mirror of
https://github.com/MichaelCade/90DaysOfDevOps.git
synced 2025-01-13 08:14:43 +07:00
109 lines
2.3 KiB
Go
109 lines
2.3 KiB
Go
package main
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import (
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"database/sql"
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"errors"
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"fmt"
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_ "github.com/go-sql-driver/mysql"
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nats "github.com/nats-io/nats.go"
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"time"
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)
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func storeString(input string) error {
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// Connect to the database
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db, err := sql.Open("mysql", "root:password@tcp(mysql:3306)/mysql")
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defer db.Close()
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// Insert the random number into the database
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_, err = db.Exec("INSERT INTO requestor_async(random_string) VALUES(?)", input)
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if err != nil {
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return err
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}
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fmt.Printf("Random string %s has been inserted into the database\n", input)
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return nil
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}
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func getStringFromDB(input string) error {
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// see if the string exists in the db, if so return nil
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// if not, return an error
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db, err := sql.Open("mysql", "root:password@tcp(mysql:3306)/mysql")
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defer db.Close()
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result, err := db.Query("SELECT * FROM requestor_async WHERE random_string = ?", input)
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if err != nil {
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return err
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}
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for result.Next() {
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var randomString string
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err = result.Scan(&randomString)
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if err != nil {
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return err
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}
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if randomString == input {
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return nil
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}
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}
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return errors.New("string not found")
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}
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func main() {
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err := createRequestordb()
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if err != nil {
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panic(err.Error())
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}
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// setup a goroutine loop calling the generator every minute, saving the result in the DB
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nc, _ := nats.Connect("nats://my-nats:4222")
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defer nc.Close()
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ticker := time.NewTicker(60 * time.Second)
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quit := make(chan struct{})
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go func() {
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for {
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select {
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case <-ticker.C:
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nc.Publish("generator", []byte(""))
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case <-quit:
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ticker.Stop()
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return
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}
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}
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}()
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nc.Subscribe("generator_reply", func(msg *nats.Msg) {
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err := storeString(string(msg.Data))
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if err != nil {
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print(err)
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}
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})
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nc.Subscribe("confirmation", func(msg *nats.Msg) {
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err := getStringFromDB(string(msg.Data))
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if err != nil {
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print(err)
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}
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nc.Publish("confirmation_reply", []byte(string(msg.Data)))
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})
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// create a goroutine here to listen for messages on the queue to check, see if we have them
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for {
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time.Sleep(10 * time.Second)
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}
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}
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func createRequestordb() error {
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db, err := sql.Open("mysql", "root:password@tcp(mysql:3306)/mysql")
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if err != nil {
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return err
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}
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defer db.Close()
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// try to create a table for us
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_, err = db.Exec("CREATE TABLE IF NOT EXISTS requestor_async(random_string VARCHAR(100))")
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return err
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}
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