Support --version flag

Fixes #41

Makefile

@@ -4,6 +4,12 @@ all: test
 
 OUTPUT = ./irel
 GO_SOURCES = $(shell find . -type f -name '*.go')
+VERSION ?= $(shell cat VERSION)
+GITSHA = $(shell git rev-parse HEAD)
+GITDIRTY = $(shell git diff --quiet HEAD || echo "dirty")
+LDFLAGS_VERSION = -X github.com/pivotal/image-relocation/pkg/irel.cli_version=$(VERSION) \
+				  -X github.com/pivotal/image-relocation/pkg/irel.cli_gitsha=$(GITSHA) \
+				  -X github.com/pivotal/image-relocation/pkg/irel.cli_gitdirty=$(GITDIRTY)
 
 test:
 	GO111MODULE=on go test ./... -coverprofile=coverage.txt -covermode=atomic
@@ -20,9 +26,9 @@ gen-mocks: check-counterfeiter
 	counterfeiter -o pkg/registry/ggcr/registryclientfakes/fake_registry_client.go ./pkg/registry/ggcr RegistryClient
 
 irel: $(GO_SOURCES)
-	GO111MODULE=on go build -o $(OUTPUT) cmd/irel/main.go
+	GO111MODULE=on go build -ldflags "$(LDFLAGS_VERSION)" -o $(OUTPUT) cmd/irel/main.go
 
 release: $(GO_SOURCES) test
-	GOOS=darwin   GOARCH=amd64 go build -o $(OUTPUT)     cmd/irel/main.go && tar -czf irel-darwin-amd64.tgz  $(OUTPUT)     && rm -f $(OUTPUT)
-	GOOS=linux    GOARCH=amd64 go build -o $(OUTPUT)     cmd/irel/main.go && tar -czf irel-linux-amd64.tgz   $(OUTPUT)     && rm -f $(OUTPUT)
-	GOOS=windows  GOARCH=amd64 go build -o $(OUTPUT).exe cmd/irel/main.go && zip -mq  irel-windows-amd64.zip $(OUTPUT).exe && rm -f $(OUTPUT).exe
+	GOOS=darwin   GOARCH=amd64 go build -ldflags "$(LDFLAGS_VERSION)" -o $(OUTPUT)     cmd/irel/main.go && tar -czf irel-darwin-amd64.tgz  $(OUTPUT)     && rm -f $(OUTPUT)
+	GOOS=linux    GOARCH=amd64 go build -ldflags "$(LDFLAGS_VERSION)" -o $(OUTPUT)     cmd/irel/main.go && tar -czf irel-linux-amd64.tgz   $(OUTPUT)     && rm -f $(OUTPUT)
+	GOOS=windows  GOARCH=amd64 go build -ldflags "$(LDFLAGS_VERSION)" -o $(OUTPUT).exe cmd/irel/main.go && zip -mq  irel-windows-amd64.zip $(OUTPUT).exe && rm -f $(OUTPUT).exe

VERSION

@@ -0,0 +1 @@
+0.7.0-snapshot

cmd/irel/main.go

@@ -23,7 +23,12 @@ import (
 )
 
 func main() {
-	if err := irel.Root.Execute(); err != nil {
+	cmd := irel.Root
+
+	cmd.Version = irel.CliVersion()
+	cmd.Flags().Bool("version", false, "display CLI version")
+
+	if err := cmd.Execute(); err != nil {
 		fmt.Println(err)
 		os.Exit(1)
 	}

pkg/irel/env.go

@@ -0,0 +1,35 @@
+/*
+ * Copyright (c) 2019-Present Pivotal Software, Inc. All rights reserved.
+ *
+ * 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 irel
+
+import "fmt"
+
+var (
+	cli_version  = "unknown"
+	cli_gitsha   = "unknown sha"
+	cli_gitdirty = ""
+)
+
+func CliVersion() string {
+	var version string
+	if cli_gitdirty == "" {
+		version = fmt.Sprintf("%s (%s)", cli_version, cli_gitsha)
+	} else {
+		version = fmt.Sprintf("%s (%s, with local modifications)", cli_version, cli_gitsha)
+	}
+	return version
+}

pkg/irel/env_test.go

@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2019-Present Pivotal Software, Inc. All rights reserved.
+ *
+ * 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 irel
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("CliVersion", func() {
+	var version string
+
+	JustBeforeEach(func() {
+		version = CliVersion()
+	})
+
+	It("should default correctly", func() {
+		Expect(version).To(Equal("unknown (unknown sha)"))
+	})
+
+	Context("when version is known", func() {
+		BeforeEach(func() {
+			cli_version = "0.0.0"
+		})
+
+		It("should include the version", func() {
+			Expect(version).To(Equal("0.0.0 (unknown sha)"))
+		})
+
+		Context("when SHA is known", func() {
+			BeforeEach(func() {
+				cli_gitsha = "abc"
+			})
+
+			It("should include the SHA", func() {
+				Expect(version).To(Equal("0.0.0 (abc)"))
+			})
+
+			Context("when repo is dirty", func() {
+				BeforeEach(func() {
+					cli_gitdirty = "dirty"
+				})
+
+				It("should note the repo is dirty", func() {
+					Expect(version).To(Equal("0.0.0 (abc, with local modifications)"))
+				})
+			})
+		})
+	})
+})

pkg/irel/irel_suite_test.go

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2019-Present Pivotal Software, Inc. All rights reserved.
+ *
+ * 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 irel_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestIrel(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Irel Suite")
+}