forked from openshift/library-go
/
generic_config_merger.go
230 lines (200 loc) · 6.73 KB
/
generic_config_merger.go
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package resourcemerge
import (
"bytes"
"encoding/json"
"fmt"
"reflect"
"k8s.io/klog"
"sigs.k8s.io/yaml"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/runtime"
kyaml "k8s.io/apimachinery/pkg/util/yaml"
)
// MergeConfigMap takes a configmap, the target key, special overlay funcs a list of config configs to overlay on top of each other
// It returns the resultant configmap and a bool indicating if any changes were made to the configmap
func MergeConfigMap(configMap *corev1.ConfigMap, configKey string, specialCases map[string]MergeFunc, configYAMLs ...[]byte) (*corev1.ConfigMap, bool, error) {
return MergePrunedConfigMap(nil, configMap, configKey, specialCases, configYAMLs...)
}
// MergePrunedConfigMap takes a configmap, the target key, special overlay funcs a list of config configs to overlay on top of each other
// It returns the resultant configmap and a bool indicating if any changes were made to the configmap.
// It roundtrips the config through the given schema.
func MergePrunedConfigMap(schema runtime.Object, configMap *corev1.ConfigMap, configKey string, specialCases map[string]MergeFunc, configYAMLs ...[]byte) (*corev1.ConfigMap, bool, error) {
configBytes, err := MergePrunedProcessConfig(schema, specialCases, configYAMLs...)
if err != nil {
return nil, false, err
}
if reflect.DeepEqual(configMap.Data[configKey], configBytes) {
return configMap, false, nil
}
ret := configMap.DeepCopy()
ret.Data[configKey] = string(configBytes)
return ret, true, nil
}
// MergeProcessConfig merges a series of config yaml files together with each later one overlaying all previous
func MergeProcessConfig(specialCases map[string]MergeFunc, configYAMLs ...[]byte) ([]byte, error) {
currentConfigYAML := configYAMLs[0]
for _, currConfigYAML := range configYAMLs[1:] {
prevConfigJSON, err := kyaml.ToJSON(currentConfigYAML)
if err != nil {
klog.Warning(err)
// maybe it's just json
prevConfigJSON = currentConfigYAML
}
prevConfig := map[string]interface{}{}
if err := json.NewDecoder(bytes.NewBuffer(prevConfigJSON)).Decode(&prevConfig); err != nil {
return nil, err
}
if len(currConfigYAML) > 0 {
currConfigJSON, err := kyaml.ToJSON(currConfigYAML)
if err != nil {
klog.Warning(err)
// maybe it's just json
currConfigJSON = currConfigYAML
}
currConfig := map[string]interface{}{}
if err := json.NewDecoder(bytes.NewBuffer(currConfigJSON)).Decode(&currConfig); err != nil {
return nil, err
}
// protected against mismatched typemeta
prevAPIVersion, _, _ := unstructured.NestedString(prevConfig, "apiVersion")
prevKind, _, _ := unstructured.NestedString(prevConfig, "kind")
currAPIVersion, _, _ := unstructured.NestedString(currConfig, "apiVersion")
currKind, _, _ := unstructured.NestedString(currConfig, "kind")
currGVKSet := len(currAPIVersion) > 0 || len(currKind) > 0
gvkMismatched := currAPIVersion != prevAPIVersion || currKind != prevKind
if currGVKSet && gvkMismatched {
return nil, fmt.Errorf("%v/%v does not equal %v/%v", currAPIVersion, currKind, prevAPIVersion, prevKind)
}
if err := mergeConfig(prevConfig, currConfig, "", specialCases); err != nil {
return nil, err
}
}
currentConfigYAML, err = runtime.Encode(unstructured.UnstructuredJSONScheme, &unstructured.Unstructured{Object: prevConfig})
if err != nil {
return nil, err
}
}
return currentConfigYAML, nil
}
// MergePrunedProcessConfig merges a series of config yaml files together with each later one overlaying all previous.
// The result is roundtripped through the given schema if it is non-nil.
func MergePrunedProcessConfig(schema runtime.Object, specialCases map[string]MergeFunc, configYAMLs ...[]byte) ([]byte, error) {
bs, err := MergeProcessConfig(specialCases, configYAMLs...)
if err != nil {
return nil, err
}
if schema == nil {
return bs, nil
}
// roundtrip through the schema
typed := schema.DeepCopyObject()
if err := yaml.Unmarshal(bs, typed); err != nil {
return nil, err
}
typedBytes, err := json.Marshal(typed)
if err != nil {
return nil, err
}
var untypedJSON map[string]interface{}
if err := json.Unmarshal(typedBytes, &untypedJSON); err != nil {
return nil, err
}
// and intersect output with input because we cannot rely on omitempty in the schema
inputBytes, err := yaml.YAMLToJSON(bs)
if err != nil {
return nil, err
}
var inputJSON map[string]interface{}
if err := json.Unmarshal(inputBytes, &inputJSON); err != nil {
return nil, err
}
return json.Marshal(intersectJSON(inputJSON, untypedJSON))
}
type MergeFunc func(dst, src interface{}, currentPath string) (interface{}, error)
// mergeConfig overwrites entries in curr by additional. It modifies curr.
func mergeConfig(curr, additional map[string]interface{}, currentPath string, specialCases map[string]MergeFunc) error {
for additionalKey, additionalVal := range additional {
fullKey := currentPath + "." + additionalKey
specialCase, ok := specialCases[fullKey]
if ok {
var err error
curr[additionalKey], err = specialCase(curr[additionalKey], additionalVal, currentPath)
if err != nil {
return err
}
continue
}
currVal, ok := curr[additionalKey]
if !ok {
curr[additionalKey] = additionalVal
continue
}
// only some scalars are accepted
switch castVal := additionalVal.(type) {
case map[string]interface{}:
currValAsMap, ok := currVal.(map[string]interface{})
if !ok {
currValAsMap = map[string]interface{}{}
curr[additionalKey] = currValAsMap
}
err := mergeConfig(currValAsMap, castVal, fullKey, specialCases)
if err != nil {
return err
}
continue
default:
if err := unstructured.SetNestedField(curr, castVal, additionalKey); err != nil {
return err
}
}
}
return nil
}
// jsonIntersection returns the intersection of both JSON object,
// preferring the values of the first argument.
func intersectJSON(x1, x2 map[string]interface{}) map[string]interface{} {
if x1 == nil || x2 == nil {
return nil
}
ret := map[string]interface{}{}
for k, v1 := range x1 {
v2, ok := x2[k]
if !ok {
continue
}
ret[k] = intersectValue(v1, v2)
}
return ret
}
func intersectArray(x1, x2 []interface{}) []interface{} {
if x1 == nil || x2 == nil {
return nil
}
ret := make([]interface{}, 0, len(x1))
for i := range x1 {
if i >= len(x2) {
break
}
ret = append(ret, intersectValue(x1[i], x2[i]))
}
return ret
}
func intersectValue(x1, x2 interface{}) interface{} {
switch x1 := x1.(type) {
case map[string]interface{}:
x2, ok := x2.(map[string]interface{})
if !ok {
return x1
}
return intersectJSON(x1, x2)
case []interface{}:
x2, ok := x2.([]interface{})
if !ok {
return x1
}
return intersectArray(x1, x2)
default:
return x1
}
}