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oauth2-proxy/env_options.go
Kirill Motkov e64e6fa514 Some code improvements
* Remove shadowing of predeclared identifier: new.
* strings.ReplaceAll instead of strings.Replace with -1.
* Change strings.ToLower comparison to strings.EqualFold.
* Rewrite if-else-if-else chain as a switch.
2019-10-09 15:44:26 +03:00

55 lines
1.4 KiB
Go

package main
import (
"os"
"reflect"
"strings"
)
// EnvOptions holds program options loaded from the process environment
type EnvOptions map[string]interface{}
// LoadEnvForStruct loads environment variables for each field in an options
// struct passed into it.
//
// Fields in the options struct must have an `env` and `cfg` tag to be read
// from the environment
func (cfg EnvOptions) LoadEnvForStruct(options interface{}) {
val := reflect.ValueOf(options)
var typ reflect.Type
if val.Kind() == reflect.Ptr {
typ = val.Elem().Type()
} else {
typ = val.Type()
}
for i := 0; i < typ.NumField(); i++ {
// pull out the struct tags:
// flag - the name of the command line flag
// deprecated - (optional) the name of the deprecated command line flag
// cfg - (optional, defaults to underscored flag) the name of the config file option
field := typ.Field(i)
fieldV := reflect.Indirect(val).Field(i)
if field.Type.Kind() == reflect.Struct && field.Anonymous {
cfg.LoadEnvForStruct(fieldV.Interface())
continue
}
flagName := field.Tag.Get("flag")
envName := field.Tag.Get("env")
cfgName := field.Tag.Get("cfg")
if cfgName == "" && flagName != "" {
cfgName = strings.ReplaceAll(flagName, "-", "_")
}
if envName == "" || cfgName == "" {
// resolvable fields must have the `env` and `cfg` struct tag
continue
}
v := os.Getenv(envName)
if v != "" {
cfg[cfgName] = v
}
}
}