operation.go

Documentation: sigs.k8s.io/structured-merge-diff/v4/internal/cli

     1  /*
     2  Copyright 2018 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 cli
    18  
    19  import (
    20  	"fmt"
    21  	"io"
    22  	"io/ioutil"
    23  
    24  	"sigs.k8s.io/structured-merge-diff/v4/typed"
    25  	"sigs.k8s.io/structured-merge-diff/v4/value"
    26  )
    27  
    28  type Operation interface {
    29  	Execute(io.Writer) error
    30  }
    31  
    32  type operationBase struct {
    33  	parser   *typed.Parser
    34  	typeName string
    35  }
    36  
    37  func (b operationBase) parseFile(path string) (tv *typed.TypedValue, err error) {
    38  	bytes, err := ioutil.ReadFile(path)
    39  	if err != nil {
    40  		return tv, fmt.Errorf("unable to read file %q: %v", path, err)
    41  	}
    42  	tv, err = b.parser.Type(b.typeName).FromYAML(typed.YAMLObject(bytes))
    43  	if err != nil {
    44  		return tv, fmt.Errorf("unable to validate file %q:\n%v", path, err)
    45  	}
    46  	return tv, nil
    47  }
    48  
    49  type validation struct {
    50  	operationBase
    51  
    52  	fileToValidate string
    53  }
    54  
    55  func (v validation) Execute(_ io.Writer) error {
    56  	_, err := v.parseFile(v.fileToValidate)
    57  	return err
    58  }
    59  
    60  type fieldset struct {
    61  	operationBase
    62  
    63  	fileToUse string
    64  }
    65  
    66  func (f fieldset) Execute(w io.Writer) error {
    67  	tv, err := f.parseFile(f.fileToUse)
    68  	if err != nil {
    69  		return err
    70  	}
    71  
    72  	empty, err := f.parser.Type(f.typeName).FromYAML(typed.YAMLObject("{}"))
    73  	if err != nil {
    74  		return err
    75  	}
    76  	c, err := empty.Compare(tv)
    77  	if err != nil {
    78  		return err
    79  	}
    80  
    81  	return c.Added.ToJSONStream(w)
    82  }
    83  
    84  type listTypes struct {
    85  	operationBase
    86  }
    87  
    88  func (l listTypes) Execute(w io.Writer) error {
    89  	for _, td := range l.parser.Schema.Types {
    90  		fmt.Fprintf(w, "%v\n", td.Name)
    91  	}
    92  	return nil
    93  }
    94  
    95  type merge struct {
    96  	operationBase
    97  
    98  	lhs string
    99  	rhs string
   100  }
   101  
   102  func (m merge) Execute(w io.Writer) error {
   103  	lhs, err := m.parseFile(m.lhs)
   104  	if err != nil {
   105  		return err
   106  	}
   107  	rhs, err := m.parseFile(m.rhs)
   108  	if err != nil {
   109  		return err
   110  	}
   111  
   112  	out, err := lhs.Merge(rhs)
   113  	if err != nil {
   114  		return err
   115  	}
   116  
   117  	yaml, err := value.ToYAML(out.AsValue())
   118  	if err != nil {
   119  		return err
   120  	}
   121  	_, err = w.Write(yaml)
   122  
   123  	return err
   124  }
   125  
   126  type compare struct {
   127  	operationBase
   128  
   129  	lhs string
   130  	rhs string
   131  }
   132  
   133  func (c compare) Execute(w io.Writer) error {
   134  	lhs, err := c.parseFile(c.lhs)
   135  	if err != nil {
   136  		return err
   137  	}
   138  	rhs, err := c.parseFile(c.rhs)
   139  	if err != nil {
   140  		return err
   141  	}
   142  
   143  	got, err := lhs.Compare(rhs)
   144  	if err != nil {
   145  		return err
   146  	}
   147  
   148  	if got.IsSame() {
   149  		_, err = fmt.Fprint(w, "No difference")
   150  		return err
   151  	}
   152  
   153  	// TODO: I think it'd be neat if we actually emitted a machine-readable
   154  	// format.
   155  
   156  	_, err = fmt.Fprintf(w, got.String())
   157  
   158  	return err
   159  }
   160
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