package com.fasterxml.clustermate.service.bdb;
import java.io.IOException;
import java.util.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.sleepycat.je.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.ObjectReader;
import com.fasterxml.jackson.databind.ObjectWriter;
import com.fasterxml.clustermate.api.KeySpace;
import com.fasterxml.clustermate.service.cluster.ActiveNodeState;
import com.fasterxml.storemate.shared.IpAndPort;
import com.fasterxml.storemate.shared.util.UTF8Encoder;
/**
* Class that handles operations on the BDB-backed Node state
* table (BDB database) and related indexes.
* This store is used for persisting enough state regarding
* peer-to-peer operations to reduce amount of re-synchronization
* needed when node instances are restarted.
*/
public class NodeStateStore
{
private final Logger LOG = LoggerFactory.getLogger(getClass());
protected final ObjectReader _jsonReader;
protected final ObjectWriter _jsonWriter;
/**
* Underlying BDB entity store ("table")
* for storing node states.
*/
protected final Database _store;
/*
/**********************************************************************
/* Life cycle
/**********************************************************************
*/
public NodeStateStore(Environment env, ObjectMapper jsonMapper) throws DatabaseException
{
_jsonReader = jsonMapper.reader(ActiveNodeState.class);
_jsonWriter = jsonMapper.writerWithType(ActiveNodeState.class);
_store = env.openDatabase(null, // no TX
"Nodes", dbConfig(env));
}
public void stop()
{
_store.close();
}
/*
/**********************************************************************
/* Content lookups
/**********************************************************************
*/
/**
* Method that can be used to find specified entry, without updating
* its last-accessed timestamp.
*/
public ActiveNodeState findEntry(IpAndPort key) throws IOException
{
DatabaseEntry dbKey = _key(key);
if (dbKey == null) {
return null;
}
DatabaseEntry data = new DatabaseEntry();
OperationStatus status = _store.get(null, dbKey, data, null);
switch (status) {
case SUCCESS:
case KEYEXIST:
return _fromDB(data);
case KEYEMPTY: // was deleted during operation.. shouldn't be getting
case NOTFOUND:
// fall through
}
return null;
}
/**
* Method for simply reading all node entries store has; called usually
* only during bootstrapping.
*/
public List<ActiveNodeState> readAll(KeySpace keyspace)
{
List<ActiveNodeState> all = new ArrayList<ActiveNodeState>(30);
CursorConfig config = new CursorConfig();
Cursor crsr = _store.openCursor(null, config);
final DatabaseEntry keyEntry;
final DatabaseEntry data = new DatabaseEntry();
keyEntry = new DatabaseEntry();
OperationStatus status = crsr.getFirst(keyEntry, data, null);
try {
int index = 0;
for (; status == OperationStatus.SUCCESS; status = crsr.getNext(keyEntry, data, null)) {
try {
all.add(_fromDB(data));
} catch (Exception e) {
String key = "N/A";
try {
IpAndPort ip = _keyFromDB(keyEntry);
key = ip.toString();
} catch (Exception e2) {
key = "[Corrupt Key]";
}
LOG.error("Invalid Node state entry in BDB, entry #{}, key '{}', skipping. Problem ({}): {}",
new Object[] { index, key, e.getClass().getName(), e.getMessage()});
}
++index;
}
} finally {
crsr.close();
}
return all;
}
/*
/**********************************************************************
/* Content modification
/**********************************************************************
*/
public void upsertEntry(ActiveNodeState entry) throws IOException
{
_store.put(null, _key(entry.getAddress()), _toDB(entry));
}
public boolean deleteEntry(IpAndPort key) {
return deleteEntry(key.toString());
}
public boolean deleteEntry(String keyStr) {
DatabaseEntry lastAccessKey = _key(keyStr);
if (lastAccessKey != null) {
OperationStatus status = _store.delete(null, lastAccessKey);
switch (status) {
case SUCCESS:
case KEYEXIST:
return true;
default:
}
}
return false;
}
/*
/**********************************************************************
/* Internal methods
/**********************************************************************
*/
protected DatabaseConfig dbConfig(Environment env)
{
DatabaseConfig dbConfig = new DatabaseConfig();
EnvironmentConfig econfig = env.getConfig();
dbConfig.setReadOnly(econfig.getReadOnly());
dbConfig.setAllowCreate(econfig.getAllowCreate());
dbConfig.setSortedDuplicates(false);
return dbConfig;
}
protected DatabaseEntry _key(IpAndPort key) {
return _key(key.toString());
}
protected DatabaseEntry _key(String key) {
return new DatabaseEntry(UTF8Encoder.encodeAsUTF8(key));
}
protected IpAndPort _keyFromDB(DatabaseEntry entry) {
return new IpAndPort(UTF8Encoder.decodeFromUTF8(entry.getData(),
entry.getOffset(), entry.getSize()));
}
protected DatabaseEntry _toDB(ActiveNodeState state) throws IOException {
return new DatabaseEntry(_jsonWriter.writeValueAsBytes(state));
}
protected ActiveNodeState _fromDB(DatabaseEntry entry) throws IOException {
return _jsonReader.readValue(entry.getData(), entry.getOffset(), entry.getSize());
}
}