NAME Log::Any::App - An easy way to use Log::Any in applications VERSION version 0.28 SYNOPSIS # in your script/application use Log::Any::App qw($log); # or, in command line % perl -MLog::Any::App -MModuleThatUsesLogAny -e ... DESCRIPTION Log::Any makes life easy for module authors. All you need to do is: use Log::Any qw($log); and you're off producing logs with $log->debug(), $log->info(), $log->error(), etc. That's it. The task of consuming logs (setting up each output, deciding which messages gets to which output, etc) rests on the shoulder of module users. Life is not equally easy for the module users (or application authors) though. The typical incantation to consume logs (assuming we use the Log::Log4perl adapter) is: use Log::Any qw($log); use Log::Any::Adapter; use Log::Log4perl; my $log4perl_config = ' some long multiline config...'; Log::Log4perl->init(\$log4perl_config); Log::Any::Adapter->set('Log4perl'); Frankly, I couldn't possibly remember all that (especially the details of Log4perl configuration), hence Log::Any::App. The goal of Log::Any::App is to make life equally easy for log consumers. All you need to do is: use Log::Any::App qw($log); or, from the command line: perl -MLog::Any::App='$log' -MModuleThatUsesLogAny -e ... and you can display the logs in screen, file(s), syslog, etc. You can also log using $log->debug(), etc as usual. Most of the time you don't need to configure anything as Log::Any::App will construct the most appropriate default Log4perl config for your application. I mostly use Log::Any;:App in oneliners and simple to medium scripts whenever I have to use Log::Any-using modules (for example: Data::Schema and Config::Tree). USING AND EXAMPLES Using Log::Any::App is very easy. Most of the time you just need to do this from command line: % perl -MLog::Any::App -MModuleThatUsesLogAny -e ... or from a script: use ModuleThatUsesLogAny; use Log::Any::App '$log'; This will send logs to screen as well as file (~/$SCRIPT_NAME.log or /var/log/$SCRIPT_NAME.log if running as root, command-line scripts by default do not log to file) with the default level of 'warn'. This means $log->error("foo") will display, while $log->info("bar") will not. The 'use Log::Any::App' statement can be issued before or after the modules that use Log::Any, it doesn't matter. Logging will be initialized in the INIT phase. Changing logging level Changing logging level can be done from the script or outside the script. From the script: use Log::Any::App '$log', -level => 'debug'; but oftentimes what you want is changing level without modifying the script itself. So leave it to Log::Any::App to determine level: use Log::Any::App '$log'; and then you can use environment variable: TRACE=1 script.pl; # setting level to trace DEBUG=1 script.pl; # setting level to debug VERBOSE=1 script.pl; # setting level to info QUIET=1 script.pl; # setting level to error LOG_LEVEL=... script.pl; # setting a specific log level or command-line options: script.pl --trace script.pl --debug script.pl --verbose script.pl --quiet script.pl --log_level=debug; # '--log-level debug' will also do Log::Any::App won't interfere with command-line processing modules like Getopt::Long or App::Options. Changing default level The default log level is 'warn'. You can change this using: use Log::Any::App '$log'; BEGIN { our $Log_Level = 'info' } and then you can still use environment or command-line options to override the setting. Changing per-output level Logging level can also be specified on a per-output level. For example, if you want your script to be chatty on the screen but still logs to file at the default 'warn' level: SCREEN_VERBOSE=1 script.pl SCREEN_DEBUG=1 script.pl SCREEN_TRACE=1 script.pl SCREEN_LOG_LEVEL=info script.pl script.pl --screen_verbose script.pl --screen-debug script.pl --screen-trace=1 script.pl --screen-log-level=info # and so on Similarly, to set only file level, use FILE_VERBOSE, FILE_LOG_LEVEL, --file-trace, etc. Setting default per-output level As with setting default level, you can also set default level on a per-output basis: use Log::Any::App '$log'; BEGIN { our $Screen_Log_Level = 'off'; our $File_Quiet = 1; # setting level to 'error' # and so on } If a per-output level is not specifed, it will default to the general log level. Enabling/disabling output To disable a certain output, you can do this: use Log::Any::App '$log', -file => 0; or: use Log::Any::App '$log', -screen => {level=>'off'}; and this won't allow it to be reenabled from outside the script. However if you do this: use Log::Any::App; BEGIN { our $Screen_Log_Level = 'off' } then you will be able to override the screen log level using environment or command-line options (SCREEN_DEBUG, --screen-verbose, and so on). Changing log file name/location By default Log::Any::App will use ~/$NAME.log (or /var/log/$NAME.log if script is running as root), where $NAME is taken from $0. But this can be changed using: use Log::Any::App '$log', -name => 'myprog'; Or, using custom path: use Log::Any::App '$log', -file => '/path/to/file'; Changing other output parameters Each output argument can accept a hashref to specify various options. For example: use Log::Any::App '$log', -screen => {color=>0}, # never use color -file => {path=>'/var/log/foo', rotate=>'10M', histories=>10, }, For all the available options of each output, see the init() function. Logging to syslog Logging to syslog is enabled by default if your script looks like a daemon, e.g.: use Net::Daemon; # this indicate your program is a daemon use Log::Any::App; # syslog logging will be turned on by default but if you are certain you don't want syslog logging: use Log::Any::App -syslog => 0; Logging to directory This is done using Log::Dispatch::Dir where each log message is logged to a different file in a specified directory. By default logging to dir is not turned on, to turn it on: use Log::Any::App '$log', -dir => 1; For all the available options of directory output, see the init() function. Multiple outputs Each output argument can accept an arrayref to specify more than one output, example: use Log::Any::App '$log', -file => ["/var/log/log1", {path=>"/var/log/debug_foo", category=>'Foo', level=>'debug'}]; Changing level of a certain module Suppose you want to shut up Foo, Bar::Baz, and Qux's logging because they are too noisy: use Log::Any::App '$log', -category_level => { Foo => 'off', 'Bar::Baz' => 'off', Qux => 'off' }; or (same thing): use Log::Any::App '$log', -category_alias => { -noisy => [qw/Foo Bar::Baz Qux/] }, -category_level => { -noisy => 'off' }; You can even specify this on a per-output basis. Suppose you only want to shut up the noisy modules on the screen, but not on the file: use Log::Any::App '$log', -category_alias => { -noisy => [qw/Foo Bar::Baz Qux/] }, -screen => { category_level => { -noisy => 'off' } }; Or perhaps, you want to shut up the noisy modules everywhere, except on the screen: use Log::Any::App '$log', -category_alias => { -noisy => [qw/Foo Bar::Baz Qux/] }, -category_level => { -noisy => 'off' }, -syslog => 1, -file => "/var/log/foo", -screen => { category_level => {} }; # do not do per-category level Preventing logging level to be changed from outside the script Sometimes, for security/audit reasons, you don't want to allow script caller to change logging level. To do so, just specify the 'level' option in the script during 'use' statement: Debugging To see the Log4perl configuration that is generated by Log::Any::App and how it came to be, set environment LOGANYAPP_DEBUG to true. FUNCTIONS init(\@args) This is the actual function that implements the setup and configuration of logging. You normally need not call this function explicitly (but see below), it will be called once in an INIT block. In fact, when you do: use Log::Any::App 'a', 'b', 'c'; it is actually passed as: init(['a', 'b', 'c']); You will need to call init() manually if you require Log::Any::App at runtime, in which case it is too late to run INIT block. If you want to run Log::Any::App in runtime phase, do this: require Log::Any::App; Log::Any::App::init(['a', 'b', 'c']); Arguments to init can be one or more of: -init => BOOL Whether to call Log::Log4perl->init() after setting up the Log4perl configuration. Default is true. You can set this to false, and you can initialize Log4perl yourself (but then there's not much point in using this module, right?) -name => STRING Change the program name. Default is taken from $0. -category_alias => {ALIAS=>CATEGORY, ...} Create category aliases so the ALIAS can be used in place of real categories in each output's category specification. For example, instead of doing this: init( -file => [category=>[qw/Foo Bar Baz/], ...], -screen => [category=>[qw/Foo Bar Baz/]], ); you can do this instead: init( -category_alias => {_fbb => [qw/Foo Bar Baz/]}, -file => [category=>'-fbb', ...], -screen => [category=>'-fbb', ...], ); -category_level => {CATEGORY=>LEVEL, ...} Specify per-category level. Categories not mentioned on this will use the general level (-level). This can be used to increase or decrease logging on certain categories/modules. -level => 'trace'|'debug'|'info'|'warn'|'error'|'fatal'|'off' Specify log level for all outputs. Each output can override this value. The default log level is determined as follow: If App::Options is present, these keys are checked in %App::options: log_level, trace (if true then level is "trace"), debug (if true then level is "debug"), verbose (if true then level is "info"), quiet (if true then level is "error"). Otherwise, it will try to scrape @ARGV for the presence of --log-level, --trace, --debug, --verbose, or --quiet (this usually works because Log::Any::App does this in the INIT phase, before you call Getopt::Long's GetOptions() or the like). Otherwise, it will look for environment variables: LOG_LEVEL, QUIET. VERBOSE, DEBUG, TRACE. Otherwise, it will try to search for package variables in the "main" namespace with names like $Log_Level or $LOG_LEVEL or $log_level, $Quiet or $QUIET or $quiet, $Verbose or $VERBOSE or $verbose, $Trace or $TRACE or $trace, $Debug or $DEBUG or $debug. If everything fails, it defaults to 'warn'. -file => 0 | 1|yes|true | PATH | {opts} | [{opts}, ...] Specify output to one or more files, using Log::Dispatch::FileRotate. If the argument is a false boolean value, file logging will be turned off. If argument is a true value that matches /^(1|yes|true)$/i, file logging will be turned on with default path, etc. If the argument is another scalar value then it is assumed to be a path. If the argument is a hashref, then the keys of the hashref must be one of: "level", "path", "max_size" (maximum size before rotating, in bytes, 0 means unlimited or never rotate), "histories" (number of old files to keep, excluding the current file), "date_pattern" (will be passed to DatePattern argument in FileRotate's constructor), "tz" (will be passed to TZ argument in FileRotate's constructor), "category" (a string of ref to array of strings), "category_level" (a hashref, similar to -category_level), "pattern_style" (see "PATTERN STYLES"), "pattern" (Log4perl pattern). If the argument is an arrayref, it is assumed to be specifying multiple files, with each element of the array as a hashref. How Log::Any::App determines defaults for file logging: If program is a one-liner script specified using "perl -e", the default is no file logging. Otherwise file logging is turned on. If the program runs as root, the default path is "/var/log/$NAME.log", where $NAME is taken from $0 (or "-name"). Otherwise the default path is ~/$NAME.log. Intermediate directories will be made with File::Path. If specified "path" ends with a slash (e.g. "/my/log/"), it is assumed to be a directory and the final file path is directory appended with $NAME.log. Default rotating behaviour is no rotate (max_size = 0). Default level for file is the same as the global level set by -level. But App::options, command line, environment, and package variables in main are also searched first (for FILE_LOG_LEVEL, FILE_TRACE, FILE_DEBUG, FILE_VERBOSE, FILE_QUIET, and the similars). -dir => 0 | 1|yes|true | PATH | {opts} | [{opts}, ...] Log messages using Log::Dispatch::Dir. Each message is logged into separate files in the directory. Useful for dumping content (e.g. HTML, network dumps, or temporary results). If the argument is a false boolean value, dir logging will be turned off. If argument is a true value that matches /^(1|yes|true)$/i, dir logging will be turned on with defaults path, etc. If the argument is another scalar value then it is assumed to be a directory path. If the argument is a hashref, then the keys of the hashref must be one of: "level", "path", "max_size" (maximum total size of files before deleting older files, in bytes, 0 means unlimited), "max_age" (maximum age of files to keep, in seconds, undef means unlimited). "histories" (number of old files to keep, excluding the current file), "category", "category_level" (a hashref, similar to -category_level), "pattern_style" (see "PATTERN STYLES"), "pattern" (Log4perl pattern), "filename_pattern" (pattern of file name). If the argument is an arrayref, it is assumed to be specifying multiple directories, with each element of the array as a hashref. How Log::Any::App determines defaults for dir logging: Directory logging is by default turned off. You have to explicitly turn it on. If the program runs as root, the default path is "/var/log/$NAME/", where $NAME is taken from $0. Otherwise the default path is ~/log/$NAME/. Intermediate directories will be created with File::Path. Program name can be changed using "-name". Default rotating parameters are: histories=1000, max_size=0, max_age=undef. Default level for dir logging is the same as the global level set by -level. But App::options, command line, environment, and package variables in main are also searched first (for DIR_LOG_LEVEL, DIR_TRACE, DIR_DEBUG, DIR_VERBOSE, DIR_QUIET, and the similars). -screen => 0 | 1|yes|true | {opts} Log messages using Log::Log4perl::Appender::ScreenColoredLevels. If the argument is a false boolean value, screen logging will be turned off. If argument is a true value that matches /^(1|yes|true)$/i, screen logging will be turned on with default settings. If the argument is a hashref, then the keys of the hashref must be one of: "color" (default is true, set to 0 to turn off color), "stderr" (default is true, set to 0 to log to stdout instead), "level", "category", "category_level" (a hashref, similar to -category_level), "pattern_style" (see "PATTERN STYLE"), "pattern" (Log4perl string pattern). How Log::Any::App determines defaults for screen logging: Screen logging is turned on by default. Default level for screen logging is the same as the global level set by -level. But App::options, command line, environment, and package variables in main are also searched first (for SCREEN_LOG_LEVEL, SCREEN_TRACE, SCREEN_DEBUG, SCREEN_VERBOSE, SCREEN_QUIET, and the similars). Color can also be turned on/off using environment variable COLOR (if color argument is not set). -syslog => 0 | 1|yes|true | {opts} Log messages using Log::Dispatch::Syslog. If the argument is a false boolean value, syslog logging will be turned off. If argument is a true value that matches /^(1|yes|true)$/i, syslog logging will be turned on with default level, ident, etc. If the argument is a hashref, then the keys of the hashref must be one of: "level", "ident", "facility", "category", "category_level" (a hashref, similar to -category_level), "pattern_style" (see "PATTERN STYLES"), "pattern" (Log4perl pattern). How Log::Any::App determines defaults for syslog logging: If a program is a daemon (determined by detecting modules like Net::Server or Proc::PID::File) then syslog logging is turned on by default and facility is set to "daemon", otherwise the default is off. Ident is program's name by default ($0, or "-name"). Default level for syslog logging is the same as the global level set by -level. But App::options, command line, environment, and package variables in main are also searched first (for SYSLOG_LOG_LEVEL, SYSLOG_TRACE, SYSLOG_DEBUG, SYSLOG_VERBOSE, SYSLOG_QUIET, and the similars). -dump => BOOL If set to true then Log::Any::App will dump the generated Log4perl config. Useful for debugging the logging. PATTERN STYLES Log::Any::App provides some styles for Log4perl patterns. You can specify "pattern_style" instead of directly specifying "pattern". example: use Log::Any::App -screen => {pattern_style=>"script_long"}; Name Description Example output ---- ----------- -------------- plain The message, the whole message, Message and nothing but the message. Used by dir logging. Equivalent to pattern: '%m' script_short For scripts that run for a short [234] Message time (a few seconds). Shows just the number of milliseconds. This is the default for screen. Equivalent to pattern: '[%r] %m%n' script_long Scripts that will run for a [2010-04-22 18:01:02] Message while (more than a few seconds). Shows date/time. Equivalent to pattern: '[%d] %m%n' daemon For typical daemons. Shows PID [pid 1234] [2010-04-22 18:01:02] Message and date/time. This is the default for file logging. Equivalent to pattern: '[pid %P] [%d] %m%n' syslog Style suitable for syslog [pid 1234] Message logging. Equivalent to pattern: '[pid %p] %m' If you have a favorite pattern style, please do share them. FAQ What's the benefit of using Log::Any::App? You get all the benefits of Log::Any, as what Log::Any::App does is just wrap Log::Any and Log::Log4perl with some nice defaults. It provides you with an easy way to consume Log::Any logs and customize level/some other options via various ways. You still produce logs with Log::Any so later should portions of your application code get refactored into modules, you don't need to change the logging part. And if your application becomes more complex and Log::Any::App doesn't suffice your custom logging needs anymore, you can just replace 'use Log::Any::App' line with something more adequate. And what's the benefit of using Log::Any? This is better described in the Log::Any documentation itself, but in short: Log::Any frees your module users to use whatever logging framework they want. It increases the reusability of your modules. Do I need Log::Any::App if I am writing modules? No, if you write modules just use Log::Any. Why use Log4perl? Log::Any::App uses the Log4perl adapter to display the logs because it is mature, flexible, featureful. The other alternative adapter is Log::Dispatch, but you can use Log::Dispatch::* output modules in Log4perl and (currently) not vice versa. Other adapters might be considered in the future, for now I'm fairly satisfied with Log4perl. Note that producing logs are still done with Log::Any as usual and not tied to Log4perl in any way. How do I create extra logger objects? The usual way as with Log::Any: my $other_log = Log::Any->get_logger(category => $category); My needs are not met by the simple configuration system of Log::Any::App! You can use Log4perl adapter directly and write your own Log4perl configuration (or even other adapters). Log::Any::App is meant for quick and simple logging output needs anyway (but do tell me if your logging output needs are reasonably simple and should be supported by Log::Any::App). BUGS/TODOS Need to provide appropriate defaults for Windows/other OS. Probably: SCREEN0_DEBUG, --file1-log-level, etc. SEE ALSO Log::Any Log::Log4perl AUTHOR Steven Haryanto COPYRIGHT AND LICENSE This software is copyright (c) 2011 by Steven Haryanto. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.