logging - Grep - print lines until line is empty -

in grep, there option show output until line meets regex? in example

foo.log:

request1: post /foo params payload  request1: tag payload  request2: post /foo params payload 

i grep foo.log information request1, this:

request1: post /foo params payload  request1: tag payload 

is possible (something -a options) or need use regexps??

try line:

awk -v rs="" -v ors="\n\n" '/request1/' foo.log