ShardingProxy服务器处理框架
启动:shardingsphere-proxy-bootstrap
@NoArgsConstructor(access = AccessLevel.PRIVATE) public final class Bootstrap { public static void main(final String[] args) throws IOException, SQLException { BootstrapArguments bootstrapArgs = new BootstrapArguments(args); YamlProxyConfiguration yamlConfig = ProxyConfigurationLoader.load(bootstrapArgs.getConfigurationPath()); createBootstrapInitializer(yamlConfig).init(yamlConfig, bootstrapArgs.getPort()); } private static BootstrapInitializer createBootstrapInitializer(final YamlProxyConfiguration yamlConfig) { return null == yamlConfig.getServerConfiguration().getGovernance() ? new StandardBootstrapInitializer() : new GovernanceBootstrapInitializer(); } }
AbstractBootstrapInitializer 初始化,看到根据配置初始化各种组件,事件监听,扩展任务执行器等,最终启动proxy
@Override public final void init(final YamlProxyConfiguration yamlConfig, final int port) throws SQLException { ProxyConfiguration proxyConfig = getProxyConfiguration(yamlConfig); MetaDataContexts metaDataContexts = decorateMetaDataContexts(createMetaDataContexts(proxyConfig)); for (MetaDataAwareEventSubscriber each : ShardingSphereServiceLoader.getSingletonServiceInstances(MetaDataAwareEventSubscriber.class)) { each.setMetaDataContexts(metaDataContexts); ShardingSphereEventBus.getInstance().register(each); } String xaTransactionMangerType = metaDataContexts.getProps().getValue(ConfigurationPropertyKey.XA_TRANSACTION_MANAGER_TYPE); TransactionContexts transactionContexts = decorateTransactionContexts(createTransactionContexts(metaDataContexts), xaTransactionMangerType); ProxyContext.getInstance().init(metaDataContexts, transactionContexts); setDatabaseServerInfo(); initScalingWorker(yamlConfig); shardingSphereProxy.start(port); }
proxy服务器启动
public final class ShardingSphereProxy { private EventLoopGroup bossGroup; private EventLoopGroup workerGroup; @SneakyThrows(InterruptedException.class) public void start(final int port) { try { createEventLoopGroup(); ServerBootstrap bootstrap = new ServerBootstrap(); initServerBootstrap(bootstrap); ChannelFuture future = bootstrap.bind(port).sync(); log.info("ShardingSphere-Proxy start success."); future.channel().closeFuture().sync(); } finally { workerGroup.shutdownGracefully(); bossGroup.shutdownGracefully(); BackendExecutorContext.getInstance().getExecutorEngine().close(); } } private void createEventLoopGroup() { bossGroup = Epoll.isAvailable() ? new EpollEventLoopGroup(1) : new NioEventLoopGroup(1); workerGroup = Epoll.isAvailable() ? new EpollEventLoopGroup() : new NioEventLoopGroup(); } private void initServerBootstrap(final ServerBootstrap bootstrap) { bootstrap.group(bossGroup, workerGroup) .channel(Epoll.isAvailable() ? EpollServerSocketChannel.class : NioServerSocketChannel.class) .option(ChannelOption.SO_BACKLOG, 128) .option(ChannelOption.WRITE_BUFFER_WATER_MARK, new WriteBufferWaterMark(8 * 1024 * 1024, 16 * 1024 * 1024)) .option(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT) .childOption(ChannelOption.ALLOCATOR, PooledByteBufAllocator.DEFAULT) .childOption(ChannelOption.TCP_NODELAY, true) .handler(new LoggingHandler(LogLevel.INFO)) .childHandler(new ServerHandlerInitializer(FrontDatabaseProtocolTypeFactory.getDatabaseType())); } }
在handler中解码请求并处理相关请求
public final class ServerHandlerInitializer extends ChannelInitializer<SocketChannel> { private final DatabaseType databaseType; @Override protected void initChannel(final SocketChannel socketChannel) { DatabaseProtocolFrontendEngine databaseProtocolFrontendEngine = DatabaseProtocolFrontendEngineFactory.newInstance(databaseType); ChannelPipeline pipeline = socketChannel.pipeline(); pipeline.addLast(new PacketCodec(databaseProtocolFrontendEngine.getCodecEngine())); pipeline.addLast(new FrontendChannelInboundHandler(databaseProtocolFrontendEngine)); } }
处理各种读写事件
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
public final class FrontendChannelInboundHandler extends ChannelInboundHandlerAdapter { private final DatabaseProtocolFrontendEngine databaseProtocolFrontendEngine; private final BackendConnection backendConnection; private volatile boolean authenticated; public FrontendChannelInboundHandler(final DatabaseProtocolFrontendEngine databaseProtocolFrontendEngine) { this.databaseProtocolFrontendEngine = databaseProtocolFrontendEngine; TransactionType transactionType = TransactionType.valueOf(ProxyContext.getInstance().getMetaDataContexts().getProps().getValue(ConfigurationPropertyKey.PROXY_TRANSACTION_TYPE)); backendConnection = new BackendConnection(transactionType); } @Override public void channelActive(final ChannelHandlerContext context) { int connectionId = databaseProtocolFrontendEngine.getAuthenticationEngine().handshake(context); ConnectionThreadExecutorGroup.getInstance().register(connectionId); backendConnection.setConnectionId(connectionId); } @Override public void channelRead(final ChannelHandlerContext context, final Object message) { if (!authenticated) { authenticated = authenticate(context, (ByteBuf) message); return; } ProxyStateContext.execute(context, message, databaseProtocolFrontendEngine, backendConnection); } private boolean authenticate(final ChannelHandlerContext context, final ByteBuf message) { try (PacketPayload payload = databaseProtocolFrontendEngine.getCodecEngine().createPacketPayload(message)) { AuthenticationResult authResult = databaseProtocolFrontendEngine.getAuthenticationEngine().authenticate(context, payload); if (authResult.isFinished()) { backendConnection.setGrantee(new Grantee(authResult.getUsername(), authResult.getHostname())); backendConnection.setCurrentSchema(authResult.getDatabase()); } return authResult.isFinished(); // CHECKSTYLE:OFF } catch (final Exception ex) { // CHECKSTYLE:ON log.error("Exception occur: ", ex); context.writeAndFlush(databaseProtocolFrontendEngine.getCommandExecuteEngine().getErrorPacket(ex, backendConnection)); context.close(); } return false; } @Override public void channelInactive(final ChannelHandlerContext context) { context.fireChannelInactive(); closeAllResources(); } private void closeAllResources() { ConnectionThreadExecutorGroup.getInstance().unregisterAndAwaitTermination(backendConnection.getConnectionId()); PrimaryVisitedManager.clear(); backendConnection.closeResultSets(); backendConnection.closeStatements(); backendConnection.closeConnections(true); backendConnection.closeFederateExecutor(); databaseProtocolFrontendEngine.release(backendConnection); } @Override public void channelWritabilityChanged(final ChannelHandlerContext context) { if (context.channel().isWritable()) { backendConnection.getResourceLock().doNotify(); } } }
ProxyStateContext类中对应各种状态执行对应的动作
static { STATES.put(StateType.OK, new OKProxyState()); STATES.put(StateType.LOCK, new LockProxyState()); STATES.put(StateType.CIRCUIT_BREAK, new CircuitBreakProxyState()); }
进入执行
public final class OKProxyState implements ProxyState { @Override public void execute(final ChannelHandlerContext context, final Object message, final DatabaseProtocolFrontendEngine databaseProtocolFrontendEngine, final BackendConnection backendConnection) { boolean supportHint = ProxyContext.getInstance().getMetaDataContexts().getProps().<Boolean>getValue(ConfigurationPropertyKey.PROXY_HINT_ENABLED); boolean isOccupyThreadForPerConnection = databaseProtocolFrontendEngine.getFrontendContext().isOccupyThreadForPerConnection(); ExecutorService executorService = CommandExecutorSelector.getExecutorService( isOccupyThreadForPerConnection, supportHint, backendConnection.getTransactionStatus().getTransactionType(), backendConnection.getConnectionId()); executorService.execute(new CommandExecutorTask(databaseProtocolFrontendEngine, backendConnection, context, message)); } }