$push example

main.go

package main

import (
	"context"
	"fmt"

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

func main() {
	client, err := mongo.Connect(context.Background())
	if err != nil {
		panic(err)
	}
	coll := client.Database("foo").Collection("bar")
	coll.Drop(context.Background())
	_, err = coll.InsertOne(context.Background(), bson.D{
		{"doc_id", "qwe123"},
		{"embedded_doc", bson.A{
			bson.D{
				{"embedded_doc_ID", "abc123"},
				{"item", 1},
				{"data", "xyz"},
				{"embedded_doc_two", bson.A{
					bson.D{
						{"createdOn", "sssss"},
					},
				}},
			},
			bson.D{
				{"embedded_doc_ID", "xyz456"},
				{"item", 1},
				{"data", "xyz"},
				{"embedded_doc_two", bson.A{
					bson.D{
						{"createdOn", "zzzzz"},
					},
				}},
			},
		}},
	})
	if err != nil {
		panic(err)
	}
	fmt.Println(coll.FindOne(context.Background(), bson.D{{"doc_id", "qwe123"}}).DecodeBytes())
	_, err = coll.UpdateOne(context.Background(), bson.D{{"doc_id", "qwe123"}}, bson.D{{"$push", bson.D{{"embedded_doc.1.embedded_doc_two", bson.D{{"createdOn", "aaaaa"}}}}}})
	if err != nil {
		panic(err)
	}
	fmt.Println(coll.FindOne(context.Background(), bson.D{{"doc_id", "qwe123"}}).DecodeBytes())
}