序
本文主要研究一下rocketmq的KVConfigManager
KVConfigManager
org/apache/rocketmq/namesrv/kvconfig/KVConfigManager.java
public class KVConfigManager {
private static final Logger log = LoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
private final NamesrvController namesrvController;
private final ReadWriteLock lock = new ReentrantReadWriteLock();
private final HashMap>();
public KVConfigManager(NamesrvController namesrvController) {
this.namesrvController = namesrvController;
}
public void load() {
String content = null;
try {
content = MixAll.file2String(this.namesrvController.getNamesrvConfig().getKvConfigPath());
} catch (IOException e) {
log.warn("Load KV config table exception", e);
}
if (content != null) {
KVConfigSerializeWrapper kvConfigSerializeWrapper =
KVConfigSerializeWrapper.fromJson(content, KVConfigSerializeWrapper.class);
if (null != kvConfigSerializeWrapper) {
this.configTable.putAll(kvConfigSerializeWrapper.getConfigTable());
log.info("load KV config table OK");
}
}
}
public void putKVConfig(final String namespace, final String key, final String value) {
try {
this.lock.writeLock().lockInterruptibly();
try {
HashMap kvTable = this.configTable.get(namespace);
if (null == kvTable) {
kvTable = new HashMap();
this.configTable.put(namespace, kvTable);
log.info("putKVConfig create new Namespace {}", namespace);
}
final String prev = kvTable.put(key, value);
if (null != prev) {
log.info("putKVConfig update config item, Namespace: {} Key: {} Value: {}",
namespace, key, value);
} else {
log.info("putKVConfig create new config item, Namespace: {} Key: {} Value: {}",
namespace, key, value);
}
} finally {
this.lock.writeLock().unlock();
}
} catch (InterruptedException e) {
log.error("putKVConfig InterruptedException", e);
}
this.persist();
}
public void persist() {
try {
this.lock.readLock().lockInterruptibly();
try {
KVConfigSerializeWrapper kvConfigSerializeWrapper = new KVConfigSerializeWrapper();
kvConfigSerializeWrapper.setConfigTable(this.configTable);
String content = kvConfigSerializeWrapper.toJson();
if (null != content) {
MixAll.string2File(content, this.namesrvController.getNamesrvConfig().getKvConfigPath());
}
} catch (IOException e) {
log.error("persist kvconfig Exception, "
+ this.namesrvController.getNamesrvConfig().getKvConfigPath(), e);
} finally {
this.lock.readLock().unlock();
}
} catch (InterruptedException e) {
log.error("persist InterruptedException", e);
}
}
public void deleteKVConfig(final String namespace, final String key) {
try {
this.lock.writeLock().lockInterruptibly();
try {
HashMap kvTable = this.configTable.get(namespace);
if (null != kvTable) {
String value = kvTable.remove(key);
log.info("deleteKVConfig delete a config item, Namespace: {} Key: {} Value: {}",
namespace, key, value);
}
} finally {
this.lock.writeLock().unlock();
}
} catch (InterruptedException e) {
log.error("deleteKVConfig InterruptedException", e);
}
this.persist();
}
public byte[] getKVListByNamespace(final String namespace) {
try {
this.lock.readLock().lockInterruptibly();
try {
HashMap kvTable = this.configTable.get(namespace);
if (null != kvTable) {
KVTable table = new KVTable();
table.setTable(kvTable);
return table.encode();
}
} finally {
this.lock.readLock().unlock();
}
} catch (InterruptedException e) {
log.error("getKVListByNamespace InterruptedException", e);
}
return null;
}
public String getKVConfig(final String namespace, final String key) {
try {
this.lock.readLock().lockInterruptibly();
try {
HashMap kvTable = this.configTable.get(namespace);
if (null != kvTable) {
return kvTable.get(key);
}
} finally {
this.lock.readLock().unlock();
}
} catch (InterruptedException e) {
log.error("getKVConfig InterruptedException", e);
}
return null;
}
public void printAllPeriodically() {
try {
this.lock.readLock().lockInterruptibly();
try {
log.info("--------------------------------------------------------");
{
log.info("configTable SIZE: {}", this.configTable.size());
Iterator>> it =
this.configTable.entrySet().iterator();
while (it.hasNext()) {
Entry> next = it.next();
Iterator> itSub = next.getValue().entrySet().iterator();
while (itSub.hasNext()) {
Entry nextSub = itSub.next();
log.info("configTable NS: {} Key: {} Value: {}", next.getKey(), nextSub.getKey(),
nextSub.getValue());
}
}
}
} finally {
this.lock.readLock().unlock();
}
} catch (InterruptedException e) {
log.error("printAllPeriodically InterruptedException", e);
}
}
} - 这里使用HashMap，然后通过ReentrantReadWriteLock进行并发控制，map的key是namespace，而value是一个HashMap
- putKVConfig及deleteKVConfig使用的是写锁
- persist、getKVListByNamespace、getKVConfig、printAllPeriodically使用的是读锁
MixAll.string2File
org/apache/rocketmq/common/MixAll.java
public static void string2File(final String str, final String fileName) throws IOException {
String tmpFile = fileName + ".tmp";
string2FileNotSafe(str, tmpFile);
String bakFile = fileName + ".bak";
String prevContent = file2String(fileName);
if (prevContent != null) {
string2FileNotSafe(prevContent, bakFile);
}
File file = new File(fileName);
file.delete();
file = new File(tmpFile);
file.renameTo(new File(fileName));
}
public static void string2FileNotSafe(final String str, final String fileName) throws IOException {
File file = new File(fileName);
File fileParent = file.getParentFile();
if (fileParent != null) {
fileParent.mkdirs();
}
FileWriter fileWriter = null;
try {
fileWriter = new FileWriter(file);
fileWriter.write(str);
} catch (IOException e) {
throw e;
} finally {
if (fileWriter != null) {
fileWriter.close();
}
}
}- 将文本内容写到指定路径的文件
- 这里先写到.tmp文件，然后备份上一个版本的内容，在删除上一个版本的文件，最后将tmp文件重命名为正式的文件名
RemotingSerializable
org/apache/rocketmq/remoting/protocol/RemotingSerializable.java
public abstract class RemotingSerializable {
private final static Charset CHARSET_UTF8 = Charset.forName("UTF-8");
public static byte[] encode(final Object obj) {
final String json = toJson(obj, false);
if (json != null) {
return json.getBytes(CHARSET_UTF8);
}
return null;
}
public static String toJson(final Object obj, boolean prettyFormat) {
return JSON.toJSONString(obj, prettyFormat);
}
public static T decode(final byte[] data, Class classOfT) {
final String json = new String(data, CHARSET_UTF8);
return fromJson(json, classOfT);
}
public static T fromJson(String json, Class classOfT) {
return JSON.parseObject(json, classOfT);
}
public byte[] encode() {
final String json = this.toJson();
if (json != null) {
return json.getBytes(CHARSET_UTF8);
}
return null;
}
public String toJson() {
return toJson(false);
}
public String toJson(final boolean prettyFormat) {
return toJson(this, prettyFormat);
}
} - 这里toJson使用的是fastjson的方法
小结
- rocketmq的KVConfigManager采用的是HashMap来存配置项，key为namespace，value为HashMap，存储的值采用的是String
- 采用ReentrantReadWriteLock进行并发控制，支持序列JSON到磁盘，也支持从磁盘文件加载到内存
doc
- KVConfigManager