“This is the 18th day of my participation in the Gwen Challenge in November. See details: The Last Gwen Challenge in 2021.”

Introduction to the

Continuing with SPF13’s project Viper is a library for reading configuration files

Viper website: github.com/spf13/viper

The website claims to be able to read all types of configuration and format, but also has hot load configuration function, very powerful

The characteristics of

Supported configuration types and formats:

  • Support for reading JSON, TOML, YAML, HCL, envfile and Java properties configuration file
  • Reading environment variables is supported
  • Supports reading configuration of remote components (ETCD or Consul)
  • Support for Go command-line arguments (flags)
  • Supports setting default and fixed values
  • The configuration is case insensitive

Configuration format priority:

  • explicit call to Set
  • flag
  • env
  • config
  • key/value store
  • default

use

This article will not demonstrate all configuration types and all functions, but only the parts that you often use

The installation

Install based on go Model

go get -u github.com/spf13/viper
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Introduced in code

import "github.com/spf13/viper"
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Example 1(simply read configuration and output)

Start by writing a yaml configuration file called dev.yaml

serverPort: 8808
logLevel: "INFO"
mysql:
  host: "127.0.0.1"
  port: 3306
  database: "viper"
  user: "viper"
  password: "viper33"
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Write the demo, read the configuration file, and print it

By default, the path, type, and name of viper are not configured

package main

import (
   "fmt"
   "github.com/spf13/viper"
)

func main(a) {
   // Define the profile name
   viper.SetConfigName("dev")
   // Define the configuration file type
   viper.SetConfigType("yaml")
   // Define the configuration path
   viper.AddConfigPath(".")
   err := viper.ReadInConfig()
   iferr ! =nil {
      panic(fmt.Errorf("Configuration file not found, error log :: %w \n", err))
   }
   
   // Read the value and print it out
   fmt.Printf("serverPort: %v\n",viper.Get("serverPort"))
   fmt.Printf("logLevel: %v\n",viper.Get("logLevel"))
   fmt.Println("mysql info:",viper.Get("mysql.host"),
      viper.Get("mysql.port"),viper.Get("mysql.database"),
      viper.Get("mysql.user"),viper.Get("mysql.password"))}Copy the code

Results the following

Example 2(hot loading and defaults)

Example 1 is used as an example for the configuration file

To set the default value, call SetDefault with k/v, but the default value is the lowest priority. If the configuration file or environment variable has the same key, the default value is invalidated

Note that, after modifying the configuration, must Ctrl+ C save, otherwise the configuration will not change

package main

import (
   "fmt"
   "github.com/spf13/viper"
   "time"
)

func main() {
   // Define the profile name
   viper.SetConfigName("dev")
   // Define the configuration file type
   viper.SetConfigType("yaml")
   // Define the configuration path
   viper.AddConfigPath(".")
   // Define default values
   viper.SetDefault("env"."production")
   err := viper.ReadInConfig()
   iferr ! = nil { panic(fmt.Errorf("Configuration file not found, error log :: %w \n", err))
   }

   // Monitor configuration file changes, automatic hot loading
   viper.WatchConfig()
   // Read the default values taken from the definition
   fmt.Printf("env: %v\n",viper.Get("env"))
   // Test configuration changes
   fmt.Printf("logLevel: %v\n",viper.Get("logLevel"))
   time.Sleep(8 * time.Second)
   fmt.Printf("logLevel: %v\n",viper.Get("logLevel"))}Copy the code

Run as follows

Remote configuration

Panic: Remote Configurations Error: No Files Found!

But there is a little elder brother blog got another set of solutions, portal: blog.huoding.com/2020/08/10/…

Nacos support

There is also a library about viper’s support for nacOS configuration, which is very good github.com/yoyofxteam/…

reference

github.com/spf13/viper