Catch Timeout on test urls

[Glutexo]

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Complete Description of Additions/Changes:

The internal methods used by the --test-connection command only used to catch ConnectionError, including ConnectionTimeout, but not other timeouts such as ReadTimeoutError. As a result, in case of a read timeout,  the failure is not fully handled. That means:

• an error message containing the failed URL is not logged;
• and in case of legacy upload, the URL fallback mechanism is interrupted.

Re-used the existing REQUEST_FAILED_EXCEPTIONS list to process all timeouts in the same way.

Card IDs:

• CCT-859

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 77.10%. Comparing base (416ed6b) to head (bafcb3d).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #4248 +/- ## ========================================== + Coverage 77.01% 77.10% +0.09% ========================================== Files 761 761 Lines 41471 41471 Branches 8763 8763 ========================================== + Hits 31937 31976 +39 + Misses 8481 8438 -43 - Partials 1053 1057 +4 ``` | [Flag](https://app.codecov.io/gh/RedHatInsights/insights-core/pull/4248/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RedHatInsights) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/RedHatInsights/insights-core/pull/4248/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RedHatInsights) | `77.09% <100.00%> (+0.09%)` | :arrow_up: | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=RedHatInsights#carryforward-flags-in-the-pull-request-comment) to find out more.

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[Glutexo]

I extracted this fix from https://github.com/RedHatInsights/insights-core/pull/4237 and originally from https://github.com/RedHatInsights/insights-core/pull/4211. https://github.com/RedHatInsights/insights-core/pull/4211 only changes exception handling in the outer test_connection method, because that is the minimal patch to fix the reported issue of a stack trace being dumped on the standard output. This new PR, on the other hand, fixes error logging and fallback mechanism in case of a read timeout.

Moreover, this would unblock https://github.com/RedHatInsights/insights-core/pull/4246 in case of https://github.com/RedHatInsights/insights-core/pull/4211 being merged first of the two. See my comment in https://github.com/RedHatInsights/insights-core/pull/4246 for more details.

[Glutexo]

This patch only updates the inner _test_urls and _legacy_test_urls methods, not the outer test_connection method. It doesn’t even change any printing or logging logic. Therefore, unlike https://github.com/RedHatInsights/insights-core/pull/4211 and https://github.com/RedHatInsights/insights-core/pull/4246, there are no tests of test_connection or integration tests.

The error log and standard out tests are the only way how to find out whether the except block fired as intended. That’s why there are log/stdout tests in place. They, however, don’t test the contents of the messages as that’s not the subject of this pull request. That will change after merging with the tests from other related PRs.

[Glutexo]

Open for review. @m-horky

[Glutexo]

To make things simpler, let‘s say this is a blocker of https://github.com/RedHatInsights/insights-core/pull/4246, which is a blocker of https://github.com/RedHatInsights/insights-core/pull/4211. Merging this first will make further reviewing and merging easier.

[Glutexo]

There is also https://github.com/RedHatInsights/insights-core/pull/4254 in the family. It neither blocks anything nor is blocked by anything. It only shares some tests.

[m-horky]

Hi, @xiangce, good to merge!