You can open a change stream on a Collection, Database, or Client by using the Watch() method.
Example
Tip
Read the Usage Examples to learn how to run this example.
The following example opens a change stream on the restaurants collection and prints inserted documents:
coll := client.Database("sample_restaurants").Collection("restaurants")
// Creates instructions to watch for insert operationspipeline := mongo.Pipeline{bson.D{{"$match", bson.D{{"operationType", "insert"}}}}}
// Creates a change stream that receives change eventscs, err := coll.Watch(context.TODO(), pipeline)if err != nil { panic(err)}defer cs.Close(context.TODO())
fmt.Println("Waiting For Change Events. Insert something in MongoDB!")
// Prints a message each time the change stream receives an eventfor cs.Next(context.TODO()) { var event bson.M if err := cs.Decode(&event); err != nil { panic(err) } output, err := json.MarshalIndent(event["fullDocument"], "", " ") if err != nil { panic(err) } fmt.Printf("%s\n", output)}if err := cs.Err(); err != nil { panic(err)}View a fully runnable example.
Expected Result
After you run the full example, run the Insert a Document usage example in a different shell. Once you run the insert operation, you should see the following output:
// results truncated{ "_id": ..., "name": "8282", "cuisine": "Korean"}Important
Make sure to shut down this usage example once you finish by closing your terminal.
Additional Information
To learn more about opening a change stream and handling potential errors, see:
Fundamentals page on change streams
MongoDB Server Manual Change Streams Documentation