Open Telemetry SDK

Prerequisites

Ensure you have the following:

• Go installed on your system.
• The Nebula OTel package added to your project.
• Viper for configuration management.
• Cobra for command-line argument parsing.

Configuration

This package uses Viper to read configurations from:

1. Environment Variables
2. Command-Line Flags
3. YAML Configuration File

The default configuration values are defined within the InitializeFlags function.

YAML Configuration File Example

Create a YAML configuration file (e.g., config.yaml) with the following structure to customize OTel settings:

otel:
  traces:
    enabled: false             # Enable or disable tracing
    exporter: "otel"           # Tracing exporter (e.g., "otel" or "stdout")
  metrics:
    enabled: false             # Enable or disable metrics collection
    exporter: "otel"           # Metrics exporter (e.g., "otel" or "stdout")
  logs:
    enabled: false             # Enable or disable logging
    exporter: "otel"           # Logging exporter (e.g., "otel" or "stdout")
  service_name: "cli"    # Name of the service
  endpoint: "http://localhost:4318"  # Endpoint for the OTel collector
  ignore: []                   # Routes to ignore in OTel propagation middleware

Environment Variables

Environment variables can override values in the YAML file:

• OTEL_TRACES_ENABLED
• OTEL_TRACES_EXPORTER
• OTEL_METRICS_ENABLED
• OTEL_METRICS_EXPORTER
• OTEL_LOGS_ENABLED
• OTEL_LOGS_EXPORTER
• OTEL_SERVICE_NAME
• OTEL_EXPORTER_OTLP_ENDPOINT
• OTEL_MW_IGNORE

Command-Line Flags

These flags can be set to override YAML and environment settings:

• --otel-traces
• --otel-traces-exporter
• --otel-metrics
• --otel-metrics-exporter
• --otel-logs
• --otel-logs-exporter
• --otel-service-name
• --otel-endpoint
• --otel-ignore

Initialization

Add the following code to initialize the OTel configuration with default settings.

// rootCmd represents the base command when called without any subcommands
var rootCmd = &cobra.Command{
	Use:   "root command",
	PersistentPostRun: func(cmd *cobra.Command, args []string) {
		// Flush OpenTelemetry data before exiting
		otel.Flush(cmd.Context())
	},

}

// Execute adds all child commands to the root command and sets flags appropriately.
// This is called by main.main(). It only needs to happen once to the rootCmd.
func Execute() {
	err := rootCmd.Execute()
	if err != nil {
		os.Exit(1)
	}
}

func init() {
	initConfig()
	otel.InitializeFlags(rootCmd)
	cobra.OnInitialize(otel.InitOtel)

    fmt.Println("service name: " + viper.GetString("otel.service_name") )
	fmt.Println("otel traces enabled: " + viper.GetString("otel.traces.enabled") )
	fmt.Println("otel metrics enabled: " + viper.GetString("otel.traces.enabled") )
	fmt.Println("otel logs enabled: " + viper.GetString("otel.traces.enabled") )
	fmt.Println("exporting otel data to collector: " + viper.GetString("otel.endpoint") )
	
}

InitializeFlags Function

The InitializeFlags function binds environment variables, command-line flags, and default values.

InitOtel Function

The InitOtel function sets up tracing, metrics, and logging providers. It uses the settings defined in the YAML file, environment variables, or command-line flags.