README
¶
DEPRECATION WARNING
This repo was moved at 20140912-1451 to [go-goodies/go_jsoncfg] (https://github.com/go-goodies/go_jsoncfg)
jsoncfgo
A Go library for reading configuration settings from JSON files.
Installation
$ go get github.com/l3x/jsoncfgo
Usage
jsoncfgo can handle the following data types from the .json configuration file that it reads:
- bool
- int
- int64
- string
- []string
- []int64
You can also call the Validate function to validate attempts to read non-existent variables.
jsconfgo Advanced Features
- Read environment variables
- Handle included file objects that refer to other config files
- Handle nested json objects within the config file
- Validation:
- Validate existence of required variables
- Validate attempt to read non-existent variable
Usage
simple-config.json
{
"host": "localhost",
"port": 5432,
"bignNumber": 999999999999999,
"active": true,
"appList": ["myapp", "sharedapp"],
"numbers": [9, 8, 7, 6]
}
simple_config.go
package main
import (
"fmt"
"time"
"log"
"github.com/l3x/jsoncfgo"
)
func main() {
cfg := jsoncfgo.Load("/Users/lex/dev/go/data/jsoncfgo/simple-config.json")
host := cfg.String("host")
fmt.Printf("host: %v\n", host)
bogusHost := cfg.String("bogusHost", "default_host_name")
fmt.Printf("host: %v\n\n", bogusHost)
port := cfg.Int("port")
fmt.Printf("port: %v\n", port)
bogusPort := cfg.Int("bogusPort", 9000)
fmt.Printf("bogusPort: %v\n\n", bogusPort)
bigNumber := cfg.Int64("bignNumber")
fmt.Printf("bigNumber: %v\n", bigNumber)
bogusBigNumber := cfg.Int64("bogusBigNumber", 9000000000000000000)
fmt.Printf("bogusBigNumber: %v\n\n", bogusBigNumber)
active := cfg.Bool("active")
fmt.Printf("active: %v\n", active)
bogusFalseActive := cfg.Bool("bogusFalseActive", false)
fmt.Printf("bogusFalseActive: %v\n", bogusFalseActive)
bogusTrueActive := cfg.Bool("bogusTrueActive", true)
fmt.Printf("bogusTrueActive: %v\n\n", bogusTrueActive)
appList := cfg.List("appList")
fmt.Printf("appList: %v\n", appList)
bogusAppList := cfg.List("bogusAppList", []string{"app1", "app2", "app3"})
fmt.Printf("bogusAppList: %v\n\n", bogusAppList)
numbers := cfg.IntList("numbers")
fmt.Printf("numbers: %v\n", numbers)
bogusSettings := cfg.IntList("bogusSettings", []int64{1, 2, 3})
fmt.Printf("bogusAppList: %v\n\n", bogusSettings)
if err := cfg.Validate(); err != nil {
time.Sleep(100 * time.Millisecond)
defer log.Fatalf("ERROR - Invalid config file...\n%v", err)
return
}
}
Output
host: localhost
host: default_host_name
port: 5432
bogusPort: 9000
bigNumber: 999999999999999
bogusBigNumber: 9000000000000000000
active: true
bogusFalseActive: false
bogusTrueActive: true
appList: [myapp sharedapp]
bogusAppList: [app1 app2 app3]
numbers: [9 8 7 6]
bogusAppList: [1 2 3]
2014/07/25 19:25:03 ERROR - Invalid config file...
Multiple errors: Missing required config key "bogusAppList" (list of strings), Missing required config key "bogusSettings" (list of ints)
exit status 1
Process finished with exit code 1
Notes
See interface documenation at [package jsoncfgo] (http://godoc.org/github.com/l3x/jsoncfgo)
See companion article at [jsoncfgo - A JSON Config File Reader] (http://l3x.github.io/golang-code-examples/2014/07/25/jsoncfgo-config-file-reader-advanced.html)
For a code example of how to use some of the advanced features of jsoncfgo, see [jsoncfgo - Advanced Usage] (http://l3x.github.io/golang-code-examples/2014/07/25/jsoncfgo-config-file-reader-advanced.html)
Documentation
¶
Overview ¶
Package jsoncfgo defines a helper type for JSON objects to be used for configuration.
Index ¶
- func RegisterFunc(name string, fn func(c *ConfigParser, v []interface{}) (interface{}, error))
- type ConfigParser
- type File
- type Obj
- func (jc Obj) Bool(key string, args ...interface{}) bool
- func (jc Obj) Int(key string, args ...interface{}) int
- func (jc Obj) Int64(key string, args ...interface{}) int64
- func (jc Obj) IntList(key string, args ...interface{}) []int64
- func (jc Obj) List(key string, args ...interface{}) []string
- func (jc Obj) Object(key string) Obj
- func (jc Obj) OptionalBool(key string, def bool) bool
- func (jc Obj) OptionalInt(key string, def int) int
- func (jc Obj) OptionalInt64(key string, def int64) int64
- func (jc Obj) OptionalList(key string) []string
- func (jc Obj) OptionalObject(key string) Obj
- func (jc Obj) OptionalString(key, def string) string
- func (jc Obj) OptionalStringOrObject(key string) interface{}
- func (jc Obj) OptionalUint(key string, def uint) uint
- func (jc Obj) RequiredBool(key string) bool
- func (jc Obj) RequiredInt(key string) int
- func (jc Obj) RequiredInt64(key string) int64
- func (jc Obj) RequiredList(key string) []string
- func (jc Obj) RequiredObject(key string) Obj
- func (jc Obj) RequiredString(key string) string
- func (jc Obj) RequiredStringOrObject(key string) interface{}
- func (jc Obj) RequiredUint(key string) uint
- func (jc Obj) String(key string, args ...interface{}) string
- func (jc Obj) StringOrObject(key string) interface{}
- func (jc Obj) Uint(key string, args ...interface{}) uint
- func (jc Obj) UnknownKeys() []string
- func (jc Obj) Validate() error
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func RegisterFunc ¶
func RegisterFunc(name string, fn func(c *ConfigParser, v []interface{}) (interface{}, error))
RegisterFunc registers a new function that may be called from JSON configs using an array of the form ["_name", arg0, argN...]. The provided name must begin with an underscore.
Types ¶
type ConfigParser ¶
type ConfigParser struct {
// Open optionally specifies an opener function.
Open func(filename string) (File, error)
// IncludeDirs optionally specifies where to find the other config files which are child
// objects of this config, if any. Even if nil, the working directory is always searched
// first.
IncludeDirs []string
// contains filtered or unexported fields
}
ConfigParser specifies the environment for parsing a config file and evaluating expressions.
func (*ConfigParser) CheckTypes ¶
func (c *ConfigParser) CheckTypes(m map[string]interface{}) error
CheckTypes parses m and returns an error if it encounters a type or value that is not supported by this package.
func (*ConfigParser) ConfigFilePath ¶
func (c *ConfigParser) ConfigFilePath(configFile string) (path string, err error)
ConfigFilePath checks if configFile is found and returns a usable path to it. It first checks if configFile is an absolute path, or if it's found in the current working directory. If not, it then checks if configFile is in one of c.IncludeDirs. It returns an error if configFile is absolute and could not be statted, or os.ErrNotExist if configFile was not found.
type File ¶
type File interface {
io.ReadSeeker
io.Closer
Name() string
}
A File is the type returned by ConfigParser.Open.
type Obj ¶
type Obj map[string]interface{}
Obj is a JSON configuration map.
func Load ¶
Load calls ReadFile to read json config data from the file specified by configPath If an error occurs, it will log the error.
func (Obj) OptionalList ¶
func (Obj) OptionalObject ¶
func (Obj) OptionalString ¶
func (Obj) OptionalStringOrObject ¶
func (Obj) RequiredBool ¶
func (Obj) RequiredInt ¶
func (Obj) RequiredInt64 ¶
func (Obj) RequiredList ¶
func (Obj) RequiredObject ¶
func (Obj) RequiredString ¶
func (Obj) RequiredStringOrObject ¶
func (Obj) RequiredUint ¶
func (Obj) StringOrObject ¶
StringOrObject is an OptionalStringOrObject
func (Obj) UnknownKeys ¶
UnknownKeys returns the keys from the config that have not yet been discovered by one of the RequiredT or OptionalT calls.
Source Files