Slack chat.postMessage errors are not caught

[ordovicia]

postMessage function assumes that HTTP responses have a meaningful status code (2xx for success, 4xx or 5xx for error).

notification-controller/internal/notifier/client.go

Line 103 in 2763e54

if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusAccepted && resp.StatusCode != http.StatusCreated {

Slack chat.postMessage API does not satisfy this assumption.
https://api.slack.com/methods/chat.postMessage
Seems that it always responds with 200 OK.
ok and error fields in response body JSON indicate an error, if any.

Thus, Slack errors are not caught by postMessage function, and will not appear in notification-controller logs nor Alert resource Events.

[matheuscscp]

@ordovicia are you willing to contribute this fix?

The way I see it, we should create an option for that fuction that we can pass at the end of the args through reqOpts ...requestOptFunc. By passing this option only in the slack provider we would modify the behavior of this function only for slack. We may need to improve the definition of an option as it only accepts a pointer to retryablehttp.Request:

type requestOptFunc func(*retryablehttp.Request)

So to pass a boolean or something we would probably need an options struct and modify the function type above to accept both things, something along those lines...

[ordovicia]

I will try to contribute to a fix in a few months.
If anyone is interested in this, please feel free to take over.

[ordovicia]

Hi, I am preparing a fix in #1086
It's still in draft, but could you take a look?
I would like to make sure that we agree on the implementation direction.