Use a prom variable and not a synapse role variable

group_vars/matrix_servers

@@ -1768,6 +1768,7 @@ matrix_prometheus_container_http_host_bind_port: "{{ '' if matrix_nginx_proxy_en
 
 matrix_prometheus_scraper_synapse_enabled: "{{ matrix_synapse_enabled and matrix_synapse_metrics_enabled }}"
 matrix_prometheus_scraper_synapse_targets: ['matrix-synapse:{{ matrix_synapse_metrics_port }}']
+matrix_prometheus_scraper_synapse_workers_enabled_list: "{{ matrix_synapse_workers_enabled_list }}"
 matrix_prometheus_scraper_synapse_rules_synapse_tag: "{{ matrix_synapse_docker_image_tag }}"
 
 matrix_prometheus_scraper_node_enabled: "{{ matrix_prometheus_node_exporter_enabled }}"

roles/matrix-prometheus/defaults/main.yml

@@ -34,6 +34,7 @@ matrix_prometheus_scraper_synapse_rules_synapse_tag: "master"
 matrix_prometheus_scraper_synapse_rules_download_url: "https://raw.githubusercontent.com/matrix-org/synapse/{{ matrix_prometheus_scraper_synapse_rules_synapse_tag }}/contrib/prometheus/synapse-v2.rules"
 
 matrix_prometheus_scraper_synapse_targets: []
+matrix_prometheus_scraper_synapse_workers_enabled_list: []
 
 # Tells whether the "node" scraper configuration is enabled.
 # This configuration aims to scrape the current node (this server).

roles/matrix-prometheus/templates/prometheus.yml.j2

@@ -35,7 +35,7 @@ scrape_configs:
         instance: {{ matrix_domain }}
         job: master
         index: 0
-  {% for worker in matrix_synapse_workers_enabled_list|d([]) %}
+  {% for worker in matrix_prometheus_scraper_synapse_workers_enabled_list %}
   {% if worker.metrics_port != 0 %}
     - targets: ['matrix-synapse-worker-{{ worker.type }}-{{ worker.instanceId }}:{{ worker.metrics_port }}']
       labels: