Use standard config location for alertmanager to ease amtool usage

pica-metrologie/alertmanager/Dockerfile

@@ -8,4 +8,4 @@ USER root
 RUN chmod +x /entrypoint.sh
 
 ENTRYPOINT [ "/entrypoint.sh" ]
-CMD [ "/bin/alertmanager", "--config.file=/config/alertmanager-with-secrets.yml", "--storage.path=/alertmanager" ]
+CMD [ "/bin/alertmanager", "--config.file=/etc/amtool/config.yml", "--storage.path=/alertmanager" ]

pica-metrologie/alertmanager/entrypoint.sh

@@ -12,9 +12,10 @@ fi
 # a long debate about whether env variable should be used for configuration,
 # and they voted no. See https://github.com/prometheus/prometheus/issues/2357 for exemple.
 # We have no other trivial way if we want to commit the configuration file without secrets inside.
-cp /config/alertmanager.yml /config/alertmanager-with-secrets.yml
-sed -i "s@\$MATTERMOST_WEBHOOK@${MATTERMOST_WEBHOOK}@g" /config/alertmanager-with-secrets.yml
-sed -i "s@\$MATTERMOST_CHANNEL@${MATTERMOST_CHANNEL}@g" /config/alertmanager-with-secrets.yml
+mkdir -p /etc/amtool
+cp /config/alertmanager.yml /etc/amtool/config.yml
+sed -i "s@\$MATTERMOST_WEBHOOK@${MATTERMOST_WEBHOOK}@g" /etc/amtool/config.yml
+sed -i "s@\$MATTERMOST_CHANNEL@${MATTERMOST_CHANNEL}@g" /etc/amtool/config.yml
 
 # Substitue shell with `command` in Dockerfile
 exec $@