metrics: Add condition gauge

Fixes #395

docs/references/monitoring.md

@@ -11,27 +11,28 @@ in Prometheus format.
 | `release_count` | Count of releases managed by the operator. |
 | `release_duration_seconds` | Release synchronization duration in seconds. This duration includes one or many `release_phase_durations`. |
 | `release_phase_duration_seconds` | Release phase synchronization duration in seconds. |
-| `release_phase_info` | The (negative) integer equaling the current phase of a release. Negative values are failed phases, `0` equals to unknown. See [release phases](#release-phases).
+| `release_condition_info` | Release condition status gauge, see [release conditions](#release-conditions).
 | `release_queue_length_count` | Count of release jobs waiting in the queue to be processed. |
 
+### Release conditions
 
-### Release phases
+#### Labels
 
-The following is a table of the values the `release_phase_info` metric exposes,
-and the phase they represent:
+| Label          | Label Value |
+|----------------|---
+| `namespace`    | `metadata.namespace` of `HelmRelease`
+| `name`         | `metadata.name` of `HelmRelease`
+| `condition`    | [condition type](helmrelease-custom-resource.md#helm.fluxcd.io/v1.HelmReleaseConditionType)
 
-| Value | Phase |
+#### Values
+
+Values represent the [condition status](helmrelease-custom-resource.md#helm.fluxcd.io/v1.ConditionStatus).
+
+| Value | Condition Status |
 |-------|---
-| `-4`  | `ChartFetchFailed`
-| `-3`  | `Failed`
-| `-2`  | `RollbackFailed`
-| `-1 ` | `RolledBack`
+| `-1`  | `False`
 | `0`   | `Unknown`
-| `1`   | `RollingBack`
-| `2`   | `Installing`
-| `3`   | `Upgrading`
-| `4`   | `ChartFetched`
-| `5`   | `Succeeded`
+| `1`   | `True`
 
 ## Prometheus alert rules examples
 
@@ -51,12 +52,12 @@ for: 30m
 
 ```yaml
 alert: HelmReleaseRolledBack
-expr: flux_helm_operator_release_phase_info == -1
+expr: flux_helm_operator_release_condition_info{condition="RolledBack"} == 1
 ```
 
 ### `HelmRelease` subject to an error
 
 ```yaml
 alert: HelmReleaseError
-expr: flux_helm_operator_release_phase_info < -1
+expr: flux_helm_operator_release_phase_info{condition="Released"} == -1
 ```

pkg/status/conditions.go

@@ -53,6 +53,7 @@ func SetCondition(client v1client.HelmReleaseInterface, hr *v1.HelmRelease, cond
 			set(cHr)
 		}
 
+		ObserveReleaseConditions(*hr, *cHr)
 		_, err = client.UpdateStatus(cHr)
 		firstTry = false
 		return

pkg/status/metrics.go

@@ -0,0 +1,46 @@
+package status
+
+import (
+	v1 "github.com/fluxcd/helm-operator/pkg/apis/helm.fluxcd.io/v1"
+	"github.com/go-kit/kit/metrics/prometheus"
+	stdprometheus "github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	LabelNamespace = "namespace"
+	LabelName      = "name"
+	LabelCondition = "condition"
+)
+
+var (
+	conditionStatusToGaugeValue = map[v1.ConditionStatus]float64{
+		v1.ConditionFalse:   -1,
+		v1.ConditionUnknown: 0,
+		v1.ConditionTrue:    1,
+	}
+	releaseCondition = prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
+		Namespace: "flux",
+		Subsystem: "helm_operator",
+		Name:      "release_condition_info",
+		Help:      "Current HelmRelease condition status. Values are -1 (false), 0 (unknown or absent), 1 (true)",
+	}, []string{LabelNamespace, LabelName, LabelCondition})
+)
+
+func ObserveReleaseConditions(old v1.HelmRelease, new v1.HelmRelease) {
+	conditions := make(map[v1.HelmReleaseConditionType]v1.ConditionStatus)
+	for _, condition := range old.Status.Conditions {
+		// Initialize conditions from old status to unknown, so that if
+		// they are removed in new status, they do not contain stale data.
+		conditions[condition.Type] = v1.ConditionUnknown
+	}
+	for _, condition := range new.Status.Conditions {
+		conditions[condition.Type] = condition.Status
+	}
+	for conditionType, conditionStatus := range conditions {
+		releaseCondition.With(
+			LabelNamespace, new.Namespace,
+			LabelName, new.Name,
+			LabelCondition, string(conditionType),
+		).Set(conditionStatusToGaugeValue[conditionStatus])
+	}
+}