move condition metrics recorder to separate repository (#15)

* move condition metrics recorder to separate repository

* remove readme conflicts

Author: sourcehawk

.gitignore

@@ -28,5 +28,5 @@ go.work.sum
 .env
 
 # Editor/IDE
- .idea/
- .vscode/
+.idea/
+.vscode/

README.md

@@ -2,10 +2,6 @@
 
 A flexible, memory efficient Prometheus `GaugeVec` wrapper for managing **sets** of metrics.
 
----
-
-## GaugeVecSet
-
 The `GaugeVecSet` is a high-performance wrapper around Prometheus `GaugeVec` that enables bulk operations on series 
 by specified index and grouping labels.
 
@@ -105,162 +101,13 @@ deleted := PodPhase.DeleteByIndex("prod")
 
 ### GaugeVecSet: DeleteByGroup
 
-Delete all series that match the given (index, group)
+Delete all series that match the given (index, group). The number of index and group values this method requires 
+coincides with the number of values the gauge was initialized with, meaning you cannot specify partial values for
+deletion.
 
 ```go
 deleted := PodPhase.DeleteByGroup(
     []string{"prod"}, // index
     "nginx-6f4c",     // group
 )
-```
-
-## ConditionMetricsRecorder
-
-The `ConditionMetricsRecorder` is an implementation of `GaugeVecSet` for kubernetes operators. It enables
-controllers to record metrics for it's kubernetes `metav1.Conditions` on custom resources.
-
-It is inspired by kube-state-metrics patterns for metrics such as `kube_pod_status_phase`. KSM exports one time series 
-per phase for each (namespace, pod), and marks exactly one as active (1) while the others are inactive (0). This metric 
-can be thought of as a `GaugeVecSet` with the index label `namespace`, the group `pod` and the `extra` labels 
-(i.e. variants per group) as the options for `phase`.
-
-Example:
-
-```
-kube_pod_status_phase{namespace="default", pod="nginx", phase="Running"} 1
-kube_pod_status_phase{namespace="default", pod="nginx", phase="Pending"} 0
-kube_pod_status_phase{namespace="default", pod="nginx", phase="Failed"}  0
-```
-
-We adopt the same pattern for controller Conditions, but we export only one time series per (status, reason) variant, 
-meaning we delete all other variants in the group when we set the metric, ensuring the cardinality stays under control.
-Additionally, rather than return 1/0 indicating the activeness of the metric, we set the last transition time of the
-condition as the value (unix timestamp).
-
-Example metric:
-
-```
-operator_controller_condition{
-    controller="my_controller",
-    resource_kind="MyCR",
-    resource_name="my-cr",
-    resource_namespace="default",
-    condition="Ready",
-    status="False",
-    reason="FailedToProvision"
-} 17591743210
-```
-
-- **Index**: controller, resource_kind, resource_name, resource_namespace
-- **Group**: condition
-- **Extra**: status, reason
-- **Metric Value**: Unix timestamp of last transition of given condition
-
-### Initialization
-
-The metric should be initialized and registered once.
-
-You can embed the `ControllerMetricsRecorder` in your controller's recorder.
-
-```go
-package my_metrics
-
-import (
-    controllermetrics "sigs.k8s.io/controller-runtime/pkg/metrics"
-    ocg "github.com/sourcehawk/go-prometheus-gaugevecset/pkg/operator_condition_metrics"
-)
-
-// We need this variable later to create the ConditionMetricsRecorder
-var OperatorConditionsGauge *ocg.OperatorConditionsGauge
-
-// Initialize the operator condition gauge once
-func init() {
-    OperatorConditionsGauge = ocg.NewOperatorConditionsGauge("my-operator")
-    controllermetrics.Registry.MustRegister(OperatorConditionsGauge)
-}
-
-// Embed in existing metrics recorder
-type MyControllerRecorder struct {
-    ocg.ConditionMetricRecorder
-}
-```
-
-When constructing your reconciler, initialize the condition metrics recorder with the
-operator conditions gauge and a unique name for each controller.
-
-_cmd/main.go_
-```go
-package main
-
-import (
-    mymetrics "path/to/pkg/my_metrics"
-    ocg "github.com/sourcehawk/go-prometheus-gaugevecset/pkg/operator_condition_metrics"
-)
-
-func main() {
-    // ...
-    recorder := mymetrics.MyControllerRecorder{
-        ConditionMetricRecorder: ocg.ConditionMetricRecorder{
-            Controller: "my-controller", // unique name per reconciler
-            OperatorConditionsGauge: mymetrics.OperatorConditionsGauge,
-        },
-    }
-	
-    reconciler := &MyReconciler{
-        Recorder: recorder, 
-    }
-    // ...
-}
-```
-
-## Usage
-
-The easiest drop-in way to start using the metrics recorder is by creating a `SetStatusCondition` wrapper, which 
-comes instead of `meta.SetStatusCondition`.
-
-To delete the metrics for a given custom resource, simply call `RemoveConditionsFor` and pass the object.
-
-```go
-const (
-	kind = "MyCR"
-)
-
-// SetStatusCondition utility function which replaces and wraps meta.SetStatusCondition calls
-func (r *MyReconciler) SetStatusCondition(cr *v1.MyCR, cond metav1.Condition) bool {
-    changed := meta.SetStatusCondition(&cr.Status.Conditions, cond)
-    if changed {
-        // refetch the condition to get the updated version
-        updated := meta.FindStatusCondition(cr.Status.Conditions, cond.Type)
-        if updated != nil {
-            r.Recorder.RecordConditionFor(
-                kind, cr, updated.Type, string(updated.Status), updated.Reason, updated.LastTransitionTime,
-            )
-        }
-    }
-    return changed
-}
-
-func (r *MyReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
-    // Get the resource we're reconciling
-    cr := new(v1.MyCR)
-    if err = r.Get(ctx, req.NamespacedName, cr); err != nil {
-        return ctrl.Result{}, client.IgnoreNotFound(err)
-    }
-	
-    // Remove the metrics when the CR is deleted
-    if cr.DeletionTimestamp != nil {
-        r.Recorder.RemoveConditionsFor(kind, cr)
-    }
-	
-    // ...
-	
-    // Update the status conditions using the recorder (it records the metric if changed)
-    if r.SetStatusCondition(cr, condition) {
-        if err = r.Status().Update(ctx, cr); err != nil {
-            return ctrl.Result{}, err
-        }
-    }
-	
-    return ctrl.Result{}, nil
-}
-```
+```