For a hobby project (books.cihanbatasul.com) I have a golang application that runs on my backend as a docker container. The application has a database container and the API container.

The error happens on my frontend when I try to interact with the backend (register, searching for a book. It says:

index-149c02ff.js:166 
        
        
       POST https://cihanbatasul.com:8081/register net::ERR_CONNECTION_REFUSED
st @ index-149c02ff.js:166
(anonymous) @ index-149c02ff.js:166
await in (anonymous) (async)
Nb @ index-149c02ff.js:37
Tb @ index-149c02ff.js:37
Ub @ index-149c02ff.js:37
nf @ index-149c02ff.js:37
se$2 @ index-149c02ff.js:37
(anonymous) @ index-149c02ff.js:37
Rk @ index-149c02ff.js:40
Jb @ index-149c02ff.js:37
hd @ index-149c02ff.js:37
fd @ index-149c02ff.js:37
ed @ index-149c02ff.js:37
index-149c02ff.js:166 TypeError: Failed to fetch
    at st (index-149c02ff.js:166:107788)
    at index-149c02ff.js:166:98541

My main.go file accepts three origins:

package main

import (
    "crypto/rand"
    "crypto/tls"
    "database/sql"
    "encoding/base64"
    "flag"
    "fmt"
    "log"
    "net/http"
    "os"

    "github.com/cihanbatasul/bookapi/internal/models"
    "github.com/joho/godotenv"
    _ "github.com/lib/pq"
    "github.com/rs/cors"
)

type application struct {
    error_log    *log.Logger
    info_log     *log.Logger
    books        *models.BookServiceImplementation
    users        *models.UserServiceImplementation
    user_helpers *models.UserHelperServiceImplementation
    ai           *models.AiServiceImplementation
}

func openDB(dsn string) (*sql.DB, error) {
    db, err := sql.Open("postgres", dsn)
    if err != nil {
        return nil, err
    }

    if err = db.Ping(); err != nil {
        return nil, err
    }

    return db, nil
}

func generateRandomSecret(length int) (string, error) {
    secretBytes := make([]byte, length)
    _, err := rand.Read(secretBytes)
    if err != nil {
        return "", err
    }
    return base64.StdEncoding.EncodeToString(secretBytes), nil
}

func main() {

    if err := godotenv.Load(".env"); err != nil {
        log.Fatalf("Fehler beim Laden der .env-Datei %v", err)
    }

    cors := cors.New(cors.Options{
        AllowedOrigins:   []string{"https://cihanbatasul.com", "http://localhost", "https://books.cihanbatasul.com"},
        AllowedMethods:   []string{"GET", "POST", "OPTIONS"},
        AllowedHeaders:   []string{"Content-Type"},
        AllowCredentials: true,
    })

    addr := flag.String("addr", ":8081", "HTTPS network address")
    flag.Parse()

    dsn := fmt.Sprintf("host=%s port=%s user=%s password=%s dbname=%s sslmode=disable", os.Getenv("HOST"), os.Getenv("DB_PORT"), os.Getenv("USER_NAME"), os.Getenv("PASSWORD"), os.Getenv("DB_NAME"))

    info_log := log.New(os.Stdout, "INFOt", log.Ldate|log.Ltime)
    error_log := log.New(os.Stderr, "ERRORt", log.Ldate|log.Ltime|log.Lshortfile)

    db, err := openDB(dsn)
    if err != nil {
        fmt.Printf("%s", dsn)
        error_log.Fatal(err)
    }

    defer db.Close()

    app := &application{
        error_log:    error_log,
        info_log:     info_log,
        books:        &models.BookServiceImplementation{},
        users:        &models.UserServiceImplementation{DB: db},
        user_helpers: &models.UserHelperServiceImplementation{},
        ai:           &models.AiServiceImplementation{},
    }

    handler := cors.Handler(app.Routes())

    certPath := "certs/cert.pem"
    keyPath := "certs/privkey.pem"
    // Load TLS certificate and key
    cert, err := tls.LoadX509KeyPair(certPath, keyPath)
    if err != nil {
        log.Fatal("Error loading certificate and key:", err)
    }

    // Create TLS config
    tlsConfig := &tls.Config{
        Certificates: []tls.Certificate{cert},
    }

    // Create HTTPS server
    srv := &http.Server{
        Addr:      *addr,
        ErrorLog:  app.error_log,
        Handler:   handler,
        TLSConfig: tlsConfig,
    }

    info_log.Println("Starting server on port ", *addr)

    // Start HTTPS server
    err = srv.ListenAndServeTLS("", "")
    if err != nil {
        app.error_log.Fatal(err)
    }
}

When the error happens the API container exits:

CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
ca807a67f67a booksbackend “./main” 14 minutes ago Exited (1) 4 minutes ago booksbackend_container
3516610db914 booksbackend_db “docker-entrypoint.s…” 14 minutes ago Up 14 minutes 0.0.0.0:5432->5432/tcp, :::5432->5432/tcp booksbackend_db_container
6a2f27202298 portfolio2023:latest “portfolio2023 -p 80…” 2 days ago Up 2 days 0.0.0.0:8080->8080/tcp, :::8080->8080/tcp portfolio_backend

with the docker logs saying this:

intero@231:~$ sudo docker logs booksbackend_container
ERROR 2024/06/12 18:13:55 main.go:75: dial tcp 92.205.28.231:5432: connect: connection timed out

I don’t know what the issue could be. I hope someone can help me solve this problem. Sadly I don’t have a lot of experience which is why I don’t know which kind of information would be valuable in solving this issue. If you need further information, please let me know.