Craft 5 Logging Example

app.php

<?php

use craft\helpers\App;

return [
    'id' => App::env('CRAFT_APP_ID') ?: 'CraftCMS',
    'components' => [
        'log' => [
            'targets' => [
                function() {
                    // @see https://craftcms.com/docs/5.x/system/logging.html#targets for filtering options
                    $target = new \craft\log\MonologTarget([
                        'name' => 'azure-blob',
                    ]);

                    $connection = 'DefaultEndpointsProtocol=https;AccountName=<name>;AccountKey=<key>';
                    $client = \MicrosoftAzure\Storage\Blob\BlobRestProxy::createBlobService($connection);
                    $handler = \Blue32a\Monolog\Handler\AzureBlobStorageHandler($client, 'container', 'append-blob.log');
                    $target->getLogger()->setHandlers([$handler]);

                    return $target;
                },
            ]
        ]
    ],
];