how to create a mongo db package - mongodb

Question

I'd like to build an infrastructure, which is a package for the project. So that other developers can import this package to perform CRUD operations on the DB.
But I've got an error during the test:
type Students struct {
Name string
Age int
}
type InsertOneResult struct {
InsertedID interface{}
}
func dbGetOne(coll, document interface{}) (*InsertOneResult, error) {
...
}
func dbUpdateOne(coll, document interface{}) (*InsertOneResult, error) {
...
}
func dbDeleteOne(coll, document interface{}) (*InsertOneResult, error) {
...
}
func dbInsertOne(coll, document interface{}) (*InsertOneResult, error) {
res, err := coll.InsertOne(context.TODO(), document)
if err != nil {
log.Fatal(err)
}
return &InsertOneResult{InsertedID: res[0]}, err
}
func main() {
client, err := mongo.NewClient(options.Client().ApplyURI("mongodb://<user>:<password>#<host>:<port>/<dbname>"))
if err != nil {
log.Fatal(err)
}
ctx, _ := context.WithTimeout(context.Background(), 30*time.Second)
err = client.Connect(ctx)
if err != nil {
log.Fatal(err)
}
coll := client.Database("db").Collection("students")
data := Students{"Amy", 10}
res, err := dbInsertOne(coll, data)
if err != nil {
log.Fatal(err)
}
fmt.Printf("inserted document with ID %v\n", res.InsertedID)
}
Here's the error:
./main.go:24:18: coll.InsertOne undefined (type interface {} is interface with no methods)
Is there any way to solve this? Thanks in advance.

Answer 1

Hey it looks like the error could be coming from a type conversion issue. The solution would be to clearly define the type for coll as *mongo.Collection in the dbInsertOne() function. This allows the compiler at compile time to figure out the structure of the input instead of having to rely on an abstract interface.
func dbInsertOne(coll *mongo.Collection, document interface{}) (*InsertOneResult, error) {
res, err := coll.InsertOne(context.TODO(), document)
if err != nil {
log.Fatal(err)
}
return &InsertOneResult{InsertedID: res.InsertedID}, err
}
I would further suggest that the 2nd argument document should also be a typed known term if possible. e.g.
func dbInsertOne(coll *mongo.Collection, document Students)
Static typing will help quite a bit and clear up any confusion.