/**
* Copyright (C) 2010 - 2016 52°North Initiative for Geospatial Open Source
* Software GmbH
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* If the program is linked with libraries which are licensed under one of
* the following licenses, the combination of the program with the linked
* library is not considered a "derivative work" of the program:
*
* • Apache License, version 2.0
* • Apache Software License, version 1.0
* • GNU Lesser General Public License, version 3
* • Mozilla Public License, versions 1.0, 1.1 and 2.0
* • Common Development and Distribution License (CDDL), version 1.0
*
* Therefore the distribution of the program linked with libraries licensed
* under the aforementioned licenses, is permitted by the copyright holders
* if the distribution is compliant with both the GNU General Public
* License version 2 and the aforementioned licenses.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
* Public License for more details.
*/
package org.n52.wps.server.r.util;
import java.io.IOException;
import java.util.Arrays;
import org.n52.wps.server.r.FilteredRConnection;
import org.rosuda.REngine.REXP;
import org.rosuda.REngine.REXPMismatchException;
import org.rosuda.REngine.Rserve.RserveException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class RConnector {
private static final long START_ATTEMPT_SLEEP = 1000l;
private static final int START_ATTEMP_COUNT = 5;
private static Logger log = LoggerFactory.getLogger(RConnector.class);
private RStarter starter;
public RConnector(RStarter starter) {
this.starter = starter;
}
public FilteredRConnection getNewConnection(boolean enableBatchStart,
String host,
int port,
String user,
String password) throws RserveException {
FilteredRConnection con = null;
log.debug("Creating new RConnection");
con = getNewConnection(enableBatchStart, host, port);
// Login MUSST be the next request after connection
// otherwise the connection is broken even if login is requested later
if (con != null && con.needLogin()) {
log.debug("Connection requires login... logging in with user {}", user);
con.login(user, password);
}
RLogger.log(con, "New connection from WPS4R");
REXP info = con.eval("capture.output(sessionInfo())");
try {
log.debug("NEW CONNECTION >>> sessionInfo:\n{}", Arrays.deepToString(info.asStrings()));
}
catch (REXPMismatchException e) {
log.warn("Error creating session info.", e);
}
return con;
}
private FilteredRConnection getNewConnection(boolean enableBatchStart, String host, int port) throws RserveException {
log.debug("New connection using batch = {} at {}:{}", enableBatchStart, host, port);
FilteredRConnection con = null;
try {
con = new FilteredRConnection(host, port);
}
catch (RserveException rse) {
log.error("Could not connect to RServe.", rse);
if (rse.getMessage().startsWith("Cannot connect") && enableBatchStart) {
log.info("Attempting to start RServe.");
try {
con = attemptStarts(host, port);
}
catch (Exception e) {
log.error("Attempted to start Rserve and establish a connection failed", e);
// Throwable#addSuppressed() only supported by Java 1.7+
// rse.addSuppressed(e);
}
}
else
throw rse;
}
if (con == null)
throw new RserveException(null,
"Cannot connect with Rserve, connection is null. Is Rserve configured for remote connections? It is not by default. See http://www.rforge.net/Rserve/doc.html");
return con;
}
private FilteredRConnection attemptStarts(String host, int port) throws InterruptedException,
IOException,
RserveException {
this.starter.startR();
int attempt = 1;
FilteredRConnection con = null;
while (attempt <= START_ATTEMP_COUNT) {
try {
Thread.sleep(START_ATTEMPT_SLEEP); // wait for R to startup,
// then establish connection
con = new FilteredRConnection(host, port);
break;
}
catch (RserveException rse) {
if (attempt >= 5) {
throw rse;
}
attempt++;
}
}
return con;
}
}