grpcjavaclient,goserver错误io.grpc.StatusRuntimeException:UNAVAILABLE

java client 获取 channel 的代码如下:

public ManagedChannel getChannel() { ManagedChannel channel = ManagedChannelBuilder.forAddress(config.getGrpc().getHost(), config.getGrpc().getPort()) .disableRetry() .idleTimeout(2, TimeUnit.SECONDS) .build(); return channel; }

Sping boot 报如下错，没有任何其它提示。

[2019-11-14 15:15:02] [ERROR] o.a.c.c.C.[.[.[.[dispatcherServlet] [DirectJDKLog.java:175] - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is io.grpc.StatusRuntimeException: UNAVAILABLE: io exception] with root cause java.io.IOException: 远程主机强迫关闭了一个现有的连接。 at sun.nio.ch.SocketDispatcher.read0(Native Method) at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:43) at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223) at sun.nio.ch.IOUtil.read(IOUtil.java:192) at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380) at io.grpc.netty.shaded.io.netty.buffer.PooledUnsafeDirectByteBuf.setBytes(PooledUnsafeDirectByteBuf.java:288) at io.grpc.netty.shaded.io.netty.buffer.AbstractByteBuf.writeBytes(AbstractByteBuf.java:1108) at io.grpc.netty.shaded.io.netty.channel.socket.nio.NioSocketChannel.doReadBytes(NioSocketChannel.java:345) at io.grpc.netty.shaded.io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:148) at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:646) at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:581) at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:498) at io.grpc.netty.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:460) at io.grpc.netty.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:884) at io.grpc.netty.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) at java.lang.Thread.run(Thread.java:748)

go server 不设置 logger 连日志都没有，加了日志输出如下错误:

2019/11/14 15:14:12 rpc server listeing on :50051 log from Warningln [grpc: Server.Serve failed to create ServerTransport: connection error: desc = "transport: http2Server.HandleStreams received bogus greeting from client: "\x16\x03\x01\x00\x94\x01\x00\x00\x90\x03\x03\xd7\xf9\x81\x8cf\xa8\xeb\xcc{\xb2r\x19N""] log from Warningln [grpc: Server.Serve failed to create ServerTransport: connection error: desc = "transport: http2Server.HandleStreams received bogus greeting from client: "\x16\x03\x01\x00\x94\x01\x00\x00\x90\x03\x03\xadt\xcb\xed\x1c\xab~˺\xe5\x8dM\x14""] log from Warningln [grpc: Server.Serve failed to create ServerTransport: connection error: desc = "transport: http2Server.HandleStreams received bogus greeting from client: "\x16\x03\x01\x00\x94\x01\x00\x00\x90\x03\x03Cm:\x0e\xf8Ǭ8\a\xdb[3\x95""]

断点和源码找到输出这个日志的地方: google.golang.org/grpc/internal/transport/http2_server.go

原因是 preface 和源码中的 clientPreface 不相等，clientPreface 是这个: []byte(http2.ClientPreface)，ClientPreface = "PRI * HTTP/2.0rnrnSMrnrn"。

快去看看 ClientPreface 是什么:

stackoverflow 说创建 Channel 时要加 usePlaintext,。好吧~。