make build with version tags

Makefile

@@ -0,0 +1,33 @@
+REPO := boson-project/faas
+BIN  := faas
+
+CODE := $(shell find . -name '*.go')
+DATE := $(shell date -u +"%Y%m%dT%H%M%SZ")
+HASH := $(shell git rev-parse --short HEAD 2>/dev/null)
+BRCH := $(shell git symbolic-ref --short -q HEAD | sed 's/\//-/g')
+VTAG := $(shell git tag --points-at HEAD)
+VERS := $(shell [ -z $(VTAG) ] && echo 'tip' || echo $(VTAG) )
+
+all: $(BIN)
+
+$(BIN): $(CODE)
+	go build -ldflags "-X main.brch=$(BRCH) -X main.date=$(DATE) -X main.vers=$(VERS) -X main.hash=$(HASH)" ./cmd/$(BIN)
+
+test:
+	go test -cover -coverprofile=coverage.out ./...
+
+build: Dockerfile
+	docker build -t $(REPO):$(BRCH) \
+	             -t $(REPO):$(VERS) \
+	             -t $(REPO):$(HASH) \
+	             -t $(REPO):$(BRCH)-$(DATE)-$(VERS)-$(HASH) .
+
+push: build
+	docker push $(REPO):$(BRCH)
+	docker push $(REPO):$(VERS)
+	docker push $(REPO):$(HASH)
+	docker push $(REPO):$(BRCH)-$(DATE)-$(VERS)-$(HASH)
+
+clean:
+	-@rm -f $(BIN)
+	-@rm -f coverage.out

cmd/faas/main.go

@@ -1,7 +1,14 @@
 package main
 
-import "github.com/boson-project/faas/cmd"
+import (
+	"github.com/boson-project/faas/cmd"
+)
+
+// Statically-populated build metadata set
+// by `make build`.
+var brch, date, vers, hash string
 
 func main() {
+	cmd.SetMeta(brch, date, vers, hash)
 	cmd.Execute()
 }

cmd/root.go

@@ -19,7 +19,7 @@ var (
 var root = &cobra.Command{
 	Use:           "faas",
 	Short:         "Function as a Service",
-	Version:       Version,
+	Version:       verboseVersion(),
 	SilenceErrors: true, // we explicitly handle errors in Execute()
 	SilenceUsage:  true, // no usage dump on error
 	Long: `Function as a Service

cmd/version.go

@@ -6,10 +6,6 @@ import (
 	"github.com/spf13/cobra"
 )
 
-// Version
-// Printed on subcommand `version` or flag `--version`
-const Version = "v0.2.1"
-
 func init() {
 	root.AddCommand(versionCmd)
 }
@@ -21,5 +17,32 @@ var versionCmd = &cobra.Command{
 }
 
 func version(cmd *cobra.Command, args []string) {
-	fmt.Println(Version)
+	fmt.Println(verboseVersion())
+}
+
+// Populated at build time by `make build`, plumbed through
+// main using SetMeta()
+var (
+	brch string // the branch built from
+	date string // datestamp
+	vers string // verstionof git commit or `tip`
+	hash string // git hash built from
+)
+
+// SetMeta from the build process, used for verbose version tagging.
+func SetMeta(buildBranch, buildTimestamp, commitVersionTag, commitHash string) {
+	brch = buildBranch
+	date = buildTimestamp
+	vers = commitVersionTag
+	hash = commitHash
+}
+
+func verboseVersion() string {
+	// If building from source (i.e. from `go install` or `go build` directly,
+	// simply print 'v0.0.0-source`, a semver-valid version indicating no version
+	// number.  Otherwise print the verbose version populated during `make build`.
+	if vers == "" { // not statically populatd
+		return "v0.0.0-source"
+	}
+	return fmt.Sprintf("%s-%s-%s-%s", brch, date, vers, hash)
 }