Log aws.firecracker's version since supporting -version is hard

Because the shim's flag parsing is owned by containerd's shim package,
supporting -version/-v is not straightforward. Instead the binary logs
the version.

Signed-off-by: Kazuyoshi Kato <katokazu@amazon.com>

runtime/Makefile

@@ -22,6 +22,8 @@ DOCKER_IMAGE_TAG?=latest
 GO_CACHE_VOLUME_NAME?=gocache
 FIRECRACKER_CONTAINERD_TEST_IMAGE?=localhost/firecracker-containerd-test
 
+REVISION=$(shell git rev-parse HEAD)
+
 INTEG_TEST_SUFFIX := _Isolated
 INTEG_TESTNAMES=$(shell docker run --rm \
 	--network=none \
@@ -37,7 +39,7 @@ all: runtime
 runtime: containerd-shim-aws-firecracker
 
 containerd-shim-aws-firecracker: $(SOURCES) $(GOMOD) $(GOSUM)
-	go build -o containerd-shim-aws-firecracker $(EXTRAGOARGS)
+	go build -o containerd-shim-aws-firecracker $(EXTRAGOARGS) -ldflags "-X main.revision=$(REVISION)"
 
 install: containerd-shim-aws-firecracker
 	install -D -o root -g root -m755 -t $(INSTALLROOT)/bin containerd-shim-aws-firecracker

runtime/main.go

@@ -23,6 +23,8 @@ import (
 
 const shimID = "aws.firecracker"
 
+var revision string
+
 func init() {
 	logrus.SetFormatter(&logrus.TextFormatter{
 		TimestampFormat: log.RFC3339NanoFixed,

runtime/service.go

@@ -215,6 +215,12 @@ func NewService(shimCtx context.Context, id string, remotePublisher shim.Publish
 		return nil, err
 	}
 
+	// The shim cannot support -version flag since
+	// - flag.Parse() is called by shim.Run(). So our main() cannot call flag.Parse()
+	// - NewService() won't be called when the TTRPC address is not specified by the flags
+	// Instead we log the version informaion
+	s.logger.Infof("successfully started %s (%s) for VM %s", shimID, revision, vmID)
+
 	return s, nil
 }