Clash Royale CLAN TAG#URR8PPP

yaml: unmarshal errors: cannot unmarshal string into time.Duration in Golang

I have struct as below:

type Connect struct
ClientID string `yaml:"clientid"`
Password string `yaml:"password"`
Timeout time.Duration `yaml:"timeout"`


c1 := `
id: 'client1'
password: 'hhhhhhha'
timeout: 10
`

c2 := `
id: 'client2'
password: 'llllllla'
timeout: '10'
`

c3 := `
id: 'client3'
password: 'hhhhhhha'
timeout: 10s
`

c4 := `
id: 'client4'
password: 'llllllla'
timeout: '10s'
`


as shown above, type of Timeout is time.Duration, the default unit is Nanosecond, but I want to get the result: c1 && c2 has error, c3 && c4 is valid(the config of Timeout must have unit). How should I do to rewrite the UnmarshalYAML() Method for yaml? Thanks a lot.

2 Answers
2

I would create an aliased type in the UnmarshalYAML function so that all the values could be unmarshaled to some primitive types. Then I will rewrite those values that match and convert those which do not:

UnmarshalYAML

package main

import (
"fmt"
"time"

"gopkg.in/yaml.v2"
)

type Connect struct
ClientID string `yaml:"clientid"`
Password string `yaml:"password"`
Timeout time.Duration `yaml:"timeout"`


func (ut *Connect) UnmarshalYAML(unmarshal func(interface) error) error
type alias struct
ClientID string `yaml:"clientid"`
Password string `yaml:"password"`
Timeout string `yaml:"timeout"`


var tmp alias
if err := unmarshal(&tmp); err != nil
return err


t, err := time.ParseDuration(tmp.Timeout)
if err != nil
return fmt.Errorf("failed to parse '%s' to time.Duration: %v", tmp.Timeout, err)


ut.ClientID = tmp.ClientID
ut.Password = tmp.Password
ut.Timeout = t

return nil


func main()
c1 := `
id: 'client1'
password: 'hhhhhhha'
timeout: 10
`

c2 := `
id: 'client2'
password: 'llllllla'
timeout: '10'
`

c3 := `
id: 'client3'
password: 'hhhhhhha'
timeout: 10s
`

c4 := `
id: 'client4'
password: 'llllllla'
timeout: '10s'
`

cc := stringc1, c2, c3, c4
for i, cstr := range cc
var c Connect
err := yaml.Unmarshal(byte(cstr), &c)
if err != nil
fmt.Printf("Error for c%d: %vn", (i + 1), err)
continue

fmt.Printf("c%d: %+vn", (i + 1), c)




The output looks as follows:

$ go run main.go
Error for c1: failed to parse '10' to time.Duration: time: missing unit in duration10
Error for c2: failed to parse '10' to time.Duration: time: missing unit in duration10
c3: ClientID: Password:hhhhhhha Timeout:10s
c4: ClientID: Password:llllllla Timeout:10s


One way would be to make a custom type for Timeout that implements the Unmarshaler interface, if you're not able to do it in the UnmarshalYAML method of Connect:

Timeout

UnmarshalYAML

Connect

type Connect struct
ClientID string `yaml:"clientid"`
Password string `yaml:"password"`
Timeout UnmarshalingTimeout `yaml:"timeout"`


type UnmarshalingTimeout time.Duration

func (ut UnmarshalingTimeout) UnmarshalYAML(unmarshal func(interface) error) error
// implement unmarshaling here



time.Duration(Connect.Timeout)

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