// WithTransactionExample is an example of using the Session.WithTransaction function.
func WithTransactionExample() {
ctx := context.Background()
// For a replica set, include the replica set name and a seedlist of the members in the URI string; e.g.
// uri := "mongodb://mongodb0.example.com:27017,mongodb1.example.com:27017/?replicaSet=myRepl"
// For a sharded cluster, connect to the mongos instances; e.g.
// uri := "mongodb://mongos0.example.com:27017,mongos1.example.com:27017/"
var uri string
clientOpts := options.Client().ApplyURI(uri)
client, err := mongo.Connect(ctx, clientOpts)
if err != nil {
panic(err)
}
defer func() { _ = client.Disconnect(ctx) }()
// Prereq: Create collections.
wcMajority := writeconcern.New(writeconcern.WMajority(), writeconcern.WTimeout(1*time.Second))
wcMajorityCollectionOpts := options.Collection().SetWriteConcern(wcMajority)
fooColl := client.Database("mydb1").Collection("foo", wcMajorityCollectionOpts)
barColl := client.Database("mydb1").Collection("bar", wcMajorityCollectionOpts)
// Step 1: Define the callback that specifies the sequence of operations to perform inside the transaction.
callback := func(sessCtx mongo.SessionContext) (interface{}, error) {
// Important: You must pass sessCtx as the Context parameter to the operations for them to be executed in the
// transaction.
if _, err := fooColl.InsertOne(sessCtx, bson.D{{"abc", 1}}); err != nil {
return nil, err
}
if _, err := barColl.InsertOne(sessCtx, bson.D{{"xyz", 999}}); err != nil {
return nil, err
}
return nil, nil
}
// Step 2: Start a session and run the callback using WithTransaction.
session, err := client.StartSession()
if err != nil {
panic(err)
}
defer session.EndSession(ctx)
result, err := session.WithTransaction(ctx, callback)
if err != nil {
panic(err)
}
fmt.Printf("result: %v\n", result)
}
