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Add CachingPoller and ApplyTimeMutator injection
This allows resources to be cached and retrieved more abstractly, without injecting the cache or dynamic client into task context or modifying the runner to update the cache.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,15 @@ | ||
| package cache | ||
|
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| import ( | ||
| "k8s.io/apimachinery/pkg/apis/meta/v1/unstructured" | ||
| "sigs.k8s.io/cli-utils/pkg/object" | ||
| ) | ||
|
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| // ResourceCache stores unstructured resource objects in memory | ||
| type ResourceCache interface { | ||
| Put(obj *unstructured.Unstructured) error | ||
| Set(objMeta object.ObjMetadata, obj *unstructured.Unstructured) | ||
| Get(objMeta object.ObjMetadata) (*unstructured.Unstructured, bool) | ||
| Remove(objMeta object.ObjMetadata) | ||
| Clear() | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,60 @@ | ||
| package cache | ||
|
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| import ( | ||
| "context" | ||
|
|
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| "sigs.k8s.io/cli-utils/pkg/apply/poller" | ||
| "sigs.k8s.io/cli-utils/pkg/kstatus/polling" | ||
| pollevent "sigs.k8s.io/cli-utils/pkg/kstatus/polling/event" | ||
| "sigs.k8s.io/cli-utils/pkg/kstatus/status" | ||
| "sigs.k8s.io/cli-utils/pkg/object" | ||
| ) | ||
|
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| // ResourceCachingPoller wraps a poller with an in-memory cache that is updated on | ||
| // every ResourceUpdateEvent. | ||
| type ResourceCachingPoller struct { | ||
| Poller poller.Poller | ||
| ResourceCache ResourceCache | ||
| } | ||
|
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| // Poll starts polling using the wrapped Poller, caching the unstructured | ||
| // resources as their updates are received. | ||
| // All inputs are passed to the wrapped poller. | ||
| // All events are passed to the caller on the return channel. | ||
| // Shut down the poller by closing the Context.Done channel. | ||
| func (cp *ResourceCachingPoller) Poll(ctx context.Context, identifiers []object.ObjMetadata, options polling.Options) <-chan pollevent.Event { | ||
| outCh := make(chan pollevent.Event) | ||
| inCh := cp.Poller.Poll(ctx, identifiers, options) | ||
|
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| // Assume the wrapped Poller will close the output channel when the context is done. | ||
| // This avoids losing any events sent after the context is done. | ||
|
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| go func() { | ||
| // close the output channel on exit to signal completion to the caller | ||
| defer close(outCh) | ||
|
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| for { | ||
| // Process events from the inCh and send to the outCh | ||
| event, ok := <-inCh | ||
|
|
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| // if input channel is closed, stop watching events | ||
| if !ok { | ||
| break | ||
| } | ||
|
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| // Update cache on resource update events | ||
| if event.EventType == pollevent.ResourceUpdateEvent { | ||
| if event.Resource.Status == status.NotFoundStatus { | ||
| cp.ResourceCache.Remove(event.Resource.Identifier) | ||
| } else { | ||
| cp.ResourceCache.Set(event.Resource.Identifier, event.Resource.Resource) | ||
| } | ||
| } | ||
|
|
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| // echo the input event to the caller | ||
| outCh <- event | ||
| } | ||
| }() | ||
|
|
||
| return outCh | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,176 @@ | ||
| package mutator | ||
|
|
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| import ( | ||
| "context" | ||
| "fmt" | ||
| "strings" | ||
|
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| "github.com/pkg/errors" | ||
| "k8s.io/apimachinery/pkg/api/meta" | ||
| metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" | ||
| "k8s.io/apimachinery/pkg/apis/meta/v1/unstructured" | ||
| "k8s.io/client-go/dynamic" | ||
| "k8s.io/klog/v2" | ||
| "sigs.k8s.io/cli-utils/pkg/apply/cache" | ||
| "sigs.k8s.io/cli-utils/pkg/object" | ||
| "sigs.k8s.io/cli-utils/pkg/object/mutation" | ||
| ) | ||
|
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| // ApplyTimeMutator mutates a resource by injecting values specified by the | ||
| // apply-time-mutation annotation. | ||
| // The optional ResourceCache will be used to speed up source reosurce lookups, | ||
| // if specified. | ||
| // Implements the Mutator interface | ||
| type ApplyTimeMutator struct { | ||
| Client dynamic.Interface | ||
| Mapper meta.RESTMapper | ||
| ResourceCache cache.ResourceCache | ||
| } | ||
|
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| // Name returns a mutator identifier for logging. | ||
| func (atm *ApplyTimeMutator) Name() string { | ||
| return "ApplyTimeMutator" | ||
| } | ||
|
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| // Mutate parses the apply-time-mutation annotation and loops through the | ||
| // substitutions, applying each of them to the supplied target object. | ||
| // Returns true with a reason, if mutation was performed. | ||
| func (atm *ApplyTimeMutator) Mutate(obj *unstructured.Unstructured) (bool, string, error) { | ||
| mutated := false | ||
| reason := "" | ||
|
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| if !mutation.HasAnnotation(obj) { | ||
| return mutated, reason, nil | ||
| } | ||
|
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| subs, err := mutation.ReadAnnotation(obj) | ||
| if err != nil { | ||
| return mutated, reason, errors.Wrapf(err, "failed to read jsonpath field in target resource: %v", mutation.NewResourceReference(obj)) | ||
| } | ||
|
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| targetID := object.UnstructuredToObjMetaOrDie(obj) | ||
| klog.V(5).Infof("target resource %s/%s: %#v", targetID.Namespace, targetID.Name, obj) | ||
|
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| for _, sub := range subs { | ||
| sourceRef := sub.SourceRef | ||
|
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| // lookup source resource from cache or cluster | ||
| sourceObj, err := atm.getObject(sourceRef) | ||
| if err != nil { | ||
| return mutated, reason, errors.Wrapf(err, "failed to retrieve resource from sourceRef: %v", sourceRef) | ||
| } | ||
|
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| sourceID := object.UnstructuredToObjMetaOrDie(sourceObj) | ||
| klog.V(5).Infof("source resource %s/%s: %#v", sourceID.Namespace, sourceID.Name, sourceObj) | ||
|
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| // lookup target field in target resource | ||
| targetValue, err := readFieldValue(obj, sub.TargetPath) | ||
| if err != nil { | ||
| return mutated, reason, errors.Wrapf(err, "failed to reading jsonpath field from target resource: %v", mutation.NewResourceReference(obj)) | ||
| } | ||
|
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| // lookup source field in source resource | ||
| sourceValue, err := readFieldValue(sourceObj, sub.SourcePath) | ||
| if err != nil { | ||
| return mutated, reason, errors.Wrapf(err, "failed to reading jsonpath field from source resource: %v", sourceRef) | ||
| } | ||
|
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| // substitute token for source field value | ||
| newValue := strings.ReplaceAll(targetValue, sub.Token, sourceValue) | ||
|
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| klog.V(5).Infof("substitution on %s/%s: source=%q, token=%q, old=%q, new=%q", | ||
| targetID.Namespace, targetID.Name, sourceValue, sub.Token, targetValue, newValue) | ||
|
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| // update target field in target resource | ||
| err = writeFieldValue(obj, sub.TargetPath, newValue) | ||
| if err != nil { | ||
| return mutated, reason, errors.Wrapf(err, "failed to set value to jsonpath field in target resource: %v", mutation.NewResourceReference(obj)) | ||
| } | ||
|
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| mutated = true | ||
| reason = fmt.Sprintf("resource contained annotation: %s", mutation.Annotation) | ||
| } | ||
|
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| return mutated, reason, nil | ||
| } | ||
|
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| // getObject returns a cached resource, if cached and cache exists, otherwise | ||
| // the resource is revrieved from the cluster. | ||
| func (atm *ApplyTimeMutator) getObject(ref mutation.ResourceReference) (*unstructured.Unstructured, error) { | ||
| // validate resource reference | ||
| sourceObjMeta, err := mutation.ResourceReferenceToObjMeta(ref) | ||
| if err != nil { | ||
| return nil, errors.Wrapf(err, "failed to validate resource reference: %v", ref) | ||
| } | ||
|
|
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| if atm.ResourceCache != nil { | ||
| // lookup source resource from cache | ||
| sourceObj, found := atm.ResourceCache.Get(sourceObjMeta) | ||
| if found && sourceObj != nil { | ||
| return sourceObj, nil | ||
| } | ||
| } | ||
|
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| // lookup source resource using resource version, if specified | ||
| sourceGvk := ref.GroupVersionKind() | ||
| versions := []string{} | ||
| if sourceGvk.Version == "" { | ||
| versions = append(versions, sourceGvk.Version) | ||
| } | ||
|
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| // lookup mapping of source resource | ||
| mapping, err := atm.Mapper.RESTMapping(sourceGvk.GroupKind(), versions...) | ||
| if err != nil { | ||
| return nil, errors.Wrapf(err, "failed to map resource reference to valid type: %v", ref) | ||
| } | ||
|
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| // lookup source resource from cluster | ||
| namespacedClient := atm.Client.Resource(mapping.Resource).Namespace(ref.Namespace) | ||
| sourceObj, err := namespacedClient.Get(context.TODO(), ref.Name, metav1.GetOptions{}) | ||
| if err != nil { | ||
| return nil, errors.Wrapf(err, "failed to retrieve resource from cluster: %v", ref) | ||
| } | ||
|
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| return sourceObj, nil | ||
| } | ||
|
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| func readFieldValue(obj *unstructured.Unstructured, path string) (string, error) { | ||
| if path == "" { | ||
| return "", errors.New("empty jsonpath") | ||
| } | ||
|
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| // strip optional root index | ||
| pathArray := strings.Split(path, ".") | ||
| if pathArray[0] == "$" || pathArray[0] == "" { | ||
| pathArray = pathArray[1:] | ||
| } | ||
|
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| // get path value | ||
| value, found, err := unstructured.NestedString(obj.Object, pathArray...) | ||
| if err != nil { | ||
| return "", errors.Wrapf(err, "failed to read jsonpath value: %q", path) | ||
| } | ||
| if !found { | ||
| return "", errors.Wrapf(err, "jsonpath field not found: %q", path) | ||
| } | ||
| return value, nil | ||
| } | ||
|
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| func writeFieldValue(obj *unstructured.Unstructured, path, value string) error { | ||
| if path == "" { | ||
| return errors.New("empty jsonpath") | ||
| } | ||
|
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| // strip optional root index | ||
| pathArray := strings.Split(path, ".") | ||
| if pathArray[0] == "$" || pathArray[0] == "" { | ||
| pathArray = pathArray[1:] | ||
| } | ||
|
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| // set path value | ||
| err := unstructured.SetNestedField(obj.Object, value, pathArray...) | ||
| if err != nil { | ||
| return errors.Wrapf(err, "failed to read jsonpath value: %q", path) | ||
| } | ||
| return nil | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,20 @@ | ||
| // Copyright 2021 The Kubernetes Authors. | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
|
|
||
| package mutator | ||
|
|
||
| import ( | ||
| "k8s.io/apimachinery/pkg/apis/meta/v1/unstructured" | ||
| ) | ||
|
|
||
| // Interface decouples apply-time-mutation | ||
| // from the concrete structs used for applying. | ||
| type Interface interface { | ||
| // Name returns a filter name (usually for logging). | ||
| Name() string | ||
| // Mutate returns true if the object was mutated. | ||
| // This allows the mutator to decide if mutation is needed. | ||
| // If mutated, a reason string is returned. | ||
| // If an error happens during mutation, it is returned. | ||
| Mutate(obj *unstructured.Unstructured) (bool, string, error) | ||
| } |
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