/
watch.go
76 lines (68 loc) · 2.03 KB
/
watch.go
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// Copyright 2022 Upbound Inc
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package kube
import (
"context"
"github.com/crossplane/crossplane-runtime/pkg/errors"
v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/client-go/dynamic"
)
const errClosedResults = "stopped watching before condition met"
// DynamicWatch starts a watch on the given resource type. The done callback is
// called on every received event until either timeout or context cancellation.
func DynamicWatch(ctx context.Context, r dynamic.NamespaceableResourceInterface, timeout *int64, done func(u *unstructured.Unstructured) (bool, error)) (chan error, error) {
w, err := r.Watch(ctx, v1.ListOptions{
TimeoutSeconds: timeout,
})
if err != nil {
return nil, err
}
errChan := make(chan error)
go func() {
defer close(errChan)
for {
select {
case e, ok := <-w.ResultChan():
// If we are no longer watching return with error.
if !ok {
errChan <- errors.New(errClosedResults)
return
}
u, ok := e.Object.(*unstructured.Unstructured)
if !ok {
continue
}
// If we error on event callback return early.
d, err := done(u)
if err != nil {
errChan <- err
return
}
// If event callback indicated done, return early with nil
// error.
if d {
errChan <- nil
return
}
// If context is canceled, stop watching and return error.
case <-ctx.Done():
w.Stop()
errChan <- ctx.Err()
return
}
}
}()
return errChan, nil
}