/**
* Download <code>fsimage</code> and <code>edits</code> files from the name-node.
*
* @return true if a new image has been downloaded and needs to be loaded
* @throws IOException
*/
private boolean downloadCheckpointFiles(CheckpointSignature sig) throws IOException {
checkpointImage.cTime = sig.cTime;
checkpointImage.checkpointTime = sig.checkpointTime;
boolean downloadImage = true;
String fileid;
File[] srcNames;
if (sig.imageDigest.equals(checkpointImage.imageDigest)) {
downloadImage = false;
LOG.info("Image has not changed. Will not download image.");
} else {
// get fsimage
srcNames = checkpointImage.getImageFiles();
assert srcNames.length > 0 : "No checkpoint targets.";
fileid = "getimage=1";
TransferFsImage.getFileClient(fsName, fileid, srcNames, false);
checkpointImage.imageDigest = sig.imageDigest;
LOG.info(
"Downloaded file " + srcNames[0].getName() + " size " + srcNames[0].length() + " bytes.");
}
// get edits file
fileid = "getedit=1";
srcNames = checkpointImage.getEditsFiles();
assert srcNames.length > 0 : "No checkpoint targets.";
TransferFsImage.getFileClient(fsName, fileid, srcNames, false);
LOG.info(
"Downloaded file " + srcNames[0].getName() + " size " + srcNames[0].length() + " bytes.");
checkpointImage.checkpointUploadDone(null);
return downloadImage;
}
//
// The main work loop
//
public void run() {
//
// Poll the Namenode (once every 5 minutes) to find the size of the
// pending edit log.
//
long period = 5 * 60; // 5 minutes
long lastCheckpointTime = 0;
if (checkpointPeriod < period) {
period = checkpointPeriod;
}
while (shouldRun) {
try {
Thread.sleep(1000 * period);
} catch (InterruptedException ie) {
// do nothing
}
if (!shouldRun) {
break;
}
try {
long now = System.currentTimeMillis();
long size = namenode.getEditLogSize();
if (size >= checkpointSize || now >= lastCheckpointTime + 1000 * checkpointPeriod) {
doCheckpoint();
lastCheckpointTime = now;
}
} catch (IOException e) {
LOG.error("Exception in doCheckpoint: ");
LOG.error(StringUtils.stringifyException(e));
e.printStackTrace();
checkpointImage.imageDigest = null;
} catch (Throwable e) {
LOG.error("Throwable Exception in doCheckpoint: ");
LOG.error(StringUtils.stringifyException(e));
e.printStackTrace();
Runtime.getRuntime().exit(-1);
}
}
}