Kubetest2 Version Addition

- Uses ldflags to capture HEAD rev in short form.
- Prints built commit version by default
- Adds --version support
- Fixes 108

Makefile

@@ -21,6 +21,8 @@
 REPO_ROOT:=$(shell pwd)
 export REPO_ROOT
 OUT_DIR=$(REPO_ROOT)/bin
+# record the source commit in the binary, overridable
+COMMIT?=$(shell git rev-parse --short HEAD 2>/dev/null)
 INSTALL?=install
 # make install will place binaries here
 # the default path attempts to mimic go install
@@ -47,7 +49,7 @@ SPACE:=$(subst ,, )
 SHELL:=env PATH=$(subst $(SPACE),\$(SPACE),$(PATH)) $(SHELL)
 # ==============================================================================
 # flags for reproducible go builds
-BUILD_FLAGS?=-trimpath -ldflags="-buildid="
+BUILD_FLAGS?=-trimpath -ldflags="-buildid= -X=sigs.k8s.io/kubetest2/pkg/app/shim.GitTag=$(COMMIT)"
 
 build-all:
 	go build -v $(BUILD_FLAGS) ./...

pkg/app/shim/shim.go

@@ -26,6 +26,8 @@ import (
 	"sigs.k8s.io/kubetest2/pkg/process"
 )
 
+var GitTag string // initializing default zero value. ldflags will populate this during build time.
+
 // Main implements the kubetest2 root binary entrypoint
 func Main() {
 	if err := Run(); err != nil {
@@ -66,6 +68,7 @@ func NewCommand() *cobra.Command {
 
 // runE implements the actual command logic
 func runE(cmd *cobra.Command, args []string) error {
+	cmd.Printf("Running %s version: %s\n", BinaryName, GitTag)
 	// there should be at least one argument (the deployer) unless the user
 	// is asking for help on the shim itself
 	if len(args) < 1 {
@@ -77,11 +80,16 @@ func runE(cmd *cobra.Command, args []string) error {
 		// check for -h, --help
 		flags := pflag.NewFlagSet(BinaryName, pflag.ContinueOnError)
 		help := flags.BoolP("help", "h", false, "")
+		version := flags.BoolP("version", "v", false, fmt.Sprintf("prints %s version", BinaryName))
 		// we don't care about errors, only if -h / --help was set
 		_ = flags.Parse(args)
 		if *help {
 			return cmd.Help()
 		}
+		if *version {
+			cmd.Printf("Running %s version: %s\n", BinaryName, GitTag)
+			return nil
+		}
 	}
 
 	// otherwise find and execute the deployer with the remaining arguments