[CRITICAL BUG] Build log missing since #1946

[zzh8829]

Actual behavior

All logging output from kaniko's log.Info/Warn/Debug are missing

Expected behavior

log.Info should output log

To Reproduce
Steps to reproduce the behavior:

1. Use docker image built after Bump ecr-login dep to avoid some log spam #1946 for example gcr.io/kaniko-project/executor:9969c747034aee243a630412c0d74e788eca0d2a

2. run a basic build with no-push

docker run --rm gcr.io/kaniko-project/executor:9969c747034aee243a630412c0d74e788eca0d2a --dockerfile Dockerfile --context /workspace --no-push

everything works fine

3. run a basic build with any destination

docker run --rm gcr.io/kaniko-project/executor:9969c747034aee243a630412c0d74e788eca0d2a --dockerfile Dockerfile --context /workspace --destination $DOCKER_REPO

there is no log output from kaniko

Additional Information
Reason why this happens
In #1946
https://github.com/GoogleContainerTools/kaniko/pull/1946/files#diff-b0cd856098c47c7aa75c3c9299bb998d62e14e567bced865808d76576a360336R33
Set EcrHelper's logging out put to ioutil.Discard presumably it stops aws from printing things like no valid credential found

But EcrHelper uses logrus.StandardLogger() which is shared by Kaniko's logger. When setting ecr.log to discard this will actually unexpected set kaniko's log to discard as well.

I didn't make a pull request because im not too sure how we want to fix this
removing ecr junk log is pretty nice but we can't have it remove all kaniko logs 😓

Triage Notes for the Maintainers

Description	Yes/No
Please check if this a new feature you are proposing
Please check if the build works in docker but not in kaniko
Please check if this error is seen when you use --cache flag
Please check if your dockerfile is a multistage dockerfile

[zzh8829]

I believe this is also the root cause for #1954

[imjasonh]

Ugh, that is unfortunate. And entirely my own oversight, since I was too focused on disabling logrus for users who don't want it, and didn't even think about those who would want it. 😞

Let me think on it a bit and see if we can come up with something. It might require changes to ecr-login to make them use a dedicated logger (set to stderr by default), so that it can be selectively disabled without disabling the shared global logger.

edit: awslabs/amazon-ecr-credential-helper#312

[imjasonh]

In the meantime, I've patched the ecr-login PR above and built:

gcr.io/imjasonh/executor@sha256:4e322efeee7de6b1cb963263e366f2c83f29726f6b2e3da93eeb1a4fc6444100

...which seems to fix the issue. Please let me know if you see other behavior.

[imjasonh]

This is also why integration tests are failing. Tests check for some log output, and don't find it.

If the ecr-login change isn't merged soon I may revert the breaking commit, or patch it.

Sorry for missing this.