func main()

in custom-metrics-stackdriver-adapter/adapter.go [172:260]
79 lines of code
13 McCabe index (conditional complexity)

func main() {
	logs.InitLogs()
	defer logs.FlushLogs()

	cmd := &StackdriverAdapter{
		basecmd.AdapterBase{
			Name: "custom-metrics-stackdriver-adapter",
		},
	}

	if cmd.OpenAPIConfig == nil {
		cmd.OpenAPIConfig = genericapiserver.DefaultOpenAPIConfig(generatedopenapi.GetOpenAPIDefinitions, openapinamer.NewDefinitionNamer(api.Scheme, customexternalmetrics.Scheme))
		cmd.OpenAPIConfig.Info.Title = "custom-metrics-stackdriver-adapter"
		cmd.OpenAPIConfig.Info.Version = "1.0.0"
	}

	flags := cmd.Flags()

	flags.AddGoFlagSet(flag.CommandLine) // make sure we get the klog flags

	serverOptions := stackdriverAdapterServerOptions{
		UseNewResourceModel:         false,
		EnableCustomMetricsAPI:      true,
		EnableExternalMetricsAPI:    true,
		FallbackForContainerMetrics: false,
		EnableCoreMetricsAPI:        false,
		EnableDistributionSupport:   false,
		ListFullCustomMetrics:       false,
		ExternalMetricsCacheSize:    defaultExternalMetricsCacheSize,
	}

	flags.BoolVar(&serverOptions.UseNewResourceModel, "use-new-resource-model", serverOptions.UseNewResourceModel,
		"whether to use new Stackdriver resource model")
	flags.BoolVar(&serverOptions.EnableCustomMetricsAPI, "enable-custom-metrics-api", serverOptions.EnableCustomMetricsAPI,
		"whether to enable Custom Metrics API")
	flags.BoolVar(&serverOptions.EnableExternalMetricsAPI, "enable-external-metrics-api", serverOptions.EnableExternalMetricsAPI,
		"whether to enable External Metrics API")
	flags.BoolVar(&serverOptions.FallbackForContainerMetrics, "fallback-for-container-metrics", serverOptions.FallbackForContainerMetrics,
		"If true, fallbacks to k8s_container resource when given metric is not present on k8s_pod. At most one container with given metric is allowed for each pod.")
	flags.BoolVar(&serverOptions.EnableCoreMetricsAPI, "enable-core-metrics-api", serverOptions.EnableCoreMetricsAPI,
		"Experimental, do not use. Whether to enable Core Metrics API.")
	flags.BoolVar(&serverOptions.ListFullCustomMetrics, "list-full-custom-metrics", serverOptions.ListFullCustomMetrics,
		"whether to supporting list full custom metrics. This is a featuragate to list full custom metrics back, which should keep as false to return only 1 metric. Otherwise, it would have high memory usage issue.")
	flags.StringVar(&serverOptions.MetricsAddress, "metrics-address", "",
		"Endpoint with port on which Prometheus metrics server should be enabled. Example: localhost:8080. If there is no flag, Prometheus metric server is disabled and monitoring metrics are not collected.")
	flags.StringVar(&serverOptions.StackdriverEndpoint, "stackdriver-endpoint", "",
		"Stackdriver Endpoint used by adapter. Default is https://monitoring.googleapis.com/")
	flags.BoolVar(&serverOptions.EnableDistributionSupport, "enable-distribution-support", serverOptions.EnableDistributionSupport,
		"enables support for scaling based on distribution values")
	flags.DurationVar(&serverOptions.ExternalMetricsCacheTTL, "external-metric-cache-ttl", serverOptions.ExternalMetricsCacheTTL,
		"The duration (e.g., 1m, 5s) for which external metric values are cached.")
	flags.IntVar(&serverOptions.ExternalMetricsCacheSize, "external-metric-cache-size", serverOptions.ExternalMetricsCacheSize,
		"The maximum number of entries in the external metric cache.")

	flags.Parse(os.Args)

	klog.Info("serverOptions: ", serverOptions)
	if !serverOptions.UseNewResourceModel && serverOptions.FallbackForContainerMetrics {
		klog.Fatalf("Container metrics work only with new resource model")
	}
	if !serverOptions.UseNewResourceModel && serverOptions.EnableCoreMetricsAPI {
		klog.Fatalf("Core metrics work only with new resource model")
	}
	if serverOptions.ListFullCustomMetrics {
		klog.Infof("ListFullCustomMetrics is enabled, which would increase memory usage a lot. Please keep it as false, unless have to.")
	} else {
		klog.Infof("ListFullCustomMetrics is disabled, which would only list 1 metric resource to reduce memory usage. Add --list-full-custom-metrics to list full metric resources for debugging.")
	}

	// TODO(holubwicz): move duration config to server options
	metricsProvider, translator := cmd.makeProviderOrDie(&serverOptions, 5*time.Minute, 1*time.Minute)
	if serverOptions.EnableCustomMetricsAPI {
		cmd.WithCustomMetrics(metricsProvider)
	}
	if serverOptions.EnableExternalMetricsAPI {
		cmd.WithExternalMetrics(metricsProvider)
	}
	if serverOptions.EnableCoreMetricsAPI {
		if err := cmd.withCoreMetrics(translator); err != nil {
			klog.Fatalf("unable to install resource metrics API: %v", err)
		}
	}
	if serverOptions.MetricsAddress != "" {
		go runPrometheusMetricsServer(serverOptions.MetricsAddress)
	}
	if err := cmd.Run(wait.NeverStop); err != nil {
		klog.Fatalf("unable to run custom metrics adapter: %v", err)
	}
}