feat: add & remove default filter(s) to analyze.

[matthisholleville]

Closes #158

📑 Description

This MR allows the addition of custom default filters. As discussed here #158, it would be interesting for the user to have the possibility to manage the analyzers they are interested in and for example not have to execute PDB analyzers when they do not use them.

✅ Checks

• My pull request adheres to the code style of this project
• My code requires changes to the documentation
• I have updated the documentation as required
• All the tests have passed

ℹ Additional Information

I have done a lot of testing of adding/removing filters in the configuration file and have not found any side effects. If you would like me to perform additional tests, please let me know which ones.

This version does not include a breaking change.

[AlexsJones]

Available filters :
> Service
> Ingress
> Pod
> ReplicaSet
> PersistentVolumeClaim
alex@alpha:~/Code/k8sgpt$ go run main.go filters remove ReplicaSet
Filter(s) ReplicaSet does not exist in configuration file. Please use k8sgpt filters add.
exit status 1

[AlexsJones]

It looks like this would be a breaking change, we would have to ask people to regenerate their k8sgpt.yaml?

[matthisholleville]

No breaking change. I handle the fact that the default_filters key does not exist in the file.

[matthisholleville]

#161 (comment)

This error is correct. You are trying to remove a filter that is not defined in your configuration file.
Isn't the error message precise enough?

➜  k8sgpt git:(feature/add-and-remove-filters) ./k8sgpt filters list
Available filters : 
> ReplicaSet
> PersistentVolumeClaim
> Service
> Ingress
> Pod
➜  k8sgpt git:(feature/add-and-remove-filters) ./k8sgpt filters add ReplicaSet
Filter ReplicaSet added
➜  k8sgpt git:(feature/add-and-remove-filters) ./k8sgpt filters remove ReplicaSet
Filter(s) ReplicaSet removed

[AlexsJones]

#161 (comment)

This error is correct. You are trying to remove a filter that is not defined in your configuration file. Isn't the error message precise enough?

➜  k8sgpt git:(feature/add-and-remove-filters) ./k8sgpt filters list
Available filters : 
> ReplicaSet
> PersistentVolumeClaim
> Service
> Ingress
> Pod
➜  k8sgpt git:(feature/add-and-remove-filters) ./k8sgpt filters add ReplicaSet
Filter ReplicaSet added
➜  k8sgpt git:(feature/add-and-remove-filters) ./k8sgpt filters remove ReplicaSet
Filter(s) ReplicaSet removed

Okay, so maybe this is a DX issue.
Here is the assumption I have:

As a user when I run K8sGPT I'll have some sensible defaults enabled e.g.

Active:
> > ReplicaSet
> > PersistentVolumeClaim
> > Service
> > Ingress
> > Pod

Let's say I actually don't find Ingress information useful and just spammy in my cluster.
I then say okay k8sgpt filter remove Ingress
That then gives me:

Active:
> > ReplicaSet
> > PersistentVolumeClaim
> > Service
> > Pod
Unused:
> > Ingress

Maybe I didn't articulate this, but it seems we have the "built in" concept vs the "user defined default list"

WDYT?

[matthisholleville]

@AlexsJones That's very clear and makes sense. I'll make you an implementation proposal.

[matthisholleville]

@AlexsJones New version available. I have taken your requests into account. Below you will find my tests:

➜  k8sgpt git:(feature/add-and-remove-filters) ✗ cat ~/.k8sgpt.yaml
backend_type: openai
kubernetesclient: {}
openai_key: xxxxxx                                                                                                     
➜  k8sgpt git:(feature/add-and-remove-filters) ✗ ./k8sgpt filters list
Active: 
> Service
> Ingress
> Pod
> ReplicaSet
> PersistentVolumeClaim
➜  k8sgpt git:(feature/add-and-remove-filters) ✗ ./k8sgpt filters add Pod
Duplicate filters found: Pod
➜  k8sgpt git:(feature/add-and-remove-filters) ✗ ./k8sgpt filters remove Pod
Filter(s) Pod removed
➜  k8sgpt git:(feature/add-and-remove-filters) ✗ cat ~/.k8sgpt.yaml         
active_filters:
    - ReplicaSet
    - PersistentVolumeClaim
    - Service
    - Ingress
backend_type: openai
kubernetesclient: {}
openai_key: xxxxxx

I also took the opportunity to rename the concept of default_filters to active_filters, which seems more meaningful to me.

[AlexsJones]

This is an awesome contribution thank you @matthisholleville

[AlexsJones]

👍🏽