---
name: "Log::Contextual::WarnLogger"
section: "3pm"
platform: "linux"
package: "liblog-contextual-perl"
version: "0.009001-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Log::Contextual::WarnLogger"
---

# Log::Contextual::WarnLogger(3pm)

logger for libraries using Log::Contextual

## NAME

Log::Contextual::WarnLogger - logger for libraries using Log::Contextual

## VERSION

version 0.009001

## SYNOPSIS

```
  package My::Package;
  use Log::Contextual::WarnLogger;
  use Log::Contextual qw( :log ),
    -default_logger => Log::Contextual::WarnLogger->new({
      env_prefix => 'MY_PACKAGE',
      levels => [ qw(debug info notice warning error critical alert emergency) ],
    });
  # warns '[info] program started' if $ENV{MY_PACKAGE_TRACE} is set
  log_info { 'program started' }; # no-op because info is not in levels
  sub foo {
    # warns '[debug] entered foo' if $ENV{MY_PACKAGE_DEBUG} is set
    log_debug { 'entered foo' };
    ...
  }
```

## DESCRIPTION

This module is a simple logger made for libraries using Log::Contextual.  We recommend the use of this logger as your default logger as it is simple and useful for most users, yet users can use "set\_logger" in Log::Contextual to override your choice of logger in their own code thanks to the way Log::Contextual works.

## METHODS

### new

Arguments: `"Dict[ env_prefix => Str, levels => List ] $conf"`

```
  my $l = Log::Contextual::WarnLogger->new({ env_prefix => 'BAR' });
```

or:

```
  my $l = Log::Contextual::WarnLogger->new({
    env_prefix => 'BAR',
    levels => [ 'level1', 'level2' ],
  });
```

Creates a new logger object where `"env_prefix"` defines what the prefix is for the environment variables that will be checked for the log levels.

The log levels may be customized, but if not defined, these are used:

- trace

  - debug

  - info

  - warn

  - error

  - fatal

  For example, if `"env_prefix"` is set to `"FREWS_PACKAGE"` the following environment variables will be used:

```
  FREWS_PACKAGE_UPTO
  FREWS_PACKAGE_TRACE
  FREWS_PACKAGE_DEBUG
  FREWS_PACKAGE_INFO
  FREWS_PACKAGE_WARN
  FREWS_PACKAGE_ERROR
  FREWS_PACKAGE_FATAL
```

Note that `"UPTO"` is a convenience variable.  If you set `"FOO_UPTO=TRACE"` it will enable all log levels.  Similarly, if you set it to `"FATAL"` only fatal will be enabled.

### $level

Arguments: `@anything`

All of the following six methods work the same.  The basic pattern is:

```
  sub $level {
    my $self = shift;
    warn "[$level] " . join qq{\n}, @_;
      if $self->is_$level;
  }
```

*trace*

```
  $l->trace( 'entered method foo with args ' join q{,}, @args );
```

*debug*

```
  $l->debug( 'entered method foo' );
```

*info*

```
  $l->info( 'started process foo' );
```

*warn*

```
  $l->warn( 'possible misconfiguration at line 10' );
```

*error*

```
  $l->error( 'non-numeric user input!' );
```

*fatal*

```
  $l->fatal( '1 is never equal to 0!' );
```

If different levels are specified, appropriate functions named for your custom levels work as you expect.

**Note:** `"fatal"` does not call `"die"` for you, see "EXCEPTIONS AND ERROR HANDLING" in Log::Contextual

### is\_$level

All of the following six functions just return true if their respective environment variable is enabled.

*is\_trace*

```
  say 'tracing' if $l->is_trace;
```

*is\_debug*

```
  say 'debuging' if $l->is_debug;
```

*is\_info*

```
  say q{info'ing} if $l->is_info;
```

*is\_warn*

```
  say 'warning' if $l->is_warn;
```

*is\_error*

```
  say 'erroring' if $l->is_error;
```

*is\_fatal*

```
  say q{fatal'ing} if $l->is_fatal;
```

If different levels are specified, appropriate is\_$level functions work as you would expect.

## BUGS

Please report any bugs or feature requests on the bugtracker website \<https://github.com/haarg/Log-Contextual/issues\>

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.

## AUTHOR

Arthur Axel "fREW" Schmidt \<frioux+cpan@gmail.com\>

## COPYRIGHT AND LICENSE

This software is copyright (c) 2024 by Arthur Axel "fREW" Schmidt.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.