add smaller interfaces local to packages using them

apis/v1alpha1/opentelemetrycollector_types.go

@@ -160,8 +160,8 @@ type OpenTelemetryTargetAllocator struct {
 	// +optional
 	AllocationStrategy string `json:"allocationStrategy,omitempty"`
 	// FilterStrategy determines how to filter targets before allocating them among the collectors.
-	// The current options are no-op (no filtering) and relabel-config (drops targets based on prom relabel_config)
-	// The default is no-op
+	// The only current option is relabel-config (drops targets based on prom relabel_config).
+	// Filtering is disabled by default.
 	// +optional
 	FilterStrategy string `json:"filterStrategy,omitempty"`
 	// ServiceAccount indicates the name of an existing service account to use with this instance.

bundle/manifests/opentelemetry.io_opentelemetrycollectors.yaml

@@ -1703,9 +1703,9 @@ spec:
                     type: boolean
                   filterStrategy:
                     description: FilterStrategy determines how to filter targets before
-                      allocating them among the collectors. The current options are
-                      no-op (no filtering) and relabel-config (drops targets based
-                      on prom relabel_config) The default is no-op
+                      allocating them among the collectors. The only current option
+                      is relabel-config (drops targets based on prom relabel_config).
+                      Filtering is disabled by default.
                     type: string
                   image:
                     description: Image indicates the container image to use for the

cmd/otel-allocator/allocation/consistent_hashing.go

@@ -53,7 +53,7 @@ type consistentHashingAllocator struct {
 
 	log logr.Logger
 
-	filterFunction prehook.Hook
+	filterFunction Filter
 }
 
 func newConsistentHashingAllocator(log logr.Logger, opts ...AllocOption) Allocator {
@@ -78,8 +78,8 @@ func newConsistentHashingAllocator(log logr.Logger, opts ...AllocOption) Allocat
 }
 
 // SetHook sets the filtering hook to use.
-func (c *consistentHashingAllocator) SetHook(hook prehook.Hook) {
-	c.filterFunction = hook
+func (c *consistentHashingAllocator) SetFilter(filterFunction Filter) {
+	c.filterFunction = filterFunction
 }
 
 // addTargetToTargetItems assigns a target to the collector based on its hash and adds it to the allocator's targetItems
@@ -163,16 +163,8 @@ func (c *consistentHashingAllocator) SetTargets(targets map[string]*target.Targe
 
 	if c.filterFunction != nil {
 		targets = c.filterFunction.Apply(targets)
-	} else {
-		// If no filterFunction is set, then filtering will be a no-op.
-		// Add metrics for targets kept and dropped in the no-op case.
-		targetsPerJob := prehook.GetTargetsPerJob(targets)
-
-		for jName, numTargets := range targetsPerJob {
-			prehook.TargetsDropped.WithLabelValues(jName).Set(0)
-			prehook.TargetsKept.WithLabelValues(jName).Set(numTargets)
-		}
 	}
+	prehook.RecordTargetsKeptPerJob(targets)
 
 	c.m.Lock()
 	defer c.m.Unlock()

cmd/otel-allocator/allocation/least_weighted.go

@@ -52,12 +52,12 @@ type leastWeightedAllocator struct {
 
 	log logr.Logger
 
-	filterFunction prehook.Hook
+	filterFunction Filter
 }
 
 // SetHook sets the filtering hook to use.
-func (allocator *leastWeightedAllocator) SetHook(hook prehook.Hook) {
-	allocator.filterFunction = hook
+func (allocator *leastWeightedAllocator) SetFilter(filterFunction Filter) {
+	allocator.filterFunction = filterFunction
 }
 
 // TargetItems returns a shallow copy of the targetItems map.
@@ -175,16 +175,8 @@ func (allocator *leastWeightedAllocator) SetTargets(targets map[string]*target.T
 
 	if allocator.filterFunction != nil {
 		targets = allocator.filterFunction.Apply(targets)
-	} else {
-		// if no filterFunction is set, then filtering will be a no-op.
-		// add metrics for targets kept and dropped in the no-op case.
-		targetsPerJob := prehook.GetTargetsPerJob(targets)
-
-		for jName, numTargets := range targetsPerJob {
-			prehook.TargetsDropped.WithLabelValues(jName).Set(0)
-			prehook.TargetsKept.WithLabelValues(jName).Set(numTargets)
-		}
 	}
+	prehook.RecordTargetsKeptPerJob(targets)
 
 	allocator.m.Lock()
 	defer allocator.m.Unlock()

cmd/otel-allocator/allocation/strategy.go

@@ -23,7 +23,6 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 
-	"github.com/open-telemetry/opentelemetry-operator/cmd/otel-allocator/prehook"
 	"github.com/open-telemetry/opentelemetry-operator/cmd/otel-allocator/target"
 )
 
@@ -50,9 +49,13 @@ var (
 
 type AllocOption func(Allocator)
 
-func WithFilter(hook prehook.Hook) AllocOption {
+type Filter interface {
+	Apply(map[string]*target.TargetItem) map[string]*target.TargetItem
+}
+
+func WithFilter(filterFunction Filter) AllocOption {
 	return func(allocator Allocator) {
-		allocator.SetHook(hook)
+		allocator.SetFilter(filterFunction)
 	}
 }
 
@@ -76,7 +79,7 @@ type Allocator interface {
 	SetTargets(targets map[string]*target.TargetItem)
 	TargetItems() map[string]*target.TargetItem
 	Collectors() map[string]*Collector
-	SetHook(hook prehook.Hook)
+	SetFilter(filterFunction Filter)
 }
 
 var _ consistent.Member = Collector{}

cmd/otel-allocator/discovery/discovery.go

@@ -26,7 +26,6 @@ import (
 	"github.com/prometheus/prometheus/discovery"
 	"github.com/prometheus/prometheus/model/relabel"
 
-	"github.com/open-telemetry/opentelemetry-operator/cmd/otel-allocator/prehook"
 	"github.com/open-telemetry/opentelemetry-operator/cmd/otel-allocator/target"
 	allocatorWatcher "github.com/open-telemetry/opentelemetry-operator/cmd/otel-allocator/watcher"
 )
@@ -44,10 +43,14 @@ type Manager struct {
 	logger     log.Logger
 	close      chan struct{}
 	configsMap map[allocatorWatcher.EventSource]*config.Config
-	hook       prehook.Hook
+	hook       discoveryHook
 }
 
-func NewManager(log logr.Logger, ctx context.Context, logger log.Logger, hook prehook.Hook, options ...func(*discovery.Manager)) *Manager {
+type discoveryHook interface {
+	SetConfig(map[string][]*relabel.Config)
+}
+
+func NewManager(log logr.Logger, ctx context.Context, logger log.Logger, hook discoveryHook, options ...func(*discovery.Manager)) *Manager {
 	manager := discovery.NewManager(ctx, logger, options...)
 
 	go func() {

cmd/otel-allocator/prehook/prehook.go

@@ -35,10 +35,6 @@ var (
 		Name: "opentelemetry_allocator_targets_kept",
 		Help: "Number of targets kept after filtering.",
 	}, []string{"job_name"})
-	TargetsDropped = promauto.NewGaugeVec(prometheus.GaugeOpts{
-		Name: "opentelemetry_allocator_targets_dropped",
-		Help: "Number of targets dropped after filtering.",
-	}, []string{"job_name"})
 )
 
 type Hook interface {
@@ -53,13 +49,17 @@ var (
 	registry = map[string]HookProvider{}
 )
 
-func GetTargetsPerJob(targets map[string]*target.TargetItem) map[string]float64 {
+func RecordTargetsKeptPerJob(targets map[string]*target.TargetItem) map[string]float64 {
 	targetsPerJob := make(map[string]float64)
 
 	for _, tItem := range targets {
 		targetsPerJob[tItem.JobName] += 1
 	}
 
+	for jName, numTargets := range targetsPerJob {
+		TargetsKept.WithLabelValues(jName).Set(numTargets)
+	}
+
 	return targetsPerJob
 }
 

cmd/otel-allocator/prehook/relabel.go

@@ -49,16 +49,12 @@ func convertLabelToPromLabelSet(lbls model.LabelSet) []labels.Label {
 
 func (tf *RelabelConfigTargetFilter) Apply(targets map[string]*target.TargetItem) map[string]*target.TargetItem {
 	numTargets := len(targets)
-	var droppedTargetsPerJob, targetsPerJob map[string]float64
 
 	// need to wait until relabelCfg is set
 	if len(tf.relabelCfg) == 0 {
 		return targets
 	}
 
-	droppedTargetsPerJob = make(map[string]float64)
-	targetsPerJob = GetTargetsPerJob(targets)
-
 	// Note: jobNameKey != tItem.JobName (jobNameKey is hashed)
 	for jobNameKey, tItem := range targets {
 		keepTarget := true
@@ -74,16 +70,7 @@ func (tf *RelabelConfigTargetFilter) Apply(targets map[string]*target.TargetItem
 
 		if !keepTarget {
 			delete(targets, jobNameKey)
-			droppedTargetsPerJob[tItem.JobName] += 1
 		}
-
-	}
-
-	// add metrics for number of targets kept and dropped per job.
-	for jName, numTargets := range targetsPerJob {
-		numDropped := droppedTargetsPerJob[jName]
-		TargetsDropped.WithLabelValues(jName).Set(numDropped)
-		TargetsKept.WithLabelValues(jName).Set(numTargets-numDropped)
 	}
 
 	tf.log.V(2).Info("Filtering complete", "seen", numTargets, "kept", len(targets))

config/crd/bases/opentelemetry.io_opentelemetrycollectors.yaml

@@ -1701,9 +1701,9 @@ spec:
                     type: boolean
                   filterStrategy:
                     description: FilterStrategy determines how to filter targets before
-                      allocating them among the collectors. The current options are
-                      no-op (no filtering) and relabel-config (drops targets based
-                      on prom relabel_config) The default is no-op
+                      allocating them among the collectors. The only current option
+                      is relabel-config (drops targets based on prom relabel_config).
+                      Filtering is disabled by default.
                     type: string
                   image:
                     description: Image indicates the container image to use for the

docs/api.md

@@ -4546,7 +4546,7 @@ TargetAllocator indicates a value which determines whether to spawn a target all
         <td><b>filterStrategy</b></td>
         <td>string</td>
         <td>
-          FilterStrategy determines how to filter targets before allocating them among the collectors. The current options are no-op (no filtering) and relabel-config (drops targets based on prom relabel_config) The default is no-op<br/>
+          FilterStrategy determines how to filter targets before allocating them among the collectors. The only current option is relabel-config (drops targets based on prom relabel_config). Filtering is disabled by default.<br/>
         </td>
         <td>false</td>
       </tr><tr>

pkg/collector/reconcile/configmap.go

@@ -122,9 +122,8 @@ func desiredTAConfigMap(params Params) (corev1.ConfigMap, error) {
 
 	if len(params.Instance.Spec.TargetAllocator.FilterStrategy) > 0 {
 		taConfig["filter_strategy"] = params.Instance.Spec.TargetAllocator.FilterStrategy
-	} else {
-		taConfig["filter_strategy"] = "no-op"
 	}
+
 	taConfigYAML, err := yaml.Marshal(taConfig)
 	if err != nil {
 		return corev1.ConfigMap{}, err

pkg/collector/reconcile/configmap_test.go

@@ -194,7 +194,6 @@ config:
     - targets:
       - 0.0.0.0:8888
       - 0.0.0.0:9999
-filter_strategy: no-op
 label_selector:
   app.kubernetes.io/component: opentelemetry-collector
   app.kubernetes.io/instance: default.test
@@ -327,7 +326,6 @@ func TestExpectedConfigMap(t *testing.T) {
 		}
 		taConfig["config"] = parmConfig
 		taConfig["allocation_strategy"] = "least-weighted"
-		taConfig["filter_strategy"] = "no-op"
 		taConfigYAML, _ := yaml.Marshal(taConfig)
 
 		assert.Equal(t, string(taConfigYAML), actual.Data["targetallocator.yaml"])