Add alertmanager render script with optional thread id

monitoring/alertmanager/alertmanager.tmpl.yml

@@ -23,6 +23,4 @@ receivers:
         disable_notifications: false
         api_url: "https://api.telegram.org"
         send_resolved: true
-        {{- if .Env.TELEGRAM_THREAD_ID }}
-        message_thread_id: ${TELEGRAM_THREAD_ID}
-        {{- end }}
+        __THREAD_LINE__

monitoring/alertmanager/render.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env sh
+set -e
+
+tmp=/etc/alertmanager/alertmanager.yml
+
+envsubst < /etc/alertmanager/alertmanager.tmpl.yml > "$tmp"
+
+if [ -n "$TELEGRAM_THREAD_ID" ]; then
+  sed -i "s#__THREAD_LINE__#message_thread_id: $TELEGRAM_THREAD_ID#" "$tmp"
+else
+  sed -i "s#__THREAD_LINE__##" "$tmp"
+fi
+
+exec /bin/alertmanager --config.file="$tmp" --storage.path=/alertmanager