I have standart formlogin and it works, my app saves user data into db in register page and checks data and authenticate user in login page. But when I use docker I get “Bad credentials” error in login page even if I wrote proper login and password. Here’s my code:

application.properties:

spring.jpa.hibernate.ddl-auto=create

spring.datasource.url=jdbc:postgresql://localhost:5432/postgres
spring.datasource.username=postgres
spring.datasource.password=41Zuteho!

spring.datasource.driver-class-name=org.postgresql.Driver
spring.jpa.database=postgresql
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQL10Dialect

spring.main.allow-circular-references=true

management.endpoints.web.exposure.include=*
management.trace.http.include=RESPONSE_HEADERS, PRINCIPAL

docker-compose:

version: '3.4'

services:
  app:
    image: app
    build:
      context: .
      dockerfile: ./Dockerfile
    ports:
      - 8080:8080
    container_name: app
    depends_on:
      - db
    environment:
      - SPRING_DATASOURCE_URL=jdbc:postgresql://db:5432/postgres
      - SPRING_DATASOURCE_USERNAME=postgres
      - SPRING_DATASOURCE_PASSWORD=41Zuteho!
      - SPRING_JPA_HIBERNATE_DDL_AUTO=create
      - spring.datasource.driver-class-name=org.postgresql.Driver
      - spring.jpa.database=postgresql
      - spring.jpa.database-platform=org.hibernate.dialect.PostgreSQL10Dialect

  db:
    image: 'postgres:13.1-alpine'
    container_name: db
    volumes:
            - sample_db:/var/lib/postgresql/data
    environment:
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=41Zuteho!
      - POSTGRES_DB=postgres
      - PGDATA=/var/lib/postgresql/data/pgdata
    ports:
      - 5432:5432
volumes:
  sample_db: {}
    

controller:

  @GetMapping("/register")
public String showRegistrationForm(Model model) {
    model.addAttribute("user", new User());
    return "signup";
}

@PostMapping("/process_register")
public String processRegister(User user) {
    BCryptPasswordEncoder passwordEncoder = new BCryptPasswordEncoder();
    String encodedPassword = passwordEncoder.encode(user.getPassword());
    user.setPassword(encodedPassword);
    userRepository.save(user);
    return "register_success";
}

template:

<form th:action="@{/process_register}" th:object="${user}"
            method="post" style="max-width: 600px; margin: 0 auto;">
        <div class="m-3">
            <div class="form-group row">
                <label class="col-4 col-form-label">E-mail: </label>
                <div class="col-8">
                    <input type="email" th:field="*{email}" class="form-control" required />
                </div>
            </div>
             
            <div class="form-group row">
                <label class="col-4 col-form-label">Password: </label>
                <div class="col-8">
                    <input type="password" th:field="*{password}" class="form-control"
                            required minlength="6" maxlength="10"/>
                </div>
            </div>
             
            <div>
                <button type="submit" class="btn btn-primary">Sign Up</button>
            </div>
        </div>
        </form>

User:

@Entity
@Table(name = "users")
public class User {
     
    @Id
    @GeneratedValue(strategy = GenerationType.SEQUENCE)
    private Long id;
     
    @Column(nullable = false, unique = true, length = 45)
    private String email;
     
    @Column(nullable = false, length = 64)
    private String password;

    User() {}

    public User(Long id, String email, String password) {
        this.id = id;
        this.email = email;
        this.password = password;
    }