Retry GET
from Redis for messages in the Execution Graph
#181
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In this PR I fix a race condition that happened when running
Scheduler::getFunctionExecGraph()
immediately afterScheduler::getFunctionResult()
in a distributed setting.In particular, we sometimes generated the execution graph before all remote executors had published their resulting message. As a consequence,
redis.get
would return an empty byte array, and we'd cast it to an emptyfaabric::Message
.I add a naive retry mechanism (bear in mind generating execution graphs is off the hot path), and a test that reproduces the failure with very little retries (in fact 10 tries might be an overkill).