docker-compose.yml

#@ load("@ytt:sha256", "sha256")
#@ load("@ytt:data", "data")
---
version: "3"
services:
  monitoring-config:
    image: hairyhenderson/gomplate:v3.10.0-alpine
    container_name: monitoring-config
    entrypoint: ["/bin/sh","-c"]
    command:
      - gomplate -i '{{ tmpl.Inline .Env.CONFIG }}' -o /etc/prometheus/prometheus.yml
    environment:
      CONFIG: #@ data.read("prometheus.yml")
    volumes:
      - /docker/docker-data/prometheus/conf:/etc/prometheus

  prometheus:
    image: prom/prometheus:latest
    container_name: prometheus
    depends_on:
      - monitoring-config
    volumes:
      - /docker/docker-data/prometheus/conf:/etc/prometheus
    command:
      - '--config.file=/etc/prometheus/prometheus.yml'
      - '--storage.tsdb.path=/prometheus'
      - '--storage.tsdb.retention.time=200h'
      - '--web.enable-lifecycle'
    labels:
      checkusum: #@ sha256.sum(data.read("prometheus.yml"))
    restart: unless-stopped

prometheus.yml

#@data/values
---
global:
  scrape_interval:     15s
  evaluation_interval: 15s
alerting:
  alertmanagers:
  - static_configs:
    - targets:
       - alertmanager:9093
scrape_configs:
  - job_name: 'prometheus'
    static_configs:
    - targets: ['prometheus:9090']