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>

Uses the sync package from the unofficial Go library instead
of simpler solution.

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>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

 
There was an extra newline character after the first entry in the `Interviews and podcasts` sections breaking the markdown preview. Corrected it.

Signed-off-by: Andreas Mosti <andreas.mosti@gmail.com>

Signed-off-by: Han Verstraete (OpenFaaS Ltd) <han@openfaas.com>

Signed-off-by: Han Verstraete (OpenFaaS Ltd) <han@openfaas.com>

The histogram for gateway_functions_seconds excluded the status
code that gives important information for setting up SLOs.

Fixes: #1725

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>

Signed-off-by: Han Verstraete (OpenFaaS Ltd) <han@openfaas.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alex@openfaas.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Han Verstraete <welteki@pm.me>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

update docker/distribution lib

Signed-off-by: Hilário Coelho <hilario.coelho@securityside.com>

Signed-off-by: Simon Emms <simon@simonemms.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Changes from Go 1.13 to 1.17, although this is not used
since Docker is used at build time.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

The legacy samples should not be used for anything at this
point, however this change is needed for the new alpine:3.15
base image.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Upgrades OS for some base images, no expected issues.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

* Updates OpenFaaS PRO to Pro

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Ivan Velichko <iximiuz@gmail.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Deduplicate training links

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

The defer close statement was causing issues in CI

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Signed-off-by: Johan Siebens <johan.siebens@gmail.com>

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>