Stats Saver service

README.md

@@ -59,6 +59,16 @@ Each service uses environment variables to e.g. to get the connection data of th
 * `JWT_SECRET` The secret key for JWT.
   * This should be secure and must be identical in all URL-Shorter services.
 
+### Stats Saver
+* `POSTGRES_HOST` The hostname with port for the PostgreSQL database (e.g., `127.0.0.1:5432`)
+* `POSTGRES_USERNAME` The username for the PostgreSQL database authentication
+  * Write access is required!
+* `POSTGRES_PASSWORD` The password for the PostgreSQL database authentication
+* `POSTGRES_DATABASE` The database name where the statistics are stored.
+* `HTTP_PORT` This is the port on which the HTTP server is running.
+  * If this environment variable is not passed, port `3000` is used.
+  * **This service does not have to be publicly accessible, only the Query Services need access!**
+
 ## Kubernetes
 
 If you want to run URL Shorter in a Kubernetes cluster, you can use the provided [manifest files](manifests/).

stats-saver/database/postgres.go

@@ -0,0 +1,27 @@
+package database
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"os"
+)
+
+var db *sql.DB
+
+func ConnectToPostgres() {
+	log.Println("Connecting to PostgreSQL...")
+	connectionString := fmt.Sprintf(
+		"postgresql://%s:%s@%s/%s",
+		os.Getenv("POSTGRES_USERNAME"),
+		os.Getenv("POSTGRES_PASSWORD"),
+		os.Getenv("POSTGRES_HOST"),
+		os.Getenv("POSTGRES_DATABASE"),
+	)
+	var err error
+	db, err = sql.Open("postgres", connectionString)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	log.Println("Connected to PostgreSQL!")
+}

stats-saver/main.go

@@ -1,5 +1,30 @@
 package main
 
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"os"
+	"strconv"
+
+	"github.com/Dominik48N/url-shorter/stats-saver/database"
+	"github.com/julienschmidt/httprouter"
+)
+
+const apiVersion = "v1"
+
 func main() {
+	database.ConnectToPostgres()
+
+	router := httprouter.New()
+
+	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", getHttpPort()), router))
+}
 
+func getHttpPort() int {
+	port, err := strconv.Atoi(os.Getenv("HTTP_PORT"))
+	if err != nil {
+		return 3000
+	}
+	return port
 }

users/database/postgres.go

@@ -27,21 +27,38 @@ func ConnectToPostgres() {
 }
 
 func InsertUser(username string, password string) error {
-	_, err := db.Exec("INSERT INTO users (username, password) VALUES ($1, $2)", username, password)
+	stmt, err := db.Prepare("INSERT INTO users (username, password) VALUES ($1, $2)")
+	if err != nil {
+		return err
+	}
+	defer stmt.Close()
+	_, err = stmt.Exec(username, password)
 	return err
 }
 
 func GetPassword(username string) (string, error) {
+	stmt, err := db.Prepare("SELECT password FROM users WHERE username = $1 LIMIT 1")
+	if err != nil {
+		return "", err
+	}
+	defer stmt.Close()
+
 	var password string
-	err := db.QueryRow("SELECT password FROM users WHERE username = $1 LIMIT 1", username).Scan(&password)
+	err = stmt.QueryRow(username).Scan(&password)
 	if err != nil {
 		return "", err
 	}
 	return password, nil
 }
 
 func IsUserNameExists(username string) (bool, error) {
-	err := db.QueryRow("SELECT username FROM users WHERE username = $1 LIMIT 1", username).Scan()
+	stmt, err := db.Prepare("SELECT username FROM users WHERE username = $1 LIMIT 1")
+	if err != nil {
+		return false, err
+	}
+	defer stmt.Close()
+
+	err = stmt.QueryRow(username).Scan()
 	if err == nil {
 		return true, nil
 	}