func generateClientOptions()

in exporter/collector/config.go [273:352]
73 lines of code
18 McCabe index (conditional complexity)

func generateClientOptions(ctx context.Context, clientCfg *ClientConfig, cfg *Config, scopes []string, meterProvider metric.MeterProvider) ([]option.ClientOption, error) {
	// Disable the built-in telemetry so we have full control over the telemetry produced.
	copts := []option.ClientOption{
		option.WithTelemetryDisabled(),
		option.WithGRPCDialOption(otelgrpc.DialOption(otelgrpc.Options{
			MetricsOptions: otelgrpc.MetricsOptions{
				MeterProvider: meterProvider,
			},
		})),
	}
	// grpc.WithUserAgent is used by the Trace exporter, but not the Metric exporter (see comment below)
	if cfg.UserAgent != "" {
		copts = append(copts, option.WithGRPCDialOption(grpc.WithUserAgent(cfg.UserAgent)))
	}
	if clientCfg.Endpoint != "" {
		if clientCfg.UseInsecure {
			// option.WithGRPCConn option takes precedent over all other supplied options so the
			// following user agent will be used by both exporters if we reach this branch
			dialOpts := []grpc.DialOption{
				otelgrpc.DialOption(otelgrpc.Options{
					MetricsOptions: otelgrpc.MetricsOptions{
						MeterProvider: meterProvider,
					},
				}),
				grpc.WithTransportCredentials(insecure.NewCredentials()),
			}
			if cfg.UserAgent != "" {
				dialOpts = append(dialOpts, grpc.WithUserAgent(cfg.UserAgent))
			}
			conn, err := grpc.NewClient(clientCfg.Endpoint, dialOpts...)
			if err != nil {
				return nil, fmt.Errorf("cannot configure grpc conn: %w", err)
			}
			copts = append(copts, option.WithGRPCConn(conn))
		} else {
			copts = append(copts, option.WithEndpoint(clientCfg.Endpoint))
		}
	}
	if cfg.ImpersonateConfig.TargetPrincipal != "" {
		if cfg.ProjectID == "" {
			creds, err := google.FindDefaultCredentials(ctx, scopes...)
			if err != nil {
				return nil, fmt.Errorf("error finding default application credentials: %v", err)
			}
			cfg.ProjectID = creds.ProjectID
		}
		tokenSource, err := impersonate.CredentialsTokenSource(ctx, impersonate.CredentialsConfig{
			TargetPrincipal: cfg.ImpersonateConfig.TargetPrincipal,
			Delegates:       cfg.ImpersonateConfig.Delegates,
			Subject:         cfg.ImpersonateConfig.Subject,
			Scopes:          scopes,
		})
		if err != nil {
			return nil, err
		}
		copts = append(copts, option.WithTokenSource(tokenSource))
	} else if !clientCfg.UseInsecure && (clientCfg.GetClientOptions == nil || len(clientCfg.GetClientOptions()) == 0) {
		// Only add default credentials if GetClientOptions does not
		// provide additional options since GetClientOptions could pass
		// credentials which conflict with the default creds.
		creds, err := google.FindDefaultCredentials(ctx, scopes...)
		if err != nil {
			return nil, fmt.Errorf("error finding default application credentials: %v", err)
		}
		copts = append(copts, option.WithCredentials(creds))
		if cfg.ProjectID == "" {
			cfg.ProjectID = creds.ProjectID
		}
	}
	if clientCfg.GRPCPoolSize > 0 {
		copts = append(copts, option.WithGRPCConnectionPool(clientCfg.GRPCPoolSize))
	}
	if clientCfg.GetClientOptions != nil {
		copts = append(copts, clientCfg.GetClientOptions()...)
	}
	if cfg.ProjectID == "" {
		return nil, errors.New("no project set in config, or found with application default credentials")
	}
	return copts, nil
}