From 8795fe6b900eb9946c214bfd2ddd36834e1afbff Mon Sep 17 00:00:00 2001
From: Sean Malloy <sean.malloy@kohls.com>
Date: Tue, 13 Oct 2020 00:32:44 -0500
Subject: [PATCH] Fix Version Output For Automated Container Builds

Prior to this change the output from the command "descheduler version"
when run using the official container images from k8s.gcr.io would
always output an empty string. See below for an example.

```
docker run k8s.gcr.io/descheduler/descheduler:v0.19.0 /bin/descheduler version
Descheduler version {Major: Minor: GitCommit: GitVersion: BuildDate:2020-09-01T16:43:23+0000 GoVersion:go1.15 Compiler:gc Platform:linux/amd64}
```

This change makes it possible to pass the descheduler version
information to the automated container image build process and
also makes it work for local builds too.
---
 Dockerfile                     |  3 ++-
 Makefile                       |  9 ++++-----
 cmd/descheduler/app/version.go | 23 +++++++++++++++--------
 3 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 7799e92ca..0208b970b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -15,7 +15,8 @@ FROM golang:1.15.2
 
 WORKDIR /go/src/sigs.k8s.io/descheduler
 COPY . .
-RUN make
+ARG VERSION
+RUN VERSION=${VERSION} make
 
 FROM scratch
 
diff --git a/Makefile b/Makefile
index 852b5c17e..f74f26c00 100644
--- a/Makefile
+++ b/Makefile
@@ -14,13 +14,12 @@
 
 .PHONY: test
 
-# VERSION is currently based on the last commit
-VERSION?=$(shell git describe --tags --match "v*")
-COMMIT=$(shell git rev-parse HEAD)
+# VERSION is based on a date stamp plus the last commit
+VERSION?=v$(shell date +%Y%m%d)-$(shell git describe --tags --match "v*")
 BUILD=$(shell date +%FT%T%z)
 LDFLAG_LOCATION=sigs.k8s.io/descheduler/cmd/descheduler/app
 
-LDFLAGS=-ldflags "-X ${LDFLAG_LOCATION}.version=${VERSION} -X ${LDFLAG_LOCATION}.buildDate=${BUILD} -X ${LDFLAG_LOCATION}.gitCommit=${COMMIT}"
+LDFLAGS=-ldflags "-X ${LDFLAG_LOCATION}.version=${VERSION} -X ${LDFLAG_LOCATION}.buildDate=${BUILD}"
 
 GOLANGCI_VERSION := v1.30.0
 HAS_GOLANGCI := $(shell ls _output/bin/golangci-lint)
@@ -52,7 +51,7 @@ dev-image: build
 	docker build -f Dockerfile.dev -t $(IMAGE) .
 
 image:
-	docker build -t $(IMAGE) .
+	docker build --build-arg VERSION="$(VERSION)" -t $(IMAGE) .
 
 push-container-to-gcloud: image
 	gcloud auth configure-docker
diff --git a/cmd/descheduler/app/version.go b/cmd/descheduler/app/version.go
index 5bf43ac06..a59f92336 100644
--- a/cmd/descheduler/app/version.go
+++ b/cmd/descheduler/app/version.go
@@ -18,6 +18,7 @@ package app
 
 import (
 	"fmt"
+	"regexp"
 	"runtime"
 	"strings"
 
@@ -25,9 +26,6 @@ import (
 )
 
 var (
-	// gitCommit is a constant representing the source version that
-	// generated this build. It should be set during build via -ldflags.
-	gitCommit string
 	// version is a constant representing the version tag that
 	// generated this build. It should be set during build via -ldflags.
 	version string
@@ -40,7 +38,6 @@ var (
 type Info struct {
 	Major      string `json:"major"`
 	Minor      string `json:"minor"`
-	GitCommit  string `json:"gitCommit"`
 	GitVersion string `json:"gitVersion"`
 	BuildDate  string `json:"buildDate"`
 	GoVersion  string `json:"goVersion"`
@@ -55,7 +52,6 @@ func Get() Info {
 	return Info{
 		Major:      majorVersion,
 		Minor:      minorVersion,
-		GitCommit:  gitCommit,
 		GitVersion: version,
 		BuildDate:  buildDate,
 		GoVersion:  runtime.Version(),
@@ -81,7 +77,18 @@ func splitVersion(version string) (string, string) {
 	if version == "" {
 		return "", ""
 	}
-	// A sample version would be of form v0.1.0-7-ge884046, so split at first '.' and
-	// then return 0 and 1+(+ appended to follow semver convention) for major and minor versions.
-	return strings.Trim(strings.Split(version, ".")[0], "v"), strings.Split(version, ".")[1] + "+"
+
+	// Version from an automated container build environment for a tag. For example v20200521-v0.18.0.
+	m1, _ := regexp.MatchString(`^v\d{8}-v\d+\.\d+\.\d+$`, version)
+
+	// Version from an automated container build environment(not a tag) or a local build. For example v20201009-v0.18.0-46-g939c1c0.
+	m2, _ := regexp.MatchString(`^v\d{8}-v\d+\.\d+\.\d+-\w+-\w+$`, version)
+
+	if m1 || m2 {
+		semVer := strings.Split(version, "-")[1]
+		return strings.Trim(strings.Split(semVer, ".")[0], "v"), strings.Split(semVer, ".")[1] + "+"
+	}
+
+	// Something went wrong
+	return "", ""
 }