[SPARK-42412][WIP] Initial PR of Spark connect ML

connector/connect/common/src/main/protobuf/spark/connect/base.proto

@@ -23,6 +23,7 @@ import "google/protobuf/any.proto";
 import "spark/connect/commands.proto";
 import "spark/connect/relations.proto";
 import "spark/connect/types.proto";
+import "spark/connect/ml.proto";
 
 option java_multiple_files = true;
 option java_package = "org.apache.spark.connect.proto";
@@ -35,6 +36,7 @@ message Plan {
   oneof op_type {
     Relation root = 1;
     Command command = 2;
+    MlCommand ml_command = 3;
   }
 }
 
@@ -228,6 +230,9 @@ message ExecutePlanResponse {
     // Special case for executing SQL commands.
     SqlCommandResult sql_command_result = 5;
 
+    // ML command response
+    MlCommandResponse ml_command_result = 6;
+
     // Support arbitrary result objects.
     google.protobuf.Any extension = 999;
   }

connector/connect/common/src/main/protobuf/spark/connect/expressions.proto

@@ -172,6 +172,12 @@ message Expression {
       CalendarInterval calendar_interval = 19;
       int32 year_month_interval = 20;
       int64 day_time_interval = 21;
+
+      List list = 99;
+    }
+
+    message List {
+      repeated Expression.Literal elements = 1;
     }
 
     message Decimal {

connector/connect/common/src/main/protobuf/spark/connect/ml.proto

@@ -0,0 +1,136 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+syntax = 'proto3';
+
+package spark.connect;
+
+import "google/protobuf/any.proto";
+import "spark/connect/expressions.proto";
+import "spark/connect/types.proto";
+import "spark/connect/relations.proto";
+import "spark/connect/ml_common.proto";
+
+option java_multiple_files = true;
+option java_package = "org.apache.spark.connect.proto";
+
+
+message Evaluator {
+  string name = 1;
+  Params params = 2;
+  string uid = 3;
+}
+
+
+message MlCommand {
+  oneof ml_command_type {
+    Fit fit = 1;
+    ModelAttr model_attr = 2;
+    ModelSummaryAttr model_summary_attr = 3;
+    LoadModel load_model = 4;
+    SaveModel save_model = 5;
+    Evaluate evaluate = 6;
+  }
+
+  message Fit {
+    Stage estimator = 1;
+    Relation dataset = 2;
+  }
+
+  message Evaluate {
+    Evaluator evaluator = 1;
+  }
+
+  message LoadModel {
+    string name = 1;
+    string path = 2;
+  }
+
+  message SaveModel {
+    int64 model_ref_id = 1;
+    string path = 2; // saving path
+    bool overwrite = 3;
+    map<string, string> options = 4; // saving options
+  }
+
+  message ModelAttr {
+    int64 model_ref_id = 1;
+    string name = 2;
+  }
+
+  message ModelSummaryAttr {
+    int64 model_ref_id = 1;
+    string name = 2;
+    Params params = 3;
+
+    // Evaluation dataset that it uses to computes
+    // the summary attribute
+    // If not set, get attributes from
+    // model.summary (i.e. the summary on training dataset)
+    optional Relation evaluation_dataset = 4;
+  }
+}
+
+
+message MlCommandResponse {
+  oneof ml_command_response_type {
+    Expression.Literal literal = 1;
+    ModelInfo model_info = 2;
+    Vector vector = 3;
+    Matrix matrix = 4;
+  }
+  message ModelInfo {
+    int64 model_ref_id = 1;
+    string model_uid = 2;
+  }
+}
+
+
+message Vector {
+  oneof one_of {
+    Dense dense = 1;
+    Sparse sparse = 2;
+  }
+  message Dense {
+    repeated double values = 1;
+  }
+  message Sparse {
+    int32 size = 1;
+    repeated double indices = 2;
+    repeated double values = 3;
+  }
+}
+
+message Matrix {
+  oneof one_of {
+    Dense dense = 1;
+    Sparse sparse = 2;
+  }
+  message Dense {
+    int32 num_rows = 1;
+    int32 num_cols = 2;
+    repeated double values = 3;
+  }
+  message Sparse {
+    int32 num_rows = 1;
+    int32 num_cols = 2;
+    repeated double colptrs = 3;
+    repeated double row_indices = 4;
+    repeated double values = 5;
+    bool is_transposed = 6;
+  }
+}

connector/connect/common/src/main/protobuf/spark/connect/ml_common.proto

@@ -0,0 +1,44 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+syntax = 'proto3';
+
+package spark.connect;
+
+import "google/protobuf/any.proto";
+import "spark/connect/expressions.proto";
+import "spark/connect/types.proto";
+
+option java_multiple_files = true;
+option java_package = "org.apache.spark.connect.proto";
+
+
+message Params {
+  map<string, Expression.Literal> params = 1;
+  map<string, Expression.Literal> default_params = 2;
+}
+
+message Stage {
+  string name = 1;
+  Params params = 2;
+  string uid = 3;
+  StageType type = 4;
+  enum StageType {
+    ESTIMATOR = 0;
+    TRANSFORMER = 1;
+  }
+}

connector/connect/common/src/main/protobuf/spark/connect/relations.proto

@@ -23,6 +23,7 @@ import "google/protobuf/any.proto";
 import "spark/connect/expressions.proto";
 import "spark/connect/types.proto";
 import "spark/connect/catalog.proto";
+import "spark/connect/ml_common.proto";
 
 option java_multiple_files = true;
 option java_package = "org.apache.spark.connect.proto";
@@ -80,13 +81,50 @@ message Relation {
     // Catalog API (experimental / unstable)
     Catalog catalog = 200;
 
+    // ML relation
+    MlRelation ml_relation = 300;
+
     // This field is used to mark extensions to the protocol. When plugins generate arbitrary
     // relations they can add them here. During the planning the correct resolution is done.
     google.protobuf.Any extension = 998;
     Unknown unknown = 999;
   }
 }
 
+message MlRelation {
+  oneof ml_relation_type {
+    ModelTransform model_transform = 1;
+    FeatureTransform feature_transform = 2;
+    ModelAttr model_attr = 3;
+    ModelSummaryAttr model_summary_attr = 4;
+  }
+  message ModelTransform {
+    Relation input = 1;
+    int64 model_ref_id = 2;
+    Params params = 3;
+  }
+  message FeatureTransform {
+    Relation input = 1;
+    Stage transformer = 2;
+  }
+  message ModelAttr {
+    int64 model_ref_id = 1;
+    string name = 2;
+  }
+  message ModelSummaryAttr {
+    int64 model_ref_id = 1;
+    string name = 2;
+    Params params = 3;
+
+    // Evaluation dataset that it uses to computes
+    // the summary attribute
+    // If not set, get attributes from
+    // model.summary (i.e. the summary on training dataset)
+    optional Relation evaluation_dataset = 4;
+  }
+}
+
+
 // Used for testing purposes only.
 message Unknown {}
 

connector/connect/server/pom.xml

@@ -93,6 +93,18 @@
         </exclusion>
       </exclusions>
     </dependency>
+    <dependency>
+      <groupId>org.apache.spark</groupId>
+      <artifactId>spark-mllib_${scala.binary.version}</artifactId>
+      <version>${project.version}</version>
+      <scope>provided</scope>
+      <exclusions>
+        <exclusion>
+          <groupId>com.google.guava</groupId>
+          <artifactId>guava</artifactId>
+        </exclusion>
+      </exclusions>
+    </dependency>
     <dependency>
       <groupId>org.apache.spark</groupId>
       <artifactId>spark-catalyst_${scala.binary.version}</artifactId>