func AppendRelabelConfig()

in otelcollector/shared/configmap/mp/prometheus-config-merger.go [207:257]
41 lines of code
11 McCabe index (conditional complexity)

func AppendRelabelConfig(yamlConfigFile string, relabelConfig []map[string]interface{}, keepRegex string) {
	fmt.Printf("Adding relabel config for %s\n", yamlConfigFile)

	// Read YAML config file
	data, err := os.ReadFile(yamlConfigFile)
	if err != nil {
		fmt.Printf("Error reading config file %s: %v. The relabel config will not be added\n", yamlConfigFile, err)
		return
	}

	// Unmarshal YAML data
	var config map[string]interface{}
	err = yaml.Unmarshal(data, &config)
	if err != nil {
		fmt.Printf("Error unmarshalling YAML for %s: %v. The relabel config will not be added\n", yamlConfigFile, err)
		return
	}

	// Append relabel config for keep list to each scrape config
	if scrapeConfigs, ok := config["scrape_configs"].([]interface{}); ok {
		for _, scfg := range scrapeConfigs {
			if scfgMap, ok := scfg.(map[interface{}]interface{}); ok {
				relabelCfgs, exists := scfgMap["relabel_configs"]
				if !exists {
					scfgMap["relabel_configs"] = relabelConfig
				} else if relabelCfgsSlice, ok := relabelCfgs.([]interface{}); ok {
					for _, rc := range relabelConfig {
						relabelCfgsSlice = append(relabelCfgsSlice, rc)
					}
					scfgMap["relabel_configs"] = relabelCfgsSlice
				}
			}
		}

		// Marshal updated config back to YAML
		cfgYamlWithRelabelConfig, err := yaml.Marshal(config)
		if err != nil {
			fmt.Printf("Error marshalling YAML for %s: %v. The relabel config will not be added\n", yamlConfigFile, err)
			return
		}

		// Write updated YAML back to file
		err = os.WriteFile(yamlConfigFile, []byte(cfgYamlWithRelabelConfig), fs.FileMode(0644))
		if err != nil {
			fmt.Printf("Error writing to file %s: %v. The relabel config will not be added\n", yamlConfigFile, err)
			return
		}
	} else {
		fmt.Printf("No 'scrape_configs' found in the YAML. The relabel config will not be added.\n")
	}
}