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feat: Support Go observability initialization independent of plugins. (#230)
## Summary Allow for initialization of Go observability independent of the LaunchDarkly SDK. This allows for advanced use-cases where the LD SDK may not be in use, or may not be readily accessible. I called it `PreInitialize`, but I am not attached to that name. You do this: ```go // Initialize the observability plugin ahead of the LaunchDarkly client. // This is generally only required for advanced use cases and is not the // recommended way to initialize observability. // Observability can also be used without the LaunchDarkly client at all // by using this method. Some features will not be available when using // observability without the LaunchDarkly client. ldobserve.PreInitialize(os.Getenv("LAUNCHDARKLY_SDK_KEY"), ldobserve.WithEnvironment("test"), ldobserve.WithServiceName("go-plugin-example"), ldobserve.WithServiceVersion(version.Commit), ) ``` And now observability it setup. You can then later optionally use the plugin to facilitate registering hooks. ``` client, _ := ld.MakeCustomClient(os.Getenv("LAUNCHDARKLY_SDK_KEY"), ld.Config{ Plugins: []ldplugins.Plugin{ // This special form of constructing the observability plugin // is used when observability has been pre-initialized. ldobserve.NewObservabilityPluginWithoutInit(), }, }, 5*time.Second) ``` Or you can directly use the ldotel hook instead. Using the plugin will be more resilient in case we add more hooks. ## How did you test this change? Manual testing.
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‎e2e/go-plugin/README.md‎

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@@ -29,6 +29,7 @@ This project contains several examples, each demonstrating the LaunchDarkly Obse
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- [Gorilla Mux Example](#3-gorilla-mux-example-cmdgorillamux)
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- [Standard HTTP Example](#4-standard-http-example-cmdhttp)
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- [Logrus Example](#5-logrus-example-cmdlogrus)
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- [Pre-Initialize Example](#6-pre-initialize-example-cmdpreinit)
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### 1. Fiber Example (`cmd/fiber/`)
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@@ -117,4 +118,29 @@ go run cmd/logrus/logrus.go
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**Endpoints:**
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- `GET /log` - Logs structured data with various field types and demonstrates Logrus + OpenTelemetry integration
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### 6. Pre-Initialize Example (`cmd/preinit/`)
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A web server demonstrating advanced observability initialization patterns, including pre-initializing the observability plugin before the LaunchDarkly client.
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**Features:**
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- Uses `ldobserve.PreInitialize()` to initialize observability before the LaunchDarkly client
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- Demonstrates using observability without the LaunchDarkly client (with limited features)
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- Shows the `NewObservabilityPluginWithoutInit()` pattern for pre-initialized observability
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- Uses standard `net/http` package with OpenTelemetry instrumentation
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- Includes graceful shutdown handling
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- Demonstrates manual span creation and attribute setting
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**To run:**
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```bash
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go run cmd/preinit/preinit.go
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```
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**Endpoints:**
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- `GET /rolldice` - Rolls a dice and returns the result, with verbose output controlled by the `verbose-response` feature flag
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**Use Cases:**
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- Advanced initialization scenarios where you need observability before the LaunchDarkly client
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- Using observability features without a LaunchDarkly client (some features will be unavailable)
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- Custom initialization timing requirements
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‎e2e/go-plugin/cmd/preinit/preinit.go‎

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package main
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import (
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"context"
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"log"
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"net"
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"net/http"
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"os"
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"os/signal"
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"time"
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"go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp"
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"go.opentelemetry.io/otel/attribute"
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"go.opentelemetry.io/otel/trace"
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ld "github.com/launchdarkly/go-server-sdk/v7"
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"github.com/launchdarkly/go-server-sdk/v7/ldplugins"
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ldobserve "github.com/launchdarkly/observability-sdk/go"
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appcontext "dice/internal/context"
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"dice/internal/dice"
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"dice/internal/version"
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)
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func main() {
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if err := run(); err != nil {
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log.Fatalln(err)
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}
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}
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func run() (err error) {
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// Handle SIGINT (CTRL+C) gracefully.
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ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
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defer stop()
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// Initialize the observability plugin ahead of the LaunchDarkly client.
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// This is generally only required for advanced use cases and is not the
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// recommended way to initialize observability.
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// Observability can also be used without the LaunchDarkly client at all
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// by using this method. Some features will not be available when using
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// observability without the LaunchDarkly client.
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ldobserve.PreInitialize(os.Getenv("LAUNCHDARKLY_SDK_KEY"),
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ldobserve.WithEnvironment("test"),
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ldobserve.WithServiceName("go-plugin-example"),
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ldobserve.WithServiceVersion(version.Commit),
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)
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client, _ := ld.MakeCustomClient(os.Getenv("LAUNCHDARKLY_SDK_KEY"),
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ld.Config{
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Plugins: []ldplugins.Plugin{
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// This special form of constructing the observability plugin
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// is used when observability has been pre-initialized.
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ldobserve.NewObservabilityPluginWithoutInit(),
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},
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}, 5*time.Second)
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ctx = appcontext.WithLaunchDarklyClient(ctx, client)
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// Start HTTP server.
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srv := &http.Server{
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Addr: ":8080",
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BaseContext: func(_ net.Listener) context.Context { return ctx },
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ReadTimeout: time.Second,
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WriteTimeout: 10 * time.Second,
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Handler: newHTTPHandler(),
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}
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srvErr := make(chan error, 1)
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go func() {
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srvErr <- srv.ListenAndServe()
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}()
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// Wait for interruption.
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select {
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case err = <-srvErr:
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// Error when starting HTTP server.
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return err
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case <-ctx.Done():
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stop()
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}
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ldobserve.Shutdown()
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// When Shutdown is called, ListenAndServe immediately returns ErrServerClosed.
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err = srv.Shutdown(context.Background())
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return err
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}
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func newHTTPHandler() http.Handler {
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mux := http.NewServeMux()
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_, span := ldobserve.StartSpan(context.Background(), "test-span", []trace.SpanStartOption{})
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span.SetAttributes(attribute.String("test-attribute", "test-value"))
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span.End()
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// handleFunc is a replacement for mux.HandleFunc
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// which enriches the handler's HTTP instrumentation with the pattern as the http.route.
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handleFunc := func(pattern string, handlerFunc func(http.ResponseWriter, *http.Request)) {
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// Configure the "http.route" for the HTTP instrumentation.
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handler := otelhttp.WithRouteTag(pattern, http.HandlerFunc(handlerFunc))
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mux.Handle(pattern, handler)
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}
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// Register handlers.Als
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handleFunc("/rolldice", dice.Rolldice)
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// Add HTTP instrumentation for the whole server.
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handler := otelhttp.NewHandler(
108+
mux,
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"/",
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otelhttp.WithSpanNameFormatter(func(operation string, r *http.Request) string {
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// Return the route as the span name
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return r.URL.Path
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}))
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return handler
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}

‎go/initialize.go‎

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package ldobserve
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import (
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"context"
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"net/http"
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"github.com/Khan/genqlient/graphql"
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"go.opentelemetry.io/otel/attribute"
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"go.opentelemetry.io/otel/sdk/trace"
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semconv "go.opentelemetry.io/otel/semconv/v1.34.0"
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12+
"github.com/launchdarkly/observability-sdk/go/attributes"
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"github.com/launchdarkly/observability-sdk/go/internal/gql"
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"github.com/launchdarkly/observability-sdk/go/internal/logging"
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"github.com/launchdarkly/observability-sdk/go/internal/metadata"
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"github.com/launchdarkly/observability-sdk/go/internal/otel"
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)
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func getSamplingConfig(projectId string, config observabilityConfig) (*gql.GetSamplingConfigResponse, error) {
20+
var ctx context.Context
21+
if config.context != nil {
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ctx = config.context
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} else {
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ctx = context.Background()
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}
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client := graphql.NewClient(config.backendURL, http.DefaultClient)
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return gql.GetSamplingConfig(ctx, client, projectId)
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}
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func setupOtel(sdkKey string, config observabilityConfig) {
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attributes := []attribute.KeyValue{
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semconv.TelemetryDistroNameKey.String(metadata.InstrumentationName),
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semconv.TelemetryDistroVersionKey.String(metadata.InstrumentationVersion),
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attribute.String(attributes.ProjectIDAttribute, sdkKey),
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}
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if config.environment != "" {
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attributes = append(attributes, semconv.DeploymentEnvironmentName(config.environment))
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}
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if config.serviceName != "" {
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attributes = append(attributes, semconv.ServiceNameKey.String(config.serviceName))
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}
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if config.serviceVersion != "" {
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attributes = append(attributes, semconv.ServiceVersionKey.String(config.serviceVersion))
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}
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if config.debug {
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logging.SetLogger(logging.ConsoleLogger{})
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}
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var s trace.Sampler
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if len(config.samplingRateMap) > 0 {
51+
s = getSampler(config.samplingRateMap)
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} else {
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s = nil
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}
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otel.SetConfig(otel.Config{
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OtlpEndpoint: config.otlpEndpoint,
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ResourceAttributes: attributes,
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Sampler: s,
59+
})
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if !config.manualStart {
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err := otel.StartOTLP()
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if err != nil {
63+
logging.GetLogger().Errorf("failed to start otel: %v", err)
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}
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}
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go func() {
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cfg, err := getSamplingConfig(sdkKey, config)
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if err != nil {
69+
logging.GetLogger().Errorf("failed to get sampling config: %v", err)
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return
71+
}
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logging.GetLogger().Infof("got sampling config: %v", cfg)
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otel.SetSamplingConfig(cfg)
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}()
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if config.context != nil {
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go func() {
77+
<-config.context.Done()
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otel.Shutdown()
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}()
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}
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}
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// PreInitialize initializes the observability plugin independently of the
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// LaunchDarkly client.
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//
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// In most situations the plugin should be used instead of this function.
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// In cases where the usage of observability needs to be flagged, the plugin
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// can be used with the WithManualStart option.
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//
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// This function is provided for situations where the LaunchDarkly client is not
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// readily available, or when observability needs to be initialized earlier than
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// the LaunchDarkly client.
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func PreInitialize(sdkKey string, opts ...Option) {
94+
config := defaultConfig()
95+
for _, opt := range opts {
96+
opt(&config)
97+
}
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99+
setupOtel(sdkKey, config)
100+
}

‎go/plugin.go‎

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@@ -5,30 +5,15 @@
55
package ldobserve
66

77
import (
8-
"context"
9-
"net/http"
10-
11-
"github.com/Khan/genqlient/graphql"
12-
13-
"github.com/launchdarkly/observability-sdk/go/attributes"
14-
"github.com/launchdarkly/observability-sdk/go/internal/gql"
15-
"github.com/launchdarkly/observability-sdk/go/internal/logging"
16-
"github.com/launchdarkly/observability-sdk/go/internal/metadata"
17-
18-
"go.opentelemetry.io/otel/attribute"
19-
"go.opentelemetry.io/otel/sdk/trace"
20-
semconv "go.opentelemetry.io/otel/semconv/v1.34.0"
21-
228
"github.com/launchdarkly/go-server-sdk/ldotel"
239
"github.com/launchdarkly/go-server-sdk/v7/interfaces"
2410
"github.com/launchdarkly/go-server-sdk/v7/ldhooks"
2511
"github.com/launchdarkly/go-server-sdk/v7/ldplugins"
26-
"github.com/launchdarkly/observability-sdk/go/internal/otel"
2712
)
2813

2914
// ObservabilityPlugin represents the LaunchDarkly observability plugin.
3015
type ObservabilityPlugin struct {
31-
config observabilityConfig
16+
config *observabilityConfig
3217
ldplugins.Unimplemented
3318
}
3419

@@ -40,10 +25,18 @@ func NewObservabilityPlugin(opts ...Option) *ObservabilityPlugin {
4025
}
4126

4227
return &ObservabilityPlugin{
43-
config: config,
28+
config: &config,
4429
}
4530
}
4631

32+
// NewObservabilityPluginWithoutInit creates a new observability plugin without
33+
// for performing initialization.
34+
// This method generally does not need to be used, and should only be used in
35+
// conjunction with InitializeWithoutPlugin.
36+
func NewObservabilityPluginWithoutInit() *ObservabilityPlugin {
37+
return &ObservabilityPlugin{}
38+
}
39+
4740
// GetHooks returns the hooks for the observability plugin.
4841
func (p ObservabilityPlugin) GetHooks(_ ldplugins.EnvironmentMetadata) []ldhooks.Hook {
4942
return []ldhooks.Hook{
@@ -56,67 +49,10 @@ func (p ObservabilityPlugin) Metadata() ldplugins.Metadata {
5649
return ldplugins.NewMetadata("launchdarkly-observability")
5750
}
5851

59-
func (p ObservabilityPlugin) getSamplingConfig(projectId string) (*gql.GetSamplingConfigResponse, error) {
60-
var ctx context.Context
61-
if p.config.context != nil {
62-
ctx = p.config.context
63-
} else {
64-
ctx = context.Background()
65-
}
66-
client := graphql.NewClient(p.config.backendURL, http.DefaultClient)
67-
return gql.GetSamplingConfig(ctx, client, projectId)
68-
}
69-
7052
// Register registers the observability plugin with the LaunchDarkly client.
7153
func (p ObservabilityPlugin) Register(client interfaces.LDClientInterface, ldmd ldplugins.EnvironmentMetadata) {
72-
attributes := []attribute.KeyValue{
73-
semconv.TelemetryDistroNameKey.String(metadata.InstrumentationName),
74-
semconv.TelemetryDistroVersionKey.String(metadata.InstrumentationVersion),
75-
attribute.String(attributes.ProjectIDAttribute, ldmd.SdkKey),
76-
}
77-
if p.config.environment != "" {
78-
attributes = append(attributes, semconv.DeploymentEnvironmentName(p.config.environment))
79-
}
80-
if p.config.serviceName != "" {
81-
attributes = append(attributes, semconv.ServiceNameKey.String(p.config.serviceName))
82-
}
83-
if p.config.serviceVersion != "" {
84-
attributes = append(attributes, semconv.ServiceVersionKey.String(p.config.serviceVersion))
85-
}
86-
if p.config.debug {
87-
logging.SetLogger(logging.ConsoleLogger{})
88-
}
89-
90-
var s trace.Sampler
91-
if len(p.config.samplingRateMap) > 0 {
92-
s = getSampler(p.config.samplingRateMap)
93-
} else {
94-
s = nil
95-
}
96-
otel.SetConfig(otel.Config{
97-
OtlpEndpoint: p.config.otlpEndpoint,
98-
ResourceAttributes: attributes,
99-
Sampler: s,
100-
})
101-
if !p.config.manualStart {
102-
err := otel.StartOTLP()
103-
if err != nil {
104-
logging.GetLogger().Errorf("failed to start otel: %v", err)
105-
}
106-
}
107-
go func() {
108-
cfg, err := p.getSamplingConfig(ldmd.SdkKey)
109-
if err != nil {
110-
logging.GetLogger().Errorf("failed to get sampling config: %v", err)
111-
return
112-
}
113-
logging.GetLogger().Infof("got sampling config: %v", cfg)
114-
otel.SetSamplingConfig(cfg)
115-
}()
116-
if p.config.context != nil {
117-
go func() {
118-
<-p.config.context.Done()
119-
otel.Shutdown()
120-
}()
54+
if p.config == nil {
55+
return
12156
}
57+
setupOtel(ldmd.SdkKey, *p.config)
12258
}

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