decouple BuildWriters from ConfigureSharding

Signed-off-by: Walther Lee <[email protected]>

Author: waltherlee

internal/discovery/discovery.go

@@ -236,7 +236,7 @@ func (r *CRDiscoverer) PollForCacheUpdates(
 			r.WasUpdated = false
 		})
 		// Update metric handler with the new configs.
-		m.ReconfigureSharding(ctx)
+		m.BuildWriters(ctx)
 	}
 	go func() {
 		for range t.C {

pkg/metricshandler/metrics_handler.go

@@ -71,34 +71,32 @@ func New(opts *options.Options, kubeClient kubernetes.Interface, storeBuilder ks
 
 // ReconfigureSharding reconfigures sharding with the current shard and totalShards, and
 // it's a no-op if both values are 0.
-func (m *MetricsHandler) ReconfigureSharding(ctx context.Context) {
-	m.mtx.RLock()
-	hasShardsSet := m.curShard != 0 || m.curTotalShards != 0
-	m.mtx.RUnlock()
-	if !hasShardsSet {
-		return
+func (m *MetricsHandler) BuildWriters(ctx context.Context) {
+	m.mtx.Lock()
+	defer m.mtx.Unlock()
+
+	if m.cancel != nil {
+		m.cancel()
 	}
-	m.ConfigureSharding(ctx, m.curShard, m.curTotalShards)
+	ctx, m.cancel = context.WithCancel(ctx)
+	m.storeBuilder.WithContext(ctx)
+	m.metricsWriters = m.storeBuilder.Build()
 }
 
 // ConfigureSharding configures sharding. Configuration can be used mutlitple times and
 // concurrently.
 func (m *MetricsHandler) ConfigureSharding(ctx context.Context, shard int32, totalShards int) {
 	m.mtx.Lock()
-	defer m.mtx.Unlock()
 
-	if m.cancel != nil {
-		m.cancel()
-	}
 	if totalShards != 1 {
 		klog.InfoS("Configuring sharding of this instance to be shard index (zero-indexed) out of total shards", "shard", shard, "totalShards", totalShards)
 	}
-	ctx, m.cancel = context.WithCancel(ctx)
-	m.storeBuilder.WithSharding(shard, totalShards)
-	m.storeBuilder.WithContext(ctx)
-	m.metricsWriters = m.storeBuilder.Build()
 	m.curShard = shard
 	m.curTotalShards = totalShards
+	m.storeBuilder.WithSharding(shard, totalShards)
+	m.mtx.Unlock()
+
+	m.BuildWriters(ctx)
 }
 
 // Run configures the MetricsHandler's sharding and if autosharding is enabled