allow path patterns in --allow-paths and --ignore-paths

[raptorsun]

This pull request make it possible to use URL patterns matching.
For example, we can use --allow-paths="/pre/fix1/*" to allow URL such as "/pre/fix1/AAA", "/pre/fix1/BBB"

We intent to make it possible to proxy requests using URL suffixes delimited by slashes as a method to pass arguments, such as this uses case to pass through query of label values to Prometheus. The URL can be /api/v1/label//values. Because keeping an exhaust list of labels' names is both time-costing and complicated especially when new labels are created during runtime. So we believe allowing pattern match for URL is a good solution.

[simonpasquier]

For context, we had a discussion on whether to allow regex matching when implementing the --allow-paths flag in #83. At that time it was dismissed since we had no concrete use case.

[fpetkovski]

Should we add some sort of a test for this? It was a bit hard to validate the correctness of the change

[raptorsun]

I wonder what will be the best way to test a branch the main function. 🤔 Le mar. 27 juil. 2021 à 08:31, Filip Petkovski ***@***.***> a écrit :

…

Should we add some sort of a test for this? It was a bit hard to validate the correctness of the change — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#135 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABOC3AFLWM6RL7LTOVY6ZJTTZZHFDANCNFSM5A7ZBK5A> .

[fpetkovski]

You can extract this section into a function that returns found/not found and test it in isolation

[simonpasquier]

cc @s-urbaniak since it seems to overlap with the discussion happening in #130

[s-urbaniak]

oh sorry, i missed this thread (still iterating over concrete mentions after PTO). Are there any concerns using https://pkg.go.dev/path#Match as outlined in #130 (comment)?

[raptorsun]

Updated PR with path pattern match for both --alow-paths and --ignore-paths

[s-urbaniak]

any reason we cannot leave this as "path"?

[raptorsun]

because "path" is already used as a symbol for variable in the scope, I rename the module import to avoid confusing the compiler.

[s-urbaniak]

I think it is reasonable to rename the local variable to p. The usage distance of that variable is bound to the for loop.

[raptorsun]

ok, i will rename local variable 👍

[s-urbaniak]

This will exit the whole process with error code 255 at runtime. Note this is a handler not bootstrapping code. Please simply return in this case.

According to https://pkg.go.dev/path#Match:

The only possible returned error is ErrBadPattern, when pattern is malformed.

We could leverage this and iterate before the handler in the bootstrapping main goroutine:

for _, path := range cfg.allowPaths {
  _, err := path.Match(path, "")
  if err != nil {
    klog.Fatalf("Failed to verify allow path: %s", path)
  }
}

[raptorsun]

thanks, I will replace the klog.Fatalf by a simple return.

[raptorsun]

check for allowPaths and ignorePaths are added,too.

[s-urbaniak]

@raptorsun this change lgtm in general, but please add some test, and at least one e2e test.

[raptorsun]

OK, more e2e test will be added. Le mer. 28 juil. 2021 à 17:50, Sergiusz Urbaniak ***@***.***> a écrit :

…

@raptorsun <https://github.com/raptorsun> this change lgtm in general, but please add some test, and at least one e2e test. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#135 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABOC3AA7VHITKWVWYIPRWETT2ARLZANCNFSM5A7ZBK5A> .

[raptorsun]

E2E tests have been added. 🧪

[s-urbaniak]

lgtm, thank you for the contribution 🎉