Microservices Aggregate Pattern

This is another pattern that is very useful for serving mobile native applications. The mobile app just sends one request to an aggregate API and it will call multiple APIs to gather info and send back to the consumer. This avoids mobile device to call multiple APIs to get data on a slow network.

This tutorial shows you how to build 4 services with one of them the aggregator. And it will be the foundation for our microserives benchmarks.

API AA -> API AB
      -> API AC
      -> API AD

API AA calls API AB, API AC and API AD to fulfill its request.

It is a very long tutorial as we want to package as much info as possible. So we have separated the it into the following steps.

  1. Environment preparation
  2. Create specification
  3. Generate and Build
  4. API to API Communication
  5. Performance Test

Preparation

All specifications and code of the services are on github.com but we are going to redo it again by following the steps in the tutorial. Let’s first create a workspace. I have created a directory named networknt under user home directory. Checkout related projects. cd ~/networknt git clone https://github.com/networknt/light-codegen.git git clone https://github.com/networknt/light-example-4j.git git clone https://github.com/networknt/model-config.git git clone https://github.com/networknt/light-oauth2.git git clone https://github.com/networknt/light-docker.git git clone https://github.com/networknt/light-config-test.git As we are going to regenerate API AA, AB, AC and AD, let’s rename ms_aggregate folder from light-example-4j. Read More »

Specification

Light-rest-4j microservices framework encourages Design Driven API building and OpenAPI Specification is the central piece to drive the runtime for security and validation. Also, the specification can be used to scaffold a running server project the first time so that developers can focus their efforts on the domain business logic implementation without worrying about how each component are wired together. During the service implementation phase, specification might be changed and you can regenerate the service codebase again without overwriting your handlers and test cases for handlers. Read More »

Generation

Now we have four openapi.yaml files and four openapi.json files available. Let’s use light-codegen to start four projects in light-example-4j/rest/openapi/ms_aggregate. In a normal API build, you should create a repo for each API. For us, we have to user light-example-4j for all the examples and tutorial for easy management in networknt github organization. Build light-codege The project is cloned to the local already during the preparation stage. Let’s build it. Read More »

API to API communication

In the previous step, we have generated four APIs and tested the first one. Now these APIs are working if you start them and they will output the mock responses generated based on the API specifications. Let’s take a look at the API handler itself and update it based on our business logic, you can call API AA and subsequently all other APIs will be called by API AA. Prepare Environment Before starting this step, let’s create a folder called https in each sub folder under ms-aggregate and copy everything from generated folder to the https. Read More »

Aggregate Performance

Now let’s see if these servers are performing with wrk. To learn how to use it, please see my article in tool here. Assume you have wrk installed, run the following command. wrk -t4 -c128 -d30s https://localhost:7441 -s pipeline.lua --latency -- /v1/data 1024 And here is what I got on my i5 desktop steve@joy:~$ wrk -t4 -c128 -d30s https://localhost:7441 -s pipeline.lua --latency -- /v1/data 1024 Running 30s test @ https://localhost:7441 4 threads and 128 connections Thread Stats Avg Stdev Max +/- Stdev Latency 0. Read More »