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78 lines
3.3 KiB
Markdown
78 lines
3.3 KiB
Markdown
Wrangler [In Development - Does Not Work]
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--------
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Framework for wrapping clients, informers, listers into a simple
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usable controller pattern that promotes some good practices.
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More documentation to follow but if you want to see what it
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looks like to write a controller with this framework refer to
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[main.go](https://github.com/rancher/wrangler/blob/master/sample/main.go) and [controller.go](https://github.com/rancher/wrangler/blob/master/sample/controller.go) in
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the [sample](https://github.com/rancher/wrangler/blob/master/sample).
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Sample Project
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------
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The sample project does the same things as the standard Kubernetes [sample controller](https://github.com/kubernetes/sample-controller) but
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just using this framework and patterns.
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To use the sample clone this project to a proper GOPATH and then
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```bash
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cd $GOPATH/src/github.com/rancher/wrangler/sample
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go generate
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go build .
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./sample
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```
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How it works
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------------
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Most people writing controllers are a bit lost when they go to write a controller as they
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find that there is nothing in Kubernetes that is like `type Controller interface` where you
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can just do `NewController`. Instead a controller is really just a pattern of how you use
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the generated clientsets, informers, and listers combined with some custom event handlers and
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a workqueue.
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Wrangler providers a code generator that will generate the clientset, informers, listers and
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additionally generate a controller per type. The interface to the
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controller looks as follows
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To use the controller all one needs to do is register simple OnChange handlers. Also in the
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interface is access to the client and caches in a simple flat API. refer to
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[main.go](https://github.com/rancher/wrangler/blob/master/sample/main.go) and [controller.go](https://github.com/rancher/wrangler/blob/master/sample/controller.go) in
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the [sample project](https://github.com/rancher/wrangler/blob/master/sample) for more complete usage.
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```golang
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type FooHandler func(string, *v1alpha1.Foo) (*v1alpha1.Foo, error)
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type FooController interface {
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Create(*v1alpha1.Foo) (*v1alpha1.Foo, error)
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Update(*v1alpha1.Foo) (*v1alpha1.Foo, error)
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UpdateStatus(*v1alpha1.Foo) (*v1alpha1.Foo, error)
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Delete(namespace, name string, options *metav1.DeleteOptions) error
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DeleteCollection(namespace string, options *metav1.DeleteOptions, listOptions metav1.ListOptions) error
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Get(namespace, name string, options metav1.GetOptions) (*v1alpha1.Foo, error)
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List(namespace string, opts metav1.ListOptions) (*v1alpha1.FooList, error)
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Watch(namespace string, opts metav1.ListOptions) (watch.Interface, error)
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Patch(namespace, name string, pt types.PatchType, data []byte, subresources ...string) (result *v1alpha1.Foo, err error)
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Cache() FooControllerCache
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OnChange(ctx context.Context, name string, sync FooHandler)
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OnRemove(ctx context.Context, name string, sync FooHandler)
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Enqueue(namespace, name string)
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Informer() cache.SharedIndexInformer
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GroupVersionKind() schema.GroupVersionKind
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}
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type FooControllerCache interface {
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Get(namespace, name string) (*v1alpha1.Foo, error)
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List(namespace string, selector labels.Selector) ([]*v1alpha1.Foo, error)
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AddIndexer(indexName string, indexer FooIndexer)
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GetByIndex(indexName, key string) ([]*v1alpha1.Foo, error)
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}
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type FooIndexer func(obj *v1alpha1.Foo) ([]string, error)
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```
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