MongoDB Find using golang

MongoDB Find using golang

This article explains how to use MongoDB Find method in Golong using mongodb-drivers

create application directory for golang application, and create init go module as below

mkdir mongodbfind
cd mongodbfind
go mod init github.com/freedomtutorials/mongodbfind

import mongodb-drivers in go module, for this issue the below command

go get go.mongodb.org/mongo-driver

Connect to MongoDB, using below code

    // set the mongodb uri 
    clientOptions := options.Client().ApplyURI("mongodb://127.0.0.1:27017")
	
    //connect to mongodb
    client, err := mongo.Connect(context.TODO(), clientOptions)

    if err != nil {
        log.Fatal(err)
    }

    err = client.Ping(context.TODO(), nil)

    if err != nil {
        log.Fatal(err)
    }

    fmt.Println("Connected to MongoDB!")

    freedomtutorialsDB := client.Database("freedomtutorials")
    mydataCollection := freedomtutorialsDB.Collection("mydata")

Reading All Documents from a Collection using cursor.All

	cursor, err := mydataCollection.Find( context.TODO(), bson.M{})
	if err != nil {
		log.Fatal(err)
	}

	var device []Device
	if err = cursor.All( context.TODO(), &device); err != nil {
		log.Fatal(err)
	}
	fmt.Println(device)

---

or we can Read one document at a time from cursor and append to slice

	cursor, err := mydataCollection.Find( context.TODO(), bson.M{})
	if err != nil {
		log.Fatal(err)
	}

	for cursor.Next( context.TODO()) {
		var device Device
		if err = cursor.Decode( &device); err != nil {
			log.Fatal(err)
		}
		devices = append( devices, device)
	}
	
	fmt.Println(devices)

close the cursor

cursor.Close( context.TODO())

code can be download from below Github URL

https://github.com/freedomtutorials/mongodbfind