// CreateTwoWayMergePatch creates a patch that can be passed to StrategicMergePatch from an original
// document and a modified document, which are passed to the method as json encoded content. It will
// return a patch that yields the modified document when applied to the original document, or an error
// if either of the two documents is invalid.
func CreateTwoWayMergePatch(original, modified []byte, dataStruct interface{}, fns ...PreconditionFunc) ([]byte, error) {
originalMap := map[string]interface{}{}
if len(original) > 0 {
if err := json.Unmarshal(original, &originalMap); err != nil {
return nil, errBadJSONDoc
}
}
modifiedMap := map[string]interface{}{}
if len(modified) > 0 {
if err := json.Unmarshal(modified, &modifiedMap); err != nil {
return nil, errBadJSONDoc
}
}
t, err := getTagStructType(dataStruct)
if err != nil {
return nil, err
}
patchMap, err := diffMaps(originalMap, modifiedMap, t, false, false)
if err != nil {
return nil, err
}
// Apply the preconditions to the patch, and return an error if any of them fail.
for _, fn := range fns {
if !fn(patchMap) {
return nil, newErrPreconditionFailed(patchMap)
}
}
return json.Marshal(patchMap)
}
// StrategicMergePatch applies a strategic merge patch. The patch and the original document
// must be json encoded content. A patch can be created from an original and a modified document
// by calling CreateStrategicMergePatch.
func StrategicMergePatch(original, patch []byte, dataStruct interface{}) ([]byte, error) {
if original == nil {
original = []byte("{}")
}
if patch == nil {
patch = []byte("{}")
}
originalMap := map[string]interface{}{}
err := json.Unmarshal(original, &originalMap)
if err != nil {
return nil, errBadJSONDoc
}
patchMap := map[string]interface{}{}
err = json.Unmarshal(patch, &patchMap)
if err != nil {
return nil, errBadJSONDoc
}
t, err := getTagStructType(dataStruct)
if err != nil {
return nil, err
}
result, err := mergeMap(originalMap, patchMap, t)
if err != nil {
return nil, err
}
return json.Marshal(result)
}
// This function takes a JSON map and sorts all the lists that should be merged
// by key. This is needed by tests because in JSON, list order is significant,
// but in Strategic Merge Patch, merge lists do not have significant order.
// Sorting the lists allows for order-insensitive comparison of patched maps.
func sortMergeListsByName(mapJSON []byte, dataStruct interface{}) ([]byte, error) {
var m map[string]interface{}
err := json.Unmarshal(mapJSON, &m)
if err != nil {
return nil, err
}
newM, err := sortMergeListsByNameMap(m, reflect.TypeOf(dataStruct))
if err != nil {
return nil, err
}
return json.Marshal(newM)
}
// CreateThreeWayMergePatch reconciles a modified configuration with an original configuration,
// while preserving any changes or deletions made to the original configuration in the interim,
// and not overridden by the current configuration. All three documents must be passed to the
// method as json encoded content. It will return a strategic merge patch, or an error if any
// of the documents is invalid, or if there are any preconditions that fail against the modified
// configuration, or, if overwrite is false and there are conflicts between the modified and current
// configurations. Conflicts are defined as keys changed differently from original to modified
// than from original to current. In other words, a conflict occurs if modified changes any key
// in a way that is different from how it is changed in current (e.g., deleting it, changing its
// value).
func CreateThreeWayMergePatch(original, modified, current []byte, dataStruct interface{}, overwrite bool, fns ...PreconditionFunc) ([]byte, error) {
originalMap := map[string]interface{}{}
if len(original) > 0 {
if err := json.Unmarshal(original, &originalMap); err != nil {
return nil, errBadJSONDoc
}
}
modifiedMap := map[string]interface{}{}
if len(modified) > 0 {
if err := json.Unmarshal(modified, &modifiedMap); err != nil {
return nil, errBadJSONDoc
}
}
currentMap := map[string]interface{}{}
if len(current) > 0 {
if err := json.Unmarshal(current, ¤tMap); err != nil {
return nil, errBadJSONDoc
}
}
t, err := getTagStructType(dataStruct)
if err != nil {
return nil, err
}
// The patch is the difference from current to modified without deletions, plus deletions
// from original to modified. To find it, we compute deletions, which are the deletions from
// original to modified, and delta, which is the difference from current to modified without
// deletions, and then apply delta to deletions as a patch, which should be strictly additive.
deltaMap, err := diffMaps(currentMap, modifiedMap, t, false, true)
if err != nil {
return nil, err
}
deletionsMap, err := diffMaps(originalMap, modifiedMap, t, true, false)
if err != nil {
return nil, err
}
patchMap, err := mergeMap(deletionsMap, deltaMap, t)
if err != nil {
return nil, err
}
// Apply the preconditions to the patch, and return an error if any of them fail.
for _, fn := range fns {
if !fn(patchMap) {
return nil, newErrPreconditionFailed(patchMap)
}
}
// If overwrite is false, and the patch contains any keys that were changed differently,
// then return a conflict error.
if !overwrite {
changedMap, err := diffMaps(originalMap, currentMap, t, false, false)
if err != nil {
return nil, err
}
hasConflicts, err := MergingMapsHaveConflicts(patchMap, changedMap, dataStruct)
if err != nil {
return nil, err
}
if hasConflicts {
return nil, newErrConflict(toYAMLOrError(patchMap), toYAMLOrError(changedMap))
}
}
return json.Marshal(patchMap)
}