Converting Primitive.ObjectID to String in Golang

In Go, the mongo-driver from go.mongodb.org/mongo-driver manages MongoDB data types. However, converting the primitive.ObjectID type to a string requires a specific approach.

When attempting to use type assertion as seen in the provided code:

mongoId := mongoDoc["_id"]
stringObjectID := mongoId.(string)

This line triggers the error:

panic: interface conversion: interface {} is primitive.ObjectID, not string

The issue arises because mongoDoc["_id"] is an interface{} containing a value of type primitive.ObjectID. Type assertion can only be performed on primitive types from interface values.

To obtain a string representation of the primitive.ObjectID, utilize the Hex() method of the primitive.ObjectID type. This method retrieves the hex representation of the ObjectId's bytes:

mongoId := mongoDoc["_id"]
stringObjectID := mongoId.(primitive.ObjectID).Hex()