How to group log files by date using dot-log

Posted by Merlin on April 26, 2021 | No Comments

As described in this article, dot-log is a powerful tool for logging messages in your application. It’s power stays in the fact that it can be implemented in a few easy steps and that it’s highly customizable.

With a little help from PHP’s date function, Version 3.1.1 takes this one step further, though. It adds the ability to use datetime formatter strings right in the stream option of your log writer. It also fixes an issue where caching dot-log configs caused logs to be written to the same file, instead of being grouped by date.

Prerequisites

You will need dot-log installed and configured inside your application. If it’s not installed, you can install it by following the steps described here. Else, make sure you’re using the latest version of dot-log by running composer update dotkernel/dot-log.

As always, we strongly suggest you to keep your packages updated. Allthough, if your application logs messages in a single file with a static name (eg: log/dk.log), you can skip the rest of this article – logging will work as before.

Configuring the logger with DotKernel

Your application should already have a config/autoload/error-handling.global.php file, similar to this:

<?php

return [
    'dot-errorhandler' => [
        'loggerEnabled' => true,
        'logger' => 'dot-log.default_logger'
    ],
    'dot_log' => [
        'loggers' => [
            'default_logger' => [
                'writers' => [
                    'FileWriter' => [
                        'name' => 'stream',
                        'priority' => \Laminas\Log\Logger::ALERT,
                        'options' => [
                            'stream' => sprintf('%s/../../log/error-log-%s.log', __DIR__, date('Y-m-d')),
                            // explicitly log all messages
                            'filters' => [
                                'allMessages' => [
                                    'name' => 'priority',
                                    'options' => [
                                        'operator' => '>=',
                                        'priority' => \Laminas\Log\Logger::EMERG,
                                    ],
                                ],
                            ],
                            'formatter' => [
                                'name' => \Laminas\Log\Formatter\Json::class,
                            ],
                        ],
                    ],
                ],
            ],
        ],
    ],
];

Inside that file, locate every instance of your log writers by navigating to: dot_log->loggers->default_logger->writers. For each writer, you’ll find a stream option containing the path to your log file. If your stream config looks like this:

'stream' => sprintf('%s/../../log/error-log-%s.log', __DIR__, date('Y-m-d'))

replace it with:

'stream' => __DIR__ . '/../../log/error-log-{Y}-{m}-{d}.log'

The last step is to clear config cache using the command:

php bin/clear-config-cache.php

If the path to your log files contains other date format specifiers, make sure you adapt it accordingly. A complete list of the specifiers can be found here.

Configuring the logger without DotKernel

Locate dot-log configs in your application (probably /config/autoload/log.global.php). They should look similar to this:

<?php

return [
    'dot_log' => [
        'loggers' => [
            'my_logger' => [
                'writers' => [
                    'FileWriter' => [
                        'name' => 'FileWriter',
                        'priority' => \Laminas\Log\Logger::ALERT,
                        'options' => [
                            'stream' => __DIR__ . '/../../log/dk.log',
                            'filters' => [
                                'allMessages' => [
                                    'name' => 'priority',
                                    'options' => [
                                        'operator' => '>=', 
                                        'priority' => \Laminas\Log\Logger::EMERG,
                                    ]
                                ],
                            ],
                        ],
                    ],
                    // Only warnings
                    'OnlyWarningsWriter' => [
                        'name' => 'stream',
                        'priority' => \Laminas\Log\Logger::ALERT,
                        'options' => [
                            'stream' => __DIR__ . '/../../log/warnings_only.log',
                            'filters' => [
                                'warningOnly' => [
                                    'name' => 'priority',
                                    'options' => [
                                        'operator' => '==',
                                        'priority' => \Laminas\Log\Logger::WARN,
                                    ],
                                ],
                            ],
                        ],
                    ],
                    // Warnings and more important messages
                    'WarningOrHigherWriter' => [
                        'name' => 'stream',
                        'priority' => \Laminas\Log\Logger::ALERT,
                        'options' => [
                            'stream' => __DIR__ . '/../../log/important_messages.log',
                            'filters' => [
                                'importantMessages' => [
                                    'name' => 'priority',
                                    'options' => [
                                        // note, the smaller the priority, the more important is the message
                                        // 0 - emergency, 1 - alert, 2- error, 3 - warn. .etc
                                        'operator' => '<=',
                                        'priority' => \Laminas\Log\Logger::WARN,
                                    ],
                                ],
                            ],
                        ],
                    ],
                ],
            ],
        ],
    ],
];

Inside that file, locate every instance of your log writers by navigating to: dot_log->loggers->my_logger->writers. For each writer, you’ll find a stream option containing the path to your log file. If your stream config looks like this:

'stream' => sprintf('%s/../../log/dk-%s.log', __DIR__, date('Y-m-d'))

replace it with:

'stream' => __DIR__ . '/../../log/error-log-{Y}-{m}-{d}.log',

If the path to your log files contains other date format specifiers, make sure you adapt it accordingly. A complete list of the specifiers can be found here.

Make sure you clear your application’s config before usage.