Read(List/Get) objects from the informer cache

[devdattakulkarni]

Currently the SDK provides a List function
https://github.com/operator-framework/operator-sdk/blob/master/pkg/sdk/query.go#L59

which is used to setup the List and Watch
https://github.com/operator-framework/operator-sdk/blob/master/pkg/sdk/informer.go#L65

when creating the SharedIndexInformer
https://github.com/operator-framework/operator-sdk/blob/master/pkg/sdk/informer.go#L54

The sample-controller approach (https://github.com/kubernetes/sample-controller) uses 'Listers'
https://github.com/kubernetes/sample-controller/blob/master/pkg/client/listers/samplecontroller/v1alpha1/foo.go#L48

for querying Objects from the local Index.

So I was wondering why Listers are not included in the design of the SDK?

Using a List function which always makes call to the API server can cause load on the server.
Listers would help reduce these calls, no?

[jhernandezb]

Just got into the same question, specially if I'm watching different kind of objects I'd like to query from the local cache.

[spahl]

Holding off until #169 is done. This will also probably require a bit of discussion about design.

[hasbro17]

With the planned refactoring to use the controller-runtime #382 , the provided split-client should allow reading(List/Get) objects from the informer cache.

[hasbro17]

Resolved via #382
See the default client doc or the delegating client for more details.