Introduces a single-flight call to a function's health
endpoint to verify that it is registered with an Istio
sidecar (Envoy) before letting the invocation through.
Results are cached for 5 seconds, before a probe is
required again.
Tested without Istio, with probe_functions environment
variable set to true, I saw a probe execute in the logs.
Fixes: #1721 for Istio users.
Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>
When querying for replicas during a scale up event, then the
gateway can overwhelm the provider with requests. This is
especially true under high concurrent load.
The changes in this PR limit the inflight requests.
Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>
The code was calling into the cache twice, even if the first
call was a cache hit and not a miss.
Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>
This type abstracts the function_query type and introduces an
interface for testing and substitution.
Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>
