*: add --version flag to commands

Since stolonctl has different subcommands, also a `version` subcommand is added
over the --version flag.

build

@@ -43,6 +43,9 @@ mkdir -p ${BINDIR}
 
 export GO15VENDOREXPERIMENT=1
 
+VERSION=$(${BASEDIR}/scripts/git-version.sh)
+LD_FLAGS="-s -X ${REPO_PATH}/cmd.Version=$VERSION"
+
 # for static compilation we need to compile with cgo disabled (CGO_ENABLED=0),
 # this will trigger a rebuild of all the packages and also the go std library
 # (using a different install suffix called `cgo`, will use this since it's the
@@ -73,23 +76,23 @@ if [ -z $use_go_install ]; then
 	echo "or manually rebuild stdlib executing the command 'CGO_ENABLED=0 go install -a -installsuffix cgo std' from a user with write access to ${go_root_dir}/pkg"
 
 	for cmd in sentinel proxy; do
-		CGO_ENABLED=0 go build -a -installsuffix cgo -ldflags '-s' -o ${BINDIR}/stolon-${cmd} ${REPO_PATH}/cmd/${cmd}
+		CGO_ENABLED=0 go build -a -installsuffix cgo -ldflags "$LD_FLAGS" -o ${BINDIR}/stolon-${cmd} ${REPO_PATH}/cmd/${cmd}
 	done
-	CGO_ENABLED=0 go build -a -installsuffix cgo -ldflags '-s' -o ${BINDIR}/stolonctl ${REPO_PATH}/cmd/stolonctl
+	CGO_ENABLED=0 go build -a -installsuffix cgo -ldflags "$LD_FLAGS" -o ${BINDIR}/stolonctl ${REPO_PATH}/cmd/stolonctl
 else
 	for cmd in sentinel proxy; do
-		CGO_ENABLED=0 go install -installsuffix cgo -ldflags '-s' ${REPO_PATH}/cmd/${cmd}
+		CGO_ENABLED=0 go install -installsuffix cgo -ldflags "$LD_FLAGS" ${REPO_PATH}/cmd/${cmd}
 		rm -f ${BINDIR}/stolon-${cmd}
 		cp ${GOPATH}/bin/${cmd} ${BINDIR}/stolon-${cmd}
 	done
-	CGO_ENABLED=0 go install -installsuffix cgo -ldflags '-s' ${REPO_PATH}/cmd/stolonctl
+	CGO_ENABLED=0 go install -installsuffix cgo -ldflags "$LD_FLAGS" ${REPO_PATH}/cmd/stolonctl
 	rm -f ${BINDIR}/stolonctl
 	cp ${GOPATH}/bin/stolonctl ${BINDIR}/
 fi
 
 # stolon-keeper cannot be statically built since it needs to get its current
 # running user and this is not available with cgo disabled
-go install ${REPO_PATH}/cmd/keeper
+go install -ldflags "$LD_FLAGS" ${REPO_PATH}/cmd/keeper
 rm -f ${BINDIR}/stolon-keeper
 cp ${GOPATH}/bin/keeper ${BINDIR}/stolon-keeper
 

cmd/keeper/keeper.go

@@ -28,6 +28,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/sorintlab/stolon/cmd"
 	"github.com/sorintlab/stolon/common"
 	"github.com/sorintlab/stolon/pkg/cluster"
 	"github.com/sorintlab/stolon/pkg/flagutil"
@@ -46,8 +47,9 @@ import (
 var log = slog.S()
 
 var cmdKeeper = &cobra.Command{
-	Use: "stolon-keeper",
-	Run: keeper,
+	Use:     "stolon-keeper",
+	Run:     keeper,
+	Version: cmd.Version,
 }
 
 type KeeperLocalState struct {

cmd/proxy/proxy.go

@@ -23,6 +23,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/sorintlab/stolon/cmd"
 	"github.com/sorintlab/stolon/common"
 	"github.com/sorintlab/stolon/pkg/cluster"
 	"github.com/sorintlab/stolon/pkg/flagutil"
@@ -39,8 +40,9 @@ import (
 var log = slog.S()
 
 var cmdProxy = &cobra.Command{
-	Use: "stolon-proxy",
-	Run: proxy,
+	Use:     "stolon-proxy",
+	Run:     proxy,
+	Version: cmd.Version,
 }
 
 type config struct {

cmd/sentinel/sentinel.go

@@ -29,6 +29,7 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/sorintlab/stolon/cmd"
 	"github.com/sorintlab/stolon/common"
 	"github.com/sorintlab/stolon/pkg/cluster"
 	"github.com/sorintlab/stolon/pkg/flagutil"
@@ -53,8 +54,9 @@ const (
 )
 
 var cmdSentinel = &cobra.Command{
-	Use: "stolon-sentinel",
-	Run: sentinel,
+	Use:     "stolon-sentinel",
+	Run:     sentinel,
+	Version: cmd.Version,
 }
 
 type config struct {

cmd/stolonctl/stolonctl.go

@@ -21,6 +21,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/sorintlab/stolon/cmd"
 	"github.com/sorintlab/stolon/common"
 	"github.com/sorintlab/stolon/pkg/cluster"
 	"github.com/sorintlab/stolon/pkg/flagutil"
@@ -35,16 +36,21 @@ const (
 )
 
 var cmdStolonCtl = &cobra.Command{
-	Use:   "stolonctl",
-	Short: "stolon command line client",
+	Use:     "stolonctl",
+	Short:   "stolon command line client",
+	Version: cmd.Version,
 	PersistentPreRun: func(cmd *cobra.Command, args []string) {
-		if cfg.clusterName == "" {
-			die("cluster name required")
-		}
-		if cfg.storeBackend == "" {
-			die("store backend type required")
+		if cmd.Name() != "stolonctl" && cmd.Name() != "version" {
+			if cfg.clusterName == "" {
+				die("cluster name required")
+			}
+			if cfg.storeBackend == "" {
+				die("store backend type required")
+			}
 		}
 	},
+	// just defined to make --version work
+	Run: func(c *cobra.Command, args []string) { c.Help() },
 }
 
 type config struct {
@@ -69,6 +75,20 @@ func init() {
 	cmdStolonCtl.PersistentFlags().StringVar(&cfg.clusterName, "cluster-name", "", "cluster name")
 }
 
+var cmdVersion = &cobra.Command{
+	Use:   "version",
+	Run:   versionCommand,
+	Short: "Display the version",
+}
+
+func init() {
+	cmdStolonCtl.AddCommand(cmdVersion)
+}
+
+func versionCommand(c *cobra.Command, args []string) {
+	stdout("stolonctl version %s", cmd.Version)
+}
+
 func main() {
 	flagutil.SetFlagsFromEnv(cmdStolonCtl.PersistentFlags(), "STOLONCTL")
 

cmd/version.go

@@ -0,0 +1,17 @@
+// Copyright 2017 Sorint.lab
+//
+// 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 cmd
+
+var Version = "No version defined at build time"

scripts/git-version.sh

@@ -0,0 +1,21 @@
+#!/bin/sh -e
+
+# parse the current git commit hash
+COMMIT=`git rev-parse HEAD`
+
+# check if the current commit has a matching tag
+TAG=$(git describe --exact-match --abbrev=0 --tags ${COMMIT} 2> /dev/null || true)
+
+# use the matching tag as the version, if available
+if [ -z "$TAG" ]; then
+    VERSION=$COMMIT
+else
+    VERSION=$TAG
+fi
+
+# check for changed files (not untracked files)
+if [ -n "$(git diff --shortstat 2> /dev/null | tail -n1)" ]; then
+    VERSION="${VERSION}-dirty"
+fi
+
+echo $VERSION