Remove redundant checks and add MetaCache (#301)

Signed-off-by: zhenshan.cao <[email protected]>

Signed-off-by: zhenshan.cao <[email protected]>

client/client.go

@@ -17,16 +17,11 @@ import (
 	"time"
 
 	"github.com/milvus-io/milvus-sdk-go/v2/entity"
+
 	"google.golang.org/grpc"
 )
 
 // Client is the interface used to communicate with Milvus
-// The common usage is like follow
-//		c, err := client.NewGrpcClient(context.Background, "address-to-milvus") // or other creation func maybe added later
-//		if err != nil {
-//		//handle err
-//		}
-//		// start doing things with client instance, note that there is no need to call Connect since NewXXXClient will do that for you
 type Client interface {
 	// Close close the remaining connection resources
 	Close() error

client/client_grpc_collection.go

@@ -19,9 +19,10 @@ import (
 
 	"github.com/golang/protobuf/proto"
 	"github.com/milvus-io/milvus-sdk-go/v2/entity"
+	"google.golang.org/grpc"
+
 	common "github.com/milvus-io/milvus-sdk-go/v2/internal/proto/common"
 	server "github.com/milvus-io/milvus-sdk-go/v2/internal/proto/server"
-	"google.golang.org/grpc"
 )
 
 // grpcClient, uses default grpc service definition to connect with Milvus2.0
@@ -231,6 +232,13 @@ func (c *grpcClient) DescribeCollection(ctx context.Context, collName string) (*
 		ConsistencyLevel: entity.ConsistencyLevel(resp.ConsistencyLevel),
 	}
 	collection.Name = collection.Schema.CollectionName
+	colInfo := collInfo{
+		ID:               collection.ID,
+		Name:             collection.Name,
+		Schema:           collection.Schema,
+		ConsistencyLevel: collection.ConsistencyLevel,
+	}
+	MetaCache.setCollectionInfo(resp.CollectionName, &colInfo)
 	return collection, nil
 }
 
@@ -250,7 +258,11 @@ func (c *grpcClient) DropCollection(ctx context.Context, collName string) error
 	if err != nil {
 		return err
 	}
-	return handleRespStatus(resp)
+	err = handleRespStatus(resp)
+	if err == nil {
+		MetaCache.setCollectionInfo(collName, nil)
+	}
+	return err
 }
 
 // HasCollection check whether collection name exists