Mongo: A MongoDB Helper for Go Language

June 1, 2020 • Go MongoDB • 3 minutes to read • Edit

I am an avid user of MongoDB; I have used it everywhere from saving machine learning parameters to storing financial details. I have recently moved to Go language from Python/C++ and at the time of writing this article, MongoDB had its package for Go language - mongo-go-driver.

Traditionally, whenever we create a document in a collection, the database creates a unique ID - _id (more on that here), this field is of type ObjectID. ObjectID is a hexadecimal string that contains - 4-byte of timestamp value, 5-byte of a random value, 3-byte of incrementing counter.

Previously, I have used PostgreSQL, yes you can’t compare RDBMS to NoSQL, but I wanted to get a flavour of it, so I created a package called mongo. RDBMS type of database depends on the id field and are unique. Instead of using, _id to do your job, I have introduced id. This id filed can be used to add your UUID string.

Having to find documents by id adds extra overhead, you will need to index id field to make things faster.

I have also tried to make the API a bit easier to use, instead of using seven lines of code, you can use two lines to do the same work.

How to use it?

You can install the package using Go modules

go get github.com/akshaybabloo/mongo

Adding a document

import (
	"fmt"

	"github.com/akshaybabloo/mongo"
)

func main() {

	type data struct {
		Id   int    `bson:"id"`
		Name string `bson:"name"`
	}

	client := mongo.NewMongoDbClient{
		ConnectionUrl: "mongodb://localhost:27017/?retryWrites=true&w=majority",
		DatabaseName:  "test",
	}

	testData := data{
		Id:   1,
		Name: "Akshay",
	}

	done, err := client.Add("test_collection", testData)
	if err != nil {
		panic(err)
	}
	fmt.Println("The ID is:", done.InsertedID)
}

Delete a document

import (
	"fmt"

	"github.com/akshaybabloo/mongo"
)

func main() {
	client := mongo.NewMongoDbClient{
		ConnectionUrl: "mongodb://localhost:27017/?retryWrites=true&w=majority",
		DatabaseName:  "test",
	}

	deleted, err := client.Delete("test_collection", 1)
	if err != nil {
		panic(err)
	}
	fmt.Println("Deleted items:", deleted.DeletedCount)
}

Update a document

import (
	"fmt"

	"github.com/akshaybabloo/mongo"
)

func main() {
	type data struct {
		Name string `bson:"name"`
	}

	client := mongo.NewMongoDbClient{
		ConnectionUrl: "mongodb://localhost:27017/?retryWrites=true&w=majority",
		DatabaseName:  "test",
	}

	testData := data{
		Name: "Akshay",
	}

	updated, err := client.Update("test_collection", 1, testData)
	if err != nil {
		panic(err)
	}
	fmt.Println("Modified items:", updated.ModifiedCount)
}

Get a document

import (
	"fmt"

	"github.com/akshaybabloo/mongo"
)

func main() {

	type data struct {
		Id   int    `bson:"id"`
		Name string `bson:"name"`
	}

	client := mongo.NewMongoDbClient{
		ConnectionUrl: "mongodb://localhost:27017/?retryWrites=true&w=majority",
		DatabaseName:  "test",
	}

	var decodeData data
	output := client.Get("test_collection", 2).Decode(&decodeData)
	if output != nil {
		panic("No data found.")
	}
	fmt.Println(decodeData)
}

Collection and DB API

In addition to the mentioned APIs, I have exposed two more APIs - client.Collection and client.DB. client.Collection returns mongo.Collection, if you are not happy with using the provided APIs you can use MongoDB driver’s API directly. Like client.Collection, client.DB exposes mongo.Database.

Conclusion

Most of you wouldn’t even need this package, if you are into lazy coding and are coming from RDBMS, this might help you. I have tried my best to keep the tests accurate, they are not mocked, I use MongoDB community to test them.