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Forum Discussion

Kirk_Jackson's avatar
Kirk_Jackson
Icon for Nimbostratus rankNimbostratus
May 01, 2018

STREAM::expression and "thread safety"

Hi, I don't think "thread safety" is the right term here, but kinda helps explain my question. STREAM::expression can be changed in an iRule, and the documentation says it affects "this connectio...
application delivery
iRules
stream
stream exp
Simon_Blakely's avatar
Simon_Blakely
Icon for Employee rankEmployee
May 14, 2018

HTTP/2 allows multiplexed requests.

 

The individual HTTP/2 requests in the TCP connection will be separated into Streams (based on Stream ID) at the HTTP_REQUEST and responses combined back into the connection at HTTP_RESPONSE.

 

Between those two events, each Stream is an individual Stream context, and items such as TCL variables and STREAM::expression only exist in that Stream context. You cannot access the Connection context from within the Stream context, so if you need to store a Connection variable for access from within the Stream context, it needs to be stored globally (i.e using table).

 

So from HTTP_REQUEST to HTTP_RESPONSE, STREAM:: is limited in scope to the Stream, and will not interfere with other request/responses.