Symfony Bundle for exporting statistics in Prometheus format

While working on different micro (and not so) services written using symfony, I faced the need to export metrics for Prometheus each time. At first, we simply copied the same code between projects, but when there were more than three of them, I decided that I could not continue like this (I won’t bore you with explanations why this is inconvenient; I think everyone understands this himself).

It was decided to allocate all this household into a separate bundle: ArtprimaPrometheusMetricsBundle .

Having chosen common metrics for all applications, I started writing a bundle. The Jimdo / prometheus_client_php client was selected as the library, which allows using the following statistics as storage: Redis (via ext-redis), APCu (via ext-apcu) and InMemory (in PHP memory, only for the duration of the process). I’ll make a reservation right away that in practice we only have APCu (I needed to have per-instance statistics, whereas in Redis they will be shared, unless I deploy Redis to each instance). And InMemory in general, IMHO, can only be used for tests.
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With Jimdo / prometheus_client_php, a problem immediately arose - there was no release for a long time, and the necessary features (APCu) in the form of a release are not available. In this regard, I made my fork client , which differs only in the fact that there is a necessary tag for the formation of the release.

The second problem I encountered is recipes for symfony. In the official repo, you can not even meddle, and in the community for a very long time, there are pull-requests (at the moment the bundle is almost a month, and the PR recipe is still under consideration). In this connection, during installation, you need to carry out the necessary settings manually. The benefit of them is not so much.

Actually, you need to configure the main configuration:

#config/packages/prometheus-metrics.yaml artprima_prometheus_metrics: # namespace     prometheus namespace: myapp #    type: in_memory #  : in_memory, apcu, redis #   ,         ignored_routes: [some_route_name, another_route_name] #     "redis" (   ) redis: host: 127.0.0.1 port: 6379 timeout: 0.1 read_timeout: 10 persistent_connections: false password: ~ 

Then you need to export the route:

 #    /metrics/prometheus app_metrics: resource: '@ArtprimaPrometheusMetricsBundle/Resources/config/routing.xml' 

Alternatively, you can configure the route manually:

 app_metrics: path: /mypath/mymetrics controller: Artprima\PrometheusMetricsBundle\Controller\MetricsController::prometheus 

Is done. As a result, your metrics will be available at http [s]: // your_host / metrics / prometheus (if you have not changed the path). And after some time you get something like this:


Naturally, the basic metrics may not be enough soon, so you always have the opportunity to write your own metrics generator (in addition to the existing one) and export it like this:

 # config/services.yaml App\Metrics\MyMetricsGenerator: tags: - { name: prometheus_metrics_bundle.metrics_generator } 

In this case, your generator must implement the Artprima\PrometheusMetricsBundle\Metrics\MetricsGeneratorInterface . You can see what a generator might look like in Artprima\PrometheusMetricsBundle\Metrics\AppMetrics . The main thing you need to know here is that the collectRequest method collectRequest called on the kernel.request event, and the collectResponse method is collectResponse on the kernel.terminate event.

I accept criticism on the merits. Both in the form of tips and PR :-)

PS Warning comments that we invented the bicycle: yes, I know that there are alternatives. And, most likely, they are certainly better. In particular, one of them is TweedeGolfPrometheusBundle . Unfortunately, I don’t remember why we didn’t choose this solution, but a little more than six months ago we tried it and refused it. One way or another, I think that having a choice is always good, so our bundle was published in OpenSource.