Flagger Canary deployments support in kubedog

[shurup]

We want to say a huge "thank you" to @daviddelucca, who has implemented a feature that has been requested for a while (#173) 👍 🥇

With his PR #218, kubedog now supports Canary deployments from Flagger. Flagger is a Kubernetes operator managing different types of deployments for your apps: Canary, A/B Testing, and Blue/Green. It is a CNCF project and a part of Flux tools.

Here is how David's implementation works:

• kubedog waits until the special Canary resource that creates Deployments becomes ready;
• When a new version of the app is deployed, Canary watches for the traffic.
• If everything is fine with traffic, new Deployments replace the old ones.

This implementation is available in the last kubedog release — v0.6.0.

Further works

Currently, while kubedog awaits for the Canary resource readiness, a simple status — Progressing — is displayed. This can be improved in the future by displaying more detailed information related to newly created Deployments & Pods, including logs.

Another field for improvement is implementing similar kubedog integrations for other well-known tools. For instance, we have recently seen this issue for Argo Rollouts: #217.