package tachyon.master;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.ObjectWriter;
import tachyon.Constants;
import tachyon.TachyonURI;
import tachyon.UnderFileSystem;
/**
* Master data image.
*/
public class Image {
private static final Logger LOG = LoggerFactory.getLogger(Constants.LOGGER_TYPE);
/**
* Write a new image to path. This method assumes having a lock on the master info.
*
* @param info the master info to generate the image
* @param path the new image path
* @throws IOException
*/
public static void create(MasterInfo info, String path) throws IOException {
String tPath = path + ".tmp";
String parentFolder = path.substring(0, path.lastIndexOf(TachyonURI.SEPARATOR));
LOG.info("Creating the image file: " + tPath);
UnderFileSystem ufs = UnderFileSystem.get(path);
if (!ufs.exists(parentFolder)) {
LOG.info("Creating parent folder " + parentFolder);
ufs.mkdirs(parentFolder, true);
}
OutputStream os = ufs.create(tPath);
DataOutputStream imageOs = new DataOutputStream(os);
ObjectWriter writer = JsonObject.createObjectMapper().writer();
info.writeImage(writer, imageOs);
imageOs.flush();
imageOs.close();
LOG.info("Succefully created the image file: " + tPath);
ufs.delete(path, false);
ufs.rename(tPath, path);
ufs.delete(tPath, false);
LOG.info("Renamed " + tPath + " to " + path);
// safe to close, nothing created here with scope outside function
ufs.close();
}
/**
* Load an image into the masterinfo.
*
* @param info the masterinfo to fill.
* @param path the data to load
* @throws IOException
*/
public static void load(MasterInfo info, String path) throws IOException {
UnderFileSystem ufs = UnderFileSystem.get(path);
if (!ufs.exists(path)) {
LOG.info("Image " + path + " does not exist.");
return;
}
LOG.info("Loading image " + path);
DataInputStream imageIs = new DataInputStream(ufs.open(path));
JsonParser parser = JsonObject.createObjectMapper().getFactory().createParser(imageIs);
info.loadImage(parser, new TachyonURI(path));
imageIs.close();
ufs.close();
}
/**
* Rename the src to the dst. Only used to rename the Image.
*
* @param src The src image path
* @param dst The dst image path
* @throws IOException
*/
public static void rename(String src, String dst) throws IOException {
UnderFileSystem ufs = UnderFileSystem.get(src);
ufs.rename(src, dst);
LOG.info("Renamed " + src + " to " + dst);
}
}