Feature: Adds support for --version

Resolves: #24

Makefile.variables

@@ -5,8 +5,8 @@ export GIT_COMMIT = $(shell git rev-parse --short HEAD)
 export GIT_DIRTY = $(shell test -n "$$(git status --porcelain)" && echo "+CHANGES" || true)
 export GIT_DESCRIBE = $(shell git describe --tags --always)
 LDFLAGS :=
-# LDFLAGS += -X ${IMPORT_PATH}/${PROJECT}.Commit=${GIT_COMMIT}
-# LDFLAGS += -X ${IMPORT_PATH}/${PROJECT}.Version=${GIT_DESCRIBE}
+LDFLAGS += -X main.GitCommit=${GIT_COMMIT}${GIT_DIRTY}
+LDFLAGS += -X main.GitDescribe=${GIT_DESCRIBE}
 
 # Windows environment?
 CYG_CHECK := $(shell hash cygpath 2>/dev/null && echo 1)
@@ -28,6 +28,7 @@ endif
 DEV_IMAGE := ${PROJECT}_dev
 
 DOCKRUN := docker run --rm \
+	-e LDFLAGS="${LDFLAGS}" \
 	-v ${ROOT}/vendor:/go/src \
 	-v ${ROOT}:/${PROJECT}/src/${IMPORT_PATH} \
 	-w /${PROJECT}/src/${IMPORT_PATH} \

README.md

@@ -29,6 +29,7 @@ Check out the [documentation](http://mikefarah.github.io/yaml/) for more detaile
 
 ```
 Usage:
+  yaml [flags]
   yaml [command]
 
 Available Commands:
@@ -43,6 +44,7 @@ Flags:
   -j, --tojson    output as json
   -t, --trim      trim yaml output (default true)
   -v, --verbose   verbose mode
+  -V, --version   Print version information and quit
 
 Use "yaml [command] --help" for more information about a command.
 ```

commands_test.go

@@ -97,6 +97,28 @@ func TestRootCmd_ToJsonShort(t *testing.T) {
 	}
 }
 
+func TestRootCmd_VersionShort(t *testing.T) {
+	cmd := getRootCommand()
+	result := runCmd(cmd, "-V")
+	if result.Error != nil {
+		t.Error(result.Error)
+	}
+	if !strings.Contains(result.Output, "yaml version") {
+		t.Error("expected version message to be printed out, but the message was not found.")
+	}
+}
+
+func TestRootCmd_VersionLong(t *testing.T) {
+	cmd := getRootCommand()
+	result := runCmd(cmd, "--version")
+	if result.Error != nil {
+		t.Error(result.Error)
+	}
+	if !strings.Contains(result.Output, "yaml version") {
+		t.Error("expected version message to be printed out, but the message was not found.")
+	}
+}
+
 func TestReadCmd(t *testing.T) {
 	cmd := getRootCommand()
 	result := runCmd(cmd, "read examples/sample.yaml b.c")

scripts/xcompile.sh

@@ -3,5 +3,5 @@
 # This assumes that gonative and gox is installed as per the 'one time setup' instructions
 # at https://github.com/inconshreveable/gonative
 
-gox -output="build/{{.Dir}}_{{.OS}}_{{.Arch}}"
+gox -ldflags "${LDFLAGS}" -output="build/{{.Dir}}_{{.OS}}_{{.Arch}}"
 

version.go

@@ -0,0 +1,52 @@
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+// The git commit that was compiled. This will be filled in by the compiler.
+var (
+	GitCommit   string
+	GitDescribe string
+
+	// Version is main version number that is being run at the moment.
+	Version = "1.13.0"
+
+	// VersionPrerelease is a pre-release marker for the version. If this is "" (empty string)
+	// then it means that it is a final release. Otherwise, this is a pre-release
+	// such as "dev" (in development), "beta", "rc1", etc.
+	VersionPrerelease = "dev"
+)
+
+// ProductName is the name of the product
+const ProductName = "yaml"
+
+// GetVersionDisplay composes the parts of the version in a way that's suitable
+// for displaying to humans.
+func GetVersionDisplay() string {
+	return fmt.Sprintf("%s version %s\n", ProductName, getHumanVersion())
+}
+
+func getHumanVersion() string {
+	version := Version
+	if GitDescribe != "" {
+		version = GitDescribe
+	}
+
+	release := VersionPrerelease
+	if GitDescribe == "" && release == "" {
+		release = "dev"
+	}
+	if release != "" {
+		if !strings.Contains(version, release) {
+			version += fmt.Sprintf("-%s", release)
+		}
+		if GitCommit != "" {
+			version += fmt.Sprintf(" (%s)", GitCommit)
+		}
+	}
+
+	// Strip off any single quotes added by the git information.
+	return strings.Replace(version, "'", "", -1)
+}

version_test.go

@@ -0,0 +1,46 @@
+package main
+
+import "testing"
+
+func TestGetVersionDisplay(t *testing.T) {
+	tests := []struct {
+		name string
+		want string
+	}{
+		{
+			name: "Display Version",
+			want: ProductName + " version " + Version + "-dev\n",
+		},
+	}
+	for _, tt := range tests {
+		if got := GetVersionDisplay(); got != tt.want {
+			t.Errorf("%q. GetVersionDisplay() = %v, want %v", tt.name, got, tt.want)
+		}
+	}
+}
+
+func Test_getHumanVersion(t *testing.T) {
+	GitDescribe = "e42813d"
+	GitCommit = "e42813d+CHANGES"
+	var wanted string
+	if VersionPrerelease == "" {
+		wanted = GitDescribe
+	} else {
+		wanted = "e42813d-" + VersionPrerelease + " (e42813d+CHANGES)"
+	}
+
+	tests := []struct {
+		name string
+		want string
+	}{
+		{
+			name: "Git Variables defined",
+			want: wanted,
+		},
+	}
+	for _, tt := range tests {
+		if got := getHumanVersion(); got != tt.want {
+			t.Errorf("%q. getHumanVersion() = %v, want %v", tt.name, got, tt.want)
+		}
+	}
+}

yaml.go

@@ -19,6 +19,7 @@ var writeScript = ""
 var outputToJSON = false
 var overwriteFlag = false
 var verbose = false
+var version = false
 var log = logging.MustGetLogger("yaml")
 
 func main() {
@@ -32,6 +33,15 @@ func main() {
 func newCommandCLI() *cobra.Command {
 	var rootCmd = &cobra.Command{
 		Use: "yaml",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if version {
+				cmd.Print(GetVersionDisplay())
+				return nil
+			}
+			cmd.Println(cmd.UsageString())
+
+			return nil
+		},
 		PersistentPreRun: func(cmd *cobra.Command, args []string) {
 			var format = logging.MustStringFormatter(
 				`%{color}%{time:15:04:05} %{shortfunc} [%{level:.4s}]%{color:reset} %{message}`,
@@ -52,6 +62,7 @@ func newCommandCLI() *cobra.Command {
 	rootCmd.PersistentFlags().BoolVarP(&trimOutput, "trim", "t", true, "trim yaml output")
 	rootCmd.PersistentFlags().BoolVarP(&outputToJSON, "tojson", "j", false, "output as json")
 	rootCmd.PersistentFlags().BoolVarP(&verbose, "verbose", "v", false, "verbose mode")
+	rootCmd.Flags().BoolVarP(&version, "version", "V", false, "Print version information and quit")
 
 	rootCmd.AddCommand(createReadCmd(), createWriteCmd(), createNewCmd(), createMergeCmd())
 	rootCmd.SetOutput(os.Stdout)