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pkg/failpoint: init failpoint package

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Failpoint is used to control the fail during API call when testing, especially
the API is complicated like CRI-RunPodSandbox. It can help us to test
the unexpected behavior without mock. The control design is based on freebsd
fail(9), but simpler.

REF: https://www.freebsd.org/cgi/man.cgi?query=fail&sektion=9&apropos=0&manpath=FreeBSD%2B10.0-RELEASE

Signed-off-by: Wei Fu <fuweid89@gmail.com>
This commit is contained in:
Wei Fu 2022-06-16 23:59:30 +08:00
parent 05a71fdc28
commit ffd59ba600
2 changed files with 427 additions and 0 deletions
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293
pkg/failpoint/fail.go Normal file
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/*
Copyright The containerd Authors.
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 failpoint
import (
"bytes"
"fmt"
"strconv"
"strings"
"sync"
"time"
)
// Type is the type of failpoint to specifies which action to take.
type Type int
const (
// TypeInvalid is invalid type
TypeInvalid Type = iota
// TypeOff takes no action
TypeOff
// TypeError triggers failpoint error with specified argument
TypeError
// TypePanic triggers panic with specified argument
TypePanic
// TypeDelay sleeps with the specified number of milliseconds
TypeDelay
)
// String returns the name of type.
func (t Type) String() string {
switch t {
case TypeOff:
return "off"
case TypeError:
return "error"
case TypePanic:
return "panic"
case TypeDelay:
return "delay"
default:
return "invalid"
}
}
// Failpoint is used to add code points where error or panic may be injected by
// user. The user controlled variable will be parsed for how the error injected
// code should fire. There is the way to set the rule for failpoint.
//
// <count>*<type>[(arg)][-><more terms>]
//
// The <type> argument specifies which action to take; it can be one of:
//
// off: Takes no action (does not trigger failpoint and no argument)
// error: Triggers failpoint error with specified argument(string)
// panic: Triggers panic with specified argument(string)
// delay: Sleep the specified number of milliseconds
//
// The <count>* modifiers prior to <type> control when <type> is executed. For
// example, "5*error(oops)" means "return error oops 5 times total". The
// operator -> can be used to express cascading terms. If you specify
// <term1>-><term2>, it means that if <term1> does not execute, <term2> will
// be evaluated. If you want the error injected code should fire in second
// call, you can specify "1*off->1*error(oops)".
//
// Based on fail(9) freebsd: https://www.freebsd.org/cgi/man.cgi?query=fail&sektion=9&apropos=0&manpath=FreeBSD%2B10.0-RELEASE
type Failpoint struct {
sync.Mutex
fnName string
entries []*failpointEntry
}
// NewFailpoint returns failpoint control.
func NewFailpoint(fnName string, terms string) (*Failpoint, error) {
entries, err := parseTerms([]byte(terms))
if err != nil {
return nil, err
}
return &Failpoint{
fnName: fnName,
entries: entries,
}, nil
}
// Evaluate evaluates a failpoint.
func (fp *Failpoint) Evaluate() error {
var target *failpointEntry
func() {
fp.Lock()
defer fp.Unlock()
for _, entry := range fp.entries {
if entry.count == 0 {
continue
}
entry.count--
target = entry
break
}
}()
if target == nil {
return nil
}
return target.evaluate()
}
// Failpoint returns the current state of control in string format.
func (fp *Failpoint) Marshal() string {
fp.Lock()
defer fp.Unlock()
res := make([]string, 0, len(fp.entries))
for _, entry := range fp.entries {
res = append(res, entry.marshal())
}
return strings.Join(res, "->")
}
type failpointEntry struct {
typ Type
arg interface{}
count int64
}
func newFailpointEntry() *failpointEntry {
return &failpointEntry{
typ: TypeInvalid,
count: 0,
}
}
func (fpe *failpointEntry) marshal() string {
base := fmt.Sprintf("%d*%s", fpe.count, fpe.typ)
switch fpe.typ {
case TypeOff:
return base
case TypeError, TypePanic:
return fmt.Sprintf("%s(%s)", base, fpe.arg.(string))
case TypeDelay:
return fmt.Sprintf("%s(%d)", base, fpe.arg.(time.Duration)/time.Millisecond)
default:
return base
}
}
func (fpe *failpointEntry) evaluate() error {
switch fpe.typ {
case TypeOff:
return nil
case TypeError:
return fmt.Errorf("%v", fpe.arg)
case TypePanic:
panic(fpe.arg)
case TypeDelay:
time.Sleep(fpe.arg.(time.Duration))
return nil
default:
panic("invalid failpoint type")
}
}
func parseTerms(term []byte) ([]*failpointEntry, error) {
var entry *failpointEntry
var err error
// count*type[(arg)]
term, entry, err = parseTerm(term)
if err != nil {
return nil, err
}
res := []*failpointEntry{entry}
// cascading terms
for len(term) > 0 {
if !bytes.HasPrefix(term, []byte("->")) {
return nil, fmt.Errorf("invalid cascading terms: %s", string(term))
}
term = term[2:]
term, entry, err = parseTerm(term)
if err != nil {
return nil, fmt.Errorf("failed to parse cascading term: %w", err)
}
res = append(res, entry)
}
return res, nil
}
func parseTerm(term []byte) ([]byte, *failpointEntry, error) {
var err error
var entry = newFailpointEntry()
// count*
term, err = parseInt64(term, '*', &entry.count)
if err != nil {
return nil, nil, err
}
// type[(arg)]
term, err = parseType(term, entry)
return term, entry, err
}
func parseType(term []byte, entry *failpointEntry) ([]byte, error) {
var nameToTyp = map[string]Type{
"off": TypeOff,
"error(": TypeError,
"panic(": TypePanic,
"delay(": TypeDelay,
}
var found bool
for name, typ := range nameToTyp {
if bytes.HasPrefix(term, []byte(name)) {
found = true
term = term[len(name):]
entry.typ = typ
break
}
}
if !found {
return nil, fmt.Errorf("invalid type format: %s", string(term))
}
switch entry.typ {
case TypePanic, TypeError:
endIdx := bytes.IndexByte(term, ')')
if endIdx <= 0 {
return nil, fmt.Errorf("invalid argument for %s type", entry.typ)
}
entry.arg = string(term[:endIdx])
return term[endIdx+1:], nil
case TypeOff:
// do nothing
return term, nil
case TypeDelay:
var msVal int64
var err error
term, err = parseInt64(term, ')', &msVal)
if err != nil {
return nil, err
}
entry.arg = time.Millisecond * time.Duration(msVal)
return term, nil
default:
panic("unreachable")
}
}
func parseInt64(term []byte, terminate byte, val *int64) ([]byte, error) {
i := 0
for ; i < len(term); i++ {
if b := term[i]; b < '0' || b > '9' {
break
}
}
if i == 0 || i == len(term) || term[i] != terminate {
return nil, fmt.Errorf("failed to parse int64 because of invalid terminate byte: %s", string(term))
}
v, err := strconv.ParseInt(string(term[:i]), 10, 64)
if err != nil {
return nil, fmt.Errorf("failed to parse int64 from %s: %v", string(term[:i]), err)
}
*val = v
return term[i+1:], nil
}

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pkg/failpoint/fail_test.go Normal file
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/*
Copyright The containerd Authors.
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 failpoint
import (
"reflect"
"testing"
"time"
)
func TestParseTerms(t *testing.T) {
cases := []struct {
terms string
hasError bool
}{
// off
{"5", true},
{"*off()", true},
{"5*off()", true},
{"5*off(nothing)", true},
{"5*off(", true},
{"5*off", false},
// error
{"10000error(oops)", true},
{"10*error(oops)", false},
{"1234*error(oops))", true},
{"12342*error()", true},
// panic
{"1panic(oops)", true},
{"1000000*panic(oops)", false},
{"12345*panic(oops))", true},
{"12*panic()", true},
// delay
{"1*delay(oops)", true},
{"1000000*delay(-1)", true},
{"1000000*delay(1)", false},
// cascading terms
{"1*delay(1)-", true},
{"10*delay(2)->", true},
{"11*delay(3)->10*off(", true},
{"12*delay(4)->10*of", true},
{"13*delay(5)->10*off->1000*panic(oops)", false},
}
for i, c := range cases {
fp, err := NewFailpoint(t.Name(), c.terms)
if (err != nil && !c.hasError) ||
(err == nil && c.hasError) {
t.Fatalf("[%v - %s] expected hasError=%v, but got %v", i, c.terms, c.hasError, err)
}
if err != nil {
continue
}
if got := fp.Marshal(); !reflect.DeepEqual(got, c.terms) {
t.Fatalf("[%v] expected %v, but got %v", i, c.terms, got)
}
}
}
func TestEvaluate(t *testing.T) {
terms := "1*error(oops-)->1*off->1*delay(1000)->1*panic(panic)"
fp, err := NewFailpoint(t.Name(), terms)
if err != nil {
t.Fatalf("unexpected error %v", err)
}
injectedFn := func() error {
if err := fp.Evaluate(); err != nil {
return err
}
return nil
}
// should return oops- error
if err := injectedFn(); err == nil || err.Error() != "oops-" {
t.Fatalf("expected error %v, but got %v", "oops-", err)
}
// should return nil
if err := injectedFn(); err != nil {
t.Fatalf("expected nil, but got %v", err)
}
// should sleep 1s and return nil
now := time.Now()
err = injectedFn()
du := time.Since(now)
if err != nil {
t.Fatalf("expected nil, but got %v", err)
}
if du < 1*time.Second {
t.Fatalf("expected sleep 1s, but got %v", du)
}
// should panic
defer func() {
if err := recover(); err == nil || err.(string) != "panic" {
t.Fatalf("should panic(panic), but got %v", err)
}
expected := "0*error(oops-)->0*off->0*delay(1000)->0*panic(panic)"
if got := fp.Marshal(); got != expected {
t.Fatalf("expected %v, but got %v", expected, got)
}
if err := injectedFn(); err != nil {
t.Fatalf("expected nil, but got %v", err)
}
}()
injectedFn()
}