[receiver/kafkareceiver] standardize on topic names for spans, metric…

…s, and logs (#30163)

**Description:**
Updates the default topics for metrics and logs consumers to be the same
as the `kafkaexporter` default topics for metrics and logs exporters.

**Link to tracking Issue:**
#27292

**Testing:** Added testing in `factory_test.go` to test that topics are
set correctly for spans, metrics, and logs consumers.

**Documentation:** Updated the comments in `config.go` and `README.md`
to match the updates.

.chloggen/kafka-receiver-standardize-default-topic.yaml

@@ -0,0 +1,31 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: kafkareceiver
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: standardizes the default topic name for metrics and logs receivers to the same topic name as the metrics and logs exporters of the kafkaexporter
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [27292]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext: |
+  If you are using the Kafka receiver in a logs and/or a metrics pipeline
+  and you are not customizing the name of the topic to read from with the `topic` property,
+  the receiver will now read from `otlp_logs` or `otlp_metrics` topic instead of `otlp_spans` topic.
+  To maintain previous behavior, set the `topic` property to `otlp_spans`.
+
+# If your change doesn't affect end users or the exported elements of any package,
+# you should instead start your pull request title with [chore] or use the "Skip Changelog" label.
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [user]

receiver/kafkareceiver/README.md

@@ -32,7 +32,7 @@ The following settings can be optionally configured:
 
 - `brokers` (default = localhost:9092): The list of kafka brokers
 - `resolve_canonical_bootstrap_servers_only` (default = false): Whether to resolve then reverse-lookup broker IPs during startup
-- `topic` (default = otlp_spans): The name of the kafka topic to read from
+- `topic` (default = otlp_spans for traces, otlp_metrics for metrics, otlp_logs for logs): The name of the kafka topic to read from
 - `encoding` (default = otlp_proto): The encoding of the payload received from kafka. Available encodings:
   - `otlp_proto`: the payload is deserialized to `ExportTraceServiceRequest`, `ExportLogsServiceRequest` or `ExportMetricsServiceRequest` respectively.
   - `jaeger_proto`: the payload is deserialized to a single Jaeger proto `Span`.

receiver/kafkareceiver/config.go

@@ -48,7 +48,7 @@ type Config struct {
 	ResolveCanonicalBootstrapServersOnly bool `mapstructure:"resolve_canonical_bootstrap_servers_only"`
 	// Kafka protocol version
 	ProtocolVersion string `mapstructure:"protocol_version"`
-	// The name of the kafka topic to consume from (default "otlp_spans")
+	// The name of the kafka topic to consume from (default "otlp_spans" for traces, "otlp_metrics" for metrics, "otlp_logs" for logs)
 	Topic string `mapstructure:"topic"`
 	// Encoding of the messages (default "otlp_proto")
 	Encoding string `mapstructure:"encoding"`

receiver/kafkareceiver/factory.go

@@ -19,7 +19,9 @@ import (
 )
 
 const (
-	defaultTopic         = "otlp_spans"
+	defaultTracesTopic   = "otlp_spans"
+	defaultMetricsTopic  = "otlp_metrics"
+	defaultLogsTopic     = "otlp_logs"
 	defaultEncoding      = "otlp_proto"
 	defaultBroker        = "localhost:9092"
 	defaultClientID      = "otel-collector"
@@ -94,7 +96,6 @@ func NewFactory(options ...FactoryOption) receiver.Factory {
 
 func createDefaultConfig() component.Config {
 	return &Config{
-		Topic:         defaultTopic,
 		Encoding:      defaultEncoding,
 		Brokers:       []string{defaultBroker},
 		ClientID:      defaultClientID,
@@ -137,13 +138,16 @@ func (f *kafkaReceiverFactory) createTracesReceiver(
 		f.tracesUnmarshalers[encoding] = unmarshal
 	}
 
-	c := cfg.(*Config)
-	unmarshaler := f.tracesUnmarshalers[c.Encoding]
+	oCfg := *(cfg.(*Config))
+	if oCfg.Topic == "" {
+		oCfg.Topic = defaultTracesTopic
+	}
+	unmarshaler := f.tracesUnmarshalers[oCfg.Encoding]
 	if unmarshaler == nil {
 		return nil, errUnrecognizedEncoding
 	}
 
-	r, err := newTracesReceiver(*c, set, unmarshaler, nextConsumer)
+	r, err := newTracesReceiver(oCfg, set, unmarshaler, nextConsumer)
 	if err != nil {
 		return nil, err
 	}
@@ -160,13 +164,16 @@ func (f *kafkaReceiverFactory) createMetricsReceiver(
 		f.metricsUnmarshalers[encoding] = unmarshal
 	}
 
-	c := cfg.(*Config)
-	unmarshaler := f.metricsUnmarshalers[c.Encoding]
+	oCfg := *(cfg.(*Config))
+	if oCfg.Topic == "" {
+		oCfg.Topic = defaultMetricsTopic
+	}
+	unmarshaler := f.metricsUnmarshalers[oCfg.Encoding]
 	if unmarshaler == nil {
 		return nil, errUnrecognizedEncoding
 	}
 
-	r, err := newMetricsReceiver(*c, set, unmarshaler, nextConsumer)
+	r, err := newMetricsReceiver(oCfg, set, unmarshaler, nextConsumer)
 	if err != nil {
 		return nil, err
 	}
@@ -183,13 +190,16 @@ func (f *kafkaReceiverFactory) createLogsReceiver(
 		f.logsUnmarshalers[encoding] = unmarshaler
 	}
 
-	c := cfg.(*Config)
-	unmarshaler, err := getLogsUnmarshaler(c.Encoding, f.logsUnmarshalers)
+	oCfg := *(cfg.(*Config))
+	if oCfg.Topic == "" {
+		oCfg.Topic = defaultLogsTopic
+	}
+	unmarshaler, err := getLogsUnmarshaler(oCfg.Encoding, f.logsUnmarshalers)
 	if err != nil {
 		return nil, err
 	}
 
-	r, err := newLogsReceiver(*c, set, unmarshaler, nextConsumer)
+	r, err := newLogsReceiver(oCfg, set, unmarshaler, nextConsumer)
 	if err != nil {
 		return nil, err
 	}

receiver/kafkareceiver/factory_test.go

@@ -23,7 +23,6 @@ func TestCreateDefaultConfig(t *testing.T) {
 	assert.NotNil(t, cfg, "failed to create default config")
 	assert.NoError(t, componenttest.CheckConfigStruct(cfg))
 	assert.Equal(t, []string{defaultBroker}, cfg.Brokers)
-	assert.Equal(t, defaultTopic, cfg.Topic)
 	assert.Equal(t, defaultGroupID, cfg.GroupID)
 	assert.Equal(t, defaultClientID, cfg.ClientID)
 	assert.Equal(t, defaultInitialOffset, cfg.InitialOffset)
@@ -62,12 +61,18 @@ func TestWithTracesUnmarshalers(t *testing.T) {
 	t.Run("custom_encoding", func(t *testing.T) {
 		cfg.Encoding = unmarshaler.Encoding()
 		receiver, err := f.CreateTracesReceiver(context.Background(), receivertest.NewNopCreateSettings(), cfg, nil)
+		tracesConsumer, ok := receiver.(*kafkaTracesConsumer)
+		require.True(t, ok)
+		require.Equal(t, defaultTracesTopic, tracesConsumer.config.Topic)
 		require.NoError(t, err)
 		require.NotNil(t, receiver)
 	})
 	t.Run("default_encoding", func(t *testing.T) {
 		cfg.Encoding = defaultEncoding
 		receiver, err := f.CreateTracesReceiver(context.Background(), receivertest.NewNopCreateSettings(), cfg, nil)
+		tracesConsumer, ok := receiver.(*kafkaTracesConsumer)
+		require.True(t, ok)
+		require.Equal(t, defaultTracesTopic, tracesConsumer.config.Topic)
 		require.NoError(t, err)
 		assert.NotNil(t, receiver)
 	})
@@ -106,12 +111,18 @@ func TestWithMetricsUnmarshalers(t *testing.T) {
 	t.Run("custom_encoding", func(t *testing.T) {
 		cfg.Encoding = unmarshaler.Encoding()
 		receiver, err := f.CreateMetricsReceiver(context.Background(), receivertest.NewNopCreateSettings(), cfg, nil)
+		metricsConsumer, ok := receiver.(*kafkaMetricsConsumer)
+		require.True(t, ok)
+		require.Equal(t, defaultMetricsTopic, metricsConsumer.config.Topic)
 		require.NoError(t, err)
 		require.NotNil(t, receiver)
 	})
 	t.Run("default_encoding", func(t *testing.T) {
 		cfg.Encoding = defaultEncoding
 		receiver, err := f.CreateMetricsReceiver(context.Background(), receivertest.NewNopCreateSettings(), cfg, nil)
+		metricsConsumer, ok := receiver.(*kafkaMetricsConsumer)
+		require.True(t, ok)
+		require.Equal(t, defaultMetricsTopic, metricsConsumer.config.Topic)
 		require.NoError(t, err)
 		assert.NotNil(t, receiver)
 	})
@@ -171,26 +182,29 @@ func TestWithLogsUnmarshalers(t *testing.T) {
 
 	t.Run("custom_encoding", func(t *testing.T) {
 		cfg.Encoding = unmarshaler.Encoding()
-		exporter, err := f.CreateLogsReceiver(context.Background(), receivertest.NewNopCreateSettings(), cfg, nil)
+		receiver, err := f.CreateLogsReceiver(context.Background(), receivertest.NewNopCreateSettings(), cfg, nil)
+		logsConsumer, ok := receiver.(*kafkaLogsConsumer)
+		require.True(t, ok)
+		require.Equal(t, defaultLogsTopic, logsConsumer.config.Topic)
 		require.NoError(t, err)
-		require.NotNil(t, exporter)
+		require.NotNil(t, receiver)
 	})
 	t.Run("default_encoding", func(t *testing.T) {
 		cfg.Encoding = defaultEncoding
-		exporter, err := f.CreateLogsReceiver(context.Background(), receivertest.NewNopCreateSettings(), cfg, nil)
+		receiver, err := f.CreateLogsReceiver(context.Background(), receivertest.NewNopCreateSettings(), cfg, nil)
+		logsConsumer, ok := receiver.(*kafkaLogsConsumer)
+		require.True(t, ok)
+		require.Equal(t, defaultLogsTopic, logsConsumer.config.Topic)
 		require.NoError(t, err)
-		assert.NotNil(t, exporter)
+		assert.NotNil(t, receiver)
 	})
 }
 
-type customTracesUnmarshaler struct {
-}
+type customTracesUnmarshaler struct{}
 
-type customMetricsUnmarshaler struct {
-}
+type customMetricsUnmarshaler struct{}
 
-type customLogsUnmarshaler struct {
-}
+type customLogsUnmarshaler struct{}
 
 var _ TracesUnmarshaler = (*customTracesUnmarshaler)(nil)