Kong yaml is not being parsed correctly

[kotyara85]

Hello,
I have this yaml:

store:
  servers:
  - test
  - test2

and this struct

type Config struct {
	Store []*Cache
}

// represents cache config
type Cache struct {
	Servers []string
}

this code

parser, err := kong.New(&cfg, kong.Configuration(kongyaml.Loader, "config/config.yaml"))
if err != nil {
return nil, nil, err
}
ctx, err := parser.Parse([]string{})
spew.Dump(cfg)

produces unparsed data

(config.Config) {
 Store: (*config.Cache) <nil>
}

Am I missing something?

Thanks

[smlx]

I don't think your yaml matches your struct. The yaml should be:

store:
- servers:
  - test
  - test2

[kotyara85]

That results into this error

json: unsupported type: map[interface {}]interface {}

[alecthomas]

The YAML keys must map directly to flags. Run app --help to see what the flags are, but I think if you add prefix:"store-" to your Store *Cache tags, it should work.

[kotyara85]

Store []*Cache `kong:"prefix='cache-'"`

store:
- servers:
  - test
  - test2

result:

Store: ([]*config.Cache) <nil>

--cache-store=CACHE-STORE,...

No error though

[alecthomas]

You need both prefix and embed

[kotyara85]

Store []*Cache `kong:"embed,prefix='cache-'"`

panic: reflect: call of reflect.Value.NumField on slice Value

goroutine 1 [running]:
reflect.flag.mustBe(...)
	/usr/local/Cellar/go@1.17/1.17.8/libexec/src/reflect/value.go:223
reflect.Value.NumField({0x15a9b80, 0xc00030e8c0, 0x360ce80})

[alecthomas]

Where's the rest of the stack?

[kotyara85]

I apologize,
here it's

 go run main.go
panic: reflect: call of reflect.Value.NumField on slice Value

goroutine 1 [running]:
reflect.flag.mustBe(...)
	/usr/local/Cellar/go@1.17/1.17.8/libexec/src/reflect/value.go:223
reflect.Value.NumField({0x15a9b80, 0xc0002808c0, 0x5477830})
	/usr/local/Cellar/go@1.17/1.17.8/libexec/src/reflect/value.go:1723 +0x8d
github.com/alecthomas/kong.flattenedFields({0x15a9b80, 0xc0002808c0, 0x0})
	/Users/user/go/src/app/vendor/github.com/alecthomas/kong/build.go:54 +0xcc
github.com/alecthomas/kong.flattenedFields({0x1684360, 0xc000280840, 0x15a4740})
	/Users/user/go/src/app/vendor/github.com/alecthomas/kong/build.go:89 +0x60e
github.com/alecthomas/kong.buildNode(0xc0000abd40, {0x1684360, 0xc000280840, 0x4}, 0x0, 0xc0002c6f70)
	/Users/user/go/src/app/vendor/github.com/alecthomas/kong/build.go:118 +0x165
github.com/alecthomas/kong.build(0xc0000abd40, {0x159ec00, 0xc000280840})
	/Users/user/go/src/app/vendor/github.com/alecthomas/kong/build.go:28 +0x2b3
github.com/alecthomas/kong.New({0x159ec00, 0xc000280840}, {0xc00019fb68, 0x1, 0x1})
	/Users/user/go/src/app/vendor/github.com/alecthomas/kong/kong.go:104 +0x3fd
app/internal/config.New()
	/Users/user/go/src/app/internal/config/config.go:61 +0x9d
main.main()
	/Users/user/go/src/app/main.go:20 +0x7a