[PPL] Add simple json formatter

plugin/src/main/java/com/amazon/opendistroforelasticsearch/sql/plugin/rest/RestPPLQueryAction.java

@@ -18,7 +18,7 @@
 import com.amazon.opendistroforelasticsearch.sql.elasticsearch.security.SecurityAccess;
 import com.amazon.opendistroforelasticsearch.sql.plugin.request.PPLQueryRequestFactory;
 import com.amazon.opendistroforelasticsearch.sql.ppl.PPLService;
-import com.amazon.opendistroforelasticsearch.sql.ppl.ResponseListener;
+import com.amazon.opendistroforelasticsearch.sql.protocol.response.ResponseListener;
 import com.amazon.opendistroforelasticsearch.sql.ppl.config.PPLServiceConfig;
 import com.amazon.opendistroforelasticsearch.sql.ppl.domain.PPLQueryResponse;
 import org.elasticsearch.client.node.NodeClient;

ppl/build.gradle

@@ -32,6 +32,7 @@ dependencies {
     compile group: 'org.springframework', name: 'spring-beans', version: '5.2.5.RELEASE'
     compile project(':common')
     compile project(':core')
+    compile project(':protocol')
 
     testCompile group: 'junit', name: 'junit', version: '4.12'
 

ppl/src/main/java/com/amazon/opendistroforelasticsearch/sql/ppl/PPLService.java

@@ -15,6 +15,7 @@
 
 package com.amazon.opendistroforelasticsearch.sql.ppl;
 
+import com.amazon.opendistroforelasticsearch.sql.protocol.response.ResponseListener;
 import com.amazon.opendistroforelasticsearch.sql.ppl.antlr.PPLSyntaxParser;
 import com.amazon.opendistroforelasticsearch.sql.ppl.domain.PPLQueryRequest;
 import com.amazon.opendistroforelasticsearch.sql.ppl.domain.PPLQueryResponse;

ppl/src/test/java/com/amazon/opendistroforelasticsearch/sql/ppl/PPLServiceTest.java

@@ -15,6 +15,7 @@
 
 package com.amazon.opendistroforelasticsearch.sql.ppl;
 
+import com.amazon.opendistroforelasticsearch.sql.protocol.response.ResponseListener;
 import com.amazon.opendistroforelasticsearch.sql.ppl.config.PPLServiceConfig;
 import com.amazon.opendistroforelasticsearch.sql.ppl.domain.PPLQueryRequest;
 import com.amazon.opendistroforelasticsearch.sql.ppl.domain.PPLQueryResponse;

protocol/build.gradle

@@ -0,0 +1,60 @@
+plugins {
+    id 'java'
+    id "io.freefair.lombok"
+    id 'jacoco'
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    compile group: 'com.google.guava', name: 'guava', version:'23.0'
+    compile group: 'org.json', name: 'json', version:'20180813' //TODO: change to other JSON lib?
+    compile project(':core')
+
+    testImplementation('org.junit.jupiter:junit-jupiter:5.6.2')
+    testCompile group: 'org.hamcrest', name: 'hamcrest-library', version: '2.1'
+    testCompile group: 'org.mockito', name: 'mockito-core', version: '3.3.3'
+    testCompile group: 'org.mockito', name: 'mockito-junit-jupiter', version: '3.3.3'
+}
+
+test {
+    useJUnitPlatform()
+    testLogging {
+        events "passed", "skipped", "failed"
+    }
+}
+
+jacoco {
+    toolVersion = "0.8.3"
+}
+jacocoTestReport {
+    reports {
+        html.enabled true
+    }
+    afterEvaluate {
+        classDirectories.setFrom(files(classDirectories.files.collect {
+            fileTree(dir: it)
+        }))
+    }
+}
+test.finalizedBy(project.tasks.jacocoTestReport)
+
+jacocoTestCoverageVerification {
+    violationRules {
+        rule {
+            limit {
+                minimum = 1.0
+            }
+
+        }
+    }
+    afterEvaluate {
+        classDirectories.setFrom(files(classDirectories.files.collect {
+            fileTree(dir: it)
+        }))
+    }
+}
+check.dependsOn jacocoTestCoverageVerification
+jacocoTestCoverageVerification.dependsOn jacocoTestReport

protocol/lombok.config

@@ -0,0 +1,3 @@
+# This file is generated by the 'io.freefair.lombok' Gradle plugin
+config.stopBubbling = true
+lombok.addLombokGeneratedAnnotation = true

protocol/src/main/java/com/amazon/opendistroforelasticsearch/sql/protocol/response/QueryResponse.java

@@ -0,0 +1,95 @@
+/*
+ *    Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License").
+ *    You may not use this file except in compliance with the License.
+ *    A copy of the License is located at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    or in the "license" file accompanying this file. This file 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.
+ *
+ */
+
+package com.amazon.opendistroforelasticsearch.sql.protocol.response;
+
+import com.amazon.opendistroforelasticsearch.sql.data.model.ExprValue;
+import com.amazon.opendistroforelasticsearch.sql.data.model.ExprValueUtils;
+import lombok.RequiredArgsConstructor;
+
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+/**
+ * Query response that encapsulates query results and isolate {@link ExprValue} related from formatter implementation.
+ */
+@RequiredArgsConstructor
+public class QueryResponse implements Iterable<Object[]> {
+
+    /**
+     * Results which are collection of expression
+     */
+    private final Collection<ExprValue> exprValues;
+
+
+    /**
+     * @return  size of results
+     */
+    public int size() {
+        return exprValues.size();
+    }
+
+    /**
+     * Parse column name from results
+     * @return  mapping from column names to its expression type
+     */
+    public Map<String, String> columnNameTypes() {
+        if (exprValues.isEmpty()) {
+            return Collections.emptyMap();
+        }
+
+        Map<String, ExprValue> tupleValue = getFirstTupleValue();
+        return populateColumnNameAndTypes(tupleValue);
+    }
+
+    @Override
+    public Iterator<Object[]> iterator() {
+        // Any chance to avoid copy for json response generation?
+        return exprValues.stream().
+                          map(ExprValueUtils::getTupleValue).
+                          map(Map::values).
+                          map(this::convertExprValuesToValues).
+                          iterator();
+    }
+
+    private Map<String, ExprValue> getFirstTupleValue() {
+        // Assume expression is always tuple on first level
+        //  and columns (keys) of all tuple values are exactly same
+        ExprValue firstValue = exprValues.iterator().next();
+        return ExprValueUtils.getTupleValue(firstValue);
+    }
+
+    private Map<String, String> populateColumnNameAndTypes(Map<String, ExprValue> tupleValue) {
+        // Use linked hashmap to maintain original order in tuple expression
+        Map<String, String> colNameTypes = new LinkedHashMap<>();
+        tupleValue.forEach((name, expr) -> colNameTypes.put(name, getTypeString(expr)));
+        return colNameTypes;
+    }
+
+    private Object[] convertExprValuesToValues(Collection<ExprValue> exprValues) {
+        return exprValues.stream().
+                          map(ExprValue::value).
+                          toArray(Object[]::new);
+    }
+
+    private String getTypeString(ExprValue exprValue) {
+        return exprValue.type().name().toLowerCase();
+    }
+
+}

protocol/src/main/java/com/amazon/opendistroforelasticsearch/sql/protocol/response/ResponseListener.java

@@ -0,0 +1,39 @@
+/*
+ *    Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License").
+ *    You may not use this file except in compliance with the License.
+ *    A copy of the License is located at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    or in the "license" file accompanying this file. This file 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.
+ *
+ */
+
+package com.amazon.opendistroforelasticsearch.sql.protocol.response;
+
+/**
+ * Response listener for response post-processing callback.
+ * This is necessary because execution engine may schedule and execute in different thread.
+ *
+ * @param <Response>    response class
+ */
+public interface ResponseListener<Response> {
+
+    /**
+     * Handle successful response.
+     * @param response  successful response
+     */
+    void onResponse(Response response);
+
+    /**
+     * Handle failed response.
+     * @param e     exception captured
+     */
+    void onFailure(Exception e);
+
+}

protocol/src/main/java/com/amazon/opendistroforelasticsearch/sql/protocol/response/format/JsonResponseFormatter.java

@@ -0,0 +1,76 @@
+/*
+ *    Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License").
+ *    You may not use this file except in compliance with the License.
+ *    A copy of the License is located at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    or in the "license" file accompanying this file. This file 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.
+ *
+ */
+
+package com.amazon.opendistroforelasticsearch.sql.protocol.response.format;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+import org.json.JSONObject;
+
+import static com.amazon.opendistroforelasticsearch.sql.protocol.response.format.JsonResponseFormatter.Style.PRETTY;
+
+/**
+ * Abstract class for all JSON formatter.
+ * @param <Response>    response generic type which could be DQL or DML response
+ */
+@RequiredArgsConstructor
+public abstract class JsonResponseFormatter<Response> implements ResponseFormatter<Response> {
+
+    /**
+     * JSON format styles: pretty format or compact format without indent and space
+     */
+    public enum Style {
+        PRETTY, COMPACT
+    }
+
+    /**
+     * JSON format style
+     */
+    private final Style style;
+
+
+    @Override
+    public String format(Response response) {
+        return jsonify(buildJsonObject(response));
+    }
+
+    @Override
+    public String format(Throwable t) {
+        JsonError error = new JsonError(t.getClass().getSimpleName(),
+                                        t.getMessage());
+        return jsonify(error);
+    }
+
+    /**
+     * Build JSON object to generate response json string.
+     * @param response  response
+     * @return          json object for response
+     */
+    protected abstract Object buildJsonObject(Response response);
+
+
+    private String jsonify(Object jsonObject) {
+        JSONObject json = new JSONObject(jsonObject);
+        return (style == PRETTY) ? json.toString(2) : json.toString();
+    }
+
+    @RequiredArgsConstructor
+    @Getter
+    public static class JsonError {
+        private final String type;
+        private final String reason;
+    }
+}

protocol/src/main/java/com/amazon/opendistroforelasticsearch/sql/protocol/response/format/ResponseFormatter.java

@@ -0,0 +1,38 @@
+/*
+ *    Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License").
+ *    You may not use this file except in compliance with the License.
+ *    A copy of the License is located at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    or in the "license" file accompanying this file. This file 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.
+ *
+ */
+
+package com.amazon.opendistroforelasticsearch.sql.protocol.response.format;
+
+/**
+ * Response formatter to format response to different formats.
+ */
+public interface ResponseFormatter<Response> {
+
+    /**
+     * Format response into string in expected format.
+     * @param response  response
+     * @return          string with response content formatted
+     */
+    String format(Response response);
+
+    /**
+     * Format an exception into string.
+     * @param t     exception occurred
+     * @return      string with exception content formatted
+     */
+    String format(Throwable t);
+
+}