Connect to mongo using mongo-go-driver and map nested results using struct

go-mongo.go

/**
//Sample user collection
db.users.findOne()
{
    "_id" : 1,
    "attrs" : {
        "name" : "Name #1",
        "age" : 25,
        "email" : "useremail1@gmail.com"
    },
    "pid" : [
        1,
        2,
        6,
        7,
        8,
    ]
}
*/

package main

import (
    "context"
    "fmt"
    "log"
    "time"

    "go.mongodb.org/mongo-driver/bson"
    "go.mongodb.org/mongo-driver/mongo"
    "go.mongodb.org/mongo-driver/mongo/options"
)

func main() {
    connectMongo()
}

//UserAttrs User Attrs Mapping
type UserAttrs struct {
    Name  string `json:"name" bson:"name"`
    Age   int    `json:"age" bson:"age"`
    Email string `json:"email" bson:"email"`
}

//Users User Mapping
type Users struct {
    ID    int `json:"id" bson:"_id"`
    Attrs UserAttrs
    Pid   []int32 `json:"pid", bson: "pid"`
}

func connectMongo() {
    ctx, _ := context.WithTimeout(context.Background(), 10*time.Second)
    client, err := mongo.Connect(ctx, options.Client().ApplyURI("mongodb://127.0.0.1:27017"))
    
    if err != nil {
        fmt.Println(err)
	}
    collection := client.Database("go_mongo").Collection("users")
    cur, err := collection.Find(ctx, bson.D{})
    if err != nil {
        log.Fatal("Error while collection find", err)
    }
    defer cur.Close(ctx)
    for cur.Next(ctx) {
        users := Users{}
        err := cur.Decode(&s)
        if err != nil {
            log.Fatal("Error while struct mapping :: ", err)
        }
        for i, v := range users.Pid {
            fmt.Printf("Key is :: %d and Value is :: %d\n", i, v)
        }
        fmt.Println("attrs : ", users.Attrs, "name : ", users.Attrs.Name)
    }
    if err := cur.Err(); err != nil {
        log.Fatal(err)
    }
}