Add support for session affinity for Gloo canaries

[paritadhandha]

We use flagger canaries with gloo with following version configurations.

Flagger version: 1.0.1/1.0.0
Kubernetes version: v1.15
Flagger-loadtester: 0.18.0
Flagger CRD version: Version: v1beta1
Config: canary with glooEnterprise (v1.4.6)

We wanted to enable session affinity for our canary deployments and found this documentation:
https://docs.flagger.app/usage/deployment-strategies#a-b-testing

There are examples for enabling session affinity for Istio, NGINX, Contour and App Mesh but there was no mention for session affinity with Gloo.

Is there any intention of adding support for session affinity with gloo?

Thank you!

[stefanprodan]

Flagger uses the Gloo UpstreamGroup API for traffic manipulation. It doesn't look like this API allows setting HTTP headers or cookies required to implement session affinity.

[mikesouza]

Flagger uses the Gloo UpstreamGroup API for traffic manipulation. It doesn't look like this API allows setting HTTP headers or cookies required to implement session affinity.

@stefanprodan Thank you for clarifying that the issue is upstream with a lack of support in Gloo. We will ask solo.io/ Gloo and see if support can be added.