/*
* 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.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import org.apache.solr.client.solrj.io.Tuple;
import org.apache.solr.client.solrj.io.comp.FieldComparator;
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.StreamExpressionNamedParameter;
import org.apache.solr.client.solrj.io.stream.expr.StreamExpressionValue;
import org.apache.solr.client.solrj.io.stream.expr.StreamFactory;
import org.apache.solr.common.params.ModifiableSolrParams;
import static org.apache.solr.common.params.CommonParams.DISTRIB;
import static org.apache.solr.common.params.CommonParams.SORT;
/**
* The ParallelStream decorates a TupleStream implementation and pushes it to N workers for parallel execution.
* Workers are chosen from a SolrCloud collection.
* Tuples that are streamed back from the workers are ordered by a Comparator.
**/
public class ParallelStream extends CloudSolrStream implements Expressible {
private TupleStream tupleStream;
private int workers;
private transient StreamFactory streamFactory;
public ParallelStream(String zkHost,
String collection,
TupleStream tupleStream,
int workers,
StreamComparator comp) throws IOException {
init(zkHost,collection,tupleStream,workers,comp);
}
public ParallelStream(String zkHost,
String collection,
String expressionString,
int workers,
StreamComparator comp) throws IOException {
TupleStream tStream = this.streamFactory.constructStream(expressionString);
init(zkHost,collection, tStream, workers,comp);
}
public void setStreamFactory(StreamFactory streamFactory) {
this.streamFactory = streamFactory;
}
public ParallelStream(StreamExpression expression, StreamFactory factory) throws IOException {
// grab all parameters out
String collectionName = factory.getValueOperand(expression, 0);
StreamExpressionNamedParameter workersParam = factory.getNamedOperand(expression, "workers");
List<StreamExpression> streamExpressions = factory.getExpressionOperandsRepresentingTypes(expression, Expressible.class, TupleStream.class);
StreamExpressionNamedParameter sortExpression = factory.getNamedOperand(expression, SORT);
StreamExpressionNamedParameter zkHostExpression = factory.getNamedOperand(expression, "zkHost");
// validate expression contains only what we want.
if(expression.getParameters().size() != streamExpressions.size() + 3 + (null != zkHostExpression ? 1 : 0)){
throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - unknown operands found", expression));
}
// Collection Name
if(null == collectionName){
throw new IOException(String.format(Locale.ROOT,"invalid expression %s - collectionName expected as first operand",expression));
}
// Workers
if(null == workersParam || null == workersParam.getParameter() || !(workersParam.getParameter() instanceof StreamExpressionValue)){
throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting a single 'workers' parameter of type positive integer but didn't find one",expression));
}
String workersStr = ((StreamExpressionValue)workersParam.getParameter()).getValue();
int workersInt = 0;
try{
workersInt = Integer.parseInt(workersStr);
if(workersInt <= 0){
throw new IOException(String.format(Locale.ROOT,"invalid expression %s - workers '%s' must be greater than 0.",expression, workersStr));
}
}
catch(NumberFormatException e){
throw new IOException(String.format(Locale.ROOT,"invalid expression %s - workers '%s' is not a valid integer.",expression, workersStr));
}
// Stream
if(1 != streamExpressions.size()){
throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting a single stream but found %d",expression, streamExpressions.size()));
}
// Sort
if(null == sortExpression || !(sortExpression.getParameter() instanceof StreamExpressionValue)){
throw new IOException(String.format(Locale.ROOT,"Invalid expression %s - expecting single 'sort' parameter telling us how to join the parallel streams but didn't find one",expression));
}
// zkHost, optional - if not provided then will look into factory list to get
String zkHost = null;
if(null == zkHostExpression){
zkHost = factory.getCollectionZkHost(collectionName);
if(zkHost == null) {
zkHost = factory.getDefaultZkHost();
}
}
else if(zkHostExpression.getParameter() instanceof StreamExpressionValue){
zkHost = ((StreamExpressionValue)zkHostExpression.getParameter()).getValue();
}
if(null == zkHost){
throw new IOException(String.format(Locale.ROOT,"invalid expression %s - zkHost not found for collection '%s'",expression,collectionName));
}
// We've got all the required items
TupleStream stream = factory.constructStream(streamExpressions.get(0));
StreamComparator comp = factory.constructComparator(((StreamExpressionValue)sortExpression.getParameter()).getValue(), FieldComparator.class);
streamFactory = factory;
init(zkHost,collectionName,stream,workersInt,comp);
}
private void init(String zkHost,String collection,TupleStream tupleStream,int workers,StreamComparator comp) throws IOException{
this.zkHost = zkHost;
this.collection = collection;
this.workers = workers;
this.comp = comp;
this.tupleStream = tupleStream;
// requires Expressible stream and comparator
if(! (tupleStream instanceof Expressible)){
throw new IOException("Unable to create ParallelStream with a non-expressible TupleStream.");
}
}
@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()));
// collection
expression.addParameter(collection);
// workers
expression.addParameter(new StreamExpressionNamedParameter("workers", Integer.toString(workers)));
if(includeStreams){
if(tupleStream instanceof Expressible){
expression.addParameter(((Expressible)tupleStream).toExpression(factory));
}
else{
throw new IOException("This ParallelStream contains a non-expressible TupleStream - it cannot be converted to an expression");
}
}
else{
expression.addParameter("<stream>");
}
// sort
expression.addParameter(new StreamExpressionNamedParameter(SORT,comp.toExpression(factory)));
// zkHost
expression.addParameter(new StreamExpressionNamedParameter("zkHost", zkHost));
return expression;
}
@Override
public Explanation toExplanation(StreamFactory factory) throws IOException {
StreamExplanation explanation = new StreamExplanation(getStreamNodeId().toString());
explanation.setFunctionName(factory.getFunctionName(this.getClass()));
explanation.setImplementingClass(this.getClass().getName());
explanation.setExpressionType(ExpressionType.STREAM_DECORATOR);
explanation.setExpression(toExpression(factory, false).toString());
// add a child for each worker
for(int idx = 0; idx < workers; ++idx){
explanation.addChild(tupleStream.toExplanation(factory));
}
return explanation;
}
public List<TupleStream> children() {
List l = new ArrayList();
l.add(tupleStream);
return l;
}
public Tuple read() throws IOException {
Tuple tuple = _read();
if(tuple.EOF) {
Map m = new HashMap();
m.put("EOF", true);
Tuple t = new Tuple(m);
/*
Map<String, Map> metrics = new HashMap();
Iterator<Entry<String,Tuple>> it = this.eofTuples.entrySet().iterator();
while(it.hasNext()) {
Map.Entry<String, Tuple> entry = it.next();
if(entry.getValue().fields.size() > 1) {
metrics.put(entry.getKey(), entry.getValue().fields);
}
}
if(metrics.size() > 0) {
t.setMetrics(metrics);
}
*/
return t;
}
return tuple;
}
public void setStreamContext(StreamContext streamContext) {
this.streamContext = streamContext;
if(streamFactory == null) {
this.streamFactory = streamContext.getStreamFactory();
}
this.tupleStream.setStreamContext(streamContext);
}
protected void constructStreams() throws IOException {
try {
Object pushStream = ((Expressible) tupleStream).toExpression(streamFactory);
List<String> shardUrls = getShards(this.zkHost, this.collection, this.streamContext);
for(int w=0; w<workers; w++) {
ModifiableSolrParams paramsLoc = new ModifiableSolrParams();
paramsLoc.set(DISTRIB,"false"); // We are the aggregator.
paramsLoc.set("numWorkers", workers);
paramsLoc.set("workerID", w);
paramsLoc.set("expr", pushStream.toString());
paramsLoc.set("qt","/stream");
String url = shardUrls.get(w);
SolrStream solrStream = new SolrStream(url, paramsLoc);
solrStreams.add(solrStream);
}
assert(solrStreams.size() == workers);
} catch (Exception e) {
throw new IOException(e);
}
}
}