Most Easegress traffic is message-based, but Easegress v2 pipeline is protocol independent, that’s it supports stream-based traffic like TCP, and there’s stream traffic even in HTTP.
Another new feature in Easegress v2 is multiple requests/responses support, this requires the payload of a request/response can be read more than once, for message-based traffic, this is simple and easy to do, as Easegress can read the full message payload into memory. But for stream-based traffic, this is impossible, as the payload may require too much memory, and/or take too much time to read it into memory.
To resolve the above issue, Easegress allow user or developer to configure whether a request/response is a stream, for example:
- We can set
clientMaxBodySizeof an HTTP server to a negative value to tell Easegress the request is a stream, and not a stream otherwise. Please refer HTTPServer for more information.
- We can set
Proxyfilter to a negative value to tell Easegress the response is a stream, and not a stream otherwise. Please refer Proxy for more information.
As we have mentioned above, the payload of a stream-based request/response can only be read once, so some features are not possible for these requests/responses, including:
- In the
ResponseBuilder, you cannot access the payload(in HTTP, the body) of an existing stream-based request/response, while it is fine to access other information of the request/response.
- Stream-based request/response cannot be cached by
HeaderToJSONfilter does not support stream-based requests/responses.
- You cannot access the payload of stream-based request/response in a