trace.go

/*
 *
 * Copyright 2015, 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 grpc

import (
	"bytes"
	"fmt"
	"io"
	"net"
	"strings"
	"time"

	"golang.org/x/net/trace"
)

// EnableTracing controls whether to trace RPCs using the golang.org/x/net/trace package.
// This should only be set before any RPCs are sent or received by this program.
var EnableTracing = true

// methodFamily returns the trace family for the given method.
// It turns "/pkg.Service/GetFoo" into "pkg.Service".
func methodFamily(m string) string {
	m = strings.TrimPrefix(m, "/") // remove leading slash
	if i := strings.Index(m, "/"); i >= 0 {
		m = m[:i] // remove everything from second slash
	}
	if i := strings.LastIndex(m, "."); i >= 0 {
		m = m[i+1:] // cut down to last dotted component
	}
	return m
}

// traceInfo contains tracing information for an RPC.
type traceInfo struct {
	tr        trace.Trace
	firstLine firstLine
}

// firstLine is the first line of an RPC trace.
type firstLine struct {
	client     bool // whether this is a client (outgoing) RPC
	remoteAddr net.Addr
	deadline   time.Duration // may be zero
}

func (f *firstLine) String() string {
	var line bytes.Buffer
	io.WriteString(&line, "RPC: ")
	if f.client {
		io.WriteString(&line, "to")
	} else {
		io.WriteString(&line, "from")
	}
	fmt.Fprintf(&line, " %v deadline:", f.remoteAddr)
	if f.deadline != 0 {
		fmt.Fprint(&line, f.deadline)
	} else {
		io.WriteString(&line, "none")
	}
	return line.String()
}

// payload represents an RPC request or response payload.
type payload struct {
	sent bool        // whether this is an outgoing payload
	msg  interface{} // e.g. a proto.Message
	// TODO(dsymonds): add stringifying info to codec, and limit how much we hold here?
}

func (p payload) String() string {
	if p.sent {
		return fmt.Sprintf("sent: %v", p.msg)
	} else {
		return fmt.Sprintf("recv: %v", p.msg)
	}
}

type fmtStringer struct {
	format string
	a      []interface{}
}

func (f *fmtStringer) String() string {
	return fmt.Sprintf(f.format, f.a...)
}