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https://github.com/nuriofernandez/simple-golang-mysql-experiment
https://github.com/nuriofernandez/simple-golang-mysql-experiment
configuration example-project experimental golang mysql service sql
Last synced: 2 days ago
JSON representation
- Host: GitHub
- URL: https://github.com/nuriofernandez/simple-golang-mysql-experiment
- Owner: nuriofernandez
- Created: 2021-06-16T17:08:07.000Z (over 3 years ago)
- Default Branch: master
- Last Pushed: 2021-06-24T00:06:04.000Z (over 3 years ago)
- Last Synced: 2024-01-03T14:36:02.172Z (10 months ago)
- Topics: configuration, example-project, experimental, golang, mysql, service, sql
- Language: Go
- Homepage:
- Size: 33.2 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# GoLang experimental project to test '[spf13/viper](https://github.com/spf13/viper)' and '[go-sql-driver/mysql](https://github.com/go-sql-driver/mysql)' libraries
I used this project to test the '[spf13/viper](https://github.com/spf13/viper)' and '[go-sql-driver/mysql](https://github.com/go-sql-driver/mysql)' libraries.
# Database connection
#### MySQL Connection handler: [Click here to see the source code](https://github.com/xXNurioXx/simple-golang-mysql-experiment/blob/master/src/database/connection/MySQL.go)
```go
var connection *sql.DB
func createSQLConnection() *sql.DB {
// Open up a database connection using the settings.yml credentials.
settings := config.ReadConfig()
sourceName := fmt.Sprintf("%s:%s@tcp(%s:%d)/%s", settings.Username, settings.Password, settings.Hostname, settings.Port, settings.Database)
connection, err := sql.Open("mysql", sourceName)
// if there is an error opening the connection, handle it
if err != nil {
panic(err.Error())
}
return connection
}
func GetConnection() *sql.DB {
if connection == nil {
// Database connection is undefined
connection = createSQLConnection()
}
if err := connection.Ping(); err != nil {
// Database connection is defined but closed
connection = createSQLConnection()
}
// Return database connection
return connection
}
```
#### Database settings struct definition: [Click here to see the source code](https://github.com/xXNurioXx/simple-golang-mysql-experiment/blob/master/src/config/Settings.go)
```go
type Settings struct {
Database string `yaml:"database"`
Username string `yaml:"username"`
Password string `yaml:"password"`
Hostname string `yaml:"hostname"`
Port int `yaml:"port"`
}
```
#### Database settings management: [Click here to see the source code](https://github.com/xXNurioXx/simple-golang-mysql-experiment/blob/master/src/config/ViperConfigLoader.go)
```go
func ReadConfig() *Settings {
// Create a new Viper configuration parser instance
config := viper.New()
// Set the file name of the configurations file
config.SetConfigName("database-settings")
config.SetConfigType("yml")
// Set the path to look for the configurations file
config.AddConfigPath(".")
if err := config.ReadInConfig(); err != nil {
fmt.Printf("Error reading config file, %s", err)
}
settings := &Settings{}
unmarshalErr := config.Unmarshal(settings)
if unmarshalErr != nil {
fmt.Printf("unable to decode into config struct, %v", unmarshalErr)
}
return settings
}
```
# Obtaining data from the database
#### Minecraft server struct definition: [Click here to see the source code](https://github.com/xXNurioXx/simple-golang-mysql-experiment/blob/master/src/structs/MinecraftServer.go)
```go
type MinecraftServer struct {
Id string `json:"id"`
Domain string `json:"domain"`
Score int `json:"score"`
Image int `json:"image"`
OnlinePlayers int `json:"onlinePlayers"`
MaxPlayers int `json:"maxPlayers"`
}
```
#### Minecraft server sql fetcher: [Click here to see the source code](https://github.com/xXNurioXx/simple-golang-mysql-experiment/blob/master/src/database/fetchers/ServerFetcher.go)
```go
const query = "SELECT `server_id`, `server_domain`, `players`, `max_players`, `server_score`, `server_icon_id` FROM `server_list` ORDER BY `last_ping` ASC LIMIT 10"
func queryForResults() *sql.Rows {
// Obtain the MySQL connection
connection := mysql.GetConnection()
// Execute the query and return the result rows
results, err := connection.Query(query)
if err != nil {
panic(err.Error()) // proper error handling instead of panic in your app
}
return results
}
func parse(results *sql.Rows) MinecraftServer {
var server MinecraftServer
// Scan the result into the MinecraftServer composite struct
err := results.Scan(&server.Id, &server.Domain, &server.OnlinePlayers, &server.MaxPlayers, &server.Score, &server.Image)
if err != nil {
panic(err.Error()) // proper error handling instead of panic
}
return server
}
func GetServers() []MinecraftServer {
// Obtain row results from sql database
results := queryForResults()
// Collect all minecraft servers structs and return them all
var servers []MinecraftServer
for results.Next() {
servers = append(servers, parse(results))
}
return servers
}
```
# Final usage of this implementation
```go
func main() {
servers := fetchers.GetServers()
for _, server := range servers {
fmt.Printf("Server '%s' has %d online players\n", server.Domain, server.OnlinePlayers)
}
}
```