Prometheus

Initial attempt. Seems to work fine.

Only tested on debian amd64 so far

roles/matrix-prometheus/tasks/init.yml

@@ -0,0 +1,5 @@
+- set_fact:
+    matrix_systemd_services_list: "{{ matrix_systemd_services_list + ['matrix-prometheus.service'] }}"
+  when: matrix_prometheus_enabled|bool
+
+

roles/matrix-prometheus/tasks/main.yml

@@ -0,0 +1,14 @@
+- import_tasks: "{{ role_path }}/tasks/init.yml"
+  tags:
+    - always
+
+- import_tasks: "{{ role_path }}/tasks/validate_config.yml"
+  when: run_setup|bool
+  tags:
+    - setup-all
+    - setup-prometheus
+
+- import_tasks: "{{ role_path }}/tasks/setup.yml"
+  tags:
+    - setup-all
+    - setup-prometheus

roles/matrix-prometheus/tasks/setup.yml

@@ -0,0 +1,93 @@
+---
+
+#
+# Tasks related to setting up matrix-prometheus
+#
+
+- name: Ensure matrix-prometheus image is pulled
+  docker_image:
+    name: "{{ matrix_prometheus_docker_image }}"
+    source: "{{ 'pull' if ansible_version.major > 2 or ansible_version.minor > 7 else omit }}"
+    force_source: "{{ matrix_prometheus_docker_image_force_pull if ansible_version.major > 2 or ansible_version.minor >= 8 else omit }}"
+    force: "{{ omit if ansible_version.major > 2 or ansible_version.minor >= 8 else matrix_prometheus_docker_image_force_pull }}"
+  when: "matrix_prometheus_enabled|bool"
+
+- name: Ensure Prometheus paths exists
+  file:
+    path: "{{ item }}"
+    state: directory
+    mode: 0750
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+  with_items:
+    - "{{ matrix_prometheus_base_path }}"
+    - "{{ matrix_prometheus_config_path }}"
+    - "{{ matrix_prometheus_data_path }}"
+  when: matrix_prometheus_enabled|bool
+  
+- name: Ensure prometheus.yml installed
+  copy:
+    content: "{{ matrix_prometheus_configuration|to_nice_yaml }}"
+    dest: "{{ matrix_prometheus_config_path }}/prometheus.yml"
+    mode: 0644
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+  when: matrix_prometheus_enabled|bool
+
+- name: Download synapse-v2.rules
+  get_url:
+    url: "{{ matrix_synapse_prometheus_rules_download_url }}"
+    dest: "{{ matrix_prometheus_config_path }}/synapse-v2.rules"
+    force: true
+    mode: 0440
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+  when: matrix_prometheus_enabled|bool
+
+
+- name: Ensure matrix-prometheus.service installed
+  template:
+    src: "{{ role_path }}/templates/systemd/matrix-prometheus.service.j2"
+    dest: "{{ matrix_systemd_path }}/matrix-prometheus.service"
+    mode: 0644
+  register: matrix_prometheus_systemd_service_result
+  when: matrix_prometheus_enabled|bool
+
+- name: Ensure systemd reloaded after matrix-prometheus.service installation
+  service:
+    daemon_reload: yes
+  when: "matrix_prometheus_enabled|bool and matrix_prometheus_systemd_service_result.changed"
+
+#
+# Tasks related to getting rid of matrix-prometheus (if it was previously enabled)
+#
+
+- name: Check existence of matrix-prometheus service
+  stat:
+    path: "{{ matrix_systemd_path }}/matrix-prometheus.service"
+  register: matrix_prometheus_service_stat
+
+- name: Ensure matrix-prometheus is stopped
+  service:
+    name: matrix-prometheus
+    state: stopped
+    daemon_reload: yes
+  register: stopping_result
+  when: "not matrix_prometheus_enabled|bool and matrix_prometheus_service_stat.stat.exists"
+
+- name: Ensure matrix-prometheus.service doesn't exist
+  file:
+    path: "{{ matrix_systemd_path }}/matrix-prometheus.service"
+    state: absent
+  when: "not matrix_prometheus_enabled|bool and matrix_prometheus_service_stat.stat.exists"
+
+- name: Ensure systemd reloaded after matrix-prometheus.service removal
+  service:
+    daemon_reload: yes
+  when: "not matrix_prometheus_enabled|bool and matrix_prometheus_service_stat.stat.exists"
+
+- name: Ensure matrix-prometheus Docker image doesn't exist
+  docker_image:
+    name: "{{ matrix_prometheus_docker_image }}"
+    state: absent
+  when: "not matrix_prometheus_enabled|bool"

roles/matrix-prometheus/tasks/validate_config.yml

@@ -0,0 +1,7 @@
+---
+
+- name: Fail if Synapse metrics not enabled
+  fail:
+    msg: >
+      You need to enable `matrix_synapse_metrics_enabled` for Prometheus grab metrics.
+  when: "not matrix_synapse_metrics_enabled"