stacks.go at 100c34b ⋅ uber-go/goleak

// Copyright (c) 2017 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

package stack

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"runtime"
	"strconv"
	"strings"
)

const _defaultBufferSize = 64 * 1024 // 64 KiB

// Stack represents a single Goroutine's stack.
type Stack struct {
	id            int
	state         string
	firstFunction string
	fullStack     *bytes.Buffer
}

// ID returns the goroutine ID.
func (s Stack) ID() int {
	return s.id
}

// State returns the Goroutine's state.
func (s Stack) State() string {
	return s.state
}

// Full returns the full stack trace for this goroutine.
func (s Stack) Full() string {
	return s.fullStack.String()
}

// FirstFunction returns the name of the first function on the stack.
func (s Stack) FirstFunction() string {
	return s.firstFunction
}

func (s Stack) String() string {
	return fmt.Sprintf(
		"Goroutine %v in state %v, with %v on top of the stack:\n%s",
		s.id, s.state, s.firstFunction, s.Full())
}

func getStacks(all bool) []Stack {
	var stacks []Stack

	var curStack *Stack
	stackReader := bufio.NewReader(bytes.NewReader(getStackBuffer(all)))
	for {
		line, err := stackReader.ReadString('\n')
		if err == io.EOF {
			break
		}
		if err != nil {
			// We're reading using bytes.NewReader which should never fail.
			panic("bufio.NewReader failed on a fixed string")
		}

		// If we see the goroutine header, start a new stack.
		isFirstLine := false
		if strings.HasPrefix(line, "goroutine ") {
			// flush any previous stack
			if curStack != nil {
				stacks = append(stacks, *curStack)
			}
			id, goState := parseGoStackHeader(line)
			curStack = &Stack{
				id:        id,
				state:     goState,
				fullStack: &bytes.Buffer{},
			}
			isFirstLine = true
		}
		curStack.fullStack.WriteString(line)
		if !isFirstLine && curStack.firstFunction == "" {
			curStack.firstFunction = parseFirstFunc(line)
		}
	}

	if curStack != nil {
		stacks = append(stacks, *curStack)
	}
	return stacks
}

// All returns the stacks for all running goroutines.
func All() []Stack {
	return getStacks(true)
}

// Current returns the stack for the current goroutine.
func Current() Stack {
	return getStacks(false)[0]
}

func getStackBuffer(all bool) []byte {
	for i := _defaultBufferSize; ; i *= 2 {
		buf := make([]byte, i)
		if n := runtime.Stack(buf, all); n < i {
			return buf[:n]
		}
	}
}

func parseFirstFunc(line string) string {
	line = strings.TrimSpace(line)
	if idx := strings.LastIndex(line, "("); idx > 0 {
		return line[:idx]
	}
	panic(fmt.Sprintf("function calls missing parents: %q", line))
}

// parseGoStackHeader parses a stack header that looks like:
// goroutine 643 [runnable]:\n
// And returns the goroutine ID, and the state.
func parseGoStackHeader(line string) (goroutineID int, state string) {
	line = strings.TrimSuffix(line, ":\n")
	parts := strings.SplitN(line, " ", 3)
	if len(parts) != 3 {
		panic(fmt.Sprintf("unexpected stack header format: %q", line))
	}

	id, err := strconv.Atoi(parts[1])
	if err != nil {
		panic(fmt.Sprintf("failed to parse goroutine ID: %v in line %q", parts[1], line))
	}

	state = strings.TrimSuffix(strings.TrimPrefix(parts[2], "["), "]")
	return id, state
}

Read our documentation on viewing source code .

1		// Copyright (c) 2017 Uber Technologies, Inc.
2		//
3		// Permission is hereby granted, free of charge, to any person obtaining a copy
4		// of this software and associated documentation files (the "Software"), to deal
5		// in the Software without restriction, including without limitation the rights
6		// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
7		// copies of the Software, and to permit persons to whom the Software is
8		// furnished to do so, subject to the following conditions:
9		//
10		// The above copyright notice and this permission notice shall be included in
11		// all copies or substantial portions of the Software.
12		//
13		// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14		// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15		// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16		// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17		// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
18		// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
19		// THE SOFTWARE.
20
21		package stack
22
23		import (
24		"bufio"
25		"bytes"
26		"fmt"
27		"io"
28		"runtime"
29		"strconv"
30		"strings"
31		)
32
33		const _defaultBufferSize = 64 * 1024 // 64 KiB
34
35		// Stack represents a single Goroutine's stack.
36		type Stack struct {
37		id int
38		state string
39		firstFunction string
40		fullStack *bytes.Buffer
41		}
42
43		// ID returns the goroutine ID.
44	3	func (s Stack) ID() int {
45	3	return s.id
46		}
47
48		// State returns the Goroutine's state.
49	3	func (s Stack) State() string {
50	3	return s.state
51		}
52
53		// Full returns the full stack trace for this goroutine.
54	3	func (s Stack) Full() string {
55	3	return s.fullStack.String()
56		}
57
58		// FirstFunction returns the name of the first function on the stack.
59	3	func (s Stack) FirstFunction() string {
60	3	return s.firstFunction
61		}
62
63	3	func (s Stack) String() string {
64	3	return fmt.Sprintf(
65	3	"Goroutine %v in state %v, with %v on top of the stack:\n%s",
66	3	s.id, s.state, s.firstFunction, s.Full())
67		}
68
69	3	func getStacks(all bool) []Stack {
70	3	var stacks []Stack
71
72	3	var curStack *Stack
73	3	stackReader := bufio.NewReader(bytes.NewReader(getStackBuffer(all)))
74	3	for {
75	3	line, err := stackReader.ReadString('\n')
76	3	if err == io.EOF {
77	3	break
78		}
79	3	if err != nil {
80		// We're reading using bytes.NewReader which should never fail.
81	0	panic("bufio.NewReader failed on a fixed string")
82		}
83
84		// If we see the goroutine header, start a new stack.
85	3	isFirstLine := false
86	3	if strings.HasPrefix(line, "goroutine ") {
87		// flush any previous stack
88	3	if curStack != nil {
89	3	stacks = append(stacks, *curStack)
90		}
91	3	id, goState := parseGoStackHeader(line)
92	3	curStack = &Stack{
93	3	id: id,
94	3	state: goState,
95	3	fullStack: &bytes.Buffer{},
96		}
97	3	isFirstLine = true
98		}
99	3	curStack.fullStack.WriteString(line)
100	3	if !isFirstLine && curStack.firstFunction == "" {
101	3	curStack.firstFunction = parseFirstFunc(line)
102		}
103		}
104
105	3	if curStack != nil {
106	3	stacks = append(stacks, *curStack)
107		}
108	3	return stacks
109		}
110
111		// All returns the stacks for all running goroutines.
112	3	func All() []Stack {
113	3	return getStacks(true)
114		}
115
116		// Current returns the stack for the current goroutine.
117	3	func Current() Stack {
118	3	return getStacks(false)[0]
119		}
120
121	3	func getStackBuffer(all bool) []byte {
122	3	for i := _defaultBufferSize; ; i *= 2 {
123	3	buf := make([]byte, i)
124	3	if n := runtime.Stack(buf, all); n < i {
125	3	return buf[:n]
126		}
127		}
128		}
129
130	3	func parseFirstFunc(line string) string {
131	3	line = strings.TrimSpace(line)
132	3	if idx := strings.LastIndex(line, "("); idx > 0 {
133	3	return line[:idx]
134		}
135	0	panic(fmt.Sprintf("function calls missing parents: %q", line))
136		}
137
138		// parseGoStackHeader parses a stack header that looks like:
139		// goroutine 643 [runnable]:\n
140		// And returns the goroutine ID, and the state.
141	3	func parseGoStackHeader(line string) (goroutineID int, state string) {
142	3	line = strings.TrimSuffix(line, ":\n")
143	3	parts := strings.SplitN(line, " ", 3)
144	3	if len(parts) != 3 {
145	0	panic(fmt.Sprintf("unexpected stack header format: %q", line))
146		}
147
148	3	id, err := strconv.Atoi(parts[1])
149	3	if err != nil {
150	0	panic(fmt.Sprintf("failed to parse goroutine ID: %v in line %q", parts[1], line))
151		}
152
153	3	state = strings.TrimSuffix(strings.TrimPrefix(parts[2], "["), "]")
154	3	return id, state
155		}

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