feat(cli): --version using ldflags

The go-modules approach is a bit broken: https://github.com/golang/go/issues/29228
To resolve that, we now compute that version using `git describe` and
set it using `ldflags`.

While this is not as nice/builtin as the other approach, it at least
works all the time and across go versions.

Furthermore, I did refactor the Makefile in preparation for an AUR
package that builds from source and for building release artifacts in CI.

Makefile

@@ -1,31 +1,35 @@
-all: check-license build generate test
+.PHONY: all check-license crossbuild build install test generate embedmd
 
 GITHUB_URL=github.com/jsonnet-bundler/jsonnet-bundler
-GOOS?=$(shell uname -s | tr A-Z a-z)
+VERSION := $(shell git describe --tags --dirty --always)
-GOARCH?=$(subst x86_64,amd64,$(patsubst i%86,386,$(shell uname -m)))
 OUT_DIR=_output
 BIN?=jb
-VERSION?=$(shell cat VERSION)
 PKGS=$(shell go list ./... | grep -v /vendor/)
 
-check-license:
+all: check-license build generate test
-	@echo ">> checking license headers"
-	@./scripts/check_license.sh
 
-crossbuild:
+
-	@GOOS=linux ARCH=amd64 $(MAKE) -s build
+# Binaries
+LDFLAGS := '-s -w -extldflags "-static" -X main.Version=${VERSION}'
+cross: clean
+	CGO_ENABLED=0 gox \
+	  -output="$(OUT_DIR)/jb-{{.OS}}-{{.Arch}}" \
+	  -ldflags=$(LDFLAGS) \
+	  -arch="amd64 arm64 arm" -os="linux" \
+	  -osarch="darwin/amd64" \
+	  ./cmd/$(BIN)
+
+static:
+	CGO_ENABLED=0 go build -ldflags=${LDFLAGS} -o $(OUT_DIR)/$(BIN) ./cmd/$(BIN)
 
 build:
-	@$(eval OUTPUT=$(OUT_DIR)/$(GOOS)/$(GOARCH)/$(BIN))
+	CGO_ENABLED=0 go build ./cmd/$(BIN)
-	@echo ">> building for $(GOOS)/$(GOARCH) to $(OUTPUT)"
-	@mkdir -p $(OUT_DIR)/$(GOOS)/$(GOARCH)
-	@CGO_ENABLED=0 go build --installsuffix cgo -o $(OUTPUT) $(GITHUB_URL)/cmd/$(BIN)
 
-install: build
+install: static
-	@$(eval OUTPUT=$(OUT_DIR)/$(GOOS)/$(GOARCH)/$(BIN))
 	@echo ">> copying $(BIN) into $(GOPATH)/bin/$(BIN)"
-	@cp $(OUTPUT) $(GOPATH)/bin/$(BIN)
+	cp $(OUT_DIR)/$(BIN) $(GOPATH)/bin/$(BIN)
 
+# Tests
 test:
 	@echo ">> running all unit tests"
 	go test -v $(PKGS)
@@ -34,12 +38,22 @@ test-integration:
 	@echo ">> running all integration tests"
 	go test -v -tags=integration $(PKGS)
 
+# Documentation
 generate: embedmd
 	@echo ">> generating docs"
 	@./scripts/generate-help-txt.sh
 	@$(GOPATH)/bin/embedmd -w `find ./ -path ./vendor -prune -o -name "*.md" -print`
 
-embedmd:
+check-license:
-	@go get github.com/campoy/embedmd
+	@echo ">> checking license headers"
+	@./scripts/check_license.sh
 
-.PHONY: all check-license crossbuild build install test generate embedmd
+embedmd:
+	pushd /tmp && GO111MODULES=on go get github.com/campoy/embedmd && popd
+
+# Other
+clean:
+	rm -rf $(OUT_DIR) $(BIN)
+
+drone:
+	drone jsonnet --format

cmd/jb/main.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/fatih/color"
 	"github.com/pkg/errors"
+	"gopkg.in/alecthomas/kingpin.v2"
 )
 
 const (
@@ -30,6 +31,8 @@ const (
 	rewriteActionName = "rewrite"
 )
 
+var Version = "dev"
+
 func main() {
 	os.Exit(Main())
 }
@@ -41,7 +44,7 @@ func Main() int {
 
 	color.Output = color.Error
 
-	a := newApp()
+	a := kingpin.New(filepath.Base(os.Args[0]), "A jsonnet package manager").Version(Version)
 	a.HelpFlag.Short('h')
 
 	a.Flag("jsonnetpkg-home", "The directory used to cache packages in.").

cmd/jb/version.go

@@ -1,34 +0,0 @@
-// Copyright 2018 jsonnet-bundler 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.
-
-// +build go1.12
-
-package main
-
-import (
-	"os"
-	"path/filepath"
-	"runtime/debug"
-
-	kingpin "gopkg.in/alecthomas/kingpin.v2"
-)
-
-func newApp() *kingpin.Application {
-	a := kingpin.New(filepath.Base(os.Args[0]), "A jsonnet package manager")
-	d, ok := debug.ReadBuildInfo()
-	if ok {
-		return a.Version(d.Main.Version)
-	}
-	return a
-}

cmd/jb/version111.go

@@ -1,29 +0,0 @@
-// Copyright 2018 jsonnet-bundler 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.
-
-// +build !go1.12
-
-package main
-
-import (
-	"os"
-	"path/filepath"
-
-	kingpin "gopkg.in/alecthomas/kingpin.v2"
-)
-
-func newApp() *kingpin.Application {
-	a := kingpin.New(filepath.Base(os.Args[0]), "A jsonnet package manager")
-	return a
-}