e2e: ExecCmd debug log on error

[p0mvn]

Closes: #XXX

What is the purpose of the change

This change was originally introduced in #1898. However, in #1898 if "error" was found, the system would fail on the following line:

osmosis/tests/e2e/containers/containers.go

Line 101 in 8f31b5a

return false

That started causing issues because some applications such as Hermes log "error" to stderr in the normal mode of operation. So the change was reverted in #1902

This log proved to be incredibly helpful, making me manually change every PR for debugging. So, a modified version is introduced here. This version does not fail but only logs when "error is encountered.

Testing and Verifying

This change is a trivial rework / code cleanup without any test coverage.

Documentation and Release Note

• Does this pull request introduce a new feature or user-facing behavior changes? no
• Is a relevant changelog entry added to the Unreleased section in CHANGELOG.md? no
• How is the feature or change documented? not applicable

[czarcas7ic]

Can you give an example where this would be useful? I am just lacking context, since as it stands when an error occurs it eventually halts the e2e test suite and prints the error to the terminal right?

[p0mvn]

eventually halts the e2e test suite and prints the error to the terminal right

It does not print anything.

The arguments are evaluated before running the callback so it prints empty. In fact, we should remove this line because it always prints empty in place of errBuf and outBuf:

"tx returned a non-zero code; stdout: %s, stderr: %s", outBuf.String(), errBuf.String()

        // 1. We start here with empty errBuf 
	require.Eventually(
		t,
		func() bool {
	                      // 3. We update errBug here (after it was evaluated in 2.)
		},
		time.Minute,
		time.Second,
		"tx returned a non-zero code; stdout: %s, stderr: %s", outBuf.String(), errBuf.String(),  // 2. This gets evaluated so this is always empty
	)

[p0mvn]

I made some updates, let me know what you think.

This change also allows us to see if there is an error right away as opposed to waiting for 1 minute to get a log without stdout or stderr

[czarcas7ic]

LGTM now!