1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
//
// Copyright 2022 The Sigstore Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package app
import (
"fmt"
"log"
"strings"
"time"
validator "github.com/go-playground/validator/v10"
"github.com/pkg/errors"
"github.com/spf13/pflag"
)
type FlagType string
const (
fileFlag FlagType = "file"
urlFlag FlagType = "url"
oidFlag FlagType = "oid"
formatFlag FlagType = "format"
timeoutFlag FlagType = "timeout"
)
type newPFlagValueFunc func() pflag.Value
var pflagValueFuncMap map[FlagType]newPFlagValueFunc
// TODO: unit tests for all of this
func initializePFlagMap() {
pflagValueFuncMap = map[FlagType]newPFlagValueFunc{
fileFlag: func() pflag.Value {
// this validates that the file exists and can be opened by the current uid
return valueFactory(fileFlag, validateString("required,file"), "")
},
urlFlag: func() pflag.Value {
// this validates that the string is a valid http/https URL
return valueFactory(urlFlag, validateString("required,url,startswith=http|startswith=https"), "")
},
oidFlag: func() pflag.Value {
// this validates for an OID, which is a sequence of positive integers separated by periods
return valueFactory(oidFlag, validateOID, "")
},
formatFlag: func() pflag.Value {
// this validates the output format requested
return valueFactory(formatFlag, validateString("required,oneof=json default"), "")
},
timeoutFlag: func() pflag.Value {
// this validates the timeout is >= 0
return valueFactory(formatFlag, validateTimeout, "")
},
}
}
// NewFlagValue creates a new pflag.Value for the specified type with the specified default value.
// If a default value is not desired, pass "" for defaultVal.
func NewFlagValue(flagType FlagType, defaultVal string) pflag.Value {
valFunc := pflagValueFuncMap[flagType]
val := valFunc()
if defaultVal != "" {
if err := val.Set(defaultVal); err != nil {
log.Fatal(errors.Wrap(err, "initializing flag"))
}
}
return val
}
type validationFunc func(string) error
func valueFactory(flagType FlagType, v validationFunc, defaultVal string) pflag.Value {
return &baseValue{
flagType: flagType,
validationFunc: v,
value: defaultVal,
}
}
// baseValue implements pflag.Value
type baseValue struct {
flagType FlagType
value string
validationFunc validationFunc
}
// Type returns the type of this Value
func (b baseValue) Type() string {
return string(b.flagType)
}
// String returns the string representation of this Value
func (b baseValue) String() string {
return b.value
}
// Set validates the provided string against the appropriate validation rule
// for b.flagType; if the string validates, it is stored in the Value and nil is returned.
// Otherwise the validation error is returned but the state of the Value is not changed.
func (b *baseValue) Set(s string) error {
if err := b.validationFunc(s); err != nil {
return err
}
b.value = s
return nil
}
// validateOID ensures that the supplied string is a valid ASN.1 object identifier
func validateOID(v string) error {
o := struct {
Oid []string `validate:"dive,numeric"`
}{strings.Split(v, ".")}
return useValidator(oidFlag, o)
}
// validateTimeout ensures that the supplied string is a valid time.Duration value >= 0
func validateTimeout(v string) error {
duration, err := time.ParseDuration(v)
if err != nil {
return err
}
d := struct {
Duration time.Duration `validate:"min=0"`
}{duration}
return useValidator(timeoutFlag, d)
}
// validateString returns a function that validates an input string against the specified tag,
// as defined in the format supported by go-playground/validator
func validateString(tag string) validationFunc {
return func(v string) error {
validator := validator.New()
return validator.Var(v, tag)
}
}
// useValidator performs struct level validation on s as defined in the struct's tags using
// the go-playground/validator library
func useValidator(flagType FlagType, s interface{}) error {
validate := validator.New()
if err := validate.Struct(s); err != nil {
return fmt.Errorf("error parsing %v flag: %w", flagType, err)
}
return nil
}
|
