Selfhosted Codestral as coding assistant

Objective: run Codestral 22b LLM locally using llama-server (llama.cpp) and expose it publicly through a reverse SSH tunnel on your VPS.

Installation

Prerequisite: NVIDIA consumer/workstation GPU with min. 16 GB VRAM, it will allow running 4.5 till 5.5 bpw quantized at 10~15 tokens/sec. This procedure assumes a Windows OS.

1. Start llama-server.exe locally (will run on port 8080) and keep it running. I ran this: llama-server.exe -m .\Codestral-22B-v0.1-Q5_K_S.gguf --api-key secret --flash-attn -ngl 100

2. Install Visual C++ Redistributable for Visual Studio 2015-2022 x64

3. Install Apache server as a service (httpd -k install), be prepared for an hour of cursing if you never touched Apache before, make Apache listen on localhost port 8888 (httpd.conf), enable Virtual Hosts (httpd.conf) and enable module mod_proxy and mod_proxy_http (httpd.conf). Then configure proxying to localhost 8080 (vhosts file):

<VirtualHost *:8888>
    ProxyPass / http://localhost:8080/
    ProxyPassReverse / http://localhost:8080/
</VirtualHost>

4. Launch another command prompt and open a reverse SSH tunnel with your VPS. I used this command: ssh -R 8888:localhost:8888 debian@yourvps (keep it running and don't forget to open port 8888 on your VPS).

5. Launch your public UI on http://yourvps:8888 and input the API key (step 1) in the UI in the section 'More options'

6. (Optional) run a more user-friendly UI instead of the standard llama-server UI, named 'Open WebUI'. It allows to store your chat history and accepts voice recordings. The easiest way to run Open WebUI is with Docker desktop. I ran this: docker run -d -p 3000:8080 -v open-webui:/app/backend/data --name open-webui --restart always ghcr.io/open-webui/open-webui:main. Launch localhost:3000, create the admin account and open Settings to specify your llama-server as an OpenAI API endpoint e.g. http://yourvps:8888/v1 and input your API key.

My first 10K+ token conversation with Codestral 22b about developing a web application

User: Write me a REST webservice with CRUD-functionality for an entity Note using Java and Spring Boot 2.7.x. I prefer in-memory HashMap.

Codestral: Sure, I can help you outline a basic structure for your application. Here's a simple example of how you might set up a Spring Boot REST service to handle CRUD operations on a Note object using in-memory HashMap storage.

java import java.util.HashMap; import java.util.Map; import org.springframework.web.bind.annotation.*;

@RestController public class NoteController {

private final Map notes = new HashMap<>();

@GetMapping("/notes/{id}")
public Note getNoteById(@PathVariable Long id) {
    return notes.get(id);
}

@PostMapping("/notes")
public void addNote(@RequestBody Note note) {
    notes.put(note.getId(), note);
}

@PutMapping("/notes/{id}")
public void updateNote(@PathVariable Long id, @RequestBody Note updatedNote) {
    if (notes.containsKey(id)) {
        notes.replace(id, updatedNote);
    }
}

@DeleteMapping("/notes/{id}")
public void deleteNoteById(@PathVariable Long id) {
    notes.remove(id);
}

}

In this code:

• @RestController annotation tells Spring that this class is a controller where each method returns the body of the HTTP response directly, and not a view to be resolved using a template engine.

• The methods are mapped to specific HTTP requests based on their annotations (e.g., @GetMapping for GET request, etc.).

• @PathVariable is used to bind URI templates variables to method parameters in your controllers.

• @RequestBody is used to map the JSON sent by a client into a Java object.

Please note that this is a very basic example and might not be suitable for production use due to lack of error handling, validation or persistence beyond the lifecycle of the application.

User: Can you provide me the entity class Notes?

Codestral: Of course! Here's a simple Note entity class:

java public class Note {

private Long id;

private String title;

private String content;

// Constructors

public Note() {}

public Note(Long id, String title, String content) {
    this.id = id;
    this.title = title;
    this.content = content;
}

// Getters and Setters

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getTitle() {
    return title;
}

public void setTitle(String title) {
    this.title = title;
}

public String getContent() {
    return content;
}

public void setContent(String content) {
    this.content = content;
}

}

This is a simple JavaBean with private fields and their corresponding getters/setters, along with an empty constructor required by Jackson for JSON serialization/deserialization.

User: Can you write me in one file: the main method, entity, service, controller and all what I missed to have a fully functioning REST API?

Codestral: Sure! Here's the complete example:

java import java.util.*;

import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.web.bind.annotation.*;

@RestController public class NoteController {

private final Map notes = new HashMap<>();

@GetMapping("/notes/{id}")
public Note getNoteById(@PathVariable Long id) {
    return notes.get(id);
}

@PostMapping("/notes")
public void addNote(@RequestBody Note note) {
    notes.put(note.getId(), note);
}

@PutMapping("/notes/{id}")
public void updateNote(@PathVariable Long id, @RequestBody Note updatedNote) {
    if (notes.containsKey(id)) {
        notes.replace(id, updatedNote);
    }
}

@DeleteMapping("/notes/{id}")
public void deleteNoteById(@PathVariable Long id) {
    notes.remove(id);
}

}

class Note {

private Long id;

private String title;

private String content;

// Constructors

public Note() {}

public Note(Long id, String title, String content) {
    this.id = id;
    this.title = title;
    this.content = content;
}

// Getters and Setters

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getTitle() {
    return title;
}

public void setTitle(String title) {
    this.title = title;
}

public String getContent() {
    return content;
}

public void setContent(String content) {
    this.content = content;
}

}

@SpringBootApplication public class Application {

public static void main(String[] args) {
    SpringApplication.run(Application.class, args);
}

}

This file contains all the code you need to have a fully functioning REST API for managing Note entities with in-memory HashMap storage using Java and Spring Boot 2.7.x.

Just create a new project on your IDE of choice, paste this content into your main application class (usually named Application), and run it. The service will start running at http://localhost:8080 by default.

You can test the API using tools like Postman or curl to send HTTP requests to create, read, update, and delete Note entities as needed.

User: Can you add the methods equals, hashCode and toString to the entity class?

Codestral: Sure! Here's how you could add equals(), hashCode() and toString() methods to your entity class:

java class Note {

private Long id;

private String title;

private String content;

// Constructors

public Note() {}

public Note(Long id, String title, String content) {
    this.id = id;
    this.title = title;
    this.content = content;
}

// Getters and Setters

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getTitle() {
    return title;
}

public void setTitle(String title) {
    this.title = title;
}

public String getContent() {
    return content;
}

public void setContent(String content) {
    this.content = content;
}

// equals, hashCode and toString methods

@Override
public boolean equals(Object o) {

  if (this == o)
      return true;

  if (!(o instanceof Note))
      return false;

  Note note = (Note) o;

  // Compare the data members and return accordingly

  return Objects.equals(id, note.getId()) &&
         title.equals(note.getTitle()) &&
         content.equals(note.getContent());
}

@Override
public int hashCode() {
    // Generate a unique hash code using the data members of your object

    return Objects.hash(id, title, content);
}

@Override
public String toString() {

   return "Note [ id = "+ this.getId() +
               ", title = "+this.getTitle()+
               ", content ="+this.getContent()+" ]";

}

}

These methods are overridden from the Object class in Java and can be very useful for debugging, logging or comparing objects based on their state rather than just reference equality (which is what == does).

• The equals(Object o) method checks if two Note instances have identical id, title and content.

• The hashCode() method returns a unique integer value that can be used to identify the object during its lifetime in an application.

• The toString() method provides a string representation of your Object which is useful for logging or debugging purposes.

You may use these methods as per your requirements and modify them according to how you want instances of Note class to behave when compared, hashed or converted into Strings.

User: Can you add error handling using Zalando's "problem-spring-web" library?

Codestral: Sure! To add error handling using Zalando's "problem-spring-web" library:

1. Firstly, you need to include the dependency in your build file (Maven/Gradle). If you are using Maven, include this line in pom.xml inside the dependencies tag:

xml

org.zalando
problem-spring-web
0.27.1

If you are using Gradle, include this line in your build.gradle inside the dependencies block:

implementation 'org.zalando:problem-spring-web:0.27.1'

2. Then, create a custom exception class that extends from RuntimeException (or any other Exception type as per your needs). This will be thrown whenever an error occurs in the service layer and caught by the @ControllerAdvice annotated class to provide appropriate HTTP response:

java @ResponseStatus(HttpStatus.NOT_FOUND) public class NoteNotFoundException extends RuntimeException { public NoteNotFoundException(Long id) { super("Could not find note with ID " + id); } }

3. Update your service methods to throw the custom exception when a requested resource is not found:

java public void updateNote(@PathVariable Long id, @RequestBody Note updatedNote) { if (!notes.containsKey(id)) { throw new NoteNotFoundException(id); }

notes.replace(id, updatedNote);

}

public void deleteNoteById(@PathVariable Long id) { if (!notes.containsKey(id)) { throw new NoteNotFoundException(id); }

notes.remove(id);

}

4. Lastly, create a custom @ControllerAdvice class that catches the custom exception and returns an appropriate Problem response:

java @ControllerAdvice public class CustomErrorHandler extends AbstractThrowableProblemHandler {

public CustomErrorHandler() {
    super(NoteNotFoundException.class);
}

@Override
protected ResponseEntity createResponseEntity(Problem problem, HttpStatus status) {
    return new ResponseEntity<>(problem, status);
}

}

In this setup:

• The custom exception NoteNotFoundException is thrown when a note with the requested ID doesn't exist.

• The @ControllerAdvice annotated class CustomErrorHandler, which extends from Zalando's AbstractThrowableProblemHandler, catches these exceptions and returns appropriate Problem responses to client applications.

This approach provides standardized error formats across your REST API while also allowing for specific exception handling as needed.

User: I want to implement DTO's, can you provide the entity class and rewrite the REST controller?

Codestral: Sure! Let me show you how you could implement Data Transfer Object (DTO) patterns in your application:

1. Firstly, create DTO classes which are used only for data transfer between the client and server. These might contain a subset of fields from your entity class or custom transformations of that data.

java public class NoteDto {

private Long id;

private String title;

// Constructors

public NoteDto() {}

public NoteDto(Long id, String title) {
    this.id = id;
    this.title = title;
}

// Getters and Setters

public Long getId() {
  return id;
}

public void setId(Long id) {
   this.id = id;
}

public String getTitle() {
    return title;
}

public void setTitle(String title) {
     this.title = title;
 }

}

2. Update your controller methods to use the DTO objects instead of the entity class:

java @RestController public class NoteController {

private final Map notes = new HashMap<>();

@GetMapping("/notes/{id}") public ResponseEntity getNoteById(@PathVariable Long id) { if (!notes.containsKey(id)) { throw new NoteNotFoundException(id); }

  // Convert entity to DTO before returning

   return ResponseEntity.ok(convertToDto(notes.get(id)));

}

@PostMapping("/notes")
public void addNote(@RequestBody Note note) {
    notes.put(note.getId(), note);
}

// Other methods...

}

3. Add a conversion method to convert the entity object into DTO:

java private NoteDto convertToDto(Note note) { return new NoteDto(note.getId(), note.getTitle()); }

This way, you are separating your data model (entity class) from how that information is transferred between the client and server (DTO). This can make it easier to evolve these components independently of each other as needed in future updates or refactors.

The convertToDto() method used above does a simple direct conversion, but you could also use tools like MapStruct for more complex conversions if necessary.

User: How would the Location header of the response be set to the url of the newly created entity?

Codestral: To add the Location header with URL of the newly created entity to your POST response:

1. Update your controller's createNote method as follows:

java @PostMapping("/notes") public ResponseEntity addNote(@RequestBody Note note, UriComponentsBuilder builder) { notes.put(note.getId(), note);

// Construct URI of the new resource

HttpHeaders headers = new HttpHeaders();

headers.setLocation(
  builder
    .path("/notes/{id}")
    .buildAndExpand(note.getId())
    .toUri());

// Return response with Location header and 201 Created status code

return new ResponseEntity<>(headers, HttpStatus.CREATED); }

In this updated method:

• The UriComponentsBuilder is a utility class to easily construct URLs based on various parameters like scheme, host, path etc.

• We're building the URI for the newly created note using the builder and then setting it as value of Location header in HttpHeaders object.

• Finally we are returning ResponseEntity with headers containing location information and HTTP status code 201 Created which indicates that request has succeeded and a new resource was created as result.

This approach follows best practices for designing REST APIs by providing clear URLs to access the newly created resources in Location header of response, thus enabling clients to easily discover those resources without needing additional information beyond what's already provided in their requests.

User: On creation of a note, can you assure the id of the new note gets included in the response as a X-headers? I also want a X-header with value 'created'.

Codestral: Sure! To include both id and status ('created') values as custom X-headers:

1. Update your controller's createNote method like this:

java @PostMapping("/notes") public ResponseEntity addNote(@RequestBody Note note, UriComponentsBuilder builder) { notes.put(note.getId(), note);

// Construct URI of the new resource

HttpHeaders headers = new HttpHeaders();

headers.setLocation(
  builder
    .path("/notes/{id}")
    .buildAndExpand(note.getId())
    .toUri());

// Add custom X-headers

headers.add("X-Note-Id", note.getId().toString());

headers.add("X-Status", "created");

// Return response with Location, X-Note-Id and X-Status headers

return new ResponseEntity<>(headers, HttpStatus.CREATED); }

In this updated method:

• We're adding two custom headers 'X-Note-Id' & 'X-Status' to the HTTP response using add() function of HttpHeaders object which accepts header name and its corresponding value as parameters.

This approach can be useful for providing additional metadata about a resource or operation in an API, allowing clients to use that information without needing to parse other parts of the HTTP message like body payload.

The X-Note-Id & X-Status headers included here contain id of newly created note and status ('created') respectively which could be used by client applications for their own purposes as per requirements.

User: Can you add some debugging to the REST controller, so that each action gets logged to the console?

Codestral: Sure! To add basic logging:

1. Firstly, you need to configure a logger in your application (Spring Boot will automatically configure Logback or Log4j2 if they are present on the classpath).

2. Then use the LoggerFactory getLogger() method to obtain an instance of Logger for your controller class and call its appropriate log methods at various points during execution.

java import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

@RestController public class NoteController {

private static final Logger logger = LoggerFactory.getLogger(NoteController.class);

// Other code...

@PostMapping("/notes")
public ResponseEntity addNote(@RequestBody Note note, UriComponentsBuilder builder) {
    notes.put(note.getId(), note);

   // Log information

     logger.info("Created new note with ID: {}", note.getId());

    HttpHeaders headers = new HttpHeaders();

  // Rest of the method...
}

@GetMapping("/notes/{id}") public ResponseEntity getNoteById(@PathVariable Long id) { if (!notes.containsKey(id)) { throw new NoteNotFoundException(id); }

  // Log information

     logger.info("Fetched note with ID: {}", id);

 // Rest of the method...

}

@PutMapping("/notes/{id}")
public void updateNote(@PathVariable Long id, @RequestBody Note updatedNote) {
   if (!notes.containsKey(id)) {
        throw new NoteNotFoundException(id);
    }

  // Log information

     logger.info("Updated note with ID: {}", id);

// Rest of the method...

}

 @DeleteMapping("/notes/{id}")
public void deleteNoteById(@PathVariable Long id) {
   if (!notes.containsKey(id)) {
        throw new NoteNotFoundException(id);
    }

  // Log information

     logger.info("Deleted note with ID: {}", id);

 notes.remove(id);

}

}

In this updated controller class, an instance of Logger is created for the current class and then used to log messages at various points during execution using appropriate methods like info(), debug() etc.

This approach can be useful for understanding how your application's components are behaving under different conditions or diagnosing issues in production environments when more detailed information about what happened may not be available otherwise (like stack traces).

The logger will log messages with severity level INFO which is a standard logging level that indicates informational messages, and by default these logs will include timestamp, thread name etc.

You can change the severity level or add additional details to your log statements as needed based on your specific requirements for monitoring and debugging purposes.

User: I would want to add auditing to my application, I prefer in-memory H2-database.

Codestral: Sure! To add auditing using Spring Data JPA with H2 database:

1. Add required dependencies in build file (Maven/Gradle):

For Maven, include these lines inside the pom.xml's dependencies tag:

xml

org.springframework.boot
spring-boot-starter-data-jpa



com.h2database
h2
runtime

For Gradle, include these lines inside the build.gradle's dependencies block:

implementation 'org.springframework.boot:spring-boot-starter-data-jpa'

runtimeOnly 'com.h2database:h2'

2. Create an AuditEntity class that will be extended by all entities needing audit information, and add appropriate fields like createdAt, updatedAt etc.:

java import java.util.*;

import javax.persistence.*;

@MappedSuperclass public abstract class AbstractAuditingEntity {

@Column(name = "created_at", nullable = false)
private Date createdAt;

@Column(name = "updated_at")
private Date updatedAt;

// Getters and Setters

}

3. Update your Note entity class to extend the AuditEntity:

java import javax.persistence.*;

@Entity public class Note extends AbstractAuditingEntity {

@Id

private Long id;

// Other fields...

}

4. Create a JPA repository interface for your entity:

java import org.springframework.data.jpa.repository.*;

public interface NoteRepository extends JpaRepository {}

5. Configure H2 database in application properties file (application.properties):

spring.h2.console.enabled=true

spring.datasource.url=jdbc:h2:mem:testdb

spring.datasource.driverClassName=org.h2.Driver

spring.datasource.username=sa

spring.datasource.password=

spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

6. Add @EnableJpaAuditing annotation to your main application class:

java @SpringBootApplication

@EnableJpaAuditing

public class Application {

public static void main(String[] args) {

    SpringApplication.run(Application.class, args);

}

}

7. Create an AuditorAwareImpl that will be used to set the current user as auditor:

java import java.util.*;

import org.springframework.data.domain.*;

public class AuditorAwareImpl implements AuditorAware {

@Override

public Optional getCurrentAuditor() {

   // Return current user name (for this example, we are setting it as 'user')

    return Optional.of("user");

}

}

8. Configure the auditing in your configuration class:

java import org.springframework.context.*;

import org.springframework.data.domain.*;

@Configuration

public class AuditConfig {

@Bean

public AuditorAware auditorProvider() {

    return new AuditorAwareImpl();

}

}

These steps will help you set up the basic structure for adding audit information to your entities using Spring Data JPA and H2 database. You can extend this approach as needed based on your specific requirements or use cases, such as storing more detailed user/auditor information etc.

By following these steps, every time a Note entity is created or updated in the application, its corresponding 'createdAt' & 'updatedAt' fields will be automatically set with current timestamp value using JPA Entity listeners provided by Spring Data JPA project which handles auditing tasks behind scenes based on configuration settings.

You can access H2 console at http://localhost:8080/h2-console to view data stored in database tables and verify if audit information is being saved properly for each entity instance as per your requirements.

User: Can you rewrite the Note entity and implement in-memory H2-database instead of HashMap?

Codestral: Sure! Here's how you could rewrite the Note entity class with JPA annotations for mapping it to a H2 database table instead of using HashMap:

1. Add required dependencies (Spring Data JPA, H2 Database) in build file (Maven/Gradle), as described earlier.

2. Update your Note entity class like this:

java import javax.persistence.*;

@Entity public class Note extends AbstractAuditingEntity {

@Id

private Long id;

private String title;

private String content;

// Constructors

public Note() {}

public Note(Long id, String title, String content) {

    this.id = id;

     this.title = title;

      this.content = content;

 }

// Getters and Setters

// Other methods

}

In this updated Note entity class:

• The @Entity annotation indicates that it is a persistent Java object which will be mapped to the database table with same name by default.

• @Id specifies primary key of Entity, which in our case is id field defined as Long data type (you can also use other data types like String etc.).

3. Create JPA repository interface for your entity:

java import org.springframework.data.jpa.repository.*;

public interface NoteRepository extends JpaRepository {}

4. Configure H2 database in application properties file (application.properties), as described earlier.

5. Inject the repository into your controller and use its methods for CRUD operations:

java @RestController

public class NoteController {

private final NoteRepository noteRepository;

// Constructor

public NoteController(NoteRepository noteRepository) {

    this.noteRepository = noteRepository;

 }

@GetMapping("/notes/{id}")

public ResponseEntity getNoteById(@PathVariable Long id) {

     Optional optionalNote = noteRepository.findById(id);

   // Rest of the method...

}

// Other methods

}

6. Update other service/controller methods to use JpaRepository's CRUD operations like save(), findById() etc., instead of direct Map manipulations.

By following these steps, you can replace in-memory HashMap storage with a persistent H2 database which supports more advanced features such as transactions, indexing and data consistency across multiple application instances or restarts.

JPA repository provided by Spring Data JPA project simplifies common CRUD operations on entities mapped to relational databases, allowing developers focus on business logic rather than low-level details of interacting with database layer directly through SQL queries etc., which can improve code maintainability and scalability over time as well.

You will still be able to use DTOs for data transfer between client applications and server side services without any issues since they don't depend on underlying storage mechanism used by the application (whether it is HashMap, H2 database or others).

User: How would I implement an API key?

Codestral: To implement an API key:

1. Create a custom interceptor that will check if request has valid API Key in Authorization header.

java import javax.servlet.*;

import org.springframework.beans.factory.annotation.*;

import org.springframework.http.*;

public class ApiKeyInterceptor implements HandlerInterceptor {

@Value("${apikey}")

private String apiKey;

// Other code...

@Override

public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {

    String headerApiKey = request.getHeader("Authorization");

   if (headerApiKey == null || !apiKey.equalsIgnoreCase(headerApiKey)) {

        response.setStatus(HttpStatus.UNAUTHORIZED.value());

       return false;

}

    return true;

}

}

In this custom interceptor class:

• The @Value annotation is used to inject API key from application properties file into a field called apiKey.

• preHandle() method checks if request contains valid API Key in Authorization header by comparing it with expected value stored in apiKey variable defined above, and returns true/false accordingly based on result of comparison operation (true indicates successful validation while false means unauthorized access).

2. Register the custom interceptor to be used globally for all controller endpoints:

java import org.springframework.context.*;

@Configuration

public class WebConfig implements WebMvcConfigurer {

@Override

public void addInterceptors(InterceptorRegistry registry) {

    registry

        .addInterceptor(new ApiKeyInterceptor())

       .order(1);

 }

}

In this configuration class:

• The WebMvcConfigurer interface is implemented to override addInterceptors() method where custom interceptor object created earlier is registered using registry.addInterceptor().

3. Configure API key value in application properties file (application.properties):

apikey=mysecretkey

By following these steps, you can protect your REST APIs from unauthorized access by checking if each request contains a valid API Key in Authorization header which matches expected value configured for the application.

This approach provides basic level of security to prevent unwanted clients or applications from consuming resources provided through exposed endpoints without proper authorization, but it is not recommended as final solution for production grade applications since it does not provide any form of encryption/hashing while transmitting sensitive information like API keys over network which could be easily intercepted by third parties.

More advanced authentication mechanisms such as OAuth2 tokens or JWTs should be considered instead based on specific requirements and use cases to ensure secure communication between client applications and server side services.

User: With all that said and done, can you give a summary of this web application? What it does? Please explain in as much detail as possible, be elaborate.

Codestral: Certainly! Here's a summary of the web application we have discussed:

The Java-based REST API is designed for managing Note entities with CRUD functionality using Spring Boot 2.7.x and JPA annotations for mapping objects to relational database tables provided by H2 in-memory database instead of HashMap storage mechanism used initially. The main features include:

1. Creation, retrieval, update & deletion operations on Note entities via HTTP endpoints (/notes/{id}) with proper request and response formats defined using DTOs to separate data model from how information is transferred between client applications and server side services.

2. Error handling mechanisms such as custom exceptions and Problem responses provided by Zalando's problem-spring-web library which allows standardized error formats across REST API while still allowing specific exception handling when needed based on requirements or use cases.

3. Debugging support through logging of various controller actions using SLF4J/Logback logger implementation so that developers can monitor and debug issues in production environment more effectively by analyzing logs generated during runtime execution, without relying solely upon stack traces etc.

4. Auditing functionality provided out-of-the-box with Spring Data JPA to track changes made over time on entities mapped to relational databases like H2 which supports transactions and data consistency across multiple application instances or restarts by maintaining audit information such as createdAt, updatedAt timestamps for each entity instance.

5. Basic level of security using API key authentication mechanism where each request is checked if it contains a valid API Key in Authorization header that matches expected value configured during runtime which prevents unauthorized access to resources provided through exposed endpoints without proper authorization. However, this approach does not provide encryption/hashing while transmitting sensitive information like API keys over network and should be considered as initial solution only for development purposes or small scale applications where security is less critical compared with production grade systems that require more advanced authentication mechanisms such as OAuth2 tokens or JWTs etc., based on specific requirements.

The application follows best practices for designing REST APIs by providing clear URL patterns, standardized response formats and appropriate HTTP status codes in responses which makes it easier to understand how different resources are accessed and manipulated within the API without needing additional documentation beyond what's already provided through code itself (like Javadoc comments).

Overall this is a simple yet powerful Java-based REST API for managing Note entities with CRUD functionality using Spring Boot, JPA annotations & H2 database which demonstrates various concepts and features of modern web development frameworks like error handling mechanisms, logging support etc., that can be extended or customized based on specific requirements or use cases to build production grade applications more easily.

User: Does Jackson for JSON serialization/deserialization need any configuration? What about the dependencies?

Codestral: Jackson library is included by default in the spring-boot-starter-web dependency when using Spring Boot as it's a part of the larger Starter Web module which provides auto-configuration for various web components like JSON serialization/deserialization, error handling mechanisms etc., out of the box without needing any additional configuration or dependencies.

Spring Boot automatically configures Jackson ObjectMapper bean with default settings when it detects that jackson-databind library is present on classpath and registers this bean as a singleton instance which can be injected into other components like controllers, services etc., wherever needed for JSON serialization/deserialization operations.

This means you don't need to manually configure ObjectMapper or add any additional dependencies in build file (Maven/Gradle) since all necessary setup is done automatically by Spring Boot based on conventions and best practices followed within the framework itself, allowing developers focus more on business logic rather than low-level details of configuring individual components separately.

However if you need to customize default settings provided out-of-the-box with Jackson ObjectMapper bean configured by Spring Boot or add additional features like support for JSR310 date/time types etc., then you can do so by creating your own @Configuration class and overriding appropriate methods defined within WebMvcConfigurerAdapter interface which provides access to low level details of configuring various components used internally by framework itself.

For example:

java import com.fasterxml.jackson.databind.*;

@Configuration

public class JacksonConfig extends WebMvcConfigurerAdapter {

@Override

public void configureMessageConverters(List> converters) {

    ObjectMapper objectMapper = new ObjectMapper();

   // Customize settings...

     converters.add(new MappingJackson2HttpMessageConverter(objectMapper));

 }

}

In this example, a custom @Configuration class is created which extends WebMvcConfigurerAdapter and overrides configureMessageConverters() method where an instance of ObjectMapper with default settings provided out-of-the-box by Jackson library can be obtained through its no-argument constructor call.

Then additional configuration changes or customizations can be made on this object as needed based on specific requirements or use cases before adding it to list of HttpMessageConverters used internally by framework for JSON serialization/deserialization operations within REST API endpoints defined in controllers etc., using add() method provided by List interface.

But keep in mind that modifying default settings provided out-of-the-box with Jackson ObjectMapper bean configured automatically by Spring Boot should be done carefully since it may have unintended side effects or break existing functionality if not handled properly, so always test thoroughly before deploying changes to production environment.

User: Please add support for Java date and time API, Hibernate types, RFC7807 Problem, ConstraintViolationProblem to the Jackson configuration.

Codestral: Sure! To add support for Java date and time API (JSR310) with Hibernate types in Jackson configuration:

1. Add required dependencies into build file (Maven/Gradle):

For Maven, include these lines inside the pom.xml's dependencies tag:

xml

com.fasterxml.jackson.datatype

jackson-datatype-jsr310 2.9.6

 org.hibernate
  hibernate-core
   5.3.7.Final

For Gradle, include these lines inside the build.gradle's dependencies block:

implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jsr310:2.9.6'

implementation 'org.hibernate:hibernate-core:5.3.7.Final'

These dependencies are required for supporting Java date and time API (JSR310) with Hibernate types in Jackson configuration, without which serialization/deserialization of such fields may result in errors or unexpected output during runtime execution depending on specific use cases.

2. Update your custom @Configuration class like this:

java import com.fasterxml.jackson.databind.*;

import org.springframework.context.*;

public class JacksonConfig {

@Bean

public Module javaTimeModule() {

     return new JavaTimeModule();

 }

}

In this updated configuration class:

• A custom bean of type Module is created which provides support for serialization/deserialization of JSR310 date and time types like LocalDate, LocalDateTime etc., using Jackson library.

This allows you to use these data types directly within your entity classes mapped by Spring Data JPA to relational databases provided Hibernate as persistence provider without needing any additional configuration or dependencies beyond what's already mentioned above.

To add support for RFC7807 Problem and ConstraintViolationProblem in Jackson configuration, you can use Zalando's problem-spring-web library which provides out of the box implementation for these types based on specifications defined by IETF standard organization.

This means all necessary setup is done automatically by library itself when it detects that appropriate dependencies are present on classpath and registers corresponding beans as singletons within Spring application context, allowing developers focus more on business logic rather than low-level details of configuring individual components separately.

So there's no need to manually configure Jackson ObjectMapper or add any additional configuration classes for these types since all necessary setup is done automatically by Zalando's problem-spring-web library based on conventions and best practices followed within the framework itself, allowing developers focus more on business logic rather than low-level details of configuring individual components separately.

However if you need to customize default settings provided out-of-the-box with Problem/ConstraintViolationProblem beans configured by Zalando's problem-spring-web library or add additional features etc., then you can do so by creating your own @Configuration class and overriding appropriate methods defined within WebMvcConfigurerAdapter interface which provides access to low level details of configuring various components used internally by framework itself.

For example:

java import org.zalando.problem.*;

@Configuration

public class ProblemConfig extends WebMvcConfigurerAdapter {

@Override

public void configureMessageConverters(List> converters) {

    ProblemModule problemModule = new ProblemModule();

   // Customize settings...

     converters.add(new ProblemJackson2HttpMessageConverter(problemModule));

 }

}

In this example, a custom @Configuration class is created which extends WebMvcConfigurerAdapter and overrides configureMessageConverters() method where an instance of ProblemModule with default settings provided out-of-the-box by Zalando's problem-spring-web library can be obtained through its no-argument constructor call.

Then additional configuration changes or customizations can be made on this object as needed based on specific requirements or use cases before adding it to list of HttpMessageConverters used internally by framework for serialization/deserialization operations within REST API endpoints defined in controllers etc., using add() method provided by List interface.

But keep in mind that modifying default settings provided out-of-the-box with ProblemModule bean configured automatically by Zalando's problem-spring-web library should be done carefully since it may have unintended side effects or break existing functionality if not handled properly, so always test thoroughly before deploying changes to production environment.

User: How to Dockerize this web app?

Codestral: To Dockerize this web application:

1. Create a Dockerfile in the root directory of your project with following content:

Use OpenJDK 8 as base image

FROM openjdk:8-jdk-alpine

ARG JAR_FILE=target/*.jar

COPY ${JAR_FILE} app.jar

ENTRYPOINT ["java","-jar","/app.jar"]

In this Dockerfile, we are using OpenJDK 8 as base image and copying the generated JAR file from build output directory (target/) into container filesystem with name 'app.jar'.

Then setting it up to be executed when container starts by defining ENTRYPOINT instruction which specifies command that should run whenever a new instance of this dockerized application is launched as standalone service or part of larger infrastructure like Kubernetes cluster etc., based on requirements and use cases.

2. Build Docker image using following command:

docker build -t my-note-app .

This will create a new docker image with tag 'my-note-app' from current directory (.) where Dockerfile is located and can be used to launch multiple instances of application container as needed depending upon specific requirements or use cases.

3. Run the Dockerized web app using following command:

docker run -p 8080:8080 my-note-app

This will start a new container instance based on 'my-note-app' docker image created earlier and map host port number 8080 to internal port number used by application within the container which allows us access REST API endpoints provided through exposed interface like http://localhost:8080/notes/{id} etc., from our local machine or other devices connected on same network as Docker host server.

4. (Optional) Push the docker image to a repository for deployment onto production environment using following command:

docker tag my-note-app /my-note-app

docker push /my-note-app

These commands will firstly create an alias/tag 'my-note-app' for existing docker image with same name created earlier and then pushes it to remote repository specified as target destination where it can be pulled down onto production environment by relevant infrastructure components like Kubernetes cluster etc., based on specific requirements or use cases.

By following these steps, you will have successfully Dockerized your Java-based REST API for managing Note entities with CRUD functionality using Spring Boot and JPA annotations for mapping objects to relational database tables provided H2 in-memory database which can be deployed onto various environments like development/testing, staging or production seamlessly without worrying about underlying infrastructure details since all necessary setup is done automatically by Docker container runtime environment itself.

This approach provides benefits such as consistent behavior across different execution environments (like local machine vs cloud provider etc.), easier deployment and scalability on large scale systems using tools like Kubernetes cluster, faster time-to-market for new features/updates compared with traditional methods of manual provisioning & configuration etc., which makes it a popular choice among modern software development teams that need to deliver applications more quickly while maintaining high level of quality standards.

User: Thanks but I prefer Docker Jib for production. How?

Codestral: Sure! To Dockerize this web application using Google's Jib:

1. Add the following plugin into build file (Maven/Gradle):

For Maven, include these lines inside the pom.xml's plugins tag:

xml

com.google.cloud.tools

jib-maven-plugin 2.3.0

For Gradle, include these lines at the end of build.gradle file:

plugins { id 'com.google.cloud.tools.jib' version '2.3.0' }

jib { to { image = '/my-note-app' }

from { image = 'openjdk:8-jdk-alpine' }

containerize {}

}

These plugins provide necessary configuration settings for building Docker images using Jib without needing any additional setup or dependencies beyond what's already mentioned above.

2. Build the docker image using following command:

For Maven, run this command in terminal/command prompt:

mvn compile jib:dockerBuild

For Gradle, run this command in terminal/command prompt:

gradle jibDockerBuild

These commands will create a new docker image with tag specified as target destination (/my-note-app) from source code located within current directory and can be used to launch multiple instances of application container as needed depending upon specific requirements or use cases.

3. Push the Dockerized web app onto production environment using following command:

docker push /my-note-app

This will upload generated docker image created earlier to remote repository specified as target destination where it can be pulled down onto production environment by relevant infrastructure components like Kubernetes cluster etc., based on specific requirements or use cases.

By following these steps, you can Dockerize your Java-based REST API for managing Note entities with CRUD functionality using Spring Boot and JPA annotations for mapping objects to relational database tables provided H2 in-memory database which can be deployed onto production environment seamlessly without worrying about underlying infrastructure details since all necessary setup is done automatically by Google's Cloud Tools for Java (Jib) plugin itself.

This approach provides benefits such as faster build times compared with traditional methods of building Docker images from scratch, consistent behavior across different execution environments (like local machine vs cloud provider etc.), easier deployment and scalability on large scale systems using tools like Kubernetes cluster etc., which makes it a popular choice among modern software development teams that need to deliver applications more quickly while maintaining high level of quality standards.

Jib is an open-source project maintained by Google Cloud Platform team that simplifies the process of building Docker images for Java applications without needing any additional setup or dependencies beyond what's already mentioned above, which makes it a great tool for automating CI/CD pipelines and ensuring consistent deployment across various environments.

User: How to configure a "development" profile to get live reload? I'm using Maven.

Codestral: To configure a "development" profile with live reload using Maven:

1. Add the following plugin into build file (Maven):

Include these lines inside the pom.xml's plugins tag:

xml

org.springframework.boot

spring-boot-maven-plugin

    false

This plugin provides necessary configuration settings for enabling live reload during development without needing any additional setup or dependencies beyond what's already mentioned above.

2. Create a new profile in pom.xml with id "development":

xml

    development
   
       
           -Dspring.devtools.livereload.enabled=true

This profile sets the necessary JVM arguments to enable live reload feature provided out of box by Spring Boot DevTools module which is included as part of spring-boot-starter-web dependency used earlier.

3. Run your application using following command:

mvn spring-boot:run -Dspring-boot.run.profiles=development

This will start the Spring Boot application in "development" profile with live reload feature enabled, allowing you to modify source code during runtime execution and see changes take effect immediately without having to restart server or refresh browser manually which makes it easier to develop new features or fix bugs more quickly.

By following these steps, you can configure a dedicated development environment for your Java-based REST API with live reload feature enabled using Maven build system, allowing developers focus on business logic rather than low level details of configuring individual components separately while ensuring consistent behavior across various stages of software development lifecycle from local machine to cloud provider etc., which makes it easier to collaborate and deliver applications more quickly.

Spring Boot DevTools module provides several other useful features like automatic restarting server when code changes are detected, live template reloading without needing manual refresh/reload operations in browser etc., that can be enabled or disabled as needed based on specific requirements or use cases.

User: Thanks, but I'll be using Webpack dev server + BrowserSync for live reload so I will need DevTools to restart but not live reload.

Codestral: No problem! To configure a "development" profile with Spring Boot DevTools to enable auto-restart feature and disable live reload using Maven:

1. Add the following plugin into build file (Maven):

Include these lines inside the pom.xml's plugins tag if not already present:

xml

org.springframework.boot

spring-boot-maven-plugin

    false

This plugin provides necessary configuration settings for enabling auto restart feature without live reload during development.

2. Create a new profile in pom.xml with id "development":

xml

    development
   
       
           -Dspring.devtools.restart.enabled=true
            -Dspring.devtools.livereload.enabled=false

This profile sets the necessary JVM arguments to enable auto restart feature and disable live reload provided out of box by Spring Boot DevTools module which is included as part of spring-boot-starter-web dependency used earlier.

3. Run your application using following command:

mvn spring-boot:run -Dspring-boot.run.profiles=development

This will start the Spring Boot application in "development" profile with auto restart feature enabled and live reload disabled,