Function traceClientFromDockerContext

internal/tracing/docker_context.go:37–77

traceClientFromDockerContext creates a gRPC OTLP client based on metadata from the active Docker CLI context.

(dockerCli command.Cli, otelEnv envMap)

// traceClientFromDockerContext creates a gRPC OTLP client based on metadata
// from the active Docker CLI context.
func traceClientFromDockerContext(dockerCli command.Cli, otelEnv envMap) (otlptrace.Client, error) {
	// attempt to extract an OTEL config from the Docker context to enable
	// automatic integration with Docker Desktop;
	cfg, err := ConfigFromDockerContext(dockerCli.ContextStore(), dockerCli.CurrentContext())
	if err != nil {
		return nil, fmt.Errorf("loading otel config from docker context metadata: %w", err)
	}

	if cfg.Endpoint == "" {
		return nil, nil
	}

	// HACK: unfortunately _all_ public OTEL initialization functions
	// 	implicitly read from the OS env, so temporarily unset them all and
	// 	restore afterwards
	defer func() {
		for k, v := range otelEnv {
			if err := os.Setenv(k, v); err != nil {
				panic(fmt.Errorf("restoring env for %q: %w", k, err))
			}
		}
	}()
	for k := range otelEnv {
		if err := os.Unsetenv(k); err != nil {
			return nil, fmt.Errorf("stashing env for %q: %w", k, err)
		}
	}

	conn, err := grpc.NewClient(cfg.Endpoint,
		grpc.WithContextDialer(memnet.DialEndpoint),
		// this dial is restricted to using a local Unix socket / named pipe,
		// so there is no need for TLS
		grpc.WithTransportCredentials(insecure.NewCredentials()),
	)
	if err != nil {
		return nil, fmt.Errorf("initializing otel connection from docker context metadata: %w", err)
	}

	client := otlptracegrpc.NewClient(otlptracegrpc.WithGRPCConn(conn))
	return client, nil
}

// ConfigFromDockerContext inspects extra metadata included as part of the
// specified Docker context to try and extract a valid OTLP client configuration.