[v8] Set custom version

version/version.go

@@ -1,6 +1,8 @@
 package version
 
 import (
+	"fmt"
+	"os"
 	"strings"
 
 	"github.com/blang/semver/v4"
@@ -12,9 +14,32 @@ var (
 	binaryVersion   string
 	binarySHA       string
 	binaryBuildDate string
+	customVersion   string
+
+	ExitFunc = os.Exit
 )
 
+func SetVersion(version string) {
+	if version == "" {
+		customVersion = ""
+		return
+	}
+
+	_, err := semver.Parse(version)
+
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Invalid semantic version format: %s\n", err)
+		ExitFunc(1)
+	}
+
+	customVersion = version
+}
+
 func VersionString() string {
+	if customVersion != "" {
+		return customVersion
+	}
+
 	// Remove the "v" prefix from the binary in case it is present
 	binaryVersion = strings.TrimPrefix(binaryVersion, "v")
 	versionString, err := semver.Make(binaryVersion)

version/version_test.go

@@ -7,11 +7,45 @@ import (
 )
 
 var _ = Describe("Version", func() {
+	BeforeEach(func() {
+		version.SetVersion("")
+	})
+
 	Describe("VersionString", func() {
 		When("passed no ldflags", func() {
 			It("returns the default version", func() {
 				Expect(version.VersionString()).To(Equal("0.0.0-unknown-version"))
 			})
 		})
+
+		When("a custom version is set", func() {
+			It("returns the custom version", func() {
+				version.SetVersion("1.2.3")
+				Expect(version.VersionString()).To(Equal("1.2.3"))
+			})
+		})
+	})
+
+	Describe("SetVersion", func() {
+		It("sets the version for valid semver versions", func() {
+			version.SetVersion("1.2.3")
+			Expect(version.VersionString()).To(Equal("1.2.3"))
+		})
+
+		It("exits with status code 1 when given an invalid semver", func() {
+			var exitCode int
+			originalExitFunc := version.ExitFunc
+
+			defer func() {
+				version.ExitFunc = originalExitFunc
+			}()
+
+			version.ExitFunc = func(code int) {
+				exitCode = code
+			}
+
+			version.SetVersion("not-a-semver")
+			Expect(exitCode).To(Equal(1))
+		})
 	})
 })