map_string_string.go

Documentation: k8s.io/component-base/cli/flag

     1  /*
     2  Copyright 2017 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 flag
    18  
    19  import (
    20  	"fmt"
    21  	"sort"
    22  	"strings"
    23  )
    24  
    25  // MapStringString can be set from the command line with the format `--flag "string=string"`.
    26  // Multiple flag invocations are supported. For example: `--flag "a=foo" --flag "b=bar"`. If this is desired
    27  // to be the only type invocation `NoSplit` should be set to true.
    28  // Multiple comma-separated key-value pairs in a single invocation are supported if `NoSplit`
    29  // is set to false. For example: `--flag "a=foo,b=bar"`.
    30  type MapStringString struct {
    31  	Map         *map[string]string
    32  	initialized bool
    33  	NoSplit     bool
    34  }
    35  
    36  // NewMapStringString takes a pointer to a map[string]string and returns the
    37  // MapStringString flag parsing shim for that map
    38  func NewMapStringString(m *map[string]string) *MapStringString {
    39  	return &MapStringString{Map: m}
    40  }
    41  
    42  // NewMapStringString takes a pointer to a map[string]string and sets `NoSplit`
    43  // value to `true` and returns the MapStringString flag parsing shim for that map
    44  func NewMapStringStringNoSplit(m *map[string]string) *MapStringString {
    45  	return &MapStringString{
    46  		Map:     m,
    47  		NoSplit: true,
    48  	}
    49  }
    50  
    51  // String implements github.com/spf13/pflag.Value
    52  func (m *MapStringString) String() string {
    53  	if m == nil || m.Map == nil {
    54  		return ""
    55  	}
    56  	pairs := []string{}
    57  	for k, v := range *m.Map {
    58  		pairs = append(pairs, fmt.Sprintf("%s=%s", k, v))
    59  	}
    60  	sort.Strings(pairs)
    61  	return strings.Join(pairs, ",")
    62  }
    63  
    64  // Set implements github.com/spf13/pflag.Value
    65  func (m *MapStringString) Set(value string) error {
    66  	if m.Map == nil {
    67  		return fmt.Errorf("no target (nil pointer to map[string]string)")
    68  	}
    69  	if !m.initialized || *m.Map == nil {
    70  		// clear default values, or allocate if no existing map
    71  		*m.Map = make(map[string]string)
    72  		m.initialized = true
    73  	}
    74  
    75  	// account for comma-separated key-value pairs in a single invocation
    76  	if !m.NoSplit {
    77  		for _, s := range strings.Split(value, ",") {
    78  			if len(s) == 0 {
    79  				continue
    80  			}
    81  			arr := strings.SplitN(s, "=", 2)
    82  			if len(arr) != 2 {
    83  				return fmt.Errorf("malformed pair, expect string=string")
    84  			}
    85  			k := strings.TrimSpace(arr[0])
    86  			v := strings.TrimSpace(arr[1])
    87  			(*m.Map)[k] = v
    88  		}
    89  		return nil
    90  	}
    91  
    92  	// account for only one key-value pair in a single invocation
    93  	arr := strings.SplitN(value, "=", 2)
    94  	if len(arr) != 2 {
    95  		return fmt.Errorf("malformed pair, expect string=string")
    96  	}
    97  	k := strings.TrimSpace(arr[0])
    98  	v := strings.TrimSpace(arr[1])
    99  	(*m.Map)[k] = v
   100  	return nil
   101  
   102  }
   103  
   104  // Type implements github.com/spf13/pflag.Value
   105  func (*MapStringString) Type() string {
   106  	return "mapStringString"
   107  }
   108  
   109  // Empty implements OmitEmpty
   110  func (m *MapStringString) Empty() bool {
   111  	return len(*m.Map) == 0
   112  }
   113
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