Add containerdVersion flag

Add version flag that only prints the static version for the binary.

This commit does not include build details for containers since
Makefile does not build them.

Closes #8

Signed-off-by: Christopher M. Luciano <cmluciano@us.ibm.com>

Makefile

@@ -17,6 +17,9 @@ EPOCH_TEST_COMMIT ?= f9e02affccd51702191e5312665a16045ffef8ab
 PROJECT := github.com/kubernetes-incubator/cri-containerd
 BINDIR ?= ${DESTDIR}/usr/local/bin
 BUILD_DIR ?= _output
+# VERSION is the version of the binary.
+VERSION:=$(shell git describe --tags --dirty)
+BUILD_TAGS:= -ldflags '-X $(PROJECT)/pkg/version.criContainerdVersion=$(VERSION)'
 
 all: binaries
 
@@ -32,6 +35,7 @@ help:
 	@echo " * 'verify'        - Execute the source code verification tools"
 	@echo " * 'install.tools' - Installs tools used by verify"
 	@echo " * 'uninstall'     - Remove installed binaries from system locations"
+	@echo " * 'version'       - Print current cri-containerd release version"
 
 .PHONY: check-gopath
 
@@ -42,6 +46,9 @@ endif
 
 verify: lint gofmt boiler
 
+version:
+	@echo $(VERSION)
+
 lint: check-gopath
 	@echo "checking lint"
 	@./hack/lint.sh
@@ -56,6 +63,7 @@ boiler:
 
 cri-containerd: check-gopath
 	$(GO) build -o $(BUILD_DIR)/$@ \
+        $(BUILD_TAGS) \
 	$(PROJECT)/cmd/cri-containerd
 
 test: 
@@ -102,4 +110,5 @@ install.tools: .install.gitvalidation .install.gometalinter
 	help \
 	install \
 	lint \
-	uninstall
+	uninstall \
+	version

cmd/cri-containerd/cri_containerd.go

@@ -17,11 +17,14 @@ limitations under the License.
 package main
 
 import (
+	"os"
+
 	"github.com/golang/glog"
 	"github.com/spf13/pflag"
 
 	"github.com/kubernetes-incubator/cri-containerd/cmd/cri-containerd/options"
 	"github.com/kubernetes-incubator/cri-containerd/pkg/server"
+	"github.com/kubernetes-incubator/cri-containerd/pkg/version"
 )
 
 func main() {
@@ -29,6 +32,11 @@ func main() {
 	o.AddFlags(pflag.CommandLine)
 	options.InitFlags()
 
+	if o.CRIContainerdVersion {
+		version.PrintVersion()
+		os.Exit(0)
+	}
+
 	glog.V(2).Infof("Connect to containerd socket %q with timeout %v", o.ContainerdSocketPath, o.ContainerdConnectionTimeout)
 	conn, err := server.ConnectToContainerd(o.ContainerdSocketPath, o.ContainerdConnectionTimeout)
 	if err != nil {

cmd/cri-containerd/options/options.go

@@ -27,6 +27,8 @@ import (
 type CRIContainerdOptions struct {
 	// CRIContainerdSocketPath is the path to the socket which cri-containerd serves on.
 	CRIContainerdSocketPath string
+	// CRIContainerdVersion is the git release version of cri-containerd
+	CRIContainerdVersion bool
 	// ContainerdSocketPath is the path to the containerd socket.
 	ContainerdSocketPath string
 	// ContainerdConnectionTimeout is the connection timeout for containerd client.
@@ -46,6 +48,8 @@ func (c *CRIContainerdOptions) AddFlags(fs *pflag.FlagSet) {
 		"/run/containerd/containerd.sock", "Path to the containerd socket.")
 	fs.DurationVar(&c.ContainerdConnectionTimeout, "containerd-connection-timeout",
 		2*time.Minute, "Connection timeout for containerd client.")
+	fs.BoolVar(&c.CRIContainerdVersion, "version",
+		false, "Print cri-containerd version information and quit.")
 }
 
 // InitFlags must be called after adding all cli options flags are defined and

pkg/version/version.go

@@ -0,0 +1,42 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package version
+
+import (
+	"fmt"
+
+	"github.com/blang/semver"
+)
+
+var criContainerdVersion = "UNKNOWN"
+
+func validateSemver(sv string) error {
+	_, err := semver.Parse(sv)
+	if err != nil {
+		return fmt.Errorf("couldn't parse cri-containerd version %q: %v", sv, err)
+	}
+	return nil
+}
+
+// PrintVersion outputs the release version of cri-containerd
+func PrintVersion() {
+	err := validateSemver(criContainerdVersion)
+	if err != nil {
+		fmt.Println(err)
+	}
+	fmt.Println(criContainerdVersion)
+}

pkg/version/version_test.go

@@ -0,0 +1,33 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package version
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestValidateSemver(t *testing.T) {
+	err := validateSemver("UNKNOWN")
+	assert := assert.New(t)
+	assert.NotNil(err)
+	err = validateSemver("0.0.0-1-gdf6a1cc-dirty")
+	assert.Nil(err)
+	err = validateSemver(criContainerdVersion)
+	assert.Nil(err)
+}