viper cannot unmarshal config

[daixiang0]

Reproduce:
main.go:

package main

import (
	"flag"
	"os"
	"path"
	"fmt"
	"strings"
    
    "github.com/cortexproject/cortex/pkg/util/flagext"
    "github.com/spf13/pflag"
    "github.com/spf13/viper"
)

type Config struct {
    ClientConfig    clientConfig    `yaml:"client,omitempty"`
    ClientConfigs   []clientConfig  `yaml:"clients,omitempty"`
}

type clientConfig struct {
    URL       flagext.URLValue
}

func (c *Config) RegisterFlags(f *flag.FlagSet) {
        c.ClientConfig.RegisterFlags(f)
}

func (c *clientConfig) RegisterFlags(flags *flag.FlagSet) {
    flags.Var(&c.URL, "client.url", "URL of log server")
} 

func main() {
	var (
		configFile = "cmd/promtail/promtail-local-config.yaml"
		config     Config
	)

	flag.StringVar(&configFile, "config.file", "promtail.yml", "The config file.")
	flagext.RegisterFlags(&config)
	pflag.CommandLine.AddGoFlagSet(flag.CommandLine)
	pflag.Parse()

	if err := viper.BindPFlags(pflag.CommandLine); err != nil {
		fmt.Println("msg", "error parsing flags", "err", err)
		os.Exit(1)
	}

	configFile = viper.GetString("config.file")
	viper.SetConfigType("yaml")
	viper.SetConfigName(strings.TrimSuffix(path.Base(configFile), path.Ext(configFile)))
	viper.AddConfigPath(path.Dir(configFile))
	if err := viper.ReadInConfig(); err != nil {
		fmt.Println("msg", "error reading config", "filename", configFile, "err", err)
		os.Exit(1)
	}

	if err := viper.Unmarshal(&config); err != nil {
		fmt.Println("msg", "error decoding config", "filename", configFile, "err", err)
		os.Exit(1)
	}
}

configfile:

clients:
  - url: http://localhost

$ go build main.go
$ ./main --config.file configfile

The bug is that config.ClientConfigs is empty.

[daixiang0]

Hi, @sagikazarmark @spf13 mind have a look?

[daixiang0]

I use 1.4.0 version.

[daixiang0]

A more simple example:

package main

import (
	"os"
	"path"
	"fmt"
	"strings"
 
        "github.com/spf13/viper"
)

type Config struct {
    ClientConfig    clientConfig    `yaml:"client,omitempty"`
    ClientConfigs   []clientConfig  `yaml:"clients,omitempty"`
}

type clientConfig struct {
    URL       string `"yaml: url"`
}


func main() {
	var (
		configFile = "cmd/promtail/promtail-local-config.yaml"
		config     Config
	)

	configFile = "path/to/config.yml"
	viper.SetConfigType("yaml")
	viper.SetConfigName(strings.TrimSuffix(path.Base(configFile), path.Ext(configFile)))
	viper.AddConfigPath(path.Dir(configFile))
	if err := viper.ReadInConfig(); err != nil {
		fmt.Println("msg", "error reading config", "filename", configFile, "err", err)
		os.Exit(1)
	}

	if err := viper.Unmarshal(&config); err != nil {
		fmt.Println("msg", "error decoding config", "filename", configFile, "err", err)
		os.Exit(1)
	}
    viper.Debug()
    for i := range config.ClientConfigs {
        fmt.Println("config: ", i)
    }
    fmt.Println("url: ",config.ClientConfig.URL)
}

All fmt print is empty.

[daixiang0]

Seems is mapstructure issue

[daixiang0]

@sagikazarmark could help me?

[sagikazarmark]

Looks like you received an answer on the mapstructure issue tracker. Is your issue resolved?

[daixiang0]

still not resolved :(

[daixiang0]

@sagikazarmark hi, i add a hook but still failed, please help me!