feat(relayer): versioning (#43)

* feat: versioning

also adds a placeholder to command selector & params

* remove placeholder

relayer/cmd/relayer.go

@@ -48,6 +48,7 @@ func init() {
 	params.SetAddressPrefixes()
 	rootCmd.PersistentFlags().String(flagLogLevel, zerolog.InfoLevel.String(), "logging level")
 	rootCmd.PersistentFlags().String(flagLogFormat, logLevelText, "logging format; must be either json or text")
+	rootCmd.AddCommand(getVersionCmd())
 }
 
 // Execute adds all child commands to the root command and sets flags appropriately.

relayer/cmd/version.go

@@ -0,0 +1,65 @@
+package cmd
+
+import (
+	"encoding/json"
+	"fmt"
+	"runtime"
+
+	"github.com/spf13/cobra"
+	"gopkg.in/yaml.v3"
+)
+
+const (
+	flagFormat = "format"
+)
+
+var (
+	// Version defines the application version (defined at compile time)
+	Version = ""
+
+	// Commit defines the application commit hash (defined at compile time)
+	Commit = ""
+
+	versionFormat string
+)
+
+type versionInfo struct {
+	Version string `json:"version" yaml:"version"`
+	Commit  string `json:"commit" yaml:"commit"`
+	Go      string `json:"go" yaml:"go"`
+}
+
+func getVersionCmd() *cobra.Command {
+	versionCmd := &cobra.Command{
+		Use:   "version",
+		Short: "Print binary version information",
+		RunE: func(_ *cobra.Command, _ []string) error {
+			verInfo := versionInfo{
+				Version: Version,
+				Commit:  Commit,
+				Go:      fmt.Sprintf("%s %s/%s", runtime.Version(), runtime.GOOS, runtime.GOARCH),
+			}
+
+			var bz []byte
+
+			var err error
+			switch versionFormat {
+			case "json":
+				bz, err = json.Marshal(verInfo)
+
+			default:
+				bz, err = yaml.Marshal(&verInfo)
+			}
+			if err != nil {
+				return err
+			}
+
+			_, err = fmt.Println(string(bz))
+			return err
+		},
+	}
+
+	versionCmd.Flags().StringVar(&versionFormat, flagFormat, "text", "Print the version in the given format (text|json)")
+
+	return versionCmd
+}