Add openvsx alert

operations/observability/mixins/IDE/rules/components/components.libsonnet

@@ -3,16 +3,5 @@
  * Licensed under the MIT License. See License-MIT.txt in the project root for license information.
  */
 
-// When implementing the first alerts and recording rules, please follow the same folder structure used by other teams' mixins
-// Ping @ArthurSens if necessary
-{
-  prometheusAlerts+:: {
-    groups+: [],
-    // IDE team doesn have any alerts yet
-  },
-
-  prometheusRules+:: {
-    groups+: [],
-    // IDE team doesn have any recording rules yet
-  },
-}
+(import './openvsx-proxy/alerts.libsonnet') +
+(import './openvsx-proxy/rules.libsonnet')

operations/observability/mixins/IDE/rules/components/openvsx-proxy/alerts.libsonnet

@@ -0,0 +1,32 @@
+/**
+ * Copyright (c) 2021 Gitpod GmbH. All rights reserved.
+ * Licensed under the MIT License. See License-MIT.txt in the project root for license information.
+ */
+
+{
+  prometheusAlerts+:: {
+    groups+: [
+      {
+        name: 'gitpod-component-openvsx-proxy-alerts',
+        rules: [
+          {
+            alert: 'GitpodOpenVSXRegistryDown',
+            labels: {
+              severity: 'critical',
+            },
+            'for': '20m',
+            annotations: {
+              runbook_url: 'https://github.com/gitpod-io/runbooks/blob/main/runbooks/GitpodOpenVsxRegistryDown.md',
+              summary: 'Open-VSX registry is possibly down',
+              description: 'Open-VSX registry is possibly down. We cannot pull VSCode extensions we don\'t have in our caches',
+            },
+            expr:
+              |||
+                sum(rate(gitpod_openvsx_proxy_requests_total{status=~"5..|error"}[5m])) / sum(rate(gitpod_openvsx_proxy_requests_total[5m])) > 0.01
+              |||,
+          },
+        ],
+      },
+    ],
+  },
+}

operations/observability/mixins/IDE/rules/components/openvsx-proxy/rules.libsonnet

@@ -0,0 +1,11 @@
+/**
+ * Copyright (c) 2021 Gitpod GmbH. All rights reserved.
+ * Licensed under the MIT License. See License-MIT.txt in the project root for license information.
+ */
+
+{
+  prometheusRules+:: {
+    groups+: [],
+    // There is no recording rules for this component.
+  },
+}