func populateDefaultPrometheusConfig()

in otelcollector/shared/configmap/ccp/prometheus-ccp-config-merger.go [120:197]
68 lines of code
31 McCabe index (conditional complexity)

func populateDefaultPrometheusConfig() {
	loadRegexHash()

	defaultConfigs := []string{}
	currentControllerType := strings.TrimSpace(strings.ToLower(os.Getenv("CONTROLLER_TYPE")))

	if enabled, exists := os.LookupEnv("AZMON_PROMETHEUS_CONTROLPLANE_KUBE_CONTROLLER_MANAGER_ENABLED"); exists && strings.ToLower(enabled) == "true" && currentControllerType == replicasetControllerType {
		fmt.Println("Kube Controller Manager enabled.")
		kubeControllerManagerMetricsKeepListRegex, exists := regexHash["CONTROLPLANE_KUBE_CONTROLLER_MANAGER_KEEP_LIST_REGEX"]
		if exists && kubeControllerManagerMetricsKeepListRegex != "" {
			fmt.Printf("Using regex for Kube Controller Manager: %s\n", kubeControllerManagerMetricsKeepListRegex)
			appendMetricRelabelConfig(controlplaneKubeControllerManagerFile, kubeControllerManagerMetricsKeepListRegex)
		}
		contents, err := os.ReadFile(controlplaneKubeControllerManagerFile)
		if err == nil {
			contents = []byte(strings.Replace(string(contents), "$$POD_NAMESPACE$$", os.Getenv("POD_NAMESPACE"), -1))
			err = os.WriteFile(controlplaneKubeControllerManagerFile, contents, fs.FileMode(0644))
		}
		defaultConfigs = append(defaultConfigs, controlplaneKubeControllerManagerFile)
	}

	if enabled, exists := os.LookupEnv("AZMON_PROMETHEUS_CONTROLPLANE_KUBE_SCHEDULER_ENABLED"); exists && strings.ToLower(enabled) == "true" && currentControllerType == replicasetControllerType {
		controlplaneKubeSchedulerKeepListRegex, exists := regexHash["CONTROLPLANE_KUBE_SCHEDULER_KEEP_LIST_REGEX"]
		if exists && controlplaneKubeSchedulerKeepListRegex != "" {
			appendMetricRelabelConfig(controlplaneKubeSchedulerDefaultFile, controlplaneKubeSchedulerKeepListRegex)
		}
		contents, err := os.ReadFile(controlplaneKubeSchedulerDefaultFile)
		if err == nil {
			contents = []byte(strings.Replace(string(contents), "$$POD_NAMESPACE$$", os.Getenv("POD_NAMESPACE"), -1))
			err = os.WriteFile(controlplaneKubeSchedulerDefaultFile, contents, fs.FileMode(0644))
		}
		defaultConfigs = append(defaultConfigs, controlplaneKubeSchedulerDefaultFile)
	}

	if enabled, exists := os.LookupEnv("AZMON_PROMETHEUS_CONTROLPLANE_APISERVER_ENABLED"); exists && strings.ToLower(enabled) == "true" && currentControllerType == replicasetControllerType {
		controlplaneApiserverKeepListRegex, exists := regexHash["CONTROLPLANE_APISERVER_KEEP_LIST_REGEX"]
		if exists && controlplaneApiserverKeepListRegex != "" {
			appendMetricRelabelConfig(controlplaneApiserverDefaultFile, controlplaneApiserverKeepListRegex)
		}
		contents, err := os.ReadFile(controlplaneApiserverDefaultFile)
		if err == nil {
			contents = []byte(strings.Replace(string(contents), "$$POD_NAMESPACE$$", os.Getenv("POD_NAMESPACE"), -1))
			err = os.WriteFile(controlplaneApiserverDefaultFile, contents, fs.FileMode(0644))
		}
		defaultConfigs = append(defaultConfigs, controlplaneApiserverDefaultFile)
	}

	if enabled, exists := os.LookupEnv("AZMON_PROMETHEUS_CONTROLPLANE_CLUSTER_AUTOSCALER_ENABLED"); exists && strings.ToLower(enabled) == "true" && currentControllerType == replicasetControllerType {
		controlplaneClusterAutoscalerKeepListRegex, exists := regexHash["CONTROLPLANE_CLUSTER_AUTOSCALER_KEEP_LIST_REGEX"]
		if exists && controlplaneClusterAutoscalerKeepListRegex != "" {
			appendMetricRelabelConfig(controlplaneClusterAutoscalerFile, controlplaneClusterAutoscalerKeepListRegex)
		}
		contents, err := os.ReadFile(controlplaneClusterAutoscalerFile)
		if err == nil {
			contents = []byte(strings.Replace(string(contents), "$$POD_NAMESPACE$$", os.Getenv("POD_NAMESPACE"), -1))
			err = os.WriteFile(controlplaneClusterAutoscalerFile, contents, fs.FileMode(0644))
		}
		defaultConfigs = append(defaultConfigs, controlplaneClusterAutoscalerFile)
	}

	if enabled, exists := os.LookupEnv("AZMON_PROMETHEUS_CONTROLPLANE_ETCD_ENABLED"); exists && strings.ToLower(enabled) == "true" && currentControllerType == replicasetControllerType {
		controlplaneEtcdKeepListRegex, exists := regexHash["CONTROLPLANE_ETCD_KEEP_LIST_REGEX"]
		if exists && controlplaneEtcdKeepListRegex != "" {
			appendMetricRelabelConfig(controlplaneEtcdDefaultFile, controlplaneEtcdKeepListRegex)
		}
		contents, err := os.ReadFile(controlplaneEtcdDefaultFile)
		if err == nil {
			contents = []byte(strings.Replace(string(contents), "$$POD_NAMESPACE$$", os.Getenv("POD_NAMESPACE"), -1))
			err = os.WriteFile(controlplaneEtcdDefaultFile, contents, fs.FileMode(0644))
		}
		defaultConfigs = append(defaultConfigs, controlplaneEtcdDefaultFile)
	}

	mergedDefaultConfigs = mergeDefaultScrapeConfigs(defaultConfigs)
	// if mergedDefaultConfigs != nil {
	// 	fmt.Printf("Merged default scrape targets: %v\n", mergedDefaultConfigs)
	// }
}