[feat] Make the cluster flag -c <cluster-name> optional

[csantanapr]

I would love to avoid to remember to pass the cluster name when I only have one cluster if I run eksdemo get cluster

Running a command like this when I have only 1 cluster Error: required flag(s) "cluster" not set

eksdemo get node
...
Error: required flag(s) "cluster" not set

or

eksdemo install aws-lb-controller --dry-run
...
Error: required flag(s) "cluster" not set

The UX I would like to see to make it easier to run use the CLI when working with a cluster

1. Create cluster

eksdemo create cluster blue

2. make sure you have 1 cluster

eksdemo get cluster

+------------+--------+---------+---------+----------+----------+
|    Age     | Status | Cluster | Version | Platform | Endpoint |
+------------+--------+---------+---------+----------+----------+
| 57 minutes | ACTIVE | *blue   |    1.29 | eks.7    | Public   |
+------------+--------+---------+---------+----------+----------+
* Indicates current context in local kubeconfig

3. Install AWS ALB Controller

eksdemo install aws-lb-controller

Additional context:
We could potentially assume the cluster in context in local kubeconfig could be the cluster to select if the flag -c is not passed, maybe the logic to implement would easier assuming the flag is always optional and it will select what ever cluster is in the context in local kubeconfig.

[aaroniscode]

Thanks for the feature request @csantanapr . I do like the idea of making eksdemo even easier to use!

Let me noodle on this for a bit on how best to implement. I had thought about this a while ago thinking about making it a setting, that would be saved on disk using and read at runtime using Viper.

While I'm all for making eksdemo easier to use, I do want to implement this with "least surprise" and want to avoid ever installing to a cluster you didn't intend.

I think you could argue this is similar to Helm as it will install in the current Kubeconfig context and if you want to override you use -c cluster just like Helm offers --kube-context.