一、入口类是Main方法，读取zoo.cfg文件
org.apache.zookeeper.server.quorum.QuorumPeerMain
public static void main(String[] args) {
QuorumPeerMain main = new QuorumPeerMain();
main.initializeAndRun(args);
}
二、读取zoo.cfg配置文件，初始化参数
protected void initializeAndRun(String[] args){
QuorumPeerConfig config = new QuorumPeerConfig();
if (args.length == 1) {
//读取zoo.cfg文件，默认通过args传递进来的
config.parse(args[0]);
}
// 启动定时任务，清理ZK的数据目录，防止文件过大
// Start and schedule the the purge task
DatadirCleanupManager purgeMgr = new DatadirCleanupManager(config
.getDataDir(), config.getDataLogDir(), config
.getSnapRetainCount(), config.getPurgeInterval());
purgeMgr.start();
if (args.length == 1 && config.servers.size() > 0) {
runFromConfig(config);
} else {
LOG.warn("Either no config or no quorum defined in config, running "
+ " in standalone mode");
// there is only server in the quorum -- run as standalone
ZooKeeperServerMain.main(args);
}
}
三、调用Properties 方法load配置文件
/**
* Parse a ZooKeeper configuration file
* @param path the patch of the configuration file
* @throws ConfigException error processing configuration
*/
public void parse(String path) throws ConfigException {
File configFile = new File(path);
LOG.info("Reading configuration from: " + configFile);
try {
if (!configFile.exists()) {
throw new IllegalArgumentException(configFile.toString()
+ " file is missing");
}
Properties cfg = new Properties();
FileInputStream in = new FileInputStream(configFile);
try {
cfg.load(in);
} finally {
in.close();
}
parseProperties(cfg);
} catch (IOException e) {
throw new ConfigException("Error processing " + path, e);
} catch (IllegalArgumentException e) {
throw new ConfigException("Error processing " + path, e);
}
}
四、遍历Properties 获取属性值
/**
* Parse config from a Properties.
* @param zkProp Properties to parse from.
* @throws IOException
* @throws ConfigException
*/
public void parseProperties(Properties zkProp)
throws IOException, ConfigException {
int clientPort = 0;
String clientPortAddress = null;
for (Entry<Object, Object> entry : zkProp.entrySet()) {
String key = entry.getKey().toString().trim();
String value = entry.getValue().toString().trim();
if (key.equals("dataDir")) {
dataDir = value;
} else if (key.equals("dataLogDir")) {
dataLogDir = value;
} else if (key.equals("clientPort")) {
clientPort = Integer.parseInt(value);
} else if (key.equals("clientPortAddress")) {
clientPortAddress = value.trim();
} else if (key.equals("tickTime")) {
tickTime = Integer.parseInt(value);
} else if (key.equals("maxClientCnxns")) {
maxClientCnxns = Integer.parseInt(value);
} else if (key.equals("minSessionTimeout")) {
minSessionTimeout = Integer.parseInt(value);
} else if (key.equals("maxSessionTimeout")) {
maxSessionTimeout = Integer.parseInt(value);
} else if (key.equals("initLimit")) {
initLimit = Integer.parseInt(value);
} else if (key.equals("syncLimit")) {
syncLimit = Integer.parseInt(value);
} else if (key.equals("electionAlg")) {
electionAlg = Integer.parseInt(value);
} else if (key.equals("quorumListenOnAllIPs")) {
quorumListenOnAllIPs = Boolean.parseBoolean(value);
} else if (key.equals("peerType")) {
if (value.toLowerCase().equals("observer")) {
peerType = LearnerType.OBSERVER;
} else if (value.toLowerCase().equals("participant")) {
peerType = LearnerType.PARTICIPANT;
} else
{
throw new ConfigException("Unrecognised peertype: " + value);
}
} else if (key.equals( "syncEnabled" )) {
syncEnabled = Boolean.parseBoolean(value);
} else if (key.equals("autopurge.snapRetainCount")) {
snapRetainCount = Integer.parseInt(value);
} else if (key.equals("autopurge.purgeInterval")) {
purgeInterval = Integer.parseInt(value);
} else if (key.startsWith("server.")) {
int dot = key.indexOf('.');
long sid = Long.parseLong(key.substring(dot + 1));
String parts[] = value.split(":");
if ((parts.length != 2) && (parts.length != 3) && (parts.length !=4)) {
//Zookeeper 配置集群的三种方法
LOG.error(value
+ " does not have the form host:port or host:port:port " +
" or host:port:port:type");
}
InetSocketAddress addr = new InetSocketAddress(parts[0],
Integer.parseInt(parts[1]));
if (parts.length == 2) {
servers.put(Long.valueOf(sid), new QuorumServer(sid, addr));
} else if (parts.length == 3) {
InetSocketAddress electionAddr = new InetSocketAddress(
parts[0], Integer.parseInt(parts[2]));
servers.put(Long.valueOf(sid), new QuorumServer(sid, addr,
electionAddr));
} else if (parts.length == 4) {
InetSocketAddress electionAddr = new InetSocketAddress(
parts[0], Integer.parseInt(parts[2]));
LearnerType type = LearnerType.PARTICIPANT;
if (parts[3].toLowerCase().equals("observer")) {
type = LearnerType.OBSERVER;
observers.put(Long.valueOf(sid), new QuorumServer(sid, addr,
electionAddr,type));
} else if (parts[3].toLowerCase().equals("participant")) {
type = LearnerType.PARTICIPANT;
servers.put(Long.valueOf(sid), new QuorumServer(sid, addr,
electionAddr,type));
} else {
throw new ConfigException("Unrecognised peertype: " + value);
}
}
} else if (key.startsWith("group")) {
int dot = key.indexOf('.');
long gid = Long.parseLong(key.substring(dot + 1));
numGroups++;
String parts[] = value.split(":");
for(String s : parts){
long sid = Long.parseLong(s);
if(serverGroup.containsKey(sid))
throw new ConfigException("Server " + sid + "is in multiple groups");
else
serverGroup.put(sid, gid);
}
} else if(key.startsWith("weight")) {
int dot = key.indexOf('.');
long sid = Long.parseLong(key.substring(dot + 1));
serverWeight.put(sid, Long.parseLong(value));
} else {
System.setProperty("zookeeper." + key, value);
}
}
// Reset to MIN_SNAP_RETAIN_COUNT if invalid (less than 3)
// PurgeTxnLog.purge(File, File, int) will not allow to purge less
// than 3.
if (snapRetainCount < MIN_SNAP_RETAIN_COUNT) {
LOG.warn("Invalid autopurge.snapRetainCount: " + snapRetainCount
+ ". Defaulting to " + MIN_SNAP_RETAIN_COUNT);
snapRetainCount = MIN_SNAP_RETAIN_COUNT;
}
if (dataDir == null) {
throw new IllegalArgumentException("dataDir is not set");
}
if (dataLogDir == null) {
dataLogDir = dataDir;
} else {
if (!new File(dataLogDir).isDirectory()) {
throw new IllegalArgumentException("dataLogDir " + dataLogDir
+ " is missing.");
}
}
if (clientPort == 0) {
throw new IllegalArgumentException("clientPort is not set");
}
if (clientPortAddress != null) {
this.clientPortAddress = new InetSocketAddress(
InetAddress.getByName(clientPortAddress), clientPort);
} else {
this.clientPortAddress = new InetSocketAddress(clientPort);
}
if (tickTime == 0) {
throw new IllegalArgumentException("tickTime is not set");
}
if (minSessionTimeout > maxSessionTimeout) {
throw new IllegalArgumentException(
"minSessionTimeout must not be larger than maxSessionTimeout");
}
if (servers.size() == 0) {
if (observers.size() > 0) {
throw new IllegalArgumentException("Observers w/o participants is an invalid configuration");
}
// Not a quorum configuration so return immediately - not an error
// case (for b/w compatibility), server will default to standalone
// mode.
return;
} else if (servers.size() == 1) {
if (observers.size() > 0) {
throw new IllegalArgumentException("Observers w/o quorum is an invalid configuration");
}
// HBase currently adds a single server line to the config, for
// b/w compatibility reasons we need to keep this here.
LOG.error("Invalid configuration, only one server specified (ignoring)");
servers.clear();
} else if (servers.size() > 1) {
if (servers.size() == 2) {
LOG.warn("No server failure will be tolerated. " +
"You need at least 3 servers.");
} else if (servers.size() % 2 == 0) {
LOG.warn("Non-optimial configuration, consider an odd number of servers.");
}
if (initLimit == 0) {
throw new IllegalArgumentException("initLimit is not set");
}
if (syncLimit == 0) {
throw new IllegalArgumentException("syncLimit is not set");
}
/*
* If using FLE, then every server requires a separate election
* port.
*/
if (electionAlg != 0) {
for (QuorumServer s : servers.values()) {
if (s.electionAddr == null)
throw new IllegalArgumentException(
"Missing election port for server: " + s.id);
}
}
/*
* Default of quorum config is majority
*/
if(serverGroup.size() > 0){
if(servers.size() != serverGroup.size())
throw new ConfigException("Every server must be in exactly one group");
/*
* The deafult weight of a server is 1
*/
for(QuorumServer s : servers.values()){
if(!serverWeight.containsKey(s.id))
serverWeight.put(s.id, (long) 1);
}
/*
* Set the quorumVerifier to be QuorumHierarchical
*/
quorumVerifier = new QuorumHierarchical(numGroups,
serverWeight, serverGroup);
} else {
/*
* The default QuorumVerifier is QuorumMaj
*/
LOG.info("Defaulting to majority quorums");
quorumVerifier = new QuorumMaj(servers.size());
}
// Now add observers to servers, once the quorums have been
// figured out
servers.putAll(observers);
File myIdFile = new File(dataDir, "myid");
if (!myIdFile.exists()) {
throw new IllegalArgumentException(myIdFile.toString()
+ " file is missing");
}
BufferedReader br = new BufferedReader(new FileReader(myIdFile));
String myIdString;
try {
myIdString = br.readLine();
} finally {
br.close();
}
try {
serverId = Long.parseLong(myIdString);
MDC.put("myid", myIdString);
} catch (NumberFormatException e) {
throw new IllegalArgumentException("serverid " + myIdString
+ " is not a number");
}
// Warn about inconsistent peer type
LearnerType roleByServersList = observers.containsKey(serverId) ? LearnerType.OBSERVER
: LearnerType.PARTICIPANT;
if (roleByServersList != peerType) {
LOG.warn("Peer type from servers list (" + roleByServersList
+ ") doesn't match peerType (" + peerType
+ "). Defaulting to servers list.");
peerType = roleByServersList;
}
}
}
五、启动清理数据文件的进程
public void start() {
if (PurgeTaskStatus.STARTED == purgeTaskStatus) {
LOG.warn("Purge task is already running.");
return;
}
// Don't schedule the purge task with zero or negative purge interval.
if (purgeInterval <= 0) {
LOG.info("Purge task is not scheduled.");
return;
}
timer = new Timer("PurgeTask", true);
TimerTask task = new PurgeTask(dataLogDir, snapDir, snapRetainCount);
timer.scheduleAtFixedRate(task, 0, TimeUnit.HOURS.toMillis(purgeInterval));
purgeTaskStatus = PurgeTaskStatus.STARTED;
}
六、启动线程进行清理
static class PurgeTask extends TimerTask {
private String logsDir;
private String snapsDir;
private int snapRetainCount;
public PurgeTask(String dataDir, String snapDir, int count) {
logsDir = dataDir;
snapsDir = snapDir;
snapRetainCount = count;
}
@Override
public void run() {
LOG.info("Purge task started.");
try {
PurgeTxnLog.purge(new File(logsDir), new File(snapsDir), snapRetainCount);
} catch (Exception e) {
LOG.error("Error occured while purging.", e);
}
LOG.info("Purge task completed.");
}
}
七、真正的过滤删除文件
/**
* purges the snapshot and logs keeping the last num snapshots
* and the corresponding logs.
* @param dataDir the dir that has the logs
* @param snapDir the dir that has the snapshots
* @param num the number of snapshots to keep
* @throws IOException
*/
public static void purge(File dataDir, File snapDir, int num) throws IOException {
if (num < 3) {
throw new IllegalArgumentException("count should be greater than 3");
}
FileTxnSnapLog txnLog = new FileTxnSnapLog(dataDir, snapDir);
// found any valid recent snapshots?
// files to exclude from deletion
Set<File> exc=new HashSet<File>();
List<File> snaps = txnLog.findNRecentSnapshots(num);
if (snaps.size() == 0)
return;
File snapShot = snaps.get(snaps.size() -1);
for (File f: snaps) {
exc.add(f);
}
long zxid = Util.getZxidFromName(snapShot.getName(),"snapshot");
exc.addAll(Arrays.asList(txnLog.getSnapshotLogs(zxid)));
final Set<File> exclude=exc;
class MyFileFilter implements FileFilter{
private final String prefix;
MyFileFilter(String prefix){
this.prefix=prefix;
}
public boolean accept(File f){
if(!f.getName().startsWith(prefix) || exclude.contains(f))
return false;
return true;
}
}
// add all non-excluded log files
List<File> files=new ArrayList<File>(
Arrays.asList(txnLog.getDataDir().listFiles(new MyFileFilter("log."))));
// add all non-excluded snapshot files to the deletion list
files.addAll(Arrays.asList(txnLog.getSnapDir().listFiles(new MyFileFilter("snapshot."))));
// remove the old files
for(File f: files)
{
System.out.println("Removing file: "+
DateFormat.getDateTimeInstance().format(f.lastModified())+
"\t"+f.getPath());
if(!f.delete()){
System.err.println("Failed to remove "+f.getPath());
}
}
}
八、这个函数功能自己研究
public void runFromConfig(QuorumPeerConfig config) throws IOException {
try {
ManagedUtil.registerLog4jMBeans();
} catch (JMException e) {
LOG.warn("Unable to register log4j JMX control", e);
}
LOG.info("Starting quorum peer");
try {
ServerCnxnFactory cnxnFactory = ServerCnxnFactory.createFactory();
cnxnFactory.configure(config.getClientPortAddress(),
config.getMaxClientCnxns());
quorumPeer = new QuorumPeer();
quorumPeer.setClientPortAddress(config.getClientPortAddress());
quorumPeer.setTxnFactory(new FileTxnSnapLog(
new File(config.getDataLogDir()),
new File(config.getDataDir())));
quorumPeer.setQuorumPeers(config.getServers());
quorumPeer.setElectionType(config.getElectionAlg());
quorumPeer.setMyid(config.getServerId());
quorumPeer.setTickTime(config.getTickTime());
quorumPeer.setMinSessionTimeout(config.getMinSessionTimeout());
quorumPeer.setMaxSessionTimeout(config.getMaxSessionTimeout());
quorumPeer.setInitLimit(config.getInitLimit());
quorumPeer.setSyncLimit(config.getSyncLimit());
quorumPeer.setQuorumVerifier(config.getQuorumVerifier());
quorumPeer.setCnxnFactory(cnxnFactory);
quorumPeer.setZKDatabase(new ZKDatabase(quorumPeer.getTxnFactory()));
quorumPeer.setLearnerType(config.getPeerType());
quorumPeer.setSyncEnabled(config.getSyncEnabled());
quorumPeer.setQuorumListenOnAllIPs(config.getQuorumListenOnAllIPs());
quorumPeer.start();
quorumPeer.join();
} catch (InterruptedException e) {
// warn, but generally this is ok
LOG.warn("Quorum Peer interrupted", e);
}
}