Scaffold Go client module

clients/go/cmd/mxgw-go/main.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"encoding/json"
+	"flag"
+	"fmt"
+	"os"
+
+	"gitea.dohertylan.com/dohertj2/mxaccessgw/clients/go/mxgateway"
+)
+
+type versionOutput struct {
+	ClientVersion          string `json:"clientVersion"`
+	GatewayProtocolVersion uint32 `json:"gatewayProtocolVersion"`
+	WorkerProtocolVersion  uint32 `json:"workerProtocolVersion"`
+}
+
+func main() {
+	if err := run(os.Args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(2)
+	}
+}
+
+func run(args []string) error {
+	if len(args) == 0 {
+		return fmt.Errorf("usage: mxgw-go version [-json]")
+	}
+
+	switch args[0] {
+	case "version":
+		return runVersion(args[1:])
+	default:
+		return fmt.Errorf("unknown command %q", args[0])
+	}
+}
+
+func runVersion(args []string) error {
+	flags := flag.NewFlagSet("version", flag.ContinueOnError)
+	flags.SetOutput(os.Stderr)
+	jsonOutput := flags.Bool("json", false, "write JSON output")
+
+	if err := flags.Parse(args); err != nil {
+		return err
+	}
+
+	output := versionOutput{
+		ClientVersion:          mxgateway.ClientVersion,
+		GatewayProtocolVersion: mxgateway.GatewayProtocolVersion,
+		WorkerProtocolVersion:  mxgateway.WorkerProtocolVersion,
+	}
+
+	if *jsonOutput {
+		encoder := json.NewEncoder(os.Stdout)
+		encoder.SetIndent("", "  ")
+		return encoder.Encode(output)
+	}
+
+	fmt.Fprintf(os.Stdout, "mxgw-go %s\n", output.ClientVersion)
+	fmt.Fprintf(os.Stdout, "gateway protocol %d\n", output.GatewayProtocolVersion)
+	fmt.Fprintf(os.Stdout, "worker protocol %d\n", output.WorkerProtocolVersion)
+	return nil
+}