Logging

As logging is a mature and well-established function, the OpenTelemetry approach is a little different for this signal.

The OpenTelemetry logger is not designed to be used directly, but rather to be integrated into existing logging libraries as a handler. In this way, you can choose to have some or all of your application logs sent to an OpenTelemetry-compatible service such as the collector.

Setup

You get a logger from a LoggerProvider. Log records get emitted via an EventLogger:

<?php
$loggerProvider = new LoggerProvider(
    new SimpleLogsProcessor(
        new ConsoleExporter()
    )
);
$logger = $loggerProvider->getLogger('demo', '1.0', 'http://schema.url', [/*attributes*/]);
$eventLogger = new EventLogger($logger, 'my-domain');

Once configured, a LogRecord can be created and sent via the event logger’s logEventmethod:

$record = (new LogRecord('hello world'))
    ->setSeverityText('INFO')
    ->setAttributes([/*attributes*/]);

$eventLogger->logEvent('foo', $record);

Integrations for 3rd-party logging libraries

Monolog

You can use the monolog handler to send monolog logs to an OpenTelemetry-capable receiver:

composer require open-telemetry/opentelemetry-logger-monolog

$loggerProvider = new LoggerProvider(/*params*/);

$handler = new \OpenTelemetry\Contrib\Logs\Monolog\Handler(
    $loggerProvider,
    \Psr\Log\LogLevel::ERROR,
);
$logger = new \Monolog\Logger('example', [$handler]);

$logger->info('hello, world');
$logger->error('oh no', [
    'foo' => 'bar',
    'exception' => new \Exception('something went wrong'),
]);

$loggerProvider->shutdown();

Last modified May 5, 2023: php documentation updates (#2654) (614c20f)