Docker Compose Services and Execution

- **Prometheus service**: This service runs the Prometheus server in a container. It uses the official Prometheus image `prom/prometheus:v2.55.0`. It exposes the Prometheus server on port `9090` and connects to the `go-network` network. You have also mounted the `prometheus.yml` file from the `Docker` directory which is present in the root directory of your project. The `prometheus.yml` file contains the Prometheus configuration to scrape the metrics from the Golang application. This is how you connect the Prometheus server to the Golang application. ```yaml global: scrape_interval: 10s evaluation_interval: 10s scrape_configs: - job_name: myapp static_configs: - targets: ["api:8000"] ``` In the `prometheus.yml` file, you have defined a job named `myapp` to scrape the metrics from the Golang application. The `targets` field specifies the target to scrape the metrics from. In this case, the target is the Golang application running on port `8000`. The `api` is the service name of the Golang application in the Docker Compose file. The Prometheus server will scrape the metrics from the Golang application every 10 seconds. - **Grafana service**: This service runs the Grafana server in a container. It uses the official Grafana image `grafana/grafana:11.3.0`. It exposes the Grafana server on port `3000` and connects to the `go-network` network. You have also mounted the `grafana.yml` file from the `Docker` directory which is present in the root directory of your project. The `grafana.yml` file contains the Grafana configuration to add the Prometheus data source. This is how you connect the Grafana server to the Prometheus server. In the environment variables, you have set the Grafana admin user and password, which will be used to log in to the Grafana dashboard. ```yaml apiVersion: 1 datasources: - name: Prometheus (Main) type: prometheus url: http://prometheus:9090 isDefault: true ``` In the `grafana.yml` file, you have defined a Prometheus data source named `Prometheus (Main)`. The `type` field specifies the type of the data source, which is `prometheus`. The `url` field specifies the URL of the Prometheus server to fetch the metrics from. In this case, the URL is `http://prometheus:9090`. `prometheus` is the service name of the Prometheus server in the Docker Compose file. The `isDefault` field specifies whether the data source is the default data source in Grafana. Apart from the services, the Docker Compose file also defines a volume named `grafana-data` to persist the Grafana data and a network named `go-network` to connect the services together. You have created a custom network `go-network` to connect the services together. The `driver: bridge` field specifies the network driver to use for the network. ## Building and running the services Now that you have the Docker Compose file, you can build the services and run them together using Docker Compose. To build and run the services, run the following command in the terminal: ```console $ docker compose up ``` The `docker compose up` command builds the services defined in the Docker Compose file and runs them together. You will see the similar output in the terminal: ```console ✔ Network go-prometheus-monitoring_go-network Created 0.0s ✔ Container grafana Created 0.3s

This section details the Prometheus and Grafana services within the Docker Compose setup, including configurations for scraping metrics and data source connections. It also covers setting up a custom network and persistent volume for Grafana data. Finally, it provides instructions on how to build and run the services using the `docker compose up` command.