grpc-go initial commit

Author: iamqizhao

LICENSE

@@ -0,0 +1,28 @@
+Copyright 2014, Google Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+    * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

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+gRPC-Go: a Go implementation of gRPC, Google's RPC library
+
+To install this package, you need to install Go 1.4 and setup your Go workspace on your computer. The simplest way to install the library is to run:
+
+go get github.com/google/grpc-go/rpc

rpc/call.go

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+/*
+ *
+ * Copyright 2014, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+package rpc
+
+import (
+	"io"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/grpc/grpc-go/rpc/codes"
+	"github.com/grpc/grpc-go/rpc/metadata"
+	"github.com/grpc/grpc-go/rpc/transport"
+	"golang.org/x/net/context"
+)
+
+// recv receives and parses an RPC response.
+// On error, it returns the error and indicates whether the call should be retried.
+//
+// TODO(zhaoq): Check whether the received message sequence is valid.
+func recv(stream *transport.Stream, reply proto.Message) error {
+	p := &parser{s: stream}
+	for {
+		if err := recvProto(p, reply); err != nil {
+			if err == io.EOF {
+				return nil
+			}
+			return err
+		}
+	}
+}
+
+// sendRPC writes out various information of an RPC such as Context and Message.
+func sendRPC(ctx context.Context, callHdr *transport.CallHdr, t transport.ClientTransport, args proto.Message, opts *transport.Options) (_ *transport.Stream, err error) {
+	stream, err := t.NewStream(ctx, callHdr)
+	if err != nil {
+		return nil, err
+	}
+	defer func() {
+		if err != nil {
+			if _, ok := err.(transport.ConnectionError); !ok {
+				t.CloseStream(stream, err)
+			}
+		}
+	}()
+	// TODO(zhaoq): Support compression.
+	outBuf, err := encode(args, compressionNone)
+	if err != nil {
+		return nil, transport.StreamErrorf(codes.Internal, "%v", err)
+	}
+	err = t.Write(stream, outBuf, opts)
+	if err != nil {
+		return nil, err
+	}
+	// Sent successfully.
+	return stream, nil
+}
+
+// callInfo contains all related configuration and information about an RPC.
+type callInfo struct {
+	failFast  bool
+	headerMD  metadata.MD
+	trailerMD metadata.MD
+}
+
+// Invoke is called by the generated code. It sends the RPC request on the
+// wire and returns after response is received.
+func Invoke(ctx context.Context, method string, args, reply proto.Message, cc *ClientConn, opts ...CallOption) error {
+	var c callInfo
+	for _, o := range opts {
+		if err := o.before(&c); err != nil {
+			return toRPCErr(err)
+		}
+	}
+	defer func() {
+		for _, o := range opts {
+			o.after(&c)
+		}
+	}()
+	callHdr := &transport.CallHdr{
+		Host:   cc.target,
+		Method: method,
+	}
+	topts := &transport.Options{
+		Last:  true,
+		Delay: false,
+	}
+	ts := 0
+	var lastErr error // record the error that happened
+	for {
+		var (
+			err    error
+			t      transport.ClientTransport
+			stream *transport.Stream
+		)
+		// TODO(zhaoq): Need a formal spec of retry strategy for non-failfast rpcs.
+		if lastErr != nil && c.failFast {
+			return lastErr
+		}
+		t, ts, err = cc.wait(ctx, ts)
+		if err != nil {
+			if lastErr != nil {
+				// This was a retry; return the error from the last attempt.
+				return lastErr
+			}
+			return err
+		}
+		stream, err = sendRPC(ctx, callHdr, t, args, topts)
+		if err != nil {
+			if _, ok := err.(transport.ConnectionError); ok {
+				lastErr = err
+				continue
+			}
+			if lastErr != nil {
+				return toRPCErr(lastErr)
+			}
+			return toRPCErr(err)
+		}
+		// Try to acquire header metadata from the server if there is any.
+		c.headerMD, err = stream.Header()
+		if err != nil {
+			return toRPCErr(err)
+		}
+		// Receive the response
+		lastErr = recv(stream, reply)
+		if _, ok := lastErr.(transport.ConnectionError); ok {
+			continue
+		}
+		c.trailerMD = stream.Trailer()
+		t.CloseStream(stream, lastErr)
+		if lastErr != nil {
+			return toRPCErr(lastErr)
+		}
+		return Errorf(stream.StatusCode(), stream.StatusDesc())
+	}
+}