From f35a4cfcc704b0d39b0dca9a665f593e50e60ebe Mon Sep 17 00:00:00 2001
From: Kohei Tokunaga <ktokunaga.mail@gmail.com>
Date: Mon, 9 May 2022 17:18:23 +0900
Subject: [PATCH] Add version command

Signed-off-by: Kohei Tokunaga <ktokunaga.mail@gmail.com>
---
 Makefile               |  7 ++++++-
 README.md              |  3 ++-
 main.go                | 13 +++++++++++++
 pkg/version/version.go |  9 +++++++++
 4 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 pkg/version/version.go

diff --git a/Makefile b/Makefile
index e318c563..8342cf8e 100644
--- a/Makefile
+++ b/Makefile
@@ -2,12 +2,17 @@ CMD_DESTDIR ?= /usr/local
 PREFIX ?= $(CURDIR)/out/
 CMD=buildg
 
+PKG=github.com/ktock/buildg
+VERSION=$(shell git describe --match 'v[0-9]*' --dirty='.m' --always --tags)
+REVISION=$(shell git rev-parse HEAD)$(shell if ! git diff --no-ext-diff --quiet --exit-code; then echo .m; fi)
+GO_LD_FLAGS=-ldflags '-s -w -X $(PKG)/pkg/version.Version=$(VERSION) -X $(PKG)/pkg/version.Revision=$(REVISION) $(GO_EXTRA_LDFLAGS)'
+
 all: build
 
 build: buildg
 
 buildg:
-	go build -o $(PREFIX)/buildg -v .
+	go build -o $(PREFIX)/buildg $(GO_LD_FLAGS) -v .
 
 install:
 	install -D -m 755 $(PREFIX)/buildg $(CMD_DESTDIR)/bin
diff --git a/README.md b/README.md
index 5c402fda..93b07b26 100644
--- a/README.md
+++ b/README.md
@@ -157,6 +157,7 @@ USAGE:
 
 COMMANDS:
    debug    Debug a build
+   version  Version info
    help, h  Shows a list of commands or help for one command
 
 GLOBAL OPTIONS:
@@ -166,7 +167,7 @@ GLOBAL OPTIONS:
 
 ### buildg debug
 
-```
+```console
 $ buildg debug --help
 NAME:
    buildg debug - Debug a build
diff --git a/main.go b/main.go
index def3fc58..ff2c9cb2 100644
--- a/main.go
+++ b/main.go
@@ -13,6 +13,7 @@ import (
 	"github.com/containerd/console"
 	"github.com/containerd/containerd/pkg/userns"
 	"github.com/containerd/containerd/snapshots/native"
+	"github.com/ktock/buildg/pkg/version"
 	"github.com/moby/buildkit/cache/remotecache"
 	"github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/cmd/buildctl/build"
@@ -51,6 +52,7 @@ func main() {
 	}
 	app.Commands = []cli.Command{
 		newDebugCommand(),
+		newVersionCommand(),
 	}
 	app.Before = func(context *cli.Context) error {
 		logrus.SetFormatter(&logrus.TextFormatter{FullTimestamp: true})
@@ -65,6 +67,17 @@ func main() {
 	}
 }
 
+func newVersionCommand() cli.Command {
+	return cli.Command{
+		Name:  "version",
+		Usage: "Version info",
+		Action: func(clicontext *cli.Context) error {
+			fmt.Println("buildg", version.Version, version.Revision)
+			return nil
+		},
+	}
+}
+
 func newDebugCommand() cli.Command {
 	var flags []cli.Flag
 	if userns.RunningInUserNS() {
diff --git a/pkg/version/version.go b/pkg/version/version.go
new file mode 100644
index 00000000..2285e29f
--- /dev/null
+++ b/pkg/version/version.go
@@ -0,0 +1,9 @@
+package version
+
+var (
+	// Version is the version number. Filled in at linking time (via Makefile).
+	Version = "<unknown>"
+
+	// Revision is the VCS (e.g. git) revision. Filled in at linking time (via Makefile).
+	Revision = "<unknown>"
+)