GODRIVER-1147 Add an API to create collections (#351)

Author: Divjot Arora

mongo/crud_examples_test.go

@@ -58,6 +58,62 @@ func ExampleClient_Watch() {
 
 // Database examples
 
+func ExampleDatabase_CreateCollection() {
+	var db *mongo.Database
+
+	// Create a "users" collection with a JSON schema validator. The validator will ensure that each document in the
+	// collection has "name" and "age" fields.
+	jsonSchema := bson.M{
+		"bsonType": "object",
+		"required": []string{"name", "age"},
+		"properties": bson.M{
+			"name": bson.M{
+				"bsonType":    "string",
+				"description": "the name of the user, which is required and must be a string",
+			},
+			"age": bson.M{
+				"bsonType":    "int",
+				"minimum":     18,
+				"description": "the age of the user, which is required and must be an integer >= 18",
+			},
+		},
+	}
+	validator := bson.M{
+		"$jsonSchema": jsonSchema,
+	}
+	opts := options.CreateCollection().SetValidator(validator)
+
+	if err := db.CreateCollection(context.TODO(), "users", opts); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func ExampleDatabase_CreateView() {
+	var db *mongo.Database
+
+	// Create a view on the "users" collection called "usernames". Specify a pipeline that concatenates the "firstName"
+	// and "lastName" fields from each document in "users" and projects the result into the "fullName" field in the
+	// view.
+	projectStage := bson.D{
+		{"$project", bson.D{
+			{"_id", 0},
+			{"fullName", bson.D{
+				{"$concat", []string{"$firstName", " ", "$lastName"}},
+			}},
+		}},
+	}
+	pipeline := mongo.Pipeline{projectStage}
+
+	// Specify the Collation option to set a default collation for the view.
+	opts := options.CreateView().SetCollation(&options.Collation{
+		Locale: "en_US",
+	})
+
+	if err := db.CreateView(context.TODO(), "usernames", "users", pipeline, opts); err != nil {
+		log.Fatal(err)
+	}
+}
+
 func ExampleDatabase_ListCollectionNames() {
 	var db *mongo.Database
 

mongo/database.go

@@ -18,6 +18,7 @@ import (
 	"go.mongodb.org/mongo-driver/mongo/readpref"
 	"go.mongodb.org/mongo-driver/mongo/writeconcern"
 	"go.mongodb.org/mongo-driver/x/bsonx"
+	"go.mongodb.org/mongo-driver/x/bsonx/bsoncore"
 	"go.mongodb.org/mongo-driver/x/mongo/driver"
 	"go.mongodb.org/mongo-driver/x/mongo/driver/description"
 	"go.mongodb.org/mongo-driver/x/mongo/driver/operation"
@@ -432,3 +433,135 @@ func (db *Database) Watch(ctx context.Context, pipeline interface{},
 	}
 	return newChangeStream(ctx, csConfig, pipeline, opts...)
 }
+
+// CreateCollection executes a create command to explicitly create a new collection with the specified name on the
+// server. If the collection being created already exists, this method will return a mongo.CommandError. This method
+// requires driver version 1.4.0 or higher.
+//
+// The opts parameter can be used to specify options for the operation (see the options.CreateCollectionOptions
+// documentation).
+func (db *Database) CreateCollection(ctx context.Context, name string, opts ...*options.CreateCollectionOptions) error {
+	cco := options.MergeCreateCollectionOptions(opts...)
+	op := operation.NewCreate(name)
+
+	if cco.Capped != nil {
+		op.Capped(*cco.Capped)
+	}
+	if cco.Collation != nil {
+		op.Collation(bsoncore.Document(cco.Collation.ToDocument()))
+	}
+	if cco.DefaultIndexOptions != nil {
+		idx, doc := bsoncore.AppendDocumentStart(nil)
+		if cco.DefaultIndexOptions.StorageEngine != nil {
+			storageEngine, err := transformBsoncoreDocument(db.registry, cco.DefaultIndexOptions.StorageEngine)
+			if err != nil {
+				return err
+			}
+
+			doc = bsoncore.AppendDocumentElement(doc, "storageEngine", storageEngine)
+		}
+		doc, err := bsoncore.AppendDocumentEnd(doc, idx)
+		if err != nil {
+			return err
+		}
+
+		op.IndexOptionDefaults(doc)
+	}
+	if cco.MaxDocuments != nil {
+		op.Max(*cco.MaxDocuments)
+	}
+	if cco.SizeInBytes != nil {
+		op.Size(*cco.SizeInBytes)
+	}
+	if cco.StorageEngine != nil {
+		storageEngine, err := transformBsoncoreDocument(db.registry, cco.StorageEngine)
+		if err != nil {
+			return err
+		}
+		op.StorageEngine(storageEngine)
+	}
+	if cco.ValidationAction != nil {
+		op.ValidationAction(*cco.ValidationAction)
+	}
+	if cco.ValidationLevel != nil {
+		op.ValidationLevel(*cco.ValidationLevel)
+	}
+	if cco.Validator != nil {
+		validator, err := transformBsoncoreDocument(db.registry, cco.Validator)
+		if err != nil {
+			return err
+		}
+		op.Validator(validator)
+	}
+
+	return db.executeCreateOperation(ctx, op)
+}
+
+// CreateView executes a create command to explicitly create a view on the server. See
+// https://docs.mongodb.com/manual/core/views/ for more information about views. This method requires driver version >=
+// 1.4.0 and MongoDB version >= 3.4.
+//
+// The viewName parameter specifies the name of the view to create.
+//
+// The viewOn parameter specifies the name of the collection or view on which this view will be created
+//
+// The pipeline parameter specifies an aggregation pipeline that will be exececuted against the source collection or
+// view to create this view.
+//
+// The opts parameter can be used to specify options for the operation (see the options.CreateViewOptions
+// documentation).
+func (db *Database) CreateView(ctx context.Context, viewName, viewOn string, pipeline interface{},
+	opts ...*options.CreateViewOptions) error {
+
+	pipelineArray, _, err := transformAggregatePipelinev2(db.registry, pipeline)
+	if err != nil {
+		return err
+	}
+
+	op := operation.NewCreate(viewName).
+		ViewOn(viewOn).
+		Pipeline(pipelineArray)
+	cvo := options.MergeCreateViewOptions(opts...)
+	if cvo.Collation != nil {
+		op.Collation(bsoncore.Document(cvo.Collation.ToDocument()))
+	}
+
+	return db.executeCreateOperation(ctx, op)
+}
+
+func (db *Database) executeCreateOperation(ctx context.Context, op *operation.Create) error {
+	sess := sessionFromContext(ctx)
+	if sess == nil && db.client.sessionPool != nil {
+		var err error
+		sess, err = session.NewClientSession(db.client.sessionPool, db.client.id, session.Implicit)
+		if err != nil {
+			return err
+		}
+		defer sess.EndSession()
+	}
+
+	err := db.client.validSession(sess)
+	if err != nil {
+		return err
+	}
+
+	wc := db.writeConcern
+	if sess.TransactionRunning() {
+		wc = nil
+	}
+	if !writeconcern.AckWrite(wc) {
+		sess = nil
+	}
+
+	selector := makePinnedSelector(sess, db.writeSelector)
+	op = op.Session(sess).
+		WriteConcern(wc).
+		CommandMonitor(db.client.monitor).
+		ServerSelector(selector).
+		ClusterClock(db.client.clock).
+		Database(db.name).
+		Deployment(db.client.deployment).
+		Crypt(db.client.crypt)
+
+	return replaceErrors(op.Execute(ctx))
+}