Find all documents in a collection with mongo go driver

mongodb go mongo-go
Kelly Flet picture Kelly Flet · Feb 26, 2019 · Viewed 11.9k times · Source

I checked out the answer here but this uses the old and unmaintained mgo. How can I find all documents in a collection using the mongo-go-driver?

I tried passing a nil filter, but this does not return any documents and instead returns nil. I also checked the documentation but did not see any mention of returning all documents. Here is what I've tried with aforementioned result.

client, err := mongo.Connect(context.TODO(), "mongodb://localhost:27017")
coll := client.Database("test").Collection("albums")
if err != nil { fmt.Println(err) }
// we can assume we're connected...right?
fmt.Println("connected to mongodb")

var results []*Album
findOptions := options.Find()
cursor, err := coll.Find(context.TODO(), nil, findOptions)
if err != nil {
   fmt.Println(err) // prints 'document is nil'
}

Also, I'm about confused about why I need to specify findOptions when I've called the Find() function on the collection (or do I not need to specify?).

Answer

Zippo picture Zippo · Feb 26, 2019

Try passing an empty bson.D instead of nil:

cursor, err := coll.Find(context.TODO(), bson.D{})

Also, FindOptions is optional.

Disclaimer: I've never used the official driver, but there are a few examples at https://godoc.org/go.mongodb.org/mongo-driver/mongo

Seems like their tutorial is outdated :/

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