Quick Start

Initialize with Go Mod

Create a new directory and initialize your project with go mod.

mkdir go-quickstart
cd go-quickstart
go mod init go-quickstart

Add MongoDB as a Dependency

Use go get to add the Go driver as a dependency.

go get go.mongodb.org/mongo-driver/mongo

Add Other Dependencies

Use go get to add any additional dependencies. This Quick Start uses the godotenv package to read a MongoDB connection string from an environment variable to avoid embedding credentials within source code.

go get github.com/joho/godotenv

Set up a Free Tier Cluster in Atlas

After setting up your Go project dependencies, create a MongoDB cluster where you can store and manage your data. Complete the Get Started with Atlas guide to set up a new Atlas account, free tier MongoDB cluster, load datasets, and interact with the data.

After completing the steps in the Atlas guide, you should have a new MongoDB cluster deployed in Atlas, a new database user, and sample datasets loaded into your cluster.

Connect to your Cluster

In this step, you create and run an application that uses the Go driver to connect to your MongoDB cluster and run a query on the sample data.

You pass instructions to the driver on where and how to connect to your MongoDB cluster in a string called the connection string. This string includes information on the hostname or IP address and port of your cluster, authentication mechanism, user credentials when applicable, and other connection options.

To retrieve your connection string for the cluster and user you created in the previous step, log into your Atlas account and navigate to the Database section and click the Connect button for the cluster that you want to connect to as shown below.

Proceed to the Connect Your Application step and select the Go driver. Then, click the Copy button to copy the connection string to your clipboard as shown below.

Save your Atlas connection string in a safe location that you can access for the next step.

To learn more about conencting to the Go driver through Atlas, see the Atlas driver connection guide and select Go from the Select your language dropdown.

Query Your MongoDB Cluster from Your Application

Next, create a file to contain your application called main.go in the base directory of your project. Use the following sample code to run a query on your sample dataset in MongoDB Atlas.

Set the value of the uri variable with your MongoDB Atlas connection string, or create an environmental variable with the name MONGODB_URI with your Atlas connection string.

export MONGODB_URI='<your atlas connection string>'

package main
import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"os"
	"github.com/joho/godotenv"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)
func main() {
	if err := godotenv.Load(); err != nil {
		log.Println("No .env file found")
	}
	uri := os.Getenv("MONGODB_URI")
	if uri == "" {
		log.Fatal("You must set your 'MONGODB_URI' environmental variable. See\n\t https://www.mongodb.com/docs/drivers/go/current/usage-examples/#environment-variable")
	}
	client, err := mongo.Connect(context.TODO(), options.Client().ApplyURI(uri))
	if err != nil {
		panic(err)
	}
	defer func() {
		if err := client.Disconnect(context.TODO()); err != nil {
			panic(err)
		}
	}()
	coll := client.Database("sample_mflix").Collection("movies")
	title := "Back to the Future"
	var result bson.M
	err = coll.FindOne(context.TODO(), bson.D{{"title", title}}).Decode(&result)
	if err == mongo.ErrNoDocuments {
		fmt.Printf("No document was found with the title %s\n", title)
		return
	}
	if err != nil {
		panic(err)
	}
	jsonData, err := json.MarshalIndent(result, "", "    ")
	if err != nil {
		panic(err)
	}
	fmt.Printf("%s\n", jsonData)
}

Run the sample code with the following command from your command line:

go run main.go

When you run main.go, it should output the details of the movie from the sample dataset which looks something like the following:

{
    "_id": "573a1398f29313caabce9682",
    ...
    "title": "Back to the Future",
    ...
}

If you receive no output or an error, check whether you properly set up your environment variable and whether you loaded the sample dataset in your MongoDB Atlas cluster.

After completing this step, you should have a working application that uses the Go driver to connect to your MongoDB cluster, run a query on the sample data, and print out the result.