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Co-authored-by: killianmuldoon <kmuldoon@vmware.com> Co-authored-by: Stefan Bueringer <buringerst@vmware.com>
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/* | ||
Copyright 2021 The Kubernetes Authors. | ||
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. | ||
*/ | ||
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package komega | ||
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import ( | ||
"bytes" | ||
"encoding/json" | ||
"fmt" | ||
"reflect" | ||
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jsonpatch "github.com/evanphx/json-patch/v5" | ||
"github.com/onsi/gomega/format" | ||
"github.com/onsi/gomega/types" | ||
"github.com/pkg/errors" | ||
"k8s.io/apimachinery/pkg/runtime" | ||
) | ||
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// This code is adappted from the mergePatch code at controllers/topology/internal/mergepatch pkg. | ||
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// These package variables hold pre-created commonly used options that can be used to reduce the manual work involved in | ||
// identifying the paths that need to be compared for testing equality between objects. | ||
var ( | ||
// IgnoreAutogeneratedMetadata contains the paths for all the metadata fields that are commonly set by the | ||
// client and APIServer. This is used as a MatchOption for situations when only user-provided metadata is relevant. | ||
IgnoreAutogeneratedMetadata = IgnorePaths{ | ||
{"metadata", "uid"}, | ||
{"metadata", "generation"}, | ||
{"metadata", "creationTimestamp"}, | ||
{"metadata", "resourceVersion"}, | ||
{"metadata", "managedFields"}, | ||
{"metadata", "deletionGracePeriodSeconds"}, | ||
{"metadata", "deletionTimestamp"}, | ||
{"metadata", "selfLink"}, | ||
{"metadata", "generateName"}, | ||
} | ||
) | ||
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// equalObjectMatcher is a Gomega matcher used to establish equality between two Kubernetes runtime.Objects. | ||
type equalObjectMatcher struct { | ||
// original holds the object that will be used to Match. | ||
original runtime.Object | ||
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// diff contains the delta between the two compared objects. | ||
diff []byte | ||
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// options holds the options that identify what should and should not be matched. | ||
options *MatchOptions | ||
} | ||
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// EqualObject returns a Matcher for the passed Kubernetes runtime.Object with the passed Options. This function can be | ||
// used as a Gomega Matcher in Gomega Assertions. | ||
func EqualObject(original runtime.Object, opts ...MatchOption) types.GomegaMatcher { | ||
matchOptions := &MatchOptions{} | ||
matchOptions = matchOptions.ApplyOptions(opts) | ||
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// set the allowPaths to '*' by default to not exclude any paths from the comparison. | ||
if len(matchOptions.allowPaths) == 0 { | ||
matchOptions.allowPaths = [][]string{{"*"}} | ||
} | ||
return &equalObjectMatcher{ | ||
options: matchOptions, | ||
original: original, | ||
} | ||
} | ||
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// Match compares the current object to the passed object and returns true if the objects are the same according to | ||
// the Matcher and MatchOptions. | ||
func (m *equalObjectMatcher) Match(actual interface{}) (success bool, err error) { | ||
// Nil checks required first here for: | ||
// 1) Nil equality which returns true | ||
// 2) One object nil which returns an error | ||
actualIsNil := reflect.ValueOf(actual).IsNil() | ||
originalIsNil := reflect.ValueOf(m.original).IsNil() | ||
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if actualIsNil && originalIsNil { | ||
return true, nil | ||
} | ||
if actualIsNil || originalIsNil { | ||
return false, fmt.Errorf("can not compare an object with a nil. original %v , actual %v", m.original, actual) | ||
} | ||
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// Calculate diff returns a json diff between the two objects. | ||
m.diff, err = m.calculateDiff(actual) | ||
if err != nil { | ||
return false, err | ||
} | ||
return bytes.Equal(m.diff, []byte("{}")), nil | ||
} | ||
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// FailureMessage returns a message comparing the full objects after an unexpected failure to match has occurred. | ||
func (m *equalObjectMatcher) FailureMessage(actual interface{}) (message string) { | ||
return fmt.Sprintf("the following fields were expected to match but did not:\n%s\n%s", string(m.diff), | ||
format.Message(actual, "expected to match", m.original)) | ||
} | ||
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// NegatedFailureMessage returns a string comparing the full objects after an unexpected match has occurred. | ||
func (m *equalObjectMatcher) NegatedFailureMessage(actual interface{}) (message string) { | ||
return format.Message("the following fields were not expected to match \n%s\n%s", string(m.diff), | ||
format.Message(actual, "expected to match", m.original)) | ||
} | ||
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// calculateDiff applies the MatchOptions and identifies the diff between the Matcher object and the actual object. | ||
func (m *equalObjectMatcher) calculateDiff(actual interface{}) ([]byte, error) { | ||
// Convert the original and actual objects to json. | ||
originalJSON, err := json.Marshal(m.original) | ||
if err != nil { | ||
return nil, err | ||
} | ||
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actualJSON, err := json.Marshal(actual) | ||
if err != nil { | ||
return nil, err | ||
} | ||
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// Use a mergePatch to produce a diff between the two objects. | ||
diff, err := jsonpatch.CreateMergePatch(originalJSON, actualJSON) | ||
if err != nil { | ||
return nil, err | ||
} | ||
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// Filter the diff according to the rules attached to the Matcher. | ||
diff, err = filterDiff(diff, m.options.allowPaths, m.options.ignorePaths) | ||
if err != nil { | ||
return nil, err | ||
} | ||
return diff, nil | ||
} | ||
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// MatchOption describes an Option that can be applied to a Matcher. | ||
type MatchOption interface { | ||
// ApplyToMatcher applies this configuration to the given MatchOption. | ||
ApplyToMatcher(options *MatchOptions) | ||
} | ||
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// MatchOptions holds the available types of MatchOptions that can be applied to a Matcher. | ||
type MatchOptions struct { | ||
ignorePaths [][]string | ||
allowPaths [][]string | ||
} | ||
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// ApplyOptions adds the passed MatchOptions to the MatchOptions struct. | ||
func (o *MatchOptions) ApplyOptions(opts []MatchOption) *MatchOptions { | ||
for _, opt := range opts { | ||
opt.ApplyToMatcher(o) | ||
} | ||
return o | ||
} | ||
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// IgnorePaths instructs the Matcher to ignore given paths when computing a diff. | ||
type IgnorePaths [][]string | ||
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// ApplyToMatcher applies this configuration to the given MatchOptions. | ||
func (i IgnorePaths) ApplyToMatcher(opts *MatchOptions) { | ||
opts.ignorePaths = append(opts.ignorePaths, i...) | ||
} | ||
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// AllowPaths instructs the Matcher to restrict its diff to the given paths. If empty the Matcher will look at all paths. | ||
type AllowPaths [][]string | ||
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// ApplyToMatcher applies this configuration to the given MatchOptions. | ||
func (i AllowPaths) ApplyToMatcher(opts *MatchOptions) { | ||
opts.allowPaths = append(opts.allowPaths, i...) | ||
} | ||
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// filterDiff limits the diff to allowPaths if given and excludes ignorePaths if given. It returns the altered diff. | ||
func filterDiff(diff []byte, allowPaths, ignorePaths [][]string) ([]byte, error) { | ||
// converts the diff into a Map | ||
diffMap := make(map[string]interface{}) | ||
err := json.Unmarshal(diff, &diffMap) | ||
if err != nil { | ||
return nil, errors.Wrap(err, "failed to unmarshal merge diff") | ||
} | ||
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// Removes from diffs everything not in the allowpaths. | ||
filterDiffMap(diffMap, allowPaths) | ||
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// Removes from diffs everything in the ignore paths. | ||
for _, path := range ignorePaths { | ||
removePath(diffMap, path) | ||
} | ||
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// Converts Map back into the diff. | ||
diff, err = json.Marshal(&diffMap) | ||
if err != nil { | ||
return nil, errors.Wrap(err, "failed to marshal merge diff") | ||
} | ||
return diff, nil | ||
} | ||
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// filterDiffMap limits the diffMap to those paths allowed by the MatchOptions. | ||
func filterDiffMap(diffMap map[string]interface{}, allowPaths [][]string) { | ||
// if the allowPaths only contains "*" return the full diffmap. | ||
if len(allowPaths) == 1 && allowPaths[0][0] == "*" { | ||
return | ||
} | ||
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// Loop through the entries in the map. | ||
for k, m := range diffMap { | ||
// Check if item is in the allowPaths. | ||
allowed := false | ||
for _, path := range allowPaths { | ||
if k == path[0] { | ||
allowed = true | ||
break | ||
} | ||
} | ||
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if !allowed { | ||
delete(diffMap, k) | ||
continue | ||
} | ||
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nestedMap, ok := m.(map[string]interface{}) | ||
if !ok { | ||
continue | ||
} | ||
nestedPaths := make([][]string, 0) | ||
for _, path := range allowPaths { | ||
if k == path[0] && len(path) > 1 { | ||
nestedPaths = append(nestedPaths, path[1:]) | ||
} | ||
} | ||
if len(nestedPaths) == 0 { | ||
continue | ||
} | ||
filterDiffMap(nestedMap, nestedPaths) | ||
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if len(nestedMap) == 0 { | ||
delete(diffMap, k) | ||
} | ||
} | ||
} | ||
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// removePath excludes any path passed in the ignorePath MatchOption from the diff. | ||
func removePath(diffMap map[string]interface{}, path []string) { | ||
switch len(path) { | ||
case 0: | ||
// If path is empty, no-op. | ||
return | ||
case 1: | ||
// If we are at the end of a path, remove the corresponding entry. | ||
delete(diffMap, path[0]) | ||
default: | ||
// If in the middle of a path, go into the nested map. | ||
nestedMap, ok := diffMap[path[0]].(map[string]interface{}) | ||
if !ok { | ||
return | ||
} | ||
removePath(nestedMap, path[1:]) | ||
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// Ensure we are not leaving empty maps around. | ||
if len(nestedMap) == 0 { | ||
delete(diffMap, path[0]) | ||
} | ||
} | ||
} |
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