fuuko/go-neb: Add alertmanager matrix receiver

README.md

@@ -14,7 +14,9 @@
      specific service the machine provides.
    + `secrets`: Nix expressions that include information that is not meant to
      be visible to everyone (e.g. accounts, password hashes, private
-     information etc.)
+     information etc.) or secrets for services that don’t provide any other
+     (easy) way of specifying them and whose secrets leaking does not pose a
+     huge threat
  * `modules`: Custom modules. Many are activated by default, since I want them
    on all systems.
  * `pkgs`: My nixpkgs overlay

machines/fuuko/services/matrix/default.nix

@@ -2,5 +2,6 @@
   imports = [
     ./synapse.nix
     ./mautrix-whatsapp.nix
+    ./go-neb.nix
   ];
 }

machines/fuuko/services/matrix/go-neb.nix

@@ -0,0 +1,56 @@
+{ config, ... }:
+let
+  synapseCfg = config.services.matrix-synapse;
+in
+{
+  services.go-neb = rec {
+    enable = true;
+    bindAddress = "127.0.0.1:8010";
+    baseUrl = "http://${bindAddress}";
+    config = {
+      clients = [
+        ({
+          UserID = "@alertmanager:${synapseCfg.server_name}";
+          HomeserverURL = synapseCfg.public_baseurl;
+          Sync = false;
+          AutoJoinRooms = false;
+          DisplayName = "Prometheus Alertmanager";
+        } // (import ../../secrets/go-neb-alertmanager.nix)) # AccessToken and DeviceID
+      ];
+      services = [
+        {
+          ID = "alertmanager_service";
+          Type = "alertmanager";
+          UserID = "@alertmanager:${synapseCfg.server_name}";
+          Config = {
+            webhook_url = "${baseUrl}/services/hooks/YWxlcnRtYW5hZ2VyX3NlcnZpY2U";
+            rooms = {
+              "!ceigaGYfREXXSeLFiH:sbruder.de" = {
+                text_template = "{{ range .Alerts }}[{{ .Status }}] {{ index .Labels \"alertname\" }}: {{ index .Annotations \"description\" }}\n{{ end }}";
+                html_template = ''
+                  {{ range .Alerts }}
+                    {{ $severity := index .Labels "severity" }}
+                    <font{{ if eq .Status "firing" -}}
+                      {{- if eq $severity "critical" }} color="red"
+                      {{- else if eq $severity "warning" }} color="orange"
+                      {{- end -}}
+                    {{- else }} color="green"
+                    {{- end }}>
+                    <strong>{{ if eq .Status "firing" -}}
+                      [firing{{ if ne $severity "" }} - {{ $severity }}{{ end }}]
+                    {{- else -}}
+                      [resolved]
+                    {{- end }}</strong>
+                    </font>
+                    {{ index .Labels "alertname" }}: {{ index .Annotations "description" }} <a href="{{ .GeneratorURL }}">source</a><br/>
+                  {{ end }}
+                '';
+                msg_type = "m.text";
+              };
+            };
+          };
+        }
+      ];
+    };
+  };
+}

machines/fuuko/services/prometheus.nix

@@ -51,10 +51,13 @@ in
         receivers = [
           {
             name = "matrix";
-            webhook_configs = [
-              # FIXME: Add correct URL
-              { url = "http://matrix-alertmanager:3000/alerts"; }
-            ];
+            webhook_configs = lib.singleton {
+              url = (lib.elemAt
+                (lib.filter
+                  ({ ID, ... }: ID == "alertmanager_service")
+                  config.services.go-neb.config.services)
+                0).Config.webhook_url;
+            };
           }
         ];
       };