e2e: add logfile for e2e tests

[parikshithb]

• Creates a log file (ramen-e2e.log) in the current directory by default.
• Log DEBUG level messages to the file and INFO level messages to the console.
• Remove caller (file:lineno) from console logs for cleaner output.
• Added ramen-e2e and ramen-e2e.log to gitignore
• Reverted 2cd063a , which previously redirected e2e test logs to ramen-e2e.log using tee. This change is no longer needed because the new logger implementation now writes to ramen-e2e.log by default.

Fixes: #1722

[nirs]

Fixes: #1722

Good to link the issue, but we should start a PR with a commit message describing the change. We can describe what was done and what will be done later. This helps people to review the change.

[nirs]

#1723 was merged, so you need to revert 2cd063a as part of your pr.

[nirs]

Looks good! just minor comments about comments.

[nirs]

Looks good, minor comment about .gitignore

[nirs]

• Reverted 2cd063a

This is clear when you look at the commits, it will help to explain int the commit/pr message why we revert the previous logging hack.

[nirs]

It seems that the best way to handle the conflict between os.Exit() and defer is to call it only once in main() or in the case of tests, in TestMain(). This also means we cannot call any function that calls os.Exit() like log.Fatal().

We can do this like this:

func TestMain(m *testing.M) {
    os.Exit(run(m))
}

func run(m *testing.M) int {
    log := ...
    defer func() {
        _ = log.Sync()
    }()
    
    ...
    if err != nil {
        log.Errorf("error message... : %s", err)
        return 1
    }

    return m.Run()
}

With this we ensure that test failure or setup failure will return non-zero exit code, and defer function will run, and the code is very simple.

But lets no dalay this good change, we can improve this later.