v-m: Add alerts for Firefly, Paperless, phpipam

_Firefly III_ and _phpipam_ don't export any Prometheus metrics, so we
have to scrape them via the Blackbox Exporter.

Paperless-ngx only exposes metrics via Flower, but since it runs in the
same container as the main application, we can assume that if the former
is unavailable, the latter is as well.

victoria-metrics/alerts.yml

@@ -248,6 +248,13 @@ groups:
 
 - name: Paperless-ngx
   rules:
+  - alert: Paperless-ngx is down
+    expr: >-
+      up{job="paperless-ngx"} == 0 or absent(up{job="paperless-ngx"})
+    annotations:
+      summary: Paperless-ngx is down
+      description: >-
+        Paperless-ngx is offline.
   - alert: Celery tasks failed
     expr: >-
       max_over_time(
@@ -279,3 +286,15 @@ groups:
         Paperless-ngx uses a scheduled Celery task to periodically poll email
         mailboxes for new messages.  If this task does not start, new email
         messages will not be downloaded and imported into the document library.
+
+- name: Firefly III
+  rules:
+  - alert: Firefly III is down
+    expr: >-
+      probe_success{job="firefly-iii"} != 1
+
+- name: phpipam
+  rules:
+  - alert: phpipam is down
+    expr: >-
+      probe_success{job="phpipam"} != 1

victoria-metrics/scrape.yml

@@ -489,3 +489,36 @@ scrape_configs:
     target_label: __address__
   - source_labels: [__address__]
     target_label: instance
+
+- job_name: firefly-iii
+  metrics_path: /probe
+  params:
+    module:
+    - http
+  static_configs:
+  - targets:
+    - https://firefly.pyrocufflink.blue/
+    - https://receipts.pyrocufflink.blue/
+  relabel_configs:
+  - source_labels: [__address__]
+    target_label: __param_target
+  - source_labels: [__param_target]
+    target_label: instance
+  - target_label: __address__
+    replacement: blackbox-exporter:9115
+
+- job_name: phpipam
+  metrics_path: /probe
+  params:
+    module:
+    - http
+  static_configs:
+  - targets:
+    - phpipam.pyrocufflink.blue
+  relabel_configs:
+  - source_labels: [__address__]
+    target_label: __param_target
+  - source_labels: [__param_target]
+    target_label: instance
+  - target_label: __address__
+    replacement: blackbox-exporter:9115