override_options.go

Documentation: k8s.io/kubectl/pkg/cmd/util

     1  /*
     2  Copyright 2021 The Kubernetes Authors.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package util
    18  
    19  import (
    20  	"fmt"
    21  
    22  	"github.com/spf13/cobra"
    23  
    24  	"k8s.io/apimachinery/pkg/runtime"
    25  	"k8s.io/kubectl/pkg/scheme"
    26  	"k8s.io/kubectl/pkg/util/i18n"
    27  )
    28  
    29  type OverrideType string
    30  
    31  const (
    32  	// OverrideTypeJSON will use an RFC6902 JSON Patch to alter the generated output
    33  	OverrideTypeJSON OverrideType = "json"
    34  
    35  	// OverrideTypeMerge will use an RFC7396 JSON Merge Patch to alter the generated output
    36  	OverrideTypeMerge OverrideType = "merge"
    37  
    38  	// OverrideTypeStrategic will use a Strategic Merge Patch to alter the generated output
    39  	OverrideTypeStrategic OverrideType = "strategic"
    40  )
    41  
    42  const DefaultOverrideType = OverrideTypeMerge
    43  
    44  type OverrideOptions struct {
    45  	Overrides    string
    46  	OverrideType OverrideType
    47  }
    48  
    49  func (o *OverrideOptions) AddOverrideFlags(cmd *cobra.Command) {
    50  	cmd.Flags().StringVar(&o.Overrides, "overrides", "", i18n.T("An inline JSON override for the generated object. If this is non-empty, it is used to override the generated object. Requires that the object supply a valid apiVersion field."))
    51  	cmd.Flags().StringVar((*string)(&o.OverrideType), "override-type", string(DefaultOverrideType), fmt.Sprintf("The method used to override the generated object: %s, %s, or %s.", OverrideTypeJSON, OverrideTypeMerge, OverrideTypeStrategic))
    52  }
    53  
    54  func (o *OverrideOptions) NewOverrider(dataStruct runtime.Object) *Overrider {
    55  	return &Overrider{
    56  		Options:    o,
    57  		DataStruct: dataStruct,
    58  	}
    59  }
    60  
    61  type Overrider struct {
    62  	Options    *OverrideOptions
    63  	DataStruct runtime.Object
    64  }
    65  
    66  func (o *Overrider) Apply(obj runtime.Object) (runtime.Object, error) {
    67  	if len(o.Options.Overrides) == 0 {
    68  		return obj, nil
    69  	}
    70  
    71  	codec := runtime.NewCodec(scheme.DefaultJSONEncoder(), scheme.Codecs.UniversalDecoder(scheme.Scheme.PrioritizedVersionsAllGroups()...))
    72  
    73  	var overrideType OverrideType
    74  	if len(o.Options.OverrideType) == 0 {
    75  		overrideType = DefaultOverrideType
    76  	} else {
    77  		overrideType = o.Options.OverrideType
    78  	}
    79  
    80  	switch overrideType {
    81  	case OverrideTypeJSON:
    82  		return JSONPatch(codec, obj, o.Options.Overrides)
    83  	case OverrideTypeMerge:
    84  		return Merge(codec, obj, o.Options.Overrides)
    85  	case OverrideTypeStrategic:
    86  		return StrategicMerge(codec, obj, o.Options.Overrides, o.DataStruct)
    87  	default:
    88  		return nil, fmt.Errorf("invalid override type: %v", overrideType)
    89  	}
    90  }
    91
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