add prometheus exporter for groupfolder metrics

defaults/main.yml

@@ -19,3 +19,6 @@ nextcloud:
     pw: None
     name: nextcloud
   groupfolders: []
+  prometheus_exporter:
+    enabled: True
+    port: 9123

files/nextcloud-prometheus-exporter.service

@@ -0,0 +1,18 @@
+[Unit]
+Description=nextcloud prometheus exporter
+After=mariadb.service
+Requires=mariadb.service
+
+[Install]
+WantedBy=multi-user.target
+
+[Service]
+ExecStart=/usr/bin/python3 /usr/local/bin/nextcloud-prometheus-exporter.py
+Environment=PYTHONUNBUFFERED=1
+Restart=always
+
+User=www-data
+Group=www-data
+
+NoNewPrivileges=True
+#ProtectSystem=strict

handlers/main.yml

@@ -0,0 +1,6 @@
+- name: restart prometheus exporter
+  service:
+    name: nextcloud-prometheus-exporter
+    enabled: True
+    daemon_reload: True
+    state: restarted

tasks/base.yml

@@ -115,3 +115,31 @@
     state: link
   notify:
   - restart nginx
+
+- name:
+  when: nextcloud.prometheus_exporter.enabled
+  block:
+  - name: install python and modules
+    apt:
+      pkg:
+        - python3
+        - python3-prometheus-client
+        - python3-schedule
+
+  - name: copy exporter script
+    notify: restart prometheus exporter
+    template:
+      src: nextcloud-prometheus-exporter.py.j2
+      dest: /usr/local/bin/nextcloud-prometheus-exporter.py
+      owner: root
+      group: root
+      mode: 0755
+
+  - name: copy systemd service file
+    notify: restart prometheus exporter
+    copy:
+      src: nextcloud-prometheus-exporter.service
+      dest: /etc/systemd/system
+      owner: root
+      group: root
+      mode: 0644

templates/nextcloud-prometheus-exporter.py.j2

@@ -0,0 +1,49 @@
+import json
+from prometheus_client import Gauge, Summary, start_http_server
+import subprocess
+import schedule
+from time import sleep
+
+
+gauge_groupfolder_quota = Gauge('nextcloud_groupfolder_quota_bytes', 'nextcloud groupfolder quota', ['folder'])
+gauge_groupfolder_size = Gauge('nextcloud_groupfolder_bytes', 'nextcloud groupfolder size', ['folder'])
+
+
+def occ(cmd):
+    args = ['/usr/bin/php', '/usr/share/nextcloud/occ', cmd, '--output=json']
+
+    process = subprocess.run(args, capture_output=True)
+
+    output = None
+
+    try:
+        process.check_returncode()
+        output = json.loads(process.stdout.decode('utf-8'))
+    except Exception as e:
+        print('OCC command returned an error:')
+        print(str(e))
+        print(process.stderr.decode('utf-8'))
+
+    return output
+
+
+def update_groupfolders():
+    groupfolders = occ('groupfolders:list')
+
+    if not groupfolders:
+        return
+
+    for groupfolder in groupfolders:
+        gauge_groupfolder_quota.labels(groupfolder['mount_point']).set(int(groupfolder['quota']))
+        gauge_groupfolder_size.labels(groupfolder['mount_point']).set(int(groupfolder['size']))
+
+
+if __name__ == '__main__':
+    update_groupfolders()
+
+    schedule.every().minute.do(update_groupfolders)
+    start_http_server(addr='127.0.0.1', port={{ nextcloud.prometheus_exporter.port }})
+
+    while True:
+        schedule.run_pending()
+        sleep(1)