[cmd/telemetrygen] Better defaults for HTTP exporter mode (open-telem…

…etry#27007)

**Description:**

- Refactored and moved `otlp-http-url-path` flag from the common flags
for each command
    - Added flag to the `traces` command with the default `/v1/traces`
    - Added flag to the `metrics` command with the default `/v1/metrics`
    - Flag was not used for the `logs` command so no longer exposed
- Handle changing the default endpoint based on the communication mode
(gRPC or HTTP)
- Flag `--otlp-endpoint` now defaults to empty string and targets a new
attribute `CustomEndpoint` on `common.Config`
- Added the `Endpoint()` getter function to the `common.Config` struct
for retrieving the correct endpoint
- When `CustomEndpoint` is empty then either `DefaultGRPCEndpoint` or
`DefaultHTTPEndpoint` are chosen based upon the value of
`config.UseHTTP`
- **Misc**: Split out the creation of trace/metric exporters into
standalone factory functions with docstrings available in `exporters.go`
in both modules
- **Misc**: Removed the "default value is" from the descriptions of some
flags as it was repeated information

**Link to tracking Issue:** open-telemetry#26999

**Testing:** 

Added new set of unit tests to cover the addition of the
`config.Endpoint()` getter.

Running `telemetrygen traces --otlp-http --otlp-insecure` now correctly
sends traces using HTTP to the default HTTP endpoint.

**Documentation:** 

No documentation added/changed but updated some command flag
descriptions.

---------

Co-authored-by: Alex Boten <aboten@lightstep.com>

.chloggen/fix_default-http-exporter-behaviour.yaml

@@ -0,0 +1,29 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: telemetrygen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: better defaults for http exporter mode
+
+# Mandatory: One or more tracking issues related to the change. You can use the PR number here if no issue exists.
+issues: [26999]
+
+# (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: | 
+  - the url path default is now correct for both traces and metrics
+  - when not provided, the endpoint is automatically set to target a local gRPC or HTTP endpoint depending on the communication mode selected
+
+# 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]

cmd/telemetrygen/config_test.go

@@ -0,0 +1,25 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestConfig_HTTPPath verifies that the HTTPPath configuration defaults are correctly set for each sub-command.
+func TestConfig_HTTPPath(t *testing.T) {
+	t.Run("LogsConfigEmptyDefaultUrlPath", func(t *testing.T) {
+		assert.Equal(t, "", logsCfg.HTTPPath)
+	})
+
+	t.Run("MetricsConfigValidDefaultUrlPath", func(t *testing.T) {
+		assert.Equal(t, "/v1/metrics", metricsCfg.HTTPPath)
+	})
+
+	t.Run("TracesConfigValidDefaultUrlPath", func(t *testing.T) {
+		assert.Equal(t, "/v1/traces", tracesCfg.HTTPPath)
+	})
+}

cmd/telemetrygen/internal/common/config.go

@@ -17,6 +17,11 @@ var (
 	errDoubleQuotesOTLPAttributes = fmt.Errorf("value should be a string wrapped in double quotes")
 )
 
+const (
+	defaultGRPCEndpoint = "localhost:4317"
+	defaultHTTPEndpoint = "localhost:4318"
+)
+
 type KeyValue map[string]string
 
 var _ pflag.Value = (*KeyValue)(nil)
@@ -51,7 +56,7 @@ type Config struct {
 	SkipSettingGRPCLogger bool
 
 	// OTLP config
-	Endpoint            string
+	CustomEndpoint      string
 	Insecure            bool
 	UseHTTP             bool
 	HTTPPath            string
@@ -60,6 +65,18 @@ type Config struct {
 	TelemetryAttributes KeyValue
 }
 
+// Endpoint returns the appropriate endpoint URL based on the selected communication mode (gRPC or HTTP)
+// or custom endpoint provided in the configuration.
+func (c *Config) Endpoint() string {
+	if c.CustomEndpoint != "" {
+		return c.CustomEndpoint
+	}
+	if c.UseHTTP {
+		return defaultHTTPEndpoint
+	}
+	return defaultGRPCEndpoint
+}
+
 func (c *Config) GetAttributes() []attribute.KeyValue {
 	var attributes []attribute.KeyValue
 
@@ -87,12 +104,11 @@ func (c *Config) CommonFlags(fs *pflag.FlagSet) {
 	fs.IntVar(&c.WorkerCount, "workers", 1, "Number of workers (goroutines) to run")
 	fs.Int64Var(&c.Rate, "rate", 0, "Approximately how many metrics per second each worker should generate. Zero means no throttling.")
 	fs.DurationVar(&c.TotalDuration, "duration", 0, "For how long to run the test")
-	fs.DurationVar(&c.ReportingInterval, "interval", 1*time.Second, "Reporting interval (default 1 second)")
+	fs.DurationVar(&c.ReportingInterval, "interval", 1*time.Second, "Reporting interval")
 
-	fs.StringVar(&c.Endpoint, "otlp-endpoint", "localhost:4317", "Target to which the exporter is going to send metrics.")
+	fs.StringVar(&c.CustomEndpoint, "otlp-endpoint", "", "Destination endpoint for exporting logs, metrics and traces")
 	fs.BoolVar(&c.Insecure, "otlp-insecure", false, "Whether to enable client transport security for the exporter's grpc or http connection")
 	fs.BoolVar(&c.UseHTTP, "otlp-http", false, "Whether to use HTTP exporter rather than a gRPC one")
-	fs.StringVar(&c.HTTPPath, "otlp-http-url-path", "/v1/metrics", "Which URL path to write to (default /v1/metrics)")
 
 	// custom headers
 	c.Headers = make(map[string]string)

cmd/telemetrygen/internal/common/config_test.go

@@ -49,3 +49,54 @@ func TestKeyValueSet(t *testing.T) {
 		})
 	}
 }
+
+func TestEndpoint(t *testing.T) {
+	tests := []struct {
+		name     string
+		endpoint string
+		http     bool
+		expected string
+	}{
+		{
+			"default-no-http",
+			"",
+			false,
+			defaultGRPCEndpoint,
+		},
+		{
+			"default-with-http",
+			"",
+			true,
+			defaultHTTPEndpoint,
+		},
+		{
+			"custom-endpoint-no-http",
+			"collector:4317",
+			false,
+			"collector:4317",
+		},
+		{
+			"custom-endpoint-with-http",
+			"collector:4317",
+			true,
+			"collector:4317",
+		},
+		{
+			"wrong-custom-endpoint-with-http",
+			defaultGRPCEndpoint,
+			true,
+			defaultGRPCEndpoint,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			cfg := &Config{
+				CustomEndpoint: tc.endpoint,
+				UseHTTP:        tc.http,
+			}
+
+			assert.Equal(t, tc.expected, cfg.Endpoint())
+		})
+	}
+}

cmd/telemetrygen/internal/logs/logs.go

@@ -54,7 +54,7 @@ func Start(cfg *Config) error {
 	}
 
 	// only support grpc in insecure mode
-	clientConn, err := grpc.DialContext(context.TODO(), cfg.Endpoint, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	clientConn, err := grpc.DialContext(context.TODO(), cfg.Endpoint(), grpc.WithTransportCredentials(insecure.NewCredentials()))
 	if err != nil {
 		return err
 	}

cmd/telemetrygen/internal/metrics/config.go

@@ -22,6 +22,9 @@ func (c *Config) Flags(fs *pflag.FlagSet) {
 	c.MetricType = metricTypeGauge
 
 	c.CommonFlags(fs)
+
+	fs.StringVar(&c.HTTPPath, "otlp-http-url-path", "/v1/metrics", "Which URL path to write to")
+
 	fs.Var(&c.MetricType, "metric-type", "Metric type enum. must be one of 'Gauge' or 'Sum'")
 	fs.IntVar(&c.NumMetrics, "metrics", 1, "Number of metrics to generate in each worker (ignored if duration is provided)")
 }

cmd/telemetrygen/internal/metrics/exporter.go

@@ -0,0 +1,50 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package metrics
+
+import (
+	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetricgrpc"
+	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
+	"google.golang.org/grpc"
+)
+
+// grpcExporterOptions creates the configuration options for a gRPC-based OTLP metric exporter.
+// It configures the exporter with the provided endpoint, connection security settings, and headers.
+func grpcExporterOptions(cfg *Config) []otlpmetricgrpc.Option {
+	grpcExpOpt := []otlpmetricgrpc.Option{
+		otlpmetricgrpc.WithEndpoint(cfg.Endpoint()),
+		otlpmetricgrpc.WithDialOption(
+			grpc.WithBlock(),
+		),
+	}
+
+	if cfg.Insecure {
+		grpcExpOpt = append(grpcExpOpt, otlpmetricgrpc.WithInsecure())
+	}
+
+	if len(cfg.Headers) > 0 {
+		grpcExpOpt = append(grpcExpOpt, otlpmetricgrpc.WithHeaders(cfg.Headers))
+	}
+
+	return grpcExpOpt
+}
+
+// httpExporterOptions creates the configuration options for an HTTP-based OTLP metric exporter.
+// It configures the exporter with the provided endpoint, URL path, connection security settings, and headers.
+func httpExporterOptions(cfg *Config) []otlpmetrichttp.Option {
+	httpExpOpt := []otlpmetrichttp.Option{
+		otlpmetrichttp.WithEndpoint(cfg.Endpoint()),
+		otlpmetrichttp.WithURLPath(cfg.HTTPPath),
+	}
+
+	if cfg.Insecure {
+		httpExpOpt = append(httpExpOpt, otlpmetrichttp.WithInsecure())
+	}
+
+	if len(cfg.Headers) > 0 {
+		httpExpOpt = append(httpExpOpt, otlpmetrichttp.WithHeaders(cfg.Headers))
+	}
+
+	return httpExpOpt
+}

cmd/telemetrygen/internal/metrics/metrics.go

@@ -17,7 +17,6 @@ import (
 	"go.opentelemetry.io/otel/sdk/resource"
 	"go.uber.org/zap"
 	"golang.org/x/time/rate"
-	"google.golang.org/grpc"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/telemetrygen/internal/common"
 )
@@ -30,35 +29,13 @@ func Start(cfg *Config) error {
 	}
 	logger.Info("starting the metrics generator with configuration", zap.Any("config", cfg))
 
-	grpcExpOpt := []otlpmetricgrpc.Option{
-		otlpmetricgrpc.WithEndpoint(cfg.Endpoint),
-		otlpmetricgrpc.WithDialOption(
-			grpc.WithBlock(),
-		),
-	}
-
-	httpExpOpt := []otlpmetrichttp.Option{
-		otlpmetrichttp.WithEndpoint(cfg.Endpoint),
-		otlpmetrichttp.WithURLPath(cfg.HTTPPath),
-	}
-
-	if cfg.Insecure {
-		grpcExpOpt = append(grpcExpOpt, otlpmetricgrpc.WithInsecure())
-		httpExpOpt = append(httpExpOpt, otlpmetrichttp.WithInsecure())
-	}
-
-	if len(cfg.Headers) > 0 {
-		grpcExpOpt = append(grpcExpOpt, otlpmetricgrpc.WithHeaders(cfg.Headers))
-		httpExpOpt = append(httpExpOpt, otlpmetrichttp.WithHeaders(cfg.Headers))
-	}
-
 	var exp sdkmetric.Exporter
 	if cfg.UseHTTP {
 		logger.Info("starting HTTP exporter")
-		exp, err = otlpmetrichttp.New(context.Background(), httpExpOpt...)
+		exp, err = otlpmetrichttp.New(context.Background(), httpExporterOptions(cfg)...)
 	} else {
 		logger.Info("starting gRPC exporter")
-		exp, err = otlpmetricgrpc.New(context.Background(), grpcExpOpt...)
+		exp, err = otlpmetricgrpc.New(context.Background(), grpcExporterOptions(cfg)...)
 	}
 
 	if err != nil {

cmd/telemetrygen/internal/traces/config.go

@@ -26,6 +26,9 @@ type Config struct {
 // Flags registers config flags.
 func (c *Config) Flags(fs *pflag.FlagSet) {
 	c.CommonFlags(fs)
+
+	fs.StringVar(&c.HTTPPath, "otlp-http-url-path", "/v1/traces", "Which URL path to write to")
+
 	fs.IntVar(&c.NumTraces, "traces", 1, "Number of traces to generate in each worker (ignored if duration is provided)")
 	fs.BoolVar(&c.PropagateContext, "marshal", false, "Whether to marshal trace context via HTTP headers")
 	fs.StringVar(&c.ServiceName, "service", "telemetrygen", "Service name to use")

cmd/telemetrygen/internal/traces/exporter.go

@@ -0,0 +1,50 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package traces
+
+import (
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracegrpc"
+	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
+	"google.golang.org/grpc"
+)
+
+// grpcExporterOptions creates the configuration options for a gRPC-based OTLP trace exporter.
+// It configures the exporter with the provided endpoint, connection security settings, and headers.
+func grpcExporterOptions(cfg *Config) []otlptracegrpc.Option {
+	grpcExpOpt := []otlptracegrpc.Option{
+		otlptracegrpc.WithEndpoint(cfg.Endpoint()),
+		otlptracegrpc.WithDialOption(
+			grpc.WithBlock(),
+		),
+	}
+
+	if cfg.Insecure {
+		grpcExpOpt = append(grpcExpOpt, otlptracegrpc.WithInsecure())
+	}
+
+	if len(cfg.Headers) > 0 {
+		grpcExpOpt = append(grpcExpOpt, otlptracegrpc.WithHeaders(cfg.Headers))
+	}
+
+	return grpcExpOpt
+}
+
+// httpExporterOptions creates the configuration options for an HTTP-based OTLP trace exporter.
+// It configures the exporter with the provided endpoint, URL path, connection security settings, and headers.
+func httpExporterOptions(cfg *Config) []otlptracehttp.Option {
+	httpExpOpt := []otlptracehttp.Option{
+		otlptracehttp.WithEndpoint(cfg.Endpoint()),
+		otlptracehttp.WithURLPath(cfg.HTTPPath),
+	}
+
+	if cfg.Insecure {
+		httpExpOpt = append(httpExpOpt, otlptracehttp.WithInsecure())
+	}
+
+	if len(cfg.Headers) > 0 {
+		httpExpOpt = append(httpExpOpt, otlptracehttp.WithHeaders(cfg.Headers))
+	}
+
+	return httpExpOpt
+}

cmd/telemetrygen/internal/traces/traces.go

@@ -22,7 +22,6 @@ import (
 	semconv "go.opentelemetry.io/otel/semconv/v1.4.0"
 	"go.uber.org/zap"
 	"golang.org/x/time/rate"
-	"google.golang.org/grpc"
 
 	"github.com/open-telemetry/opentelemetry-collector-contrib/cmd/telemetrygen/internal/common"
 )
@@ -33,35 +32,13 @@ func Start(cfg *Config) error {
 		return err
 	}
 
-	grpcExpOpt := []otlptracegrpc.Option{
-		otlptracegrpc.WithEndpoint(cfg.Endpoint),
-		otlptracegrpc.WithDialOption(
-			grpc.WithBlock(),
-		),
-	}
-
-	httpExpOpt := []otlptracehttp.Option{
-		otlptracehttp.WithEndpoint(cfg.Endpoint),
-		otlptracehttp.WithURLPath(cfg.HTTPPath),
-	}
-
-	if cfg.Insecure {
-		grpcExpOpt = append(grpcExpOpt, otlptracegrpc.WithInsecure())
-		httpExpOpt = append(httpExpOpt, otlptracehttp.WithInsecure())
-	}
-
-	if len(cfg.Headers) > 0 {
-		grpcExpOpt = append(grpcExpOpt, otlptracegrpc.WithHeaders(cfg.Headers))
-		httpExpOpt = append(httpExpOpt, otlptracehttp.WithHeaders(cfg.Headers))
-	}
-
 	var exp *otlptrace.Exporter
 	if cfg.UseHTTP {
 		logger.Info("starting HTTP exporter")
-		exp, err = otlptracehttp.New(context.Background(), httpExpOpt...)
+		exp, err = otlptracehttp.New(context.Background(), httpExporterOptions(cfg)...)
 	} else {
 		logger.Info("starting gRPC exporter")
-		exp, err = otlptracegrpc.New(context.Background(), grpcExpOpt...)
+		exp, err = otlptracegrpc.New(context.Background(), grpcExporterOptions(cfg)...)
 	}
 
 	if err != nil {

cmd/telemetrygen/main_test.go

@@ -38,7 +38,7 @@ func TestGenerateTraces(t *testing.T) {
 			Rate:                  10,
 			TotalDuration:         10 * time.Second,
 			ReportingInterval:     10,
-			Endpoint:              endpoint,
+			CustomEndpoint:        endpoint,
 			Insecure:              true,
 			UseHTTP:               false,
 			Headers:               nil,