Best Practices for Building API Gateways in a Microservice Architecture
Tags: microservices, api
Published: 2022-07-18 20:08:53

In a microservice architecture, the API gateway is a centralized hub that aggregates and distributes information from various services  It is the main entry point for all microservices in the architecture that communicates with all other microservices, parses incoming requests and responses, and then routes them to the appropriate services. It also allows clients to access the application via HTTP, forming a layer between the client and the rest of the microservice architecture. 

API gateways provide three main services:

- Authentication - The apigateway authenticates users and handles authorization. This means that it controls who can access the application.

- Authorization - The apigateway handles authorization for requests from clients, ensuring that they can only perform operations allowed by their role or permission level.

- Routing - The apigateway routes requests to appropriate microservices based on their path, as defined by a routing table definition.


## Benefits of building API gateways.
- It can handle authentication, authorization and logging for multiple microservices
- It provides a common platform for data consumption by different microservices
- It ensures standardized communication between microservices
- It can be used to cache data, which improves response time by reducing network latency and bandwidth usage
- You can easily scale your application horizontally and vertically by deploying multiple instances of the API gateway
  
  

## Best practices for setting up an effective API gateway.
  

Here are 5 best practices you can put in place to build an effective API gateway system.

  
### 1. Setup a Network Handler
      

This is a substantial setup for an API gateway. A network handler is a piece of code that is in charge of sending and retrieving data from other microservices. It communicates directly with the Rest API exposed by each microservice.

  

![Setup a Network Handler](https://i.imgur.com/J7aK510.png)

  

### 2. Consider Direct Database Queries
    

Direct Database Queries are used to retrieve data from a microservice database using a database user who has read-only access. This works best when the microservices use SQL databases, which allow for complex join queries. This might be a good idea when you need to combine query results from multiple microservices, doing so over the network handler can be expensive.

  

![Direct Database Queries](https://i.imgur.com/XP9ymkk.png)

  

### 3. Setup a Data Aggregator
    

A data aggregator's purpose is to collect data from Network Handler or Direct DB queries, process or modify it, and package it in a format that can be sent to a client.

  

![Setup a Data Aggregator](https://i.imgur.com/ZV7eT2M.png)

  

### 4. Implement caching into your Network Handler
   

Caching is essentially a method for your API gateway to save information about all previous requests so that if you receive another request with the same parameters, the gateway will know not to go through the process of actually making the call. Instead of making another call, it will simply retrieve the data from its cache memory and return it because fewer calls are made overall, the load on your servers is reduced, which improves performance and lowers costs.

  

In your network handler, caching occurs during the GET request and is then cleared or updated during the POST, UPDATE, or DELETE request. Caching should also be made optional for GET requests containing data that is likely to change frequently over time.

  

### 5. Implement event based request in your Network Handler
    
There are two types of requests you can make through your network handler: synchronous and asynchronous. Synchronous requests necessitate the network handler waiting for a response before proceeding with its own processes. Asynchronous requests do not necessitate the network handler waiting for a response before going about its business.

You can create asynchronous requests using event-based request functionality without sacrificing functionality or performance. This functionality is best suited for PUT, POST, or DELETE requests that do not require an immediate response.

  

## Conclusion.

 
So far, you have learned that API gateways are single points, the benefits of building API gateways, and lastly, 5 tips to building effective API gateway systems which are:

  
-   Setting up a Network Handler

-   Using Direct Database Queries
    
-   Setting up a Data Aggregator
    
-   Implementing caching into your Network Handler
    
-   Implementing event based request in your Network Handler


## Bonus.

  
I decided to make a simple template generator for API Gateways. This template generator implements all of the suggestions made in this article. The template generator is available on [github](https://github.com/Doctordrayfocus/ApiGateway-Generator).

  
In the meantime, the template generator only works for PHP projects; a NodeJS version is in the works. If you can help build for other languages like Python, Go, and so on, please contact me on Twitter at [drayfocus](https://twitter.com/drayfocus).


You can connect to me on Twitter  [@drayfocus](https://twitter.com/drayfocus), and Linkedin  [Akinola Ayomide](https://www.linkedin.com/in/drayfocus) 

Cheers!