OtelFiber: Add Next config setting

[emanuelef]

Just an idea for #632
If this makes sense I can go on with this idea and start testing it.

[ReneWerner87]

Tests and readme adjustments are missing

[ReneWerner87]

Why not using the skip middleware or a next function like in all other middlewares

[emanuelef]

Thanks for looking into that.
This approach is ok for what I need but let me know if there's a better way.
I looked at fiberzap and did something similar.

[emanuelef]

Where are the other config functions documented ?

[emanuelef]

@ReneWerner87 just wanted to ask if this feature is relevant, otherwise I can close the PR.
I'm using this in my fork but might be we have other ways to do that in otelfiber.
Some other go web frameworks have a similar feature for their OTel instrumentation.

[ReneWerner87]

Sorry i lost the focus on this, will check it in next days and then let you know that the decision is

[ReneWerner87]

first thank you for the effort
your feature works and offers added value

however, it would be better if we follow the lead of all other middlewares and add a config setting for a check method "Next: func(c *fiber.Ctx) bool"

We have this in all other middlewares and the users should be familiar with it.
https://github.com/search?q=repo%3Agofiber%2Ffiber%20Next%3A&type=code
https://docs.gofiber.io/api/middleware/csrf and so on

this would also give us more flexibility, because what if you don't want to use a url, but a parameter, cookie or header to skip this functionality.

i know in the 2 other contrib middlewares(Fiberzap, otelfiber) a skipurl config property was also added
this one i had unfortunately overlooked and i will add improvement reports/tasks to change this as deprecated and add a next method configuration property there as well

So that this concept is found in all middlewares and the consumers see a red trail
@emanuelef
you would help us a lot if you could adjust your pull request accordingly

[emanuelef]

@ReneWerner87 Thanks for looking into that. Yes, with Next it would be much better, I'll try to adapt my PR to use that.
Not sure if it should be a separate PR and close this one.

[emanuelef]

Not sure if to follow the pattern here should be WithNext, it's a bit different to the standard fiber middlewares where we have ConfigDefault

[ReneWerner87]

name it withNext, its a shortcut function to work with the defaults

[gaby]

LGTM

[ReneWerner87]

@emanuelef can you

• add the config possiblities to the README.md and maybe some usage examples

https://github.com/gofiber/contrib/blob/main/otelfiber/README.md

like the others
https://github.com/gofiber/contrib/blob/main/opafiber/README.md#config
https://github.com/gofiber/contrib/blob/main/paseto/README.md#config
https://github.com/gofiber/contrib/tree/main/fibersentry#config
....
and maybe a example for the usage

we will use these readme's later in our https://docs.gofiber.io/ and there it is important to have all the information about this packet

this should show up as an issue report in the repository itself or discord channel

because only a well documented software can be well used

[emanuelef]

I've added two new sections to the README, but I have some questions there.
Most of the example seems to be inspired by the example of another popular go web framework, I was wondering if we want to have something different here. Also the tests are almost exactly the same and are not covering all of the possible configs (WithSpanNameFormatter is not tested).
I would keep the example in the README minimal and point out what is really needed, in my case when I started using otelfiber in my project I ended up looking at the code to find out that I had to use UserContext() to have the trace propagated.

[gaby]

@emanuelef Totally agree, that could be done in a separate PR so this one can be merged. :-)