/usr/share/gocode/src/github.com/jacobsa/reqtrace/trace_state.go is in golang-github-jacobsa-reqtrace-dev 0.0~git20150505-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 | // Copyright 2015 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package reqtrace
import (
"log"
"math"
"os"
"strings"
"sync"
"time"
)
const logFlags = 0
var gLogger = log.New(os.Stderr, "reqtrace: ", logFlags)
type span struct {
// Fixed at creation.
desc string
start time.Time
// Updated by report functions.
finished bool
end time.Time
err error
}
// All of the state for a particular trace root. The zero value is usable.
type traceState struct {
mu sync.Mutex
// The list of spans associated with this state. Append-only.
//
// GUARDED_BY(mu)
spans []*span
}
func (ts *traceState) report(spanIndex int, err error) {
ts.mu.Lock()
defer ts.mu.Unlock()
s := ts.spans[spanIndex]
s.finished = true
s.end = time.Now()
s.err = err
}
// Associate a new span with the trace. Return a function that will report its
// completion.
func (ts *traceState) CreateSpan(desc string) (report ReportFunc) {
ts.mu.Lock()
defer ts.mu.Unlock()
index := len(ts.spans)
ts.spans = append(ts.spans, &span{desc: desc, start: time.Now()})
report = func(err error) { ts.report(index, err) }
return
}
func round(x float64) float64 {
if x < 0 {
return math.Ceil(x - 0.5)
}
return math.Floor(x + 0.5)
}
// Log information about the spans in this trace.
func (ts *traceState) Log() {
ts.mu.Lock()
defer ts.mu.Unlock()
gLogger.Println()
// Special case: we require at least one span.
if len(ts.spans) == 0 {
return
}
// Print a banner for this trace.
const bannerHalfLength = 45
gLogger.Println()
gLogger.Printf(
"%s %s %s",
strings.Repeat("=", bannerHalfLength),
ts.spans[0].desc,
strings.Repeat("=", bannerHalfLength))
gLogger.Printf("Start time: %v", ts.spans[0].start.Format(time.RFC3339Nano))
gLogger.Println()
// Find the minimum start time and maximum end time of all durations.
var minStart time.Time
var maxEnd time.Time
for _, s := range ts.spans {
if !s.finished {
continue
}
if minStart.IsZero() || s.start.Before(minStart) {
minStart = s.start
}
if maxEnd.Before(s.end) {
maxEnd = s.end
}
}
// Bail out if something weird happened.
//
// TODO(jacobsa): Be more graceful.
totalDuration := maxEnd.Sub(minStart)
if minStart.IsZero() || maxEnd.IsZero() || totalDuration <= 0 {
gLogger.Println("(Weird trace)")
return
}
// Calculate the number of nanoseconds elapsed, as a floating point number.
totalNs := float64(totalDuration / time.Nanosecond)
// Log each span with some ASCII art showing its length relative to the
// total.
const totalNumCols float64 = 120
for _, s := range ts.spans {
if !s.finished {
gLogger.Printf("(Unfinished: %s)", s.desc)
gLogger.Println()
continue
}
// Calculate the duration of the span, and its width relative to the
// longest span.
d := s.end.Sub(s.start)
if d <= 0 {
gLogger.Println("(Weird duration)")
gLogger.Println()
continue
}
durationRatio := float64(d/time.Nanosecond) / totalNs
// We will offset the label and banner proportional to the time since the
// start of the earliest span.
offsetRatio := float64(s.start.Sub(minStart)/time.Nanosecond) / totalNs
offsetChars := int(round(offsetRatio * totalNumCols))
offsetStr := strings.Repeat(" ", offsetChars)
// Print the description and duration.
gLogger.Printf("%s%v", offsetStr, s.desc)
gLogger.Printf("%s%v", offsetStr, d)
// Print a banner showing the duration graphically.
bannerChars := int(round(durationRatio * totalNumCols))
var dashes string
if bannerChars > 2 {
dashes = strings.Repeat("-", bannerChars-2)
}
gLogger.Printf("%s|%s|", offsetStr, dashes)
gLogger.Println()
}
}
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