webapp1

Example usage of aiohttp_prometheus

See src for the application code.

Building Docker image

The Python 3 based Dockerfile uses an Alpine Linux base image and expects the application source code to be volume mounted at /application when run.

To build the image:

$ docker build -t amitsaha/aiohttp_app1 -f Dockerfile.py3 .

Running the application

We can just run the web application as follows:

$ docker run  -ti -p 8080:8080 -v `pwd`/src:/application amitsaha/aiohttp_app1

Bringing up the web application, along with prometheus

The docker-compse.yml brings up the webapp service which is our web application using the image amitsaha/flask_app we built above. The docker-compose-infra.yml file brings up the prometheus service and also starts the grafana service which is available on port 3000. The config directory contains a prometheus.yml file which sets up the targets for prometheus to scrape. The scrape configuration looks as follows:

# A scrape configuration containing exactly one endpoint to scrape:
# Here it's Prometheus itself.
scrape_configs:
  # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
  - job_name: 'prometheus'

    # Override the global default and scrape targets from this job every 5 seconds.
    scrape_interval: 5s

    # metrics_path defaults to '/metrics'
    # scheme defaults to 'http'.

    static_configs:
         - targets: ['localhost:9090']
  - job_name: 'webapp'

    # Override the global default and scrape targets from this job every 5 seconds.
    scrape_interval: 5s

    # metrics_path defaults to '/metrics'
    # scheme defaults to 'http'.
    static_configs:
        - targets: ['webapp:8080']

Prometheus scrapes itself, which is the first target above. The second target is the our web application on port 5000. Since these services are running via docker-compose, webapp automatically resolves to the IP of the webapp container.

To bring up all the services:

$ docker-compose -f docker-compose.yml -f docker-compose-infra.yml up