Export new metrics for OpenFaaS Pro scaling

[alexellis]

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

Description

Export new metrics for OpenFaaS Pro scaling

Motivation and Context

• Add service target metric
• Add service min replicas metric
• Add scale type metric

These combined allow new auto-scaling modes and parameters
for OpenFaaS Pro customers.

How Has This Been Tested?

Tested with a local build of the image from within KinD. The new metrics showed up as expected when inputted via labels via faas-cli deploy.

For example:

faas-cli store deploy cows \
--label com.openfaas.scale.max=5 \
--label com.openfaas.scale.target=50 \
--label com.openfaas.scale.type=cpu \
--label com.openfaas.scale.target-proportion=0.70 \
--label com.openfaas.scale.zero=false

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

No impact to existing users is expected.

Checklist:

• My change requires a change to the documentation.

Documentation change is to follow on the metrics page.