Establish the stability of the httpClient param on a Camel HTTP4 endpoint

[ajs6f]

Making this issue because the Camel documentation workflow appears to be a bit involved and I expect it to take several days at least to work through it in order to determine whether httpClient is a reliable and supported function or not.

I will find an answer to that question and bring it back to API-X.

[ajs6f]

Can't assign myself, @birkland -- please assign me.

[birkland]

This annotation in HttpEndpoint is what suggests injectability of HttpClient as a param. Other than that annotation, I haven't found any mention that this mechanism was or was not stable/supported

[whikloj]

Good 👀 @birkland, I saw that when working a local project, but assumed that a) a lack of documentation and b) the use of the term "producer" meant it was not for consumer endpoints.

[ajs6f]

1. How did you make the googly eyes!? I need to use that all the time!
2. My hope is that this is a documentation oversight in Camel and that the response will be "Oh, yeah, you can use that, we just forgot to note it in the docs."
3. Even if they tell us otherwise, it might be not unreasonable for us to use this "feature" just until we can offload the pattern onto camel-toolkit, for which work I have created this issue.

[whikloj]

1. :eyes: -> 👀, :roll_eyes: -> 🙄
2. Documentation has always been camel's weak spot
3. If they tell us otherwise, could we use the HttpClientConfigurer to allow individuals to provide their own set of configuration for the http client? I don't fully understand this class or how it works, but it seems somewhat in line with what we want.

[ajs6f]

Tracking at https://issues.apache.org/jira/browse/CAMEL-11270

[birkland]

Fantastic, thanks so much @ajs6f ! Let's hope they bite

@whikloj I'm not sure how the HttpClientConfigurer is bound to the lifecycle of a given route. If HttpClientConfigurer is invoked only once upon initial route building, then it probably can't be used. If it's invoked per message, then it probably can. I suspect it's the former, though.

[whikloj]

@birkland I'd agree that it is probably per route

[ajs6f]

Agreed. We might be able to use it by altering the parameter in its method-- that is, swapping out the client they offer us to configure for a completely different client. But that is ugly, fugly, mugly.

[ajs6f]

We are golden. See the Camel issue linked above:

Claus Ibsen added a comment - 5 hours ago

Its documented in the ascii docs which is the new docs
https://github.com/apache/camel/blob/master/components/camel-http4/src/main/docs/http4-component.adoc

https://github.com/apache/camel/tree/master/components#components

We can safely use the httpClient parameter.