lua: add request info dynamic metadata api

[dio]

lua: add request info dynamic metadata API

Description:
This patch allows to get and set the dynamic metadata of a request via Lua.

Setting metadata,

request_handle:requestInfo():dynamicMetadata():set("envoy.lb", "foo", "bar")

Getting metadata,

-- returns a table
request_handle:requestInfo():dynamicMetadata():get("envoy.lb")
request_handle:requestInfo():dynamicMetadata():get("envoy.lb")["foo"]

Risk Level: Low

Testing: Unit and integration tests

Docs Changes:

• Added request info object API
• Added dynamic metadata object API

Release Notes:

• Added request info dynamic metadata Lua API

Fixes #3618

[stale]

This pull request has been automatically marked as stale because it has not had activity in the last 7 days. It will be closed in 7 days if no further activity occurs. Please feel free to give a status update now, ping for review, or re-open when it's ready. Thank you for your contributions!

[mattklein123]

@dio is this still WIP or does this need a reviewer?

[dio]

@mattklein123 yes it is still WIP I will add docs, support for accepting a table as param then I'll ask for a review.

Two questions,

1. Do you think this is still considered an enhancement? Since there is an effort here: 827c0a5 for making it accessible via config.
2. While this is part of the review, what do you think about the proposed API?

Thanks!

[ramaraochavali]

I have not looked at the entire code. But one quick comment here, this whole switch can be replaced with this method call

[dio]

Gotcha! Thanks @ramaraochavali!

[mattklein123]

Do you think this is still considered an enhancement?

@dio what do you mean? Are you asking if I think this feature is no longer necessary? TBH I don't know I haven't been tracking all of this very closely. In general I would prefer there is only a single way to do something where reasonable, but if there are good reasons to have multiple ways am open to it. Thoughts?

[ramaraochavali]

Not sure what @dio is referring to here. But exposing Protocol Identification attributes as described in the issue #3704 is definitely required for us and I think would be a reasonable addition.

[dio]

Sorry for introducing confusion. Will breakdown this PR into:

1. RequestInfo with protocol()
2. RequestInfo with dynamicMetadata()
3. Connection with secure() (whether the current conn using SSL or not).

I’ll continue this hopefully tonight. Thanks

[ramaraochavali]

@dio sure..no problem.. Thanks for doing #1 and #3. lmk if it becomes too much work for you.

[dio]

@ramaraochavali @mattklein123

I have put PRs related to #3704:

1. requestInfo():protocol() in lua: add requestInfo():protocol() API #3760
2. connection():ssl() in lua: add connection():ssl() API #3761

While this PR will be layered on top of #3760 if approved and merged.

Thanks.

[dio]

Closing this for now in favor of #3760 for preparing the requestInfo wrapper.

Related: #3761

[dio]

Resubmitted as #3800 for adding dynamic metadata API