refactor: Improve the OtelConfig handling (#41)

Signed-off-by: Joonas Bergius <joonas@cosmonic.com>

host.go

@@ -1,6 +1,10 @@
 package provider
 
-import "encoding/json"
+import (
+	"encoding/json"
+	"fmt"
+	"strings"
+)
 
 type RedactedString string
 
@@ -31,6 +35,118 @@ type OtelConfig struct {
 	Protocol              string `json:"protocol,omitempty"`
 }
 
+type otelSignal int
+
+const (
+	traces otelSignal = iota
+	metrics
+	logs
+
+	// https://opentelemetry.io/docs/languages/sdk-configuration/otlp-exporter/#otel_exporter_otlp_endpoint
+	OtelExporterGrpcEndpoint = "http://localhost:4317"
+	OtelExporterHttpEndpoint = "http://localhost:4318"
+
+	// https://opentelemetry.io/docs/languages/sdk-configuration/otlp-exporter/#otel_exporter_otlp_traces_endpoint
+	OtelExporterHttpTracesPath = "/v1/traces"
+	// https://opentelemetry.io/docs/languages/sdk-configuration/otlp-exporter/#otel_exporter_otlp_metrics_endpoint
+	OtelExporterHttpMetricsPath = "/v1/metrics"
+	// https://opentelemetry.io/docs/languages/sdk-configuration/otlp-exporter/#otel_exporter_otlp_logs_endpoint
+	OtelExporterHttpLogsPath = "/v1/logs"
+)
+
+// OtelProtocol returns the configured OpenTelemetry protocol if one is provided,
+// otherwise defaulting to http.
+func (config *OtelConfig) OtelProtocol() string {
+	protocol := OtelProtocolHTTP
+	if config.Protocol != "" {
+		protocol = strings.ToLower(config.Protocol)
+	}
+	return protocol
+}
+
+// TracesURL returns the configured TracesEndpoint as-is if one is provided,
+// otherwise it resolves the URL based on ObservabilityEndpoint value and the
+// Protocol appropriate path.
+func (config *OtelConfig) TracesURL() string {
+	if config.TracesEndpoint != "" {
+		return config.TracesEndpoint
+	}
+
+	return config.resolveSignalUrl(traces)
+}
+
+// MetricsURL returns the configured MetricsEndpoint as-is if one is provided,
+// otherwise it resolves the URL based on ObservabilityEndpoint value and the
+// Protocol appropriate path.
+func (config *OtelConfig) MetricsURL() string {
+	if config.MetricsEndpoint != "" {
+		return config.MetricsEndpoint
+	}
+
+	return config.resolveSignalUrl(metrics)
+}
+
+// LogsURL returns the configured LogsEndpoint as-is if one is provided,
+// otherwise it resolves the URL based on ObservabilityEndpoint value and the
+// Protocol appropriate path.
+func (config *OtelConfig) LogsURL() string {
+	if config.LogsEndpoint != "" {
+		return config.LogsEndpoint
+	}
+
+	return config.resolveSignalUrl(logs)
+}
+
+// TracesEnabled returns whether emitting traces has been enabled.
+func (config *OtelConfig) TracesEnabled() bool {
+	return config.EnableObservability || config.EnableTraces
+}
+
+// MetricsEnabled returns whether emitting metrics has been enabled.
+func (config *OtelConfig) MetricsEnabled() bool {
+	return config.EnableObservability || config.EnableMetrics
+}
+
+// LogsEnabled returns whether emitting logs has been enabled.
+func (config *OtelConfig) LogsEnabled() bool {
+	return config.EnableObservability || config.EnableLogs
+}
+
+func (config *OtelConfig) resolveSignalUrl(signal otelSignal) string {
+	endpoint := config.defaultEndpoint()
+	if config.ObservabilityEndpoint != "" {
+		endpoint = config.ObservabilityEndpoint
+	}
+	endpoint = strings.TrimRight(endpoint, "/")
+
+	return fmt.Sprintf("%s%s", endpoint, config.defaultSignalPath(signal))
+}
+
+func (config *OtelConfig) defaultEndpoint() string {
+	endpoint := OtelExporterHttpEndpoint
+	if config.OtelProtocol() == OtelProtocolGRPC {
+		endpoint = OtelExporterGrpcEndpoint
+	}
+	return endpoint
+}
+
+func (config *OtelConfig) defaultSignalPath(signal otelSignal) string {
+	// In case of gRPC, we return empty string gRPC doesn't need a path to be set for it.
+	if config.OtelProtocol() == OtelProtocolGRPC {
+		return ""
+	}
+
+	switch signal {
+	case traces:
+		return OtelExporterHttpTracesPath
+	case metrics:
+		return OtelExporterHttpMetricsPath
+	case logs:
+		return OtelExporterHttpLogsPath
+	}
+	return ""
+}
+
 type HostData struct {
 	HostID                 string                     `json:"host_id,omitempty"`
 	LatticeRPCPrefix       string                     `json:"lattice_rpc_prefix,omitempty"`

host_test.go

@@ -28,3 +28,168 @@ func TestRedactedStringLogging(t *testing.T) {
 		t.Error("text slog handler should not have contained the secret string")
 	}
 }
+
+func TestOtelConfigProtocol(t *testing.T) {
+	type test struct {
+		name     string
+		config   OtelConfig
+		protocol string
+	}
+
+	tests := []test{
+		{
+			name:     "Defaults to http",
+			config:   OtelConfig{},
+			protocol: "http",
+		},
+		{
+			name:     "Explicit Grpc Rust enum variant",
+			config:   OtelConfig{Protocol: "Grpc"},
+			protocol: "grpc",
+		},
+		{
+			name:     "Explicit Http Rust enum variant",
+			config:   OtelConfig{Protocol: "Http"},
+			protocol: "http",
+		},
+	}
+
+	for _, tc := range tests {
+		if tc.config.OtelProtocol() != tc.protocol {
+			t.Fatalf("%s / OtelProtocol: expected %q, got: %q", tc.name, tc.protocol, tc.config.OtelProtocol())
+		}
+	}
+}
+
+func TestOtelConfigURLs(t *testing.T) {
+	type test struct {
+		name       string
+		config     OtelConfig
+		tracesURL  string
+		metricsURL string
+		logsURL    string
+	}
+
+	tests := []test{
+		{
+			name:       "Defaults with HTTP",
+			config:     OtelConfig{},
+			tracesURL:  "http://localhost:4318/v1/traces",
+			metricsURL: "http://localhost:4318/v1/metrics",
+			logsURL:    "http://localhost:4318/v1/logs",
+		},
+		{
+			name:       "Defaults with gRPC",
+			config:     OtelConfig{Protocol: "Grpc"},
+			tracesURL:  "http://localhost:4317",
+			metricsURL: "http://localhost:4317",
+			logsURL:    "http://localhost:4317",
+		},
+		{
+			name:       "Custom ObservabilityEndpoint",
+			config:     OtelConfig{ObservabilityEndpoint: "https://api.opentelemetry.com"},
+			tracesURL:  "https://api.opentelemetry.com/v1/traces",
+			metricsURL: "https://api.opentelemetry.com/v1/metrics",
+			logsURL:    "https://api.opentelemetry.com/v1/logs",
+		},
+		{
+			name:       "Custom ObservabilityEndpoint with gRPC",
+			config:     OtelConfig{Protocol: "grpc", ObservabilityEndpoint: "https://api.opentelemetry.com"},
+			tracesURL:  "https://api.opentelemetry.com",
+			metricsURL: "https://api.opentelemetry.com",
+			logsURL:    "https://api.opentelemetry.com",
+		},
+		{
+			name:       "Custom TracesEndpoint",
+			config:     OtelConfig{TracesEndpoint: "https://api.opentelemetry.com/v1/traces"},
+			tracesURL:  "https://api.opentelemetry.com/v1/traces",
+			metricsURL: "http://localhost:4318/v1/metrics",
+			logsURL:    "http://localhost:4318/v1/logs",
+		},
+		{
+			name:       "Custom MetricsEndpoint",
+			config:     OtelConfig{MetricsEndpoint: "https://api.opentelemetry.com/v1/metrics"},
+			tracesURL:  "http://localhost:4318/v1/traces",
+			metricsURL: "https://api.opentelemetry.com/v1/metrics",
+			logsURL:    "http://localhost:4318/v1/logs",
+		},
+		{
+			name:       "Custom LogsEndpoint",
+			config:     OtelConfig{LogsEndpoint: "https://api.opentelemetry.com/v1/logs"},
+			tracesURL:  "http://localhost:4318/v1/traces",
+			metricsURL: "http://localhost:4318/v1/metrics",
+			logsURL:    "https://api.opentelemetry.com/v1/logs",
+		},
+	}
+
+	for _, tc := range tests {
+		if tc.config.TracesURL() != tc.tracesURL {
+			t.Fatalf("%s / TracesURL: expected %s, got: %s", tc.name, tc.tracesURL, tc.config.TracesURL())
+		}
+		if tc.config.MetricsURL() != tc.metricsURL {
+			t.Fatalf("%s / MetricsURL: expected %s, got: %s", tc.name, tc.metricsURL, tc.config.MetricsURL())
+		}
+		if tc.config.LogsURL() != tc.logsURL {
+			t.Fatalf("%s / LogsURL: expected %s, got: %s", tc.name, tc.logsURL, tc.config.LogsURL())
+		}
+	}
+}
+
+func TestOtelConfigBooleans(t *testing.T) {
+	type test struct {
+		name           string
+		config         OtelConfig
+		tracesEnabled  bool
+		metricsEnabled bool
+		logsEnabled    bool
+	}
+
+	tests := []test{
+		{
+			name:           "Defaults",
+			config:         OtelConfig{},
+			tracesEnabled:  false,
+			metricsEnabled: false,
+			logsEnabled:    false,
+		},
+		{
+			name:           "Enable all with EnableObservability",
+			config:         OtelConfig{EnableObservability: true},
+			tracesEnabled:  true,
+			metricsEnabled: true,
+			logsEnabled:    true,
+		},
+		{
+			name:           "Enable just traces",
+			config:         OtelConfig{EnableTraces: true},
+			tracesEnabled:  true,
+			metricsEnabled: false,
+			logsEnabled:    false,
+		},
+		{
+			name:           "Enable just metrics",
+			config:         OtelConfig{EnableMetrics: true},
+			tracesEnabled:  false,
+			metricsEnabled: true,
+			logsEnabled:    false,
+		},
+		{
+			name:           "Enable just logs",
+			config:         OtelConfig{EnableLogs: true},
+			tracesEnabled:  false,
+			metricsEnabled: false,
+			logsEnabled:    true,
+		},
+	}
+	for _, tc := range tests {
+		if tc.config.TracesEnabled() != tc.tracesEnabled {
+			t.Fatalf("%s / TracesEnabled: expected %t, got: %t", tc.name, tc.tracesEnabled, tc.config.TracesEnabled())
+		}
+		if tc.config.MetricsEnabled() != tc.metricsEnabled {
+			t.Fatalf("%s / MetricsEnabled: expected %t, got: %t", tc.name, tc.metricsEnabled, tc.config.MetricsEnabled())
+		}
+		if tc.config.LogsEnabled() != tc.logsEnabled {
+			t.Fatalf("%s / LogsEnabled: expected %t, got: %t", tc.name, tc.logsEnabled, tc.config.LogsEnabled())
+		}
+	}
+}

observability.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"strings"
 	"time"
 
 	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc"
@@ -43,16 +42,11 @@ func newTracerProvider(ctx context.Context, config OtelConfig, serviceResource *
 	var exporter trace.SpanExporter
 	var err error
 
-	endpoint := config.TracesEndpoint
-	if endpoint == "" {
-		endpoint = config.ObservabilityEndpoint
-	}
-
-	switch strings.ToLower(config.Protocol) {
+	switch config.OtelProtocol() {
 	case OtelProtocolGRPC:
-		exporter, err = otlptracegrpc.New(ctx, otlptracegrpc.WithEndpointURL(endpoint))
+		exporter, err = otlptracegrpc.New(ctx, otlptracegrpc.WithEndpointURL(config.TracesURL()))
 	case OtelProtocolHTTP:
-		exporter, err = otlptracehttp.New(ctx, otlptracehttp.WithEndpointURL(endpoint))
+		exporter, err = otlptracehttp.New(ctx, otlptracehttp.WithEndpointURL(config.TracesURL()))
 	default:
 		return nil, fmt.Errorf("unknown observability protocol %q", config.Protocol)
 	}
@@ -82,16 +76,11 @@ func newMeterProvider(ctx context.Context, config OtelConfig, serviceResource *r
 	var exporter metric.Exporter
 	var err error
 
-	endpoint := config.MetricsEndpoint
-	if endpoint == "" {
-		endpoint = config.ObservabilityEndpoint
-	}
-
-	switch strings.ToLower(config.Protocol) {
+	switch config.OtelProtocol() {
 	case OtelProtocolGRPC:
-		exporter, err = otlpmetricgrpc.New(ctx, otlpmetricgrpc.WithEndpointURL(endpoint))
+		exporter, err = otlpmetricgrpc.New(ctx, otlpmetricgrpc.WithEndpointURL(config.MetricsURL()))
 	case OtelProtocolHTTP:
-		exporter, err = otlpmetrichttp.New(ctx, otlpmetrichttp.WithEndpointURL(endpoint))
+		exporter, err = otlpmetrichttp.New(ctx, otlpmetrichttp.WithEndpointURL(config.MetricsURL()))
 	default:
 		return nil, fmt.Errorf("unknown observability protocol %q", config.Protocol)
 	}
@@ -113,16 +102,11 @@ func newLoggerProvider(ctx context.Context, config OtelConfig, serviceResource *
 	var exporter log.Exporter
 	var err error
 
-	endpoint := config.LogsEndpoint
-	if endpoint == "" {
-		endpoint = config.ObservabilityEndpoint
-	}
-
-	switch strings.ToLower(config.Protocol) {
+	switch config.OtelProtocol() {
 	case OtelProtocolGRPC:
-		exporter, err = otlploggrpc.New(ctx, otlploggrpc.WithEndpointURL(endpoint))
+		exporter, err = otlploggrpc.New(ctx, otlploggrpc.WithEndpointURL(config.LogsURL()))
 	case OtelProtocolHTTP:
-		exporter, err = otlploghttp.New(ctx, otlploghttp.WithEndpointURL(endpoint))
+		exporter, err = otlploghttp.New(ctx, otlploghttp.WithEndpointURL(config.LogsURL()))
 	default:
 		return nil, fmt.Errorf("unknown observability protocol %q", config.Protocol)
 	}

provider.go

@@ -125,7 +125,7 @@ func NewWithHostDataSource(source io.Reader, options ...ProviderHandler) (*Wasmc
 		return nil, err
 	}
 
-	if hostData.OtelConfig.EnableObservability || hostData.OtelConfig.EnableMetrics {
+	if hostData.OtelConfig.MetricsEnabled() {
 		meterProvider, err := newMeterProvider(context.Background(), hostData.OtelConfig, serviceResource)
 		if err != nil {
 			return nil, err
@@ -134,7 +134,7 @@ func NewWithHostDataSource(source io.Reader, options ...ProviderHandler) (*Wasmc
 		internalShutdownFuncs = append(internalShutdownFuncs, func(c context.Context) error { return meterProvider.Shutdown(c) })
 	}
 
-	if hostData.OtelConfig.EnableObservability || hostData.OtelConfig.EnableTraces {
+	if hostData.OtelConfig.TracesEnabled() {
 		tracerProvider, err := newTracerProvider(context.Background(), hostData.OtelConfig, serviceResource)
 		if err != nil {
 			return nil, err
@@ -143,7 +143,7 @@ func NewWithHostDataSource(source io.Reader, options ...ProviderHandler) (*Wasmc
 		internalShutdownFuncs = append(internalShutdownFuncs, func(c context.Context) error { return tracerProvider.Shutdown(c) })
 	}
 
-	if hostData.OtelConfig.EnableObservability || hostData.OtelConfig.EnableLogs {
+	if hostData.OtelConfig.LogsEnabled() {
 		loggerProvider, err := newLoggerProvider(context.Background(), hostData.OtelConfig, serviceResource)
 		if err != nil {
 			return nil, err