---
name: "Mojo::Log"
section: "3pm"
platform: "linux"
package: "libmojolicious-perl"
version: "9.39+dfsg-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Mojo::Log"
---

# Mojo::Log(3pm)

Simple logger

## NAME

Mojo::Log - Simple logger

## SYNOPSIS

```
  use Mojo::Log;
  # Log to STDERR
  my $log = Mojo::Log->new;
  # Customize log file location and minimum log level
  my $log = Mojo::Log->new(path => '/var/log/mojo.log', level => 'warn');
  # Log messages
  $log->trace('Doing stuff');
  $log->debug('Not sure what is happening here');
  $log->info('FYI: it happened again');
  $log->warn('This might be a problem');
  $log->error('Garden variety error');
  $log->fatal('Boom');
```

## DESCRIPTION

Mojo::Log is a simple logger for Mojo projects.

## EVENTS

Mojo::Log inherits all events from Mojo::EventEmitter and can emit the following new ones.

### message

```
  $log->on(message => sub ($log, $level, @lines) {...});
```

Emitted when a new message gets logged.

```
  $log->on(message => sub ($log, $level, @lines) { say "$level: ", @lines });
```

## ATTRIBUTES

Mojo::Log implements the following attributes.

### color

```
  my $bool = $log->color;
  $log     = $log->color($bool);
```

Colorize log messages with the levels `"warn"`, `"error"` and `"fatal"` using Term::ANSIColor, defaults to the value of the `"MOJO_LOG_COLOR"` environment variables. Note that this attribute is **EXPERIMENTAL** and might change without warning!

### format

```
  my $cb = $log->format;
  $log   = $log->format(sub {...});
```

A callback for formatting log messages.

```
  $log->format(sub ($time, $level, @lines) { "[2018-11-08 14:20:13.77168] [28320] [info] I ♥ Mojolicious\n" });
```

### handle

```
  my $handle = $log->handle;
  $log       = $log->handle(IO::Handle->new);
```

Log filehandle used by default "message" event, defaults to opening "path" or `"STDERR"`.

### history

```
  my $history = $log->history;
  $log        = $log->history([[time, 'debug', 'That went wrong']]);
```

The last few logged messages.

### level

```
  my $level = $log->level;
  $log      = $log->level('debug');
```

Active log level, defaults to `"trace"`. Available log levels are `"trace"`, `"debug"`, `"info"`, `"warn"`, `"error"` and `"fatal"`, in that order.

### max\_history\_size

```
  my $size = $log->max_history_size;
  $log     = $log->max_history_size(5);
```

Maximum number of logged messages to store in "history", defaults to `10`.

### path

```
  my $path = $log->path
  $log     = $log->path('/var/log/mojo.log');
```

Log file path used by "handle".

### short

```
  my $bool = $log->short;
  $log     = $log->short($bool);
```

Generate short log messages without a timestamp but with journald log level prefix, suitable for systemd environments, defaults to the value of the `"MOJO_LOG_SHORT"` environment variables.

## METHODS

Mojo::Log inherits all methods from Mojo::EventEmitter and implements the following new ones.

### append

```
  $log->append("[2018-11-08 14:20:13.77168] [28320] [info] I ♥ Mojolicious\n");
```

Append message to "handle".

### capture

```
  my $messages = $log->capture;
  my $messages = $log->capture('debug');
```

Capture log messages for as long as the returned object exists, useful for testing log messages.

```
  # Test your log messages
  my $messages = $log->capture('trace');
  $log->fatal('Something very bad happened');
  $log->trace('Just some debug information');
  like $messages, qr/Something very bad happened/, 'logs contain fatal message';
  like $messages->[-1], qr/Just some debug information/, 'trace message was last';
  undef $messages;
```

### context

```
  my $new = $log->context('[extra]', '[information]');
```

Construct a new child Mojo::Log object that will include context information with every log message.

```
  # Log with context
  my $log = Mojo::Log->new;
  my $context = $log->context('[17a60115]');
  $context->debug('This is a log message with context information');
  $context->info('And another');
```

### debug

```
  $log = $log->debug('You screwed up, but that is ok');
  $log = $log->debug('All', 'cool');
  $log = $log->debug(sub {...});
```

Emit "message" event and log `"debug"` message.

### error

```
  $log = $log->error('You really screwed up this time');
  $log = $log->error('Wow', 'seriously');
  $log = $log->error(sub {...});
```

Emit "message" event and log `"error"` message.

### fatal

```
  $log = $log->fatal('Its over...');
  $log = $log->fatal('Bye', 'bye');
  $log = $log->fatal(sub {...});
```

Emit "message" event and log `"fatal"` message.

### info

```
  $log = $log->info('You are bad, but you prolly know already');
  $log = $log->info('Ok', 'then');
  $log = $log->info(sub {...});
```

Emit "message" event and log `"info"` message.

### is\_level

```
  my $bool = $log->is_level('debug');
```

Check active log "level".

```
  # True
  $log->level('debug')->is_level('debug');
  $log->level('debug')->is_level('info');
  # False
  $log->level('info')->is_level('debug');
  $log->level('fatal')->is_level('warn');
```

### new

```
  my $log = Mojo::Log->new;
  my $log = Mojo::Log->new(level => 'warn');
  my $log = Mojo::Log->new({level => 'warn'});
```

Construct a new Mojo::Log object and subscribe to "message" event with default logger.

### trace

```
  $log = $log->trace('Whatever');
  $log = $log->trace('Who', 'cares');
  $log = $log->trace(sub {...});
```

Emit "message" event and log `"trace"` message.

### warn

```
  $log = $log->warn('Dont do that Dave...');
  $log = $log->warn('No', 'really');
  $log = $log->warn(sub {...});
```

Emit "message" event and log `"warn"` message.

## SEE ALSO

Mojolicious, Mojolicious::Guides, \<https://mojolicious.org\>.