func generate()

in main.go [275:368]
74 lines of code
8 McCabe index (conditional complexity)

func generate(in configInput) ([]byte, error) {
	xdsServer := server{
		ServerURI:    in.xdsServerURI,
		ChannelCreds: []creds{{Type: "google_default"}},
	}

	// Set xds_v3.
	xdsServer.ServerFeatures = append(xdsServer.ServerFeatures, "xds_v3")
	if in.isTrustedXDSServer {
		xdsServer.ServerFeatures = append(xdsServer.ServerFeatures, "trusted_xds_server")
	}

	if in.ignoreResourceDeletion {
		xdsServer.ServerFeatures = append(xdsServer.ServerFeatures, "ignore_resource_deletion")
	}

	// Setting networkIdentifier based on flags.
	networkIdentifier := in.vpcNetworkName
	if in.configMesh != "" {
		networkIdentifier = fmt.Sprintf("mesh:%s", in.configMesh)
	}

	c := &config{
		XDSServers: []server{xdsServer},
		Node: &node{
			ID:      fmt.Sprintf("projects/%d/networks/%s/nodes/%s", in.gcpProjectNumber, networkIdentifier, uuid.New().String()),
			Cluster: "cluster", // unused by TD
			Locality: &locality{
				Zone: in.zone,
			},
			Metadata: map[string]any{
				"INSTANCE_IP": in.ip,
				"TRAFFICDIRECTOR_GRPC_BOOTSTRAP_GENERATOR_SHA": in.gitCommitHash,
			},
		},
		Authorities: map[string]Authority{
			tdAuthority: {
				// Listener Resource Name format for normal TD usecases looks like:
				// xdstp://<authority>/envoy.config.listener.v3.Listener/<project_number>/<(network)|(mesh:mesh_name)>/id
				ClientListenerResourceNameTemplate: fmt.Sprintf("xdstp://%s/envoy.config.listener.v3.Listener/%d/%s/%%s", tdAuthority, in.gcpProjectNumber, networkIdentifier),
			},
			c2pAuthority: {
				// In the case of DirectPath, it is safe to assume that the operator is notified of missing resources.
				// In other words, "ignore_resource_deletion" server_features is always set.
				XDSServers: []server{{
					ServerURI:      "dns:///directpath-pa.googleapis.com",
					ChannelCreds:   []creds{{Type: "google_default"}},
					ServerFeatures: []string{"xds_v3", "ignore_resource_deletion"},
				}},
				ClientListenerResourceNameTemplate: fmt.Sprintf("xdstp://%s/envoy.config.listener.v3.Listener/%%s", c2pAuthority),
			},
		},
		ClientDefaultListenerResourceNameTemplate: fmt.Sprintf("xdstp://%s/envoy.config.listener.v3.Listener/%d/%s/%%s", tdAuthority, in.gcpProjectNumber, networkIdentifier),
	}

	for k, v := range in.metadataLabels {
		c.Node.Metadata[k] = v
	}

	// For PSM Security.
	c.CertificateProviders = map[string]certificateProviderConfig{
		"google_cloud_private_spiffe": {
			PluginName: "file_watcher",
			Config: privateSPIFFEConfig{
				CertificateFile:   path.Join(in.secretsDir, "certificates.pem"),
				PrivateKeyFile:    path.Join(in.secretsDir, "private_key.pem"),
				CACertificateFile: path.Join(in.secretsDir, "ca_certificates.pem"),
				// The file_watcher plugin will parse this a Duration proto, but it is totally
				// fine to just emit a string here.
				RefreshInterval: "600s",
			},
		},
	}

	// For Rate Limiting
	if in.includeAllowedGrpcServices {
		c.AllowedGrpcServices = map[string]allowedGrpcServiceConfig{
			getQualifiedXDSURI(in.xdsServerURI): {
				ChannelCreds: []creds{{Type: "google_default"}},
			},
		}
	}

	c.ServerListenerResourceNameTemplate = "grpc/server?xds.resource.listening_address=%s"
	if in.deploymentInfo != nil {
		c.Node.Metadata["TRAFFIC_DIRECTOR_CLIENT_ENVIRONMENT"] = in.deploymentInfo
	}

	if in.ipv6Capable {
		c.Node.Metadata["TRAFFICDIRECTOR_DIRECTPATH_C2P_IPV6_CAPABLE"] = true
	}

	return json.MarshalIndent(c, "", "  ")
}