BuildDate is always the current time

[NickLarsenNZ]

Describe the bug

The build date is always the current time.

To Reproduce

Run argocd-image-updater version twice in a row (at least a second apart).

Expected behavior

The actual binary build date time.

Additional context

This line gets the runtime datetime:

argocd-image-updater/pkg/version/version.go

Line 11 in 71551f9

buildDate = time.Now().UTC().Format(time.RFC3339)

Version

/ $ argocd-image-updater version
argocd-image-updater: v0.11.3+f62b7d7
  BuildDate: 2022-01-23T10:22:17Z
  GitCommit: f62b7d7841a42030fe4c75de1951c46b0e7fca2e
  GoVersion: go1.16.13
  GoCompiler: gc
  Platform: linux/amd64
/ $ argocd-image-updater version
argocd-image-updater: v0.11.3+f62b7d7
  BuildDate: 2022-01-23T10:27:13Z
  GitCommit: f62b7d7841a42030fe4c75de1951c46b0e7fca2e
  GoVersion: go1.16.13
  GoCompiler: gc
  Platform: linux/amd64

Logs
Please paste any relevant logs here

[NickLarsenNZ]

Here's a possible way of injecting build data: https://blog.alexellis.io/inject-build-time-vars-golang/#overridegobuild

version.go

package main

import (
   // ...
)

var BuildDate string

func newVersionCommand() *cobra.Command {
   // ...
}

go build -ldflags "-X main.BuildDate=$(datetime command here)"

[NickLarsenNZ]

argocd does it in a similar fashion:

• https://github.com/argoproj/argo-cd/blob/b37eee1054e42c873699460dd5e2447c2f9fe5a6/common/version.go#L8-L30
• https://github.com/argoproj/argo-cd/blob/b37eee1054e42c873699460dd5e2447c2f9fe5a6/Makefile#L127-L133

[NickLarsenNZ]

Ah ok, so argocd-image-updater does the same:

https://github.com/argoproj-labs/argocd-image-updater/blob/master/Makefile#L32-L35

It's just being overwritten by time.Now().UTC().Format(time.RFC3339). Is that because it is no longer static, so the linker is not updating it (or it is, and the runtime is still updating it)?

[jannfis]

Good catch. It should have been overriden at build-time.

argocd-image-updater/Makefile

Line 35 in 71551f9

-X ${VERSION_PACKAGE}.buildDate=${BUILD_DATE}

and later

argocd-image-updater/Makefile

Line 71 in 71551f9

CGO_ENABLED=0 GOOS=${OS} GOARCH=${ARCH} go build -ldflags '${LDFLAGS}' -o ${OUTDIR}/${BINNAME} cmd/*.go

But for some reason, it doesn't 🤔

[jannfis]

It's just being overwritten by time.Now().UTC().Format(time.RFC3339). Is that because it is no longer static, so the linker is not updating it (or it is, and the runtime is still updating it)?

If buildDate in the version package is set to a static string (e.g. "unknown"), the override works as expected. Probably we should set it to an empty string, and the return the value of time.Now().UTC().Format(time.RFC3339) in BuildDate() when buildDate is the empty string (so that it will print a date when run by go run ...).

[NickLarsenNZ]

Sounds good @jannfis. Just wondering, should we follow how argocd does theirs, with a static string of unix epoch?

https://github.com/argoproj/argo-cd/blob/b37eee1054e42c873699460dd5e2447c2f9fe5a6/common/version.go#L12

Or is it quite useful to have the current time when using go run?