version: show build tags and type of executable

This patch modifies the output of `rclone version`.
The `os/arch` line is split into `os/type` and `os/arch`.
The `go version` line is now tagged as `go/version` for consistency.

Additionally the `go/linking` line tells whether the rclone
was linked as a static or dynamic executable.
The new `go/tags` line shows a space separated list of build tags.

The info about linking and build tags is also added to the output
of the `core/version` RC endpoint.

cmd/cmd.go

@@ -36,6 +36,7 @@ import (
 	"github.com/rclone/rclone/fs/rc/rcflags"
 	"github.com/rclone/rclone/fs/rc/rcserver"
 	"github.com/rclone/rclone/lib/atexit"
+	"github.com/rclone/rclone/lib/buildinfo"
 	"github.com/rclone/rclone/lib/random"
 	"github.com/rclone/rclone/lib/terminal"
 	"github.com/spf13/cobra"
@@ -74,9 +75,13 @@ const (
 
 // ShowVersion prints the version to stdout
 func ShowVersion() {
+	linking, tagString := buildinfo.GetLinkingAndTags()
 	fmt.Printf("rclone %s\n", fs.Version)
-	fmt.Printf("- os/arch: %s/%s\n", runtime.GOOS, runtime.GOARCH)
-	fmt.Printf("- go version: %s\n", runtime.Version())
+	fmt.Printf("- os/type: %s\n", runtime.GOOS)
+	fmt.Printf("- os/arch: %s\n", runtime.GOARCH)
+	fmt.Printf("- go/version: %s\n", runtime.Version())
+	fmt.Printf("- go/linking: %s\n", linking)
+	fmt.Printf("- go/tags: %s\n", tagString)
 }
 
 // NewFsFile creates an Fs from a name but may point to a file.

cmd/version/version.go

@@ -29,14 +29,21 @@ var commandDefinition = &cobra.Command{
 	Use:   "version",
 	Short: `Show the version number.`,
 	Long: `
-Show the version number, the go version and the architecture.
+Show the rclone version number, the go version, the build target OS and
+architecture, build tags and the type of executable (static or dynamic).
 
-Eg
+For example:
 
     $ rclone version
-    rclone v1.41
-    - os/arch: linux/amd64
-    - go version: go1.10
+    rclone v1.54
+    - os/type: linux
+    - os/arch: amd64
+    - go/version: go1.16
+    - go/linking: static
+    - go/tags: none
+
+Note: before rclone version 1.55 the os/type and os/arch lines were merged,
+      and the "go/version" line was tagged as "go version".
 
 If you supply the --check flag, then it will do an online check to
 compare your version with the latest release and the latest beta.
@@ -89,9 +96,7 @@ func GetVersion(url string) (v *semver.Version, vs string, date time.Time, err e
 		return v, vs, date, err
 	}
 	vs = strings.TrimSpace(string(bodyBytes))
-	if strings.HasPrefix(vs, "rclone ") {
-		vs = vs[7:]
-	}
+	vs = strings.TrimPrefix(vs, "rclone ")
 	vs = strings.TrimRight(vs, "β")
 	date, err = http.ParseTime(resp.Header.Get("Last-Modified"))
 	if err != nil {

fs/rc/internal.go

@@ -17,6 +17,7 @@ import (
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config/obscure"
 	"github.com/rclone/rclone/lib/atexit"
+	"github.com/rclone/rclone/lib/buildinfo"
 )
 
 func init() {
@@ -179,6 +180,8 @@ This shows the current version of go and the go runtime
 - os - OS in use as according to Go
 - arch - cpu architecture in use according to Go
 - goVersion - version of Go runtime in use
+- linking - type of rclone executable (static or dynamic)
+- goTags - space separated build tags or "none"
 
 `,
 	})
@@ -190,6 +193,7 @@ func rcVersion(ctx context.Context, in Params) (out Params, err error) {
 	if err != nil {
 		return nil, err
 	}
+	linking, tagString := buildinfo.GetLinkingAndTags()
 	out = Params{
 		"version":    fs.Version,
 		"decomposed": version.Slice(),
@@ -198,6 +202,8 @@ func rcVersion(ctx context.Context, in Params) (out Params, err error) {
 		"os":         runtime.GOOS,
 		"arch":       runtime.GOARCH,
 		"goVersion":  runtime.Version(),
+		"linking":    linking,
+		"goTags":     tagString,
 	}
 	return out, nil
 }
@@ -425,9 +431,7 @@ func rcRunCommand(ctx context.Context, in Params) (out Params, err error) {
 		allArgs = append(allArgs, command)
 	}
 	// Add all from arg
-	for _, cur := range arg {
-		allArgs = append(allArgs, cur)
-	}
+	allArgs = append(allArgs, arg...)
 
 	// Add flags to args for e.g. --max-depth 1 comes in as { max-depth 1 }.
 	// Convert it to [ max-depth, 1 ] and append to args list

lib/buildinfo/cgo.go

@@ -0,0 +1,7 @@
+// +build cgo
+
+package buildinfo
+
+func init() {
+	Tags = append(Tags, "cgo")
+}

lib/buildinfo/cmount.go

@@ -0,0 +1,7 @@
+// +build cmount
+
+package buildinfo
+
+func init() {
+	Tags = append(Tags, "cmount")
+}

lib/buildinfo/tags.go

@@ -0,0 +1,30 @@
+package buildinfo
+
+import (
+	"sort"
+	"strings"
+)
+
+// Tags contains slice of build tags
+var Tags []string
+
+// GetLinkingAndTags tells how the rclone executable was linked
+// and returns space separated build tags or the string "none".
+func GetLinkingAndTags() (linking, tagString string) {
+	linking = "static"
+	tagList := []string{}
+	for _, tag := range Tags {
+		if tag == "cgo" {
+			linking = "dynamic"
+		} else {
+			tagList = append(tagList, tag)
+		}
+	}
+	if len(tagList) > 0 {
+		sort.Strings(tagList)
+		tagString = strings.Join(tagList, " ")
+	} else {
+		tagString = "none"
+	}
+	return
+}