesn't setting $main::Default_Log_Level work? Note that you need to set the variable's value before loading Log::ger::App, so this does not work: use Log::ger::App; our $Default_Log_Level = 'info'; this does not also: our $Default_Log_Level = 'info'; use Log::ger::App; but this does: BEGIN { our $Default_Log_Level = 'info' } use Log::ger::App; Why doesn't re-setting log level using Log::ger::Util::set_level() work? (This FAQ item is from Log::ger::Output::Composite's, slightly modified). The Log::ger::Output::Composite plugin that Log::ger::App uses sets its own levels and logs using a multilevel routine (which gets called for all levels). Re-setting log level dynamically via Log::ger::Util's "set_level" will not work as intended, which is fortunate or unfortunate depending on your need. If you want to override all levels settings with a single value, you can use "Log::ger::Output::Composite::set_level", for example: Log::ger::Util::set_level('trace'); # also set this too Log::ger::Output::Composite::set_level('trace'); This sets an internal level setting which is respected and has the highest precedence so all levels settings will use this instead. If previously you have: Log::ger::Output->set(Composite => { default_level => 'error', outputs => { File => {path=>'/foo', level=>'debug'}, Screen => {level=>'info', category_level=>{MyApp=>'warn'}}, }, category_level => { 'MyApp::SubModule1' => 'debug', }, }); then after the "Log::ger::Output::Composite::set_level('trace')", all the above per-category and per-output levels will be set to "trace". SEE ALSO Log::ger AUTHOR perlancar COPYRIGHT AND LICENSE This software is copyright (c) 2022, 2021, 2020, 2019, 2018, 2017 by perlancar . This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.