mediamtx: Add cronjob to publish mediamtx metrics to server (#3298)

* mediamtx: Add cronjob to publish mediamtx metrics to server

* dockerfile.mediamtx: Replace `ENTRYPOINT` with `CMD`

* mediamtx: Fix cron environment issues

docker/Dockerfile.mediamtx

@@ -1,23 +1,31 @@
 FROM	ubuntu:24.04
 
 # we need curl in the image as it's later used in the runOnReady command
-RUN	apt-get update \
-	&& apt-get install -y \
+RUN	apt update \
+	&& apt install -yqq \
 		ca-certificates \
 		curl \
-	&& apt-get clean \
-	&& rm -rf /var/lib/apt/lists/*
+		cron \
+	&& apt clean \
+	&& rm -rf /var/lib/apt/lists/* /etc/cron.*
+
+COPY --chmod=0644	crontab	/etc/crontab
+
+# Setup cron job for publishing metrics
+RUN	mkdir -p /var/log/ \
+	&& crontab /etc/crontab \
+	&& touch /var/log/cron.log
+
+COPY --chmod=0755	mediamtx-metrics.bash	/opt/mediamtx-metrics.bash
 
 ENV	MEDIAMTX_VERSION="1.9.3"
 
-ADD	"https://github.com/bluenviron/mediamtx/releases/download/v${MEDIAMTX_VERSION}/mediamtx_v${MEDIAMTX_VERSION}_linux_amd64.tar.gz"	/opt/mediamtx.tar.gz
+ADD	"https://github.com/bluenviron/mediamtx/releases/download/v${MEDIAMTX_VERSION}/mediamtx_v${MEDIAMTX_VERSION}_linux_amd64.tar.gz"	/opt/mediamtx/mediamtx.tar.gz
 
-RUN	tar xzf /opt/mediamtx.tar.gz -C /opt/ \
+RUN	tar xzf /opt/mediamtx/mediamtx.tar.gz -C /opt/mediamtx/ \
 	&& mkdir -p /usr/local/bin /etc/mediamtx/ \
-	&& mv /opt/mediamtx /usr/local/bin/mediamtx \
-	&& mv /opt/mediamtx.yml /etc/mediamtx/mediamtx.yml \
-	&& rm -rf /opt/
-
-COPY	mediamtx-entry.bash	/
+	&& mv /opt/mediamtx/mediamtx /usr/local/bin/mediamtx \
+	&& mv /opt/mediamtx/mediamtx.yml /etc/mediamtx/mediamtx.yml \
+	&& rm -rf /opt/mediamtx/
 
-ENTRYPOINT	["/mediamtx-entry.bash"]
+CMD	[ "/bin/bash", "-c", "declare -p >> /etc/environment && cron && /usr/local/bin/mediamtx" ]

docker/crontab

@@ -0,0 +1,4 @@
+SHELL=/bin/bash
+BASH_ENV=/etc/environment
+
+*/5 * * * * /opt/mediamtx-metrics.bash >> /var/log/cron.log 2>&1

docker/mediamtx-entry.bash → docker/mediamtx-metrics.bash

@@ -5,15 +5,18 @@
 set -euo pipefail
 
 if [ -v LP_PUBLISH_MEDIAMTX_METRICS ]; then
-  if [ -z "$LP_PUBLISH_MEDIAMTX_METRICS_ENDPOINT" ]; then
-    echo >&2 "No endpoint specified for publishing mediamtx metrics."
-  fi
-  cat <<EOF |
+  METRIC_DATA=$(
+    cat <<EOF
 # HELP version Current software version as a tag, always 1
 # TYPE version gauge
 version{app="MediaMTX",version="$MEDIAMTX_VERSION",region="$MEDIAMTX_REGION",ecosystem="$MEDIAMTX_ECOSYSTEM"} 1
 EOF
-    curl -X POST --data-binary @- "$LP_PUBLISH_MEDIAMTX_METRICS_ENDPOINT"
-fi
+  )
+  echo "$METRIC_DATA"
 
-exec "${@:-/usr/local/bin/mediamtx}"
+  if [ -z "$LP_PUBLISH_MEDIAMTX_METRICS_ENDPOINT" ]; then
+    echo >&2 "No endpoint specified for publishing mediamtx metrics."
+    exit 1
+  fi
+  echo "$METRIC_DATA" | curl -X POST --data-binary @- "$LP_PUBLISH_MEDIAMTX_METRICS_ENDPOINT"
+fi