Simple API with MongoDB backend

Hopefully, this app helps to understand how to create an API with MongoDB backend using Golang and no framework.

I also included topics such as:

• Anonymous functions, Go routines, Channels, Interfaces and Generics.
• Graceful shutdown mechanism.
• Dependency injection.
• Unit testing.

Use case

With this API an Author can submit a message in a Post. An author can also make Comments on that or any other post.

Code organization

Main folders are:

• app: containing the API logic.
• models: containing the DB models.

Data Schema

For this purpose I need to model one-to-one relationships between:

• Post and Author.
• Comment and Author.

And one-to-many relationship between:

• Post and Comments.

So basically, I'm using 2 entities: Post and Comment with an Author's name in each of them. Whereas a Post consists of the following fields:

• Id
• Content
• Author

and a Comment consists of the following fields:

• Id
• Content
• Author
• PostId (Using reverse reference to avoid limitation of a big list of Ids in the Post document)

Prerequisites

This app has been tested with:

• Git =2.37
• GNU Make =3.81
• Docker =20.10.20
• MongoDB docker image =6.0.3
• Go =1.19

How to play with this

1. Run the App

Clone this repo to your local machine:

git clone https://github.com/gjbastidas/GoSimpleAPIWithMongoDB.git

Change to the GoSimpleAPIWithMongoDB directory:

cd GoSimpleAPIWithMongoDB

Export the following environment variables:

export DB_USERNAME="replace with MongoDB username" #i.e admin
export DB_PASSWORD="replace with MongoDB user password"  #i.e secret
export DB_HOST="replace with MongoDB hostname"  #i.e db
export DB_PORT="replace with MongoDB port"  #i.e 27017

Run the app:

make app-run

This last command should trigger the local pipeline to:

1. Run linters and tests
2. Set and run the MongoDB docker container
3. Build the API docker image and run the API container

2. Interact with the API

The simplest way is by issuing CURL commands from your terminal:

Create a post

curl -X POST http://localhost:8088/post/ \
  -H 'Content-Type: application/json' \
  -d '{"content": "my first post","author": "some author"}'

Get a post

curl http://localhost:8088/post/<<replace with id>>

Update a post

curl -X PUT http://localhost:8088/post/<<replace with id>> \
  -H 'Content-Type: application/json' \
  -d '{"content": "updated post","author": "some author"}'

Delete a post

curl -X DELETE http://localhost:8088/post/<<replace with id>>

If you're using VS Code, with the Rest Client integration, I already included a script you could use here

TODO Swagger

Delete everything

Run:

make app-delete

Have fun!

... and feel free to add your comments or feedback, open PRs, etc.