feat: enforce env vars with run.sh to start prometheus

Author: apham0001

docker-compose.yml

@@ -152,9 +152,12 @@ services:
     image: prom/prometheus:${PROMETHEUS_VERSION:-v2.46.0}
     user: ":"
     networks: [dvnode]
+    environment:
+      PROM_REMOTE_WRITE_TOKEN: ${PROM_REMOTE_WRITE_TOKEN:-"obol-monitoring-token-needed"}
     volumes:
-      - ./prometheus/prometheus.yml:/etc/prometheus/prometheus.yml
+      - ./prometheus:/etc/prometheus
       - ./data/prometheus:/prometheus
+    entrypoint: /etc/prometheus/run.sh
     restart: unless-stopped
 
   grafana:

prometheus/prometheus.yml prometheus/prometheus.yml.example

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+if [ -z "$PROM_REMOTE_WRITE_TOKEN" ]
+then
+  echo "\$PROM_REMOTE_WRITE_TOKEN variable is empty"
+fi
+
+# eval is used instead of envsubst, as prometheus user doesn't have permissions to install envsubst
+eval "echo \"$(cat /etc/prometheus/prometheus.yml.example)\"" > /etc/prometheus/prometheus.yml
+
+/bin/prometheus \
+  --config.file=/etc/prometheus/prometheus.yml