WIP fix for open-telemetry/opentelemetry-java#5504

plugin/sampling/strategystore/static/fixtures/5504_strategies.json

@@ -0,0 +1,53 @@
+{
+    "default_strategy": {
+        "type": "probabilistic",
+        "param": 0.2,
+        "operation_strategies": [
+            {
+                "operation": "metrics",
+                "type": "probabilistic",
+                "param": 0.1
+            }
+        ]
+    },
+    "service_strategies": [
+        {
+            "service": "foobar",
+            "type": "ratelimiting",
+            "param": 2
+        }
+    ]    
+}
+
+// func Test5504SamplingStrategies(t *testing.T) {
+// 	logger, _ := testutils.NewLogger()
+// 	store, err := NewStrategyStore(Options{StrategiesFile: "fixtures/5504_strategies.json"}, logger)
+// 	require.NoError(t, err)
+
+// 	expected := makeResponse(api_v2.SamplingStrategyType_RATE_LIMITING, 2)
+
+// 	s, err := store.GetSamplingStrategy(context.Background(), "foobar")
+// 	require.NoError(t, err)
+// 	assert.Equal(t, api_v2.SamplingStrategyType_RATE_LIMITING, s.StrategyType)
+// 	assert.Equal(t, *expected.RateLimitingSampling, *s.RateLimitingSampling)
+
+// 	require.NotNil(t, s.OperationSampling)
+// 	os := s.OperationSampling
+// 	assert.EqualValues(t, 0.8, os.DefaultSamplingProbability)
+// 	require.Len(t, os.PerOperationStrategies, 1)
+
+// 	expected = makeResponse(api_v2.SamplingStrategyType_PROBABILISTIC, 0.2)
+
+// 	d, err := store.GetSamplingStrategy(context.Background(), "default_service")
+// 	require.NoError(t, err)
+// 	assert.Equal(t, api_v2.SamplingStrategyType_PROBABILISTIC, d.StrategyType)
+// 	assert.Equal(t, *expected.ProbabilisticSampling, *d.ProbabilisticSampling)
+
+// 	require.NotNil(t, s.OperationSampling)
+// 	os = s.OperationSampling
+// 	assert.EqualValues(t, 0.8, os.DefaultSamplingProbability)
+// 	require.Len(t, os.PerOperationStrategies, 1)
+
+// 	assert.Equal(t, "metrics", os.PerOperationStrategies[0].Operation)
+// 	assert.EqualValues(t, 0.1, os.PerOperationStrategies[0].ProbabilisticSampling.SamplingRate)
+// }

plugin/sampling/strategystore/static/strategy_store.go

@@ -229,13 +229,16 @@ func (h *strategyStore) parseStrategies(strategies *strategies) {
 		// is not merged with and only used as a fallback).
 		opS := newStore.serviceStrategies[s.Service].OperationSampling
 		if opS == nil {
-			if newStore.defaultStrategy.OperationSampling == nil ||
-				newStore.serviceStrategies[s.Service].ProbabilisticSampling == nil {
+			// no default per-operation strategies - just move on
+			if newStore.defaultStrategy.OperationSampling == nil {
 				continue
 			}
-			// Service has no per-operation strategies, so just reference the default settings and change default samplingRate.
+			// Service has no per-operation strategies, so just reference the default settings
+			// and change default samplingRate to the value defined in service strategy if value is available.
 			newOpS := *newStore.defaultStrategy.OperationSampling
-			newOpS.DefaultSamplingProbability = newStore.serviceStrategies[s.Service].ProbabilisticSampling.SamplingRate
+			if newStore.serviceStrategies[s.Service].ProbabilisticSampling != nil {
+				newOpS.DefaultSamplingProbability = newStore.serviceStrategies[s.Service].ProbabilisticSampling.SamplingRate
+			}
 			newStore.serviceStrategies[s.Service].OperationSampling = &newOpS
 			continue
 		}

plugin/sampling/strategystore/static/strategy_store_test.go

@@ -471,9 +471,12 @@ func TestServiceNoPerOperationStrategies(t *testing.T) {
 	s, err := store.GetSamplingStrategy(context.Background(), "ServiceA")
 	require.NoError(t, err)
 	assert.Equal(t, 1.0, s.OperationSampling.DefaultSamplingProbability)
+	assert.Len(t, s.OperationSampling.PerOperationStrategies, 1)
 
 	s, err = store.GetSamplingStrategy(context.Background(), "ServiceB")
 	require.NoError(t, err)
+	assert.Equal(t, 0.2, s.OperationSampling.DefaultSamplingProbability)
+	assert.Len(t, s.OperationSampling.PerOperationStrategies, 1)
 
 	expected := makeResponse(api_v2.SamplingStrategyType_RATE_LIMITING, 3)
 	assert.Equal(t, *expected.RateLimitingSampling, *s.RateLimitingSampling)