conf

Documentation

Overview

Util help loading config from yaml, environment variables and flags by convention.

example.go:

package main

import (
  "fmt"
  "github.com/chanjarster/gears/conf"
)

type MyConf struct {
  Mysql *MysqlConf
  Redis *RedisConf
}

type MysqlConf struct {
  Host string
  Port int
  Database string
}

type RedisConf struct {
  Host string
  Port int
  Password string
}

func main() {
  myConf := &MyConf{}
  conf.Load(myConf, "c")
  fmt.Println(myConf)
}

conf.yaml:

mysql:
  host: localhost
  port: 3306
  database: test
redis:
  host: localhost
  port: 6379
  password: test

Load from nothing:

./example

Load from yaml:

./example

Load from environment:

./example -c conf.yaml

Load from flag:

./example -redis-host=localhost

Load from env:

MYSQL_HOST=localhost ./example

Mix them together (flag takes the highest precedence, then environment, then yaml file):

MYSQL_PORT=3306 ./example -c conf.yaml -redis-host=localhost

Supported Field Types

Only the exported fields will be loaded. Support field types are:

string
bool
int
int64
uint
uint64
float64
string
time.Duration, any string legal to time.ParseDuration(string)
struct
pointer to above types

Name Convention

This util load fields by convention. For example, field BazBoom path is Foo.Bar.BazBoom:

type bar struct {
  BazBoom string
}
type foo struct {
  Bar *bar
}
type Conf struct {
  Foo *foo
}

So the corresponding:

flag name is `-foo-bar-baz-boom`
env name is `FOO_BAR_BAZ_BOOM`

Since this util use gopkg.in/yaml.v3 to parse yaml, so the field name appear in yaml file should be lowercase, unless you customized it the "yaml" name in the field tag:

foo:
  bar:
    bazroom: ...

Source code and other details for the project are available at GitHub:

https://github.com/chanjarster/gears

Index

• func Load(p interface{}, yamlFlagName string)

Examples

• Load

Functions

func Load

func Load(p interface{}, yamlFlagName string)

Example

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package main

import (
	"fmt"
	"os"
)

type MyConf struct {
	Mysql *MysqlConf
	Redis *RedisConf
}

func (c *MyConf) String() string {
	return fmt.Sprint("{mysql: ", c.Mysql, ", redis: ", c.Redis, "}")
}

type MysqlConf struct {
	Host     string
	Port     int
	Database string
}

func (c *MysqlConf) String() string {
	return fmt.Sprint("{host: ", c.Host, ", port: ", c.Port, ", database: ", c.Database, "}")
}

type RedisConf struct {
	Host     string
	Port     int
	Password string
}

func (c *RedisConf) String() string {
	return fmt.Sprint("{host: ", c.Host, ", port: ", c.Port, ", password: ", c.Password, "}")
}

func main() {
	os.Setenv("MYSQL_HOST", "localhost")
	os.Setenv("MYSQL_PORT", "3360")
	os.Setenv("MYSQL_DATABASE", "test")
	os.Setenv("REDIS_HOST", "localhost")
	os.Setenv("REDIS_PORT", "6379")
	os.Setenv("REDIS_PASSWORD", "foobar")
	myConf := &MyConf{}
	Load(myConf, "conf")
	fmt.Println(myConf)
}

Output:

{mysql: {host: localhost, port: 3360, database: test}, redis: {host: localhost, port: 6379, password: foobar}}