Advanced Error Handling

[mjarmoc]

This PR introduces:

• New classes for error handling: RMQError for user thrown errors and RMQTransportError for transportation/client error.
• Additional data added to error payload, host, servicename, code which makes debugging easier and more accutare.
• Added possibility to provide custom error handler (class with static method handle).

[AlariCode]

Thanks for PR, we will review it!

[AlariCode]

@mjarmoc, great PR! It will be useful to have more debugging info and ability to handle errors. But we have to keep some headers to stay consistent with .NetCore library that we use in production. Headers are:

-x-error
-x-status-code

We use -x as error marking header. So to keep naming convention, I suggest using names like:

-x-error-message -> -x-error
-x-error-code -> -x-status-code
-x-error-data -> -x-data
-x-error-service -> -x-service
-x-error-host -> -x-host
-x-error-type -> -x-type

Will it be ok?

And DEFAULT_ERROR_CODE should be deleted because it is no longer in use.

[mjarmoc]

@AlariCode sure thing, I will prepare the amendments during the weekend ;)

[AlariCode]

@mjarmoc, great, looking forward for it!

[AlariCode]

@mjarmoc great, I'll add some format and docs and merge it. But I think two types of error will lead us to code duplication. And we have default case in this code if no '-x-type' header exists:

export class RMQErrorHandler {
    public static handle(headers: any): any {
        switch (headers['-x-type']) {
            case ERROR_TYPE.TRANSPORT:
                return new RMQTransportError(
                    headers['-x-error'],
                    headers['-x-status-code'],
                    headers['-x-data'],
                    headers['-x-service'],
                    headers['-x-host']
                );
            case ERROR_TYPE.RMQ:
                return new RMQError(
                    headers['-x-error'],
                    headers['-x-status-code'],
                    headers['-x-data'],
                    headers['-x-service'],
                    headers['-x-host']
                );
            default:
                // ??
        }
    }
}

May be we can stick with one error class but with additional parameter like -x-type? Or we need to create 3rd type of error for default. What do you think?

[AlariCode]

@mjarmoc, I added docs, changed headers, user only one error class with multiple types and add more typing. Tested it and now ready to merge. Thanks for Merge Request!