pushgateway extra parameters

Allow passing in additional parameters for the pushgateway binary
* pushgateway_web_external_url - useful when running behind a reverse
  proxy
* pushgateway_cli_extra_flags - additional extra flags for
  flexibility

roles/pushgateway/defaults/main.yml

@@ -9,6 +9,13 @@ pushgateway_skip_install: false
 pushgateway_web_listen_address: "0.0.0.0:9091"
 pushgateway_web_telemetry_path: "/metrics"
 
+# External address on which pushgateway is available.
+# Useful when behind reverse proxy, e.g.: https://example.org/pushgateway
+pushgateway_web_external_url: ""
+
+# Optional extra flags to be passed to pushgateway binary
+pushgateway_cli_extra_flags: []
+
 pushgateway_tls_server_config: {}
 
 pushgateway_http_server_config: {}

roles/pushgateway/templates/pushgateway.service.j2

@@ -25,6 +25,17 @@ ExecStart={{ pushgateway_binary_install_dir }}/pushgateway \
 {%   endfor %}
 {% else %}
     '--web.listen-address={{ pushgateway_web_listen_address }}' \
+{% endif %}
+{% if pushgateway_web_external_url %}
+    --web.external-url="{{ pushgateway_web_external_url }}" \
+{% endif %}
+{% if pushgateway_cli_extra_flags and
+      pushgateway_cli_extra_flags is iterable and
+      pushgateway_cli_extra_flags is not mapping and
+      pushgateway_cli_extra_flags is not string %}
+{%   for extra_flag in pushgateway_cli_extra_flags %}
+    '{{ extra_flag }}' \
+{%   endfor %}
 {% endif %}
     '--web.telemetry-path={{ pushgateway_web_telemetry_path }}'