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Queue CloudWatch

A pmg/queue driver decorator that dispatches cloudwatch metrics when messages are sent through.

Example

use AWS\CloudWatch\CloudWatchClient;
use PMG\Queue\Driver;
use PMG\Queue\CloudWatch\MetricsDriver;

/** @var Driver $driver */
$driver = createAnActualDriverSomehow();

// this is the default metric namespace, change if desired.
$metricNamespace = 'PMG/Queue';
$finalDriver = new MetricsDriver($driver, CloudWatchClient::factory([
    'region' => 'us-east-1',
    'version' => 'latest',
]), $metricNamespace);

// now use $finalDriver in your consumers/producers

Metrics

All metrics have the dimensions...

  • QueueName - The name of the queue to which the metrics belong
  • MessageName - The value returned from Message::getName. When a message is not present for logging the metric, this dimension will be set to __none__.

Driver Metrics

  • DriverError - A Count metric unit fired when the wrapped driver throws a DriverError exception. This will have an ErrorClass dimension that contains the exception class name that was thrown.

Message Counts

There's a metric for each method on the driver, essentially. They all use Count as the metric unit.

  • MessageEnqueue - Fired on Driver::enqueue
  • MessageDequeue - Fired on Driver::dequeue. This is only fired when a message is returned from the wrapped Driver::dequeue.
  • MessageSuccess - Fired on Driver::ack
  • MessageFailure - Fired on Driver::fail
  • MessageRetry - Fired on Driver::retry
  • MessageRelease - Fired on Driver::release

You might use these message counts to alert on a high volume of message failures or retries.

Message Timers

The metrics driver will time dequeued jobs until they are acked, failed, or retried. These all use Milliseconds as their metric unit.

  • MessageTime - The amount of time a message took, tracked for every message regardless of how it finished.

The MessageTime metric will have an additional dimension named MessageStatus which is how the given message finished when the timer completed. This will be:

  • Success when the message was passed to Driver::ack
  • Failure when the message was passed to Driver::fail
  • Retry When the message was passed to Driver::retry
  • Release When the message was passed to Driver::release

Error Handling

First up, the wrapped driver is always called first. If an error occurs from the wrapped driver it's tracked and rethrown before any further metrics can be logged. The idea here is that driver errors invalidate any processes acting on a message anyway.

Errors from the cloudwatch client are caught and logged, however. You can pass a fourth $logger argument to MetricsDriver if you wish to see these errors, but a NullLogger is used by default.

use AWS\CloudWatch\CloudWatchClient;
use PMG\Queue\Driver;
use PMG\Queue\CloudWatch\MetricsDriver;

/** @var Driver $driver */
$driver = createAnActualDriverSomehow();

// this is the default metric namespace, change if desired.
$metricNamespace = 'PMG/Queue';
$finalDriver = new MetricsDriver($driver, CloudWatchClient::factory([
    'region' => 'us-east-1',
    'version' => 'latest',
]), $metricNamespace, $yourLoggerFromSomeplace);

// now use $finalDriver in your consumers/producers

Testing

./vendor/bin/phpunit

The tests include a set of integration tests that actually talk to CloudWatch. Be sure to have set up credentials. in order to run those tests. Otherwise you may exclude them with...

./vendor/bin/phpunit --exclude-group integration