Tutorial Overview

Tutorials give developers step by step guidance on how to use each component or framework. As Light is an ecosystem that delivers enterprise scale microservices, there are a lot of middleware handlers, frameworks, infrastructure services and tools that need to be covered with tutorials. In this section, some of the most important tutorials are listed and more will be added to the list.

Cross-Cutting Concerns

API Styles

Infrastructure Service

Tool Chain

Light Gateway Tutorial

We have recently combined both light-proxy and light-router to create a new light-gateway project. Like the http-sidecar, which is based on the same codebase and used as a sidecar in a Kubernetes cluster, the light-gateway can be used in Docker, Windows or Linux services. The following tutorials demonstrate the usage of the light gateway. We use two demo services to complete the full cycle: market service and petstore service. Both services are located in the light-example-4j project. Read More »

Light Scheduler

As part of infrastructure services, light-scheduler offers fully distributed task scheduling for the enterprise cloud environment. Local Confluent to support local development and test. Local development with Local Confluent API Endpoints with Postman and Curl command line. Three-node Cluster with fat jar and externalized config folders. Cluster Debug with docker-compose and IDE mix. Read More »

Http Sidecar Tutorial

Read More »

Kafka Sidecar

As part of light-mesh offering, the Kafka Sidecar is an infrastructure component to help businesses to build services interacting with enterprise Kafka clusters. In this tutorial, I will outline the major steps to get the sidecar and backend API up and running with a local Confluent and up to production deployed to a Kubernetes cluster. Local development with Confluent local Local binary demo with externalized configuration Reactive Consumer Producer backend reference implementation to receive a batch of records, transform the key with a field in the value and produce the new key/value to another topic. Read More »

Light Config Server

The config server has several backend providers, and we are going to demo all of them. Also, there are several different deployment options that we need to show users. Mongo Provider in Debug Mode View Development with local config server as backend. Read More »

Light Chaos Monkey

For large scaled microservices deployment on the cloud, many unpredictable issues might happen on production. We can always guess the application’s behaviour when something happens, but we can never verify the hypothesis. To ensure the system resiliency, Chaos engineering has been introduced, and a commonly used tool is Chaos Monkey. As light-4j addresses the cross-cutting concerns with middleware handlers in the request/response chain, we can easily design the Chaos Monkey tools with middleware handlers to injected into the live application with a disabled state by default. Read More »

AWS Lambda Function Tutorial

Before working with AWS Lambda functions, we need to install the awscli locally. I follow the official document to install the AWS CLI v2 on my Ubuntu 20.10. Also, we need to install the AWS SAM CLI by following this document There are two different ways to build and deploy Lambda functions described in the light-aws-lambda. The difference is how the cross-cutting concerns are addressed for the Lambda functions. aws-framework addresses CCC within the Lambda function built with Java 11 and AWS API Gateway JWT Authorizer. Read More »

Light Controller Tutorial

The light-controller is part of the light-portal, and it is responsible for managing live instances in a microservices deployment in real-time. For most users who cannot deploy the light-portal or just want to set up an environment for development, we have peeled the light-portal functionality and created a free open source edition. The published docker image is free to use with a docker-compose.yml in the light-controller repository for users who prefer Docker. Read More »

Light Kafka Tutorial

We are using light-kafka and light-hybrid-4j for light-portal, light-blockchain and open-banking applications with Event Sourcing and CQRS, so it is easier for us to provide examples with hybrid framework. As a lot of our users are still using light-rest-4j, so we want to provide an additional example in REST. Producer-Consumer Stream-Query Stream-Report ksqldb-query Read More »

OAuth Kafka Tutorial

Local Dev Bootstrap Token Read More »

Reference Data API

Reference API is a microservice designed to populate UI dropdown lists in real-time with relationship support. Try the link for a demo react-schema-form. In the above form, you have to select a country before the province is populated from the reference API. Once a province is select, the cities in the province will be populated in real-time. The category and subcategory have a similar relationship. Update Reference Table Read More »

Light MQ Tutorial

For documentation on the light-mq component, please refer to light-mq The source code of the light-mq is not open-sourced; however, we have published two docker images and a docker-compose file that can be executed locally for any user. The docker-compose contains two services built on top of the light-rest-4j and light-mq. One service is a producer that can put the request body into an MQ queue and publish the request body to an MQ topic. Read More »

Open Banking Tutorial

We have a lot of tutorials that demonstrate different features of Light. More and more users ask if we can provide a more realistic tutorial that combines all aspects of microservices development and deployment. In this tutorial, we are going to develop an open banking application and deploy it to the cloud. This application has four microservices and a single page application built with React. Specification Generation Hard Coded Security Docker Compose Router Proxy Tracing Client Read More »

Peformance

The light-4j framework is very light and supports millions of request per seconds on a commodity server. To show our users how to build high-performance microservices, We have submitted benchmark implementations to Techempower to compare light-4j with other frameworks on the market. The source code can be found in techempower repo, and it is an excellent example of how to build high-performance services, including database access. The benchmark result can be found at techempower benchmark Read More »

Tracing

When moving monolithic architecture to microservices, the majority of operational challenges that arise are narrowed in two areas: networking and observability. This is where Distributed Tracing can really help. Distributed Tracing helps with two fundamental challenges faced by microservices: Latency tracking One user request or transaction can travel through many different services in different runtime environments. Understanding the latency of each of these services for a particular request is critical to the understanding of the overall performance characteristics of the system as a whole, and provides valuable insight for possible improvements. Read More »

Kotlin Tutorial

Since Google announced Kotlin as the official language for Andriod development, it is getting prevalent in mobile development. It has a lot more features that are very good for server-side development as well. If you are a new developer, I would highly recommend learning Kotlin over Java. As it is effortless to mix Java and Kotlin in one project, you can try Kotlin in a project step by step. With a lot of requests from our users, we have developed a Kotlin OpenAPI generator in light-codegen and created an example application. Read More »

Spring Boot Tutorial

Recently, we have introduced light-spring-boot repository with two light-4j modules to inject light-4j middleware handlers into the Spring Boot application with embedded Undertow Servlet or embedded Undertow core. The injection is happening at the http core level so these handlers will have much better performance In most cases, you have already built the Spring Boot application and you want to leverage the Light ecosystem and numeric middleware handlers. If you are starting a brand new project, it is highly recommended using light-rest-4j directly. Read More »

Handler Routing Tutorial

When building a microservice, there are many cases where you might need different handlers to run for different request paths that your service supports. For example, the /health endpoint might not need schema validation, or the /info endpoint may not need to push traceability metrics. In any case, we need to provide a way to configure which request paths hit which handler chains. And the following tutorial will guide you through the process of what building out the config you will need to support multi handler chains. Read More »

Client Tutorial

To improve the performance and reduce the complexity of the HTTP connection pooling, we have developed Http2Client which is HTTP/2 enabled for the client to service and the service to service communication. We also support one-way SSL by default for all communication channel and two-way SSL optional with the configuration in the server.yml file. In most service to service interactions, we are using self-signed certificates which are managed by server.keystore and client. Read More »

Hybrid Tutorial

Almost all out own services are built on top of light-hybrid-4j with JSON RPC. The following are some examples. Merge two services with one server Hello World Hybrid Server and Services Eventuate Todo-list Hybrid Implementation Portal Hybrid Service initialization Portal Hybrid Query with Light Codegen Web Portal Hybrid Query with API Certification Portal Hybrid Command with Host Menu Portal Hybrid Query with Host Menu Portal Hybrid Command with Schema Form Portal Hybrid Query with Schema Form Portal Hybrid Service with User Management Taiji Blockchain Web Client Server SPA with handler. Read More »

Light Portal Tutorial

Light-portal is the central point that provides entries for all light-platform supporting services. It is a website that integrates all services with a standard UI for users to utilize and manage these services. Behind the single-page application is a light-router instance that hosts all the virtual domains and proxy API requests to the backend services. Most light-portal services are built on top of the light-hybrid-4j framework with Event Sourcing and CQRS. Read More »

Light Router Tutorial

API consumers can use Light-router if they don’t support Java 8/11, or they are implemented with other programming languages in the service to service communication. It is the service mesh feature like other service mesh providers; however, we only need a Light router for consumers built on other frameworks other than light-4j, which has an embedded gateway in every instance. Best of all, the gateway in light-router or light-4j instance can be easily extended or customized as they are all designed as pluggable middleware handlers to address certain cross-cutting concerns. Read More »

GraphQL Tutorial

GraphQL is gaining traction these days as a RESTful replacement for Mobile native applications and Single Page Applications built on top of React, Vue, and Angular. It is designed to resolve common issues with RESTful API, and has a lot of wonderful features; however, for most developers it is very hard to learn in the first place. In this section, we are going to walk through several light-graphql-4j examples and show you how to build your own GraphQL server. Read More »

Light Bot Tutorial

This is the tutorial to learn how to run the light-bot for networknt projects and how to leverage it for your organizations and repositories. As it is using config module from light-4j, the config files can be externalized to somewhere in the host filesystem. You can deploy it in one of your DevOps VMs and set it up to run automatically for developing build and test. Other tasks are triggered manually and only used occasionally. Read More »

Websocket Tutorial

Read More »

Web Server Tutorial

Most documents and articles regarding to Light-4j are about RESTful or GraphQL or Hybrid services; however, there are a lot user cases that combine the API and static site rendering together, particularly single page applications built on top of React or Angular. Handler Provider As we know, the light-4j needs a plugin to inject application logic and for API project that is based on OpenAPI specification, this is generated by the light-codegen. Read More »

Tram Tutorial

Light-tram-4j is the foundation of event driven frameworks and handles transactional messaging without XA. On top of light-tram-4j, there is light-saga-4j to handle distributed transactions across multiple microservices. There is also a framework light-eventuate-4j to support Event Sourcing and CQRS architecture. All tutorials here are showing basic message, event or command delivery from one service to another service. Todo-list This is a Hello World type of application that shows the features of light-tram-4j. Read More »

Common Tutorial

These tutorials are not specific to any frameworks but common across all type of frameworks. For example, how to do service registry and service discovery? How to use service module to bound implementations to an interface, How to inject java beans into service map so that other modules can use the singleton instance. It also covers how to test and debug services built on top of the Light platform. Test Unit test Read More »

Restful Tutorial

The Restful style of API/service is very simple and easy to be consumed by everybody, even if there are some shortcomings. Basically, almost every language has a client that can easily talk to Restful service. Light-rest-4j contains two different implementations based on different versions of specifications. Swagger 2.0 is an older specification, and OpenAPI 3.0 is a newer specification. Most of our examples are in OpenAPI 3.0, and some of Swagger 2. Read More »

Light Proxy Tutorial

Light-proxy is a critical service component that can glue all other alien APIs into the Light ecosystem without re-writing. Once putting light-proxy in front of legacy APIs, these API can enjoy all the cross-cutting concerns provided by the light-platform, such as security, metrics, auditing, traceability, validation, service registry/discovery, etc. From the consumer point of view, your backend API looks just like an API built on top of light-4j frameworks. OpenAPI 3. Read More »

Middleware Handlers

The Light platform is a plugin architecture, and there are a lot of middleware handlers provided to address all sort of cross-cutting concerns when you build a microservices. Also, users can add their own plugins within the business context. Basically, the light-4j framework is an embedded gateway that allows users to write their business logic on top of it. Before the request reaches the business handler, there are a lot of middleware handlers need to be executed to address security, metrics, audit, traceability, etc. Read More »

Security Tutorial

The Light platform is following security first design as most of our customers are big financial companies and they need to ensure confidentiality, availability, and integrity first then scale the system to lower the production cost and development cost. When the platform was designed, we focused a lot of efforts on the security details and made a lot of default configuration so that our customers won’t need to do extra things to bring up a system securely. Read More »

Eventuate Tutorial

The light-eventuate-4j framework is complex than any request/response based framework like light-rest-4j, light-graphql-4j or light-hybrid-4j as there are more moving parts. In this section, we are going to introduce some tutorials to help users to work with this framework. Before starting a service project based on light-eventuate-4j, you need to get the environment set up first, and the getting started light-eventuate-4j has all the information to help you to get infrastructure services started. Read More »

Light Codegen Tutorial

This document will give you step-by-step guidelines on how to use light-codegen which is an in-house generator to support all API frameworks/styles in the Light platform and beyond. All frameworks in the Light platform are design-driven, and you can scaffold a new project based on the IDL (Interface Definition Language) with light-codegen. Generate Restful API with Swagger 2.0 Specification Generate Restful API with OpenAPI 3.0 Specification Read More »

Light Oauth2 Tutorial

This document will give you step-by-step guidelines on how to use light-oauth2. There are two types of services in light-oauth2. The first category contains code/authorize, token, key, and provider that will be accessed from clients during the runtime. The provider service is not directly accessed from the clients, but it connects federated light-oauth2 services to form a mesh of the OAuth 2.0 providers. Othe services like the user, client, and service are connected from the light-portal to make configuration changes to the light-oauth2 services. Read More »