fix(Ingestion): Elastic http/https host support

[abiwill]

allow users to specify url scheme. enable ingestion from both TLS enabled clusters.
currently specifying the url scheme resulted in assertion error.

Checklist

• The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• Links to related issues (if applicable)
• Tests for the changes have been added/updated (if applicable)
• Docs related to the changes have been added/updated (if applicable)

[shirshanka]

Thanks for this @abiwill
I fixed up the regex to handle the old style as well..
could you add a unit test here?
https://github.com/linkedin/datahub/blob/master/metadata-ingestion/tests/unit/test_elasticsearch_source.py

That will ensure we handle different styles of host_port specification correctly.

[github-actions]

Unit Test Results (metadata ingestion)

       5 files         5 suites   41m 7s ⏱️
   333 tests    333 ✔️   0 💤 0 ❌
1 536 runs  1 498 ✔️ 38 💤 0 ❌

Results for commit 1cd4db9.

♻️ This comment has been updated with latest results.

[github-actions]

Unit Test Results (build & test)

  70 files  +  1    70 suites  +1   19m 31s ⏱️ + 11m 42s
611 tests +71  552 ✔️ +64  59 💤 +7  0 ❌ ±0 

Results for commit 1cd4db9. ± Comparison against base commit b08784e.

♻️ This comment has been updated with latest results.

[abiwill]

Unittest PR: #4194
Thanks for the fix @shirshanka
There is one more problem with the regex: \w allows use of _ which is not a valid hostname.
Instead of \w we can use [0-9a-zA-Z]

[mmmeeedddsss]

It is impressive that only changing the validation regex solves the issue. It is fascinating to see a project growing in such a way.

I want to thank you for spending your time on investigating, implementing and testing this change. 🚀

[abiwill]

I have just started my journey into programming. Trying to learn and solve :)

[shirshanka]

Since this check is really a first line of defense, I think it is okay to be a bit more loose, since the underlying elastic client will anyway complain if it cannot connect to the configured endpoint. We just want to make sure that clearly valid values are not blocked by it.

[shirshanka]

LGTM! Made changes to unit test in this PR itself.