Lessons

How to Delete Data from Mongo with Go

In this tutorial, I will show you the basics of doing a delete from a Mongo database instance with Go code. I will be on local and provide you with all steps.

Setup

I'm assuming you have Mongo installed on your local machine. I also recommend installing Mongo Compass to make it easier to see your data.

I am assuming you have Go installed and have successful compiled at least one Go file. This would confirm your environment works. We will be using my Go boierplate code to save time on setting up our code structure. It follows a handlers, models, repositories, services, and utils structure.

In short:

• handlers handles the inbound request.
• models contains all structs that represent data.
• repositories has all methods for interacting with the database.
• services contains the business logic of the app.
• utils has any helper methods.

Download the Go boilerplate. Please give it a star on Github so I know people are still using and enjoying it. Move the files into your new project root. Open the files up in a text editor.

You need to do one thing for this boilerplate to work. Open services/user_service.go and within the IsValidPassword function. You will need to switch the variable to true. Do NOT use this code in production without fixing it. I leave encryption and password requirements up to you. This will store a plain text password till you add code to GetEncryptedPassword and IsValidPassword. For demo and dev purposes, this is fine.

You will need data in your database and checkout the insert tutorial.

Delete Code

As you can imagine, we will be working with the repositories layer since it works with the database. If we open the repositories/cars_repository.go file, you can see the Delete method.

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func (c *CarsRepository) Delete(email string, carID string) error {
	docID, err := primitive.ObjectIDFromHex(carID)
	if err != nil {
		return err
	}

	filter := bson.M{"_id": docID, "email": email}
	_, err = c.db.Collection("cars").DeleteOne(context.TODO(), filter)
	if err != nil {
		return err
	}
	return nil
}

In the code above, we covert the ID from a string to an objectID. We will then set up our filter and delete one document.

Demo

In your terminal:

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go run main.go

The first step is to run sign up or sign in. I execute my sign up request with Postman. Copy down the token in the response.

Or you can run this curl command:

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curl --location --request POST 'http://localhost:8080/user/signup/' \
--header 'Content-Type: application/json' \
--data-raw '{
 "email": "me@keithweaver.ca",
 "password": "demodemo1"
}'

As mentioned, I'm assuming you have data in your database. You will need the ID. Mine is 5f7dab92ba455241a88d188d.

Here is my delete request:

Or if you would prefer the curl command:

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curl --location --request DELETE 'http://localhost:8080/cars/5f7dab92ba455241a88d188d' \
--header 'Content-Type: application/json' \
--header 'Authorization: Bearer <YOUR_TOKEN_FROM_SIGN_UP_RESPONSE>' \

And the result after execution:

That's it. You have now deleted a document from a Mongo database.

Thanks for reading!