Refactor code related to getting current version

And set version in CertMagic for User-Agent purposes

cmd/commands.go

@@ -10,8 +10,10 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strings"
 
 	"github.com/caddyserver/caddy"
+	"github.com/mholt/certmagic"
 	"github.com/mitchellh/go-ps"
 )
 
@@ -126,6 +128,11 @@ func cmdRun() (int, error) {
 		}
 	}
 
+	// set a fitting User-Agent for ACME requests
+	goModule := caddy.GoModule()
+	cleanModVersion := strings.TrimPrefix(goModule.Version, "v")
+	certmagic.UserAgent = "Caddy/" + cleanModVersion
+
 	// start the admin endpoint along with any initial config
 	err := caddy.StartAdmin(config)
 	if err != nil {
@@ -180,10 +187,10 @@ func cmdStop() (int, error) {
 }
 
 func cmdVersion() (int, error) {
-	goModule := getGoBuildModule()
+	goModule := caddy.GoModule()
 	if goModule.Sum != "" {
 		// a build with a known version will also have a checksum
-		fmt.Printf("%s (%s)\n", goModule.Version, goModule.Sum)
+		fmt.Printf("%s %s\n", goModule.Version, goModule.Sum)
 	} else {
 		fmt.Println(goModule.Version)
 	}

cmd/main.go

@@ -9,7 +9,6 @@ import (
 	"log"
 	"net"
 	"os"
-	"runtime/debug"
 )
 
 // Main executes the main function of the caddy command.
@@ -66,23 +65,3 @@ func handlePingbackConn(conn net.Conn, expect []byte) error {
 	}
 	return nil
 }
-
-// getGoBuildModule returns the build info of Caddy
-// from debug.BuildInfo (requires Go modules). If
-// no version information is available, a non-nil
-// value will still be returned, but with an
-// unknown version.
-func getGoBuildModule() *debug.Module {
-	bi, ok := debug.ReadBuildInfo()
-	if ok {
-		// The recommended way to build Caddy involves
-		// creating a separate main module, which
-		// TODO: track related Go issue: https://github.com/golang/go/issues/29228
-		for _, mod := range bi.Deps {
-			if mod.Path == "github.com/mholt/caddy" {
-				return mod
-			}
-		}
-	}
-	return &debug.Module{Version: "unknown"}
-}