Improve version handling for main module and when this project is imported (#69)

Author: joelanford

Makefile

@@ -11,16 +11,17 @@ GOBIN=$(shell go env GOBIN)
 endif
 
 # GO_BUILD_ARGS should be set when running 'go build' or 'go install'.
-REPO = $(shell go list -m)
-#TODO (anrastog): set version to repo build/tag after v1 plugin is available in master.
-VERSION = master
+VERSION_PKG = "$(shell go list -m)/internal/version"
+SCAFFOLD_VERSION = $(shell git describe --abbrev=0)
+GIT_VERSION = $(shell git describe --dirty --tags --always)
 GIT_COMMIT = $(shell git rev-parse HEAD)
 GO_BUILD_ARGS = \
   -gcflags "all=-trimpath=$(shell dirname $(shell pwd))" \
   -asmflags "all=-trimpath=$(shell dirname $(shell pwd))" \
   -ldflags " \
-    -X '$(REPO)/internal/version.Version=$(VERSION)' \
-    -X '$(REPO)/internal/version.GitCommit=$(GIT_COMMIT)' \
+    -X '$(VERSION_PKG).ScaffoldVersion=$(SCAFFOLD_VERSION)' \
+    -X '$(VERSION_PKG).GitVersion=$(GIT_VERSION)' \
+    -X '$(VERSION_PKG).GitCommit=$(GIT_COMMIT)' \
   " \
 
 #all: manager

go.mod

@@ -3,6 +3,7 @@ module github.com/joelanford/helm-operator
 go 1.15
 
 require (
+	github.com/blang/semver/v4 v4.0.0
 	github.com/go-logr/logr v0.3.0
 	github.com/iancoleman/strcase v0.1.2
 	github.com/kr/text v0.1.0

go.sum

@@ -90,7 +90,7 @@ func printVersion() {
 		"Go Version", runtime.Version(),
 		"GOOS", runtime.GOOS,
 		"GOARCH", runtime.GOARCH,
-		"helm-operator", version.Version)
+		"helm-operator", version.GitVersion)
 }
 
 func (r *run) run(cmd *cobra.Command) {

internal/cmd/run/cmd.go

@@ -16,8 +16,103 @@ limitations under the License.
 
 package version
 
+import (
+	"fmt"
+	"runtime/debug"
+	"strings"
+
+	"github.com/blang/semver/v4"
+)
+
+const (
+	Unknown    = "unknown"
+	modulePath = "github.com/joelanford/helm-operator"
+)
+
 var (
-	//TODO: Hardcode it to version string to support importing and usage in operator-sdk
-	Version   = "unknown"
-	GitCommit = "unknown"
+	GitVersion      = Unknown
+	GitCommit       = Unknown
+	ScaffoldVersion = Unknown
 )
+
+func init() {
+	// If the ScaffoldVersion was not set during the
+	// build (e.g. if this module was imported by
+	// another), try to deduce the scaffold version
+	// from the binary's embedded build info.
+	if ScaffoldVersion == Unknown {
+		ScaffoldVersion = getScaffoldVersion()
+	}
+}
+
+// getScaffoldVersion parses build info embedded in
+// the binary to deduce a tag version that is
+// appropriate to use when scaffolding files that
+// need to reference the most recent release from
+// this repository.
+//
+// This allows other projects to import and use the
+// helm plugin and have versions populated correctly
+// in the scaffolded Makefile, Dockerfile, etc.
+func getScaffoldVersion() string {
+	info, ok := debug.ReadBuildInfo()
+	if ok {
+		// Search the dependencies of the main module and
+		// if we find this module, return its most recent
+		// tag.
+		for _, m := range info.Deps {
+			if m == nil {
+				continue
+			}
+			if m.Path == modulePath {
+				return getMostRecentTag(*m)
+			}
+		}
+	}
+
+	// If there isn't build info or we couldn't
+	// find our module in the main module's deps,
+	// return Unknown.
+	return Unknown
+}
+
+// getMostRecentTag translates m into a version string
+// that corresponds to the tag at (or that precedes) the
+// commit referenced by the m's version, accounting
+// for any replacements.
+//
+// If it can't deduce a tag, it returns "unknown".
+func getMostRecentTag(m debug.Module) string {
+	// Unwind all of the replacements.
+	for m.Replace != nil {
+		m = *m.Replace
+	}
+
+	// We need to handle the possibility of a pseudo-version.
+	// See: https://golang.org/cmd/go/#hdr-Pseudo_versions
+	//
+	// We'll get the first segment and attempt to parse it as
+	// semver.
+	split := strings.Split(m.Version, "-")
+	sv, err := semver.Parse(strings.TrimPrefix(split[0], "v"))
+
+	// If the first segment was not a valid semver string,
+	// return Unknown.
+	if err != nil {
+		return Unknown
+	}
+
+	// If there were multiple segments, m.Version is
+	// a pseudo-version, in which case Go will have
+	// incremented the patch version. If the patch
+	// version is greater than zero (it should always
+	// be), we'll decrement it to get back to the
+	// previous tag.
+	//
+	// This is necessary to handle projects that
+	// import this project at untagged commits.
+	if len(split) > 1 && sv.Patch > 0 {
+		sv.Patch -= 1
+	}
+	return fmt.Sprintf("v%s", sv.FinalizeVersion())
+}

internal/cmd/version/cmd.go

@@ -55,6 +55,6 @@ func main() {
 
 func getVersion() string {
 	return fmt.Sprintf("helm-operator version: %q, commit: %q, go version: %q, GOOS: %q, GOARCH: %q\n",
-		version.Version, version.GitCommit, runtime.Version(), runtime.GOOS, runtime.GOARCH)
+		version.GitVersion, version.GitCommit, runtime.Version(), runtime.GOOS, runtime.GOARCH)
 
 }

internal/version/version.go

@@ -19,7 +19,6 @@ package scaffolds
 
 import (
 	"os"
-	"strings"
 
 	"sigs.k8s.io/kubebuilder/v2/pkg/model"
 	"sigs.k8s.io/kubebuilder/v2/pkg/model/config"
@@ -43,8 +42,7 @@ const (
 )
 
 // helmOperatorVersion is set to the version of helm-operator at compile-time.
-var helmOperatorVersion = strings.TrimSuffix(version.Version, "+git")
-
+var helmOperatorVersion = mustGetScaffoldVersion()
 var _ cmdutil.Scaffolder = &initScaffolder{}
 
 type initScaffolder struct {
@@ -110,3 +108,10 @@ func (s *initScaffolder) scaffold() error {
 		&kdefault.Kustomization{},
 	)
 }
+
+func mustGetScaffoldVersion() string {
+	if version.ScaffoldVersion == "" || version.ScaffoldVersion == version.Unknown {
+		panic("helm-operator scaffold version is unknown; it must be set during build or by importing this plugin via go modules")
+	}
+	return version.ScaffoldVersion
+}