private int findLatestIndex() throws IOException {
ImmutableMap<String, BlobMetaData> blobs = metaDataBlobContainer.listBlobsByPrefix("metadata-");
int index = -1;
for (BlobMetaData md : blobs.values()) {
if (logger.isTraceEnabled()) {
logger.trace("[findLatestMetadata]: Processing [" + md.name() + "]");
}
String name = md.name();
int fileIndex = Integer.parseInt(name.substring(name.indexOf('-') + 1));
if (fileIndex >= index) {
// try and read the meta data
byte[] data = null;
try {
data = metaDataBlobContainer.readBlobFully(name);
readMetaData(data);
index = fileIndex;
} catch (IOException e) {
logger.warn(
"[findLatestMetadata]: failed to read metadata from [{}], data_length [{}] ignoring...",
e,
name,
data == null ? "na" : data.length);
}
}
}
return index;
}
@Override
public void write(MetaData metaData) throws GatewayException {
final String newMetaData = "metadata-" + (currentIndex + 1);
CachedStreamOutput.Entry cachedEntry = CachedStreamOutput.popEntry();
try {
StreamOutput streamOutput;
if (compress) {
streamOutput = cachedEntry.bytes(CompressorFactory.defaultCompressor());
} else {
streamOutput = cachedEntry.bytes();
}
XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON, streamOutput);
builder.startObject();
MetaData.Builder.toXContent(metaData, builder, ToXContent.EMPTY_PARAMS);
builder.endObject();
builder.close();
metaDataBlobContainer.writeBlob(
newMetaData,
new ByteArrayInputStream(
cachedEntry.bytes().underlyingBytes(), 0, cachedEntry.bytes().size()),
cachedEntry.bytes().size());
} catch (IOException e) {
throw new GatewayException("Failed to write metadata [" + newMetaData + "]", e);
} finally {
CachedStreamOutput.pushEntry(cachedEntry);
}
currentIndex++;
try {
metaDataBlobContainer.deleteBlobsByFilter(
new BlobContainer.BlobNameFilter() {
@Override
public boolean accept(String blobName) {
return blobName.startsWith("metadata-") && !newMetaData.equals(blobName);
}
});
} catch (IOException e) {
logger.debug("Failed to delete old metadata, will do it next time", e);
}
}
public CommitPoint findCommitPoint(String index, int shardId) throws IOException {
BlobPath path = BlobStoreIndexGateway.shardPath(basePath, index, shardId);
ImmutableBlobContainer container = blobStore.immutableBlobContainer(path);
ImmutableMap<String, BlobMetaData> blobs = container.listBlobs();
List<CommitPoint> commitPointsList = Lists.newArrayList();
for (BlobMetaData md : blobs.values()) {
if (md.length() == 0) { // a commit point that was not flushed yet...
continue;
}
if (md.name().startsWith("commit-")) {
try {
commitPointsList.add(CommitPoints.fromXContent(container.readBlobFully(md.name())));
} catch (Exception e) {
logger.warn("failed to read commit point at path {} with name [{}]", e, path, md.name());
}
}
}
CommitPoints commitPoints = new CommitPoints(commitPointsList);
if (commitPoints.commits().isEmpty()) {
return null;
}
return commitPoints.commits().get(0);
}
@Override
public MetaData read() throws GatewayException {
try {
this.currentIndex = findLatestIndex();
} catch (IOException e) {
throw new GatewayException("Failed to find latest metadata to read from", e);
}
if (currentIndex == -1) return null;
String metaData = "metadata-" + currentIndex;
try {
return readMetaData(metaDataBlobContainer.readBlobFully(metaData));
} catch (GatewayException e) {
throw e;
} catch (Exception e) {
throw new GatewayException("Failed to read metadata [" + metaData + "] from gateway", e);
}
}