add fuzz tests to multiple receivers and processors

[AdamKorcz]

Description

Adds fuzz tests for receiver handlers and processing of metrics, logs and traces. For receivers, the fuzz test will create an HTTP request with the fuzzers testcase as its body. For processors, the fuzzer will create random logs, metrics or traces and pass it to a routine that processes the data - for the most part either a processLogs/processMetrics/processTraces method or ConsumeLogs/ConsumeTraces which will then invoke the internal process routine.

Link to tracking issue

Fixes

Testing

Documentation

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 14 days.

[github-actions]

Closed as inactive. Feel free to reopen if this PR is still being worked on.

[AdamKorcz]

Please reopen. This PR is waiting for a review.

[atoulme]

how about

Suggested change

	if err != nil {
	t.Fatal(err)
	}
	require.NoError(t, err)

[AdamKorcz]

Thanks for the suggestion. This will give some problems for the fuzzers on OSS-Fuzz. Unless it is a hard style requirement, I would prefer to skip this suggestion.

[atoulme]

Reviewed. The PR is hard to review because it spans multiple components. I think you mean to introduce fuzzing as a testing practice, which is great. Can you elaborate to what you're trying to achieve further please?

[atoulme]

Please review the CI as well, lint fails.

[AdamKorcz]

@atoulme Thank you for reviewing. Yes, this introduces a set of fuzz tests for several components. This is part of the work carried out during the Collectors fuzzing audit.

[AdamKorcz]

These fuzz tests are already running continuously via the Collectors OSS-Fuzz integration.