arguments.go

Documentation: k8s.io/kubernetes/cmd/kubeadm/app/util

     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 util
    18  
    19  import (
    20  	"fmt"
    21  	"sort"
    22  	"strings"
    23  
    24  	"github.com/pkg/errors"
    25  
    26  	"k8s.io/apimachinery/pkg/util/sets"
    27  	"k8s.io/klog/v2"
    28  	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
    29  )
    30  
    31  // ArgumentsToCommand takes two Arg slices, one with the base arguments and one
    32  // with optional override arguments. In the return list override arguments will precede base
    33  // arguments. If an argument is present in the overrides, it will cause
    34  // all instances of the same argument in the base list to be discarded, leaving
    35  // only the instances of this argument in the overrides to be applied.
    36  func ArgumentsToCommand(base []kubeadmapi.Arg, overrides []kubeadmapi.Arg) []string {
    37  	var command []string
    38  	// Copy the overrides arguments into a new slice.
    39  	args := make([]kubeadmapi.Arg, len(overrides))
    40  	copy(args, overrides)
    41  
    42  	// overrideArgs is a set of args which will replace the args defined in the base
    43  	overrideArgs := sets.New[string]()
    44  	for _, arg := range overrides {
    45  		overrideArgs.Insert(arg.Name)
    46  	}
    47  
    48  	for _, arg := range base {
    49  		if !overrideArgs.Has(arg.Name) {
    50  			args = append(args, arg)
    51  		}
    52  	}
    53  
    54  	sort.Slice(args, func(i, j int) bool {
    55  		if args[i].Name == args[j].Name {
    56  			return args[i].Value < args[j].Value
    57  		}
    58  		return args[i].Name < args[j].Name
    59  	})
    60  
    61  	for _, arg := range args {
    62  		command = append(command, fmt.Sprintf("--%s=%s", arg.Name, arg.Value))
    63  	}
    64  
    65  	return command
    66  }
    67  
    68  // ArgumentsFromCommand parses a CLI command in the form "--foo=bar" to an Arg slice
    69  func ArgumentsFromCommand(command []string) []kubeadmapi.Arg {
    70  	args := []kubeadmapi.Arg{}
    71  	for i, arg := range command {
    72  		key, val, err := parseArgument(arg)
    73  
    74  		// Ignore if the first argument doesn't satisfy the criteria, it's most often the binary name
    75  		// Warn in all other cases, but don't error out. This can happen only if the user has edited the argument list by hand, so they might know what they are doing
    76  		if err != nil {
    77  			if i != 0 {
    78  				klog.Warningf("[kubeadm] WARNING: The component argument %q could not be parsed correctly. The argument must be of the form %q. Skipping...\n", arg, "--")
    79  			}
    80  			continue
    81  		}
    82  
    83  		args = append(args, kubeadmapi.Arg{Name: key, Value: val})
    84  	}
    85  
    86  	sort.Slice(args, func(i, j int) bool {
    87  		if args[i].Name == args[j].Name {
    88  			return args[i].Value < args[j].Value
    89  		}
    90  		return args[i].Name < args[j].Name
    91  	})
    92  	return args
    93  }
    94  
    95  // parseArgument parses the argument "--foo=bar" to "foo" and "bar"
    96  func parseArgument(arg string) (string, string, error) {
    97  	if !strings.HasPrefix(arg, "--") {
    98  		return "", "", errors.New("the argument should start with '--'")
    99  	}
   100  	if !strings.Contains(arg, "=") {
   101  		return "", "", errors.New("the argument should have a '=' between the flag and the value")
   102  	}
   103  	// Remove the starting --
   104  	arg = strings.TrimPrefix(arg, "--")
   105  	// Split the string on =. Return only two substrings, since we want only key/value, but the value can include '=' as well
   106  	keyvalSlice := strings.SplitN(arg, "=", 2)
   107  
   108  	// Make sure both a key and value is present
   109  	if len(keyvalSlice) != 2 {
   110  		return "", "", errors.New("the argument must have both a key and a value")
   111  	}
   112  	if len(keyvalSlice[0]) == 0 {
   113  		return "", "", errors.New("the argument must have a key")
   114  	}
   115  
   116  	return keyvalSlice[0], keyvalSlice[1], nil
   117  }
   118
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