func updateTAConfigFile()

in otelcollector/configuration-reader-builder/main.go [89:183]
81 lines of code
16 McCabe index (conditional complexity)

func updateTAConfigFile(configFilePath string) {
	defaultsMergedConfigFileContents, err := os.ReadFile(configFilePath)
	if err != nil {
		logFatalError(fmt.Sprintf("config-reader::Unable to read file contents from: %s - %v\n", configFilePath, err))
		os.Exit(1)
	}
	var promScrapeConfig map[string]interface{}
	var otelConfig OtelConfig
	err = yaml.Unmarshal([]byte(defaultsMergedConfigFileContents), &otelConfig)
	if err != nil {
		logFatalError(fmt.Sprintf("config-reader::Unable to unmarshal merged otel configuration from: %s - %v\n", configFilePath, err))
		os.Exit(1)
	}

	promScrapeConfig = otelConfig.Receivers.Prometheus.Config
	// Removing $$ added for regex and replacement in relabel_config and metric_relabel_config added by promconfigvalidator.
	// The $$ are required by the validator's otel get method, but the TA doesnt do env substitution and hence needs to be removed, else TA crashes.
	scrapeConfigs := promScrapeConfig["scrape_configs"]
	if scrapeConfigs != nil {
		var sc = scrapeConfigs.([]interface{})
		for _, scrapeConfig := range sc {
			scrapeConfig := scrapeConfig.(map[interface{}]interface{})
			if scrapeConfig["relabel_configs"] != nil {
				relabelConfigs := scrapeConfig["relabel_configs"].([]interface{})
				for _, relabelConfig := range relabelConfigs {
					relabelConfig := relabelConfig.(map[interface{}]interface{})
					//replace $$ with $ for regex field
					if relabelConfig["regex"] != nil {
						// Adding this check here since regex can be boolean and the conversion will fail
						if _, isString := relabelConfig["regex"].(string); isString {
							regexString := relabelConfig["regex"].(string)
							modifiedRegexString := strings.ReplaceAll(regexString, "$$", "$")
							relabelConfig["regex"] = modifiedRegexString
						}
					}
					//replace $$ with $ for replacement field
					if relabelConfig["replacement"] != nil {
						replacement := relabelConfig["replacement"].(string)
						modifiedReplacementString := strings.ReplaceAll(replacement, "$$", "$")
						relabelConfig["replacement"] = modifiedReplacementString
					}
				}
			}

			if scrapeConfig["metric_relabel_configs"] != nil {
				metricRelabelConfigs := scrapeConfig["metric_relabel_configs"].([]interface{})
				for _, metricRelabelConfig := range metricRelabelConfigs {
					metricRelabelConfig := metricRelabelConfig.(map[interface{}]interface{})
					//replace $$ with $ for regex field
					if metricRelabelConfig["regex"] != nil {
						// Adding this check here since regex can be boolean and the conversion will fail
						if _, isString := metricRelabelConfig["regex"].(string); isString {
							regexString := metricRelabelConfig["regex"].(string)
							modifiedRegexString := strings.ReplaceAll(regexString, "$$", "$")
							metricRelabelConfig["regex"] = modifiedRegexString
						}
					}

					//replace $$ with $ for replacement field
					if metricRelabelConfig["replacement"] != nil {
						replacement := metricRelabelConfig["replacement"].(string)
						modifiedReplacementString := strings.ReplaceAll(replacement, "$$", "$")
						metricRelabelConfig["replacement"] = modifiedReplacementString
					}
				}
			}
		}
	}

	targetAllocatorConfig := Config{
		AllocationStrategy: "consistent-hashing",
		FilterStrategy:     "relabel-config",
		CollectorSelector: &metav1.LabelSelector{
			MatchLabels: map[string]string{
				"rsName":                         "ama-metrics",
				"kubernetes.azure.com/managedby": "aks",
			},
		},
		Config: promScrapeConfig,
		PrometheusCR: PrometheusCRConfig{
			ServiceMonitorSelector: &metav1.LabelSelector{},
			PodMonitorSelector:     &metav1.LabelSelector{},
		},
	}

	targetAllocatorConfigYaml, _ := yaml.Marshal(targetAllocatorConfig)
	if err := os.WriteFile(taConfigFilePath, targetAllocatorConfigYaml, 0644); err != nil {
		logFatalError(fmt.Sprintf("config-reader::Unable to write to: %s - %v\n", taConfigFilePath, err))
		os.Exit(1)
	}

	log.Println("Updated file - targetallocator.yaml for the TargetAllocator to pick up new config changes")
	taConfigUpdated = true
	taLivenessStartTime = time.Now()
}