feat(build/cmd): include commit/tag and time in 'version' cmd

uses tag if it matches the current commit, or the latest commit
otherwise.

fixes #113

Signed-off-by: Xavier Coulon <[email protected]>

Makefile

@@ -104,5 +104,13 @@ test: deps generate
 .PHONY: build
 ## builds the binary executable from CLI
 build: $(INSTALL_PREFIX) deps
-	@echo "building $(BINARY_PATH) ..."
-	@go build -o $(BINARY_PATH) cmd/libasciidoc/*.go
+	$(eval BUILD_COMMIT:=$(shell git rev-parse --short HEAD))
+	$(eval BUILD_TAG:=$(shell git tag --contains $(BUILD_COMMIT)))
+	$(eval BUILD_TIME:=$(shell date -u '+%Y-%m-%dT%H:%M:%SZ'))
+	@echo "building $(BINARY_PATH) (commit:$(BUILD_COMMIT) / tag:$(BUILD_TAG) / time:$(BUILD_TIME))"
+	@go build -ldflags \
+	  " -X github.com/bytesparadise/libasciidoc.BuildCommit=$(BUILD_COMMIT)\
+	    -X github.com/bytesparadise/libasciidoc.BuildTag=$(BUILD_TAG) \
+	    -X github.com/bytesparadise/libasciidoc.BuildTime=$(BUILD_TIME)" \
+	  -o $(BINARY_PATH) \
+	  cmd/libasciidoc/*.go

cmd/libasciidoc/version.go

@@ -3,13 +3,19 @@ package main
 import (
 	"fmt"
 
+	"github.com/bytesparadise/libasciidoc"
 	"github.com/spf13/cobra"
 )
 
 var versionCmd = &cobra.Command{
 	Use:   "version",
 	Short: "Print the version number of libasciidoc",
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("~HEAD")
+		if libasciidoc.BuildTag != "" {
+			fmt.Printf("tag:        %s\n", libasciidoc.BuildTag)
+		} else {
+			fmt.Printf("commit:     %s\n", libasciidoc.BuildCommit)
+		}
+		fmt.Printf("build time: %s\n", libasciidoc.BuildTime)
 	},
 }

libasciidoc.go

@@ -12,6 +12,15 @@ import (
 	log "github.com/sirupsen/logrus"
 )
 
+var (
+	// BuildCommit lastest build commit (set by Makefile)
+	BuildCommit = ""
+	// BuildTag if the `BuildCommit` matches a tag
+	BuildTag = ""
+	// BuildTime set by build script (set by Makefile)
+	BuildTime = ""
+)
+
 // ConvertFileToHTML converts the content of the given filename into an HTML document.
 // The conversion result is written in the given writer `output`, whereas the document metadata (title, etc.) (or an error if a problem occurred) is returned
 // as the result of the function call.