SOLR-10516: Add eval() Streaming Expression

solr/core/src/java/org/apache/solr/handler/StreamHandler.java

@@ -158,7 +158,8 @@ public class StreamHandler extends RequestHandlerBase implements SolrCoreAware,
          .withFunctionName("significantTerms", SignificantTermsStream.class)
       .withFunctionName("cartesianProduct", CartesianProductStream.class)
          .withFunctionName("shuffle", ShuffleStream.class)
-         .withFunctionName("eval", CalculatorStream.class)
+         .withFunctionName("calc", CalculatorStream.class)
+      .withFunctionName("eval",EvalStream.class)
       .withFunctionName("echo", EchoStream.class)
 
              // metrics

solr/solrj/src/java/org/apache/solr/client/solrj/io/stream/EvalStream.java

@@ -0,0 +1,143 @@
+/*
+ * 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.
+ */
+
+package org.apache.solr.client.solrj.io.stream;
+
+import java.io.IOException;
+import java.lang.invoke.MethodHandles;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+import org.apache.solr.client.solrj.io.Tuple;
+import org.apache.solr.client.solrj.io.comp.StreamComparator;
+import org.apache.solr.client.solrj.io.stream.expr.Explanation;
+import org.apache.solr.client.solrj.io.stream.expr.Explanation.ExpressionType;
+import org.apache.solr.client.solrj.io.stream.expr.Expressible;
+import org.apache.solr.client.solrj.io.stream.expr.StreamExplanation;
+import org.apache.solr.client.solrj.io.stream.expr.StreamExpression;
+import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class EvalStream extends TupleStream implements Expressible {
+
+  private static final Logger logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
+
+  private TupleStream stream;
+  private TupleStream evalStream;
+
+  private StreamFactory streamFactory;
+  private StreamContext streamContext;
+
+  public EvalStream(StreamExpression expression, StreamFactory factory) throws IOException {
+    // grab all parameters out
+    List<StreamExpression> streamExpressions = factory.getExpressionOperandsRepresentingTypes(expression, Expressible.class, TupleStream.class);
+
+    if(1 != streamExpressions.size()){
+      throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting a single stream but found %d",expression, streamExpressions.size()));
+    }
+
+    TupleStream stream = factory.constructStream(streamExpressions.get(0));
+    init(stream, factory);
+  }
+
+  private void init(TupleStream tupleStream, StreamFactory factory) throws IOException{
+    this.stream = tupleStream;
+    this.streamFactory = factory;
+  }
+
+  @Override
+  public StreamExpression toExpression(StreamFactory factory) throws IOException {
+    return toExpression(factory, true);
+  }
+
+  private StreamExpression toExpression(StreamFactory factory, boolean includeStreams) throws IOException {
+
+    // function name
+    StreamExpression expression = new StreamExpression(factory.getFunctionName(this.getClass()));
+
+    // stream
+    if(includeStreams) {
+      if (stream instanceof Expressible) {
+        expression.addParameter(((Expressible) stream).toExpression(factory));
+      } else {
+        throw new IOException("The EvalStream contains a non-expressible TupleStream - it cannot be converted to an expression");
+      }
+    }
+
+    return expression;
+  }
+
+  @Override
+  public Explanation toExplanation(StreamFactory factory) throws IOException {
+
+    return new StreamExplanation(getStreamNodeId().toString())
+        .withChildren(new Explanation[]{
+            stream.toExplanation(factory)
+        })
+        .withFunctionName(factory.getFunctionName(this.getClass()))
+        .withImplementingClass(this.getClass().getName())
+        .withExpressionType(ExpressionType.STREAM_DECORATOR)
+        .withExpression(toExpression(factory, false).toString());
+  }
+
+  public void setStreamContext(StreamContext streamContext) {
+    this.streamContext = streamContext;
+    this.stream.setStreamContext(streamContext);
+  }
+
+  public List<TupleStream> children() {
+    List<TupleStream> l =  new ArrayList();
+    l.add(stream);
+    return l;
+  }
+
+  public void open() throws IOException {
+    try {
+      stream.open();
+      Tuple tuple = stream.read();
+      String expr = tuple.getString("expr_s");
+
+      if(expr == null) {
+        throw new IOException("expr_s cannot be empty for the EvalStream");
+      }
+
+      evalStream = streamFactory.constructStream(expr);
+      evalStream.setStreamContext(streamContext);
+      evalStream.open();
+    } finally {
+      stream.close();
+    }
+  }
+
+  public void close() throws IOException {
+    evalStream.close();
+  }
+
+  public Tuple read() throws IOException {
+    return evalStream.read();
+  }
+
+  public StreamComparator getStreamSort(){
+    return stream.getStreamSort();
+  }
+
+  public int getCost() {
+    return 0;
+  }
+}

solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java

@@ -4787,7 +4787,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
 
   @Test
   public void testCalculatorStream() throws Exception {
-    String expr = "select(eval(), add(1, 1) as result)";
+    String expr = "select(calc(), add(1, 1) as result)";
     ModifiableSolrParams paramsLoc = new ModifiableSolrParams();
     paramsLoc.set("expr", expr);
     paramsLoc.set("qt", "/stream");
@@ -5008,6 +5008,30 @@ public class StreamExpressionTest extends SolrCloudTestCase {
 
 
 
+  }
+
+
+  @Test
+  public void testEvalStream() throws Exception {
+    UpdateRequest updateRequest = new UpdateRequest();
+    updateRequest.add(id, "hello", "test_t", "l b c d c");
+    updateRequest.commit(cluster.getSolrClient(), COLLECTIONORALIAS);
+
+    String expr = "eval(select(echo(\"search("+COLLECTIONORALIAS+", q=\\\"*:*\\\", fl=id, sort=\\\"id desc\\\")\"), echo as expr_s))";
+    ModifiableSolrParams paramsLoc = new ModifiableSolrParams();
+    paramsLoc.set("expr", expr);
+    paramsLoc.set("qt", "/stream");
+
+    String url = cluster.getJettySolrRunners().get(0).getBaseUrl().toString()+"/"+COLLECTIONORALIAS;
+    TupleStream solrStream = new SolrStream(url, paramsLoc);
+
+    StreamContext context = new StreamContext();
+    solrStream.setStreamContext(context);
+    List<Tuple> tuples = getTuples(solrStream);
+    assertTrue(tuples.size() == 1);
+    String s = (String)tuples.get(0).get("id");
+    assertTrue(s.equals("hello"));
+
   }
 
   @Test
@@ -5020,7 +5044,7 @@ public class StreamExpressionTest extends SolrCloudTestCase {
     updateRequest.commit(cluster.getSolrClient(), COLLECTIONORALIAS);
 
     //Test annotating tuple
-    String expr = "select(eval(), convert(miles, kilometers, 10) as kilometers)";
+    String expr = "select(calc(), convert(miles, kilometers, 10) as kilometers)";
     ModifiableSolrParams paramsLoc = new ModifiableSolrParams();
     paramsLoc.set("expr", expr);
     paramsLoc.set("qt", "/stream");