Include git commit in version (#1347)

* Include git commit in version

Signed-off-by: Tim Vaillancourt <tvaillancourt@slack-corp.com>

* Make --version output change less-breaking

---------

Signed-off-by: Tim Vaillancourt <tvaillancourt@slack-corp.com>

Author: timvaillancourt

build.sh

@@ -56,10 +56,14 @@ main() {
     exit 1
   fi
 
+  if [ -z "${GIT_COMMIT}" ]; then
+    GIT_COMMIT=$(git rev-parse HEAD)
+  fi
+
   buildpath=/tmp/gh-ost-release
   target=gh-ost
   timestamp=$(date "+%Y%m%d%H%M%S")
-  ldflags="-X main.AppVersion=${RELEASE_VERSION}"
+  ldflags="-X main.AppVersion=${RELEASE_VERSION} -X main.GitCommit=${GIT_COMMIT}"
 
   mkdir -p ${buildpath}
   rm -rf ${buildpath:?}/*

go/cmd/gh-ost/main.go

@@ -22,7 +22,7 @@ import (
 	"golang.org/x/term"
 )
 
-var AppVersion string
+var AppVersion, GitCommit string
 
 // acceptSignals registers for OS signals
 func acceptSignals(migrationContext *base.MigrationContext) {
@@ -165,7 +165,7 @@ func main() {
 		if appVersion == "" {
 			appVersion = "unversioned"
 		}
-		fmt.Println(appVersion)
+		fmt.Printf("%s (git commit: %s)", appVersion, GitCommit)
 		return
 	}
 
@@ -308,7 +308,7 @@ func main() {
 		migrationContext.Log.Errore(err)
 	}
 
-	log.Infof("starting gh-ost %+v", AppVersion)
+	log.Infof("starting gh-ost %+v (git commit: %s)", AppVersion, GitCommit)
 	acceptSignals(migrationContext)
 
 	migrator := logic.NewMigrator(migrationContext, AppVersion)