cmd/testwrapper: only retry flaky failed tests

Redo the testwrapper to track and only retry flaky tests instead
of retrying the entire pkg. It also fails early if a non-flaky test fails.

This also makes it so that the go test caches are used.

Fixes #7975

Signed-off-by: Maisem Ali <maisem@tailscale.com>
pull/8447/head
Maisem Ali 1 year ago committed by Maisem Ali
parent 2cf6e12790
commit 8e840489ed

@ -90,11 +90,11 @@ jobs:
- name: build test wrapper
run: ./tool/go build -o /tmp/testwrapper ./cmd/testwrapper
- name: test all
run: ./tool/go test ${{matrix.buildflags}} -exec=/tmp/testwrapper ./...
run: PATH=$PWD/tool:$PATH /tmp/testwrapper ./... ${{matrix.buildflags}}
env:
GOARCH: ${{ matrix.goarch }}
- name: bench all
run: ./tool/go test ${{matrix.buildflags}} -exec=/tmp/testwrapper -test.bench=. -test.benchtime=1x -test.run=^$ ./...
run: PATH=$PWD/tool:$PATH /tmp/testwrapper ./... ${{matrix.buildflags}} -bench=. -benchtime=1x -run=^$
env:
GOARCH: ${{ matrix.goarch }}
- name: check that no tracked files changed

@ -7,16 +7,20 @@
package flakytest
import (
"fmt"
"os"
"regexp"
"testing"
)
// InTestWrapper returns whether or not this binary is running under our test
// wrapper.
func InTestWrapper() bool {
return os.Getenv("TS_IN_TESTWRAPPER") != ""
}
// FlakyTestLogMessage is a sentinel value that is printed to stderr when a
// flaky test is marked. This is used by cmd/testwrapper to detect flaky tests
// and retry them.
const FlakyTestLogMessage = "flakytest: this is a known flaky test"
// FlakeAttemptEnv is an environment variable that is set by cmd/testwrapper
// when a flaky test is retried. It contains the attempt number, starting at 1.
const FlakeAttemptEnv = "TS_TESTWRAPPER_ATTEMPT"
var issueRegexp = regexp.MustCompile(`\Ahttps://github\.com/tailscale/[a-zA-Z0-9_.-]+/issues/\d+\z`)
@ -30,16 +34,6 @@ func Mark(t testing.TB, issue string) {
t.Fatalf("bad issue format: %q", issue)
}
if !InTestWrapper() {
return
}
t.Cleanup(func() {
if t.Failed() {
t.Logf("flakytest: signaling test wrapper to retry test")
// Signal to test wrapper that we should restart.
os.Exit(123)
}
})
fmt.Fprintln(os.Stderr, FlakyTestLogMessage) // sentinel value for testwrapper
t.Logf("flakytest: issue tracking this flaky test: %s", issue)
}

@ -3,7 +3,10 @@
package flakytest
import "testing"
import (
"os"
"testing"
)
func TestIssueFormat(t *testing.T) {
testCases := []struct {
@ -24,3 +27,14 @@ func TestIssueFormat(t *testing.T) {
}
}
}
func TestFlakeRun(t *testing.T) {
Mark(t, "https://github.com/tailscale/tailscale/issues/0") // random issue
e := os.Getenv(FlakeAttemptEnv)
if e == "" {
t.Skip("not running in testwrapper")
}
if e == "1" {
t.Fatal("failing on purpose")
}
}

@ -1,62 +1,231 @@
// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// testwrapper is a wrapper for retrying flaky tests, using the -exec flag of
// 'go test'. Tests that are flaky can use the 'flakytest' subpackage to mark
// themselves as flaky and be retried on failure.
// testwrapper is a wrapper for retrying flaky tests. It is an alternative to
// `go test` and re-runs failed marked flaky tests (using the flakytest pkg). It
// takes different arguments than go test and requires the first positional
// argument to be the pattern to test.
package main
import (
"bytes"
"context"
"encoding/json"
"errors"
"flag"
"fmt"
"io"
"log"
"os"
"os/exec"
)
"sort"
"strings"
"time"
const (
retryStatus = 123
maxIterations = 3
"golang.org/x/exp/maps"
"tailscale.com/cmd/testwrapper/flakytest"
)
func main() {
ctx := context.Background()
debug := os.Getenv("TS_TESTWRAPPER_DEBUG") != ""
const maxAttempts = 3
type testAttempt struct {
name testName
outcome string // "pass", "fail", "skip"
logs bytes.Buffer
isMarkedFlaky bool // set if the test is marked as flaky
}
type testName struct {
pkg string // "tailscale.com/types/key"
name string // "TestFoo"
}
type packageTests struct {
// pattern is the package pattern to run.
// Must be a single pattern, not a list of patterns.
pattern string // "./...", "./types/key"
// tests is a list of tests to run. If empty, all tests in the package are
// run.
tests []string // ["TestFoo", "TestBar"]
}
type goTestOutput struct {
Time time.Time
Action string
Package string
Test string
Output string
}
var debug = os.Getenv("TS_TESTWRAPPER_DEBUG") != ""
log.SetPrefix("testwrapper: ")
if !debug {
log.SetFlags(0)
func runTests(ctx context.Context, attempt int, pt *packageTests, otherArgs []string) []*testAttempt {
args := []string{"test", "-json", pt.pattern}
args = append(args, otherArgs...)
if len(pt.tests) > 0 {
runArg := strings.Join(pt.tests, "|")
args = append(args, "-run", runArg)
}
if debug {
fmt.Println("running", strings.Join(args, " "))
}
cmd := exec.CommandContext(ctx, "go", args...)
r, err := cmd.StdoutPipe()
if err != nil {
log.Printf("error creating stdout pipe: %v", err)
}
cmd.Stderr = os.Stderr
cmd.Env = os.Environ()
cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%d", flakytest.FlakeAttemptEnv, attempt))
for i := 1; i <= maxIterations; i++ {
if i > 1 {
log.Printf("retrying flaky tests (%d of %d)", i, maxIterations)
if err := cmd.Start(); err != nil {
log.Printf("error starting test: %v", err)
os.Exit(1)
}
done := make(chan struct{})
go func() {
defer close(done)
cmd.Wait()
}()
jd := json.NewDecoder(r)
resultMap := make(map[testName]*testAttempt)
var out []*testAttempt
for {
var goOutput goTestOutput
if err := jd.Decode(&goOutput); err != nil {
if errors.Is(err, io.EOF) || errors.Is(err, os.ErrClosed) {
break
}
panic(err)
}
cmd := exec.CommandContext(ctx, os.Args[1], os.Args[2:]...)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
cmd.Env = append(os.Environ(), "TS_IN_TESTWRAPPER=1")
err := cmd.Run()
if err == nil {
return
if goOutput.Test == "" {
continue
}
name := testName{
pkg: goOutput.Package,
name: goOutput.Test,
}
if test, _, isSubtest := strings.Cut(goOutput.Test, "/"); isSubtest {
name.name = test
if goOutput.Action == "output" {
resultMap[name].logs.WriteString(goOutput.Output)
}
continue
}
switch goOutput.Action {
case "start":
// ignore
case "run":
resultMap[name] = &testAttempt{
name: name,
}
case "skip", "pass", "fail":
resultMap[name].outcome = goOutput.Action
out = append(out, resultMap[name])
case "output":
if strings.TrimSpace(goOutput.Output) == flakytest.FlakyTestLogMessage {
resultMap[name].isMarkedFlaky = true
} else {
resultMap[name].logs.WriteString(goOutput.Output)
}
}
}
<-done
return out
}
func main() {
ctx := context.Background()
// We only need to parse the -v flag to figure out whether to print the logs
// for a test. We don't need to parse any other flags, so we just use the
// flag package to parse the -v flag and then pass the rest of the args
// through to 'go test'.
// We run `go test -json` which returns the same information as `go test -v`,
// but in a machine-readable format. So this flag is only for testwrapper's
// output.
v := flag.Bool("v", false, "verbose")
flag.Usage = func() {
fmt.Println("usage: testwrapper [testwrapper-flags] [pattern] [build/test flags & test binary flags]")
fmt.Println()
fmt.Println("testwrapper-flags:")
flag.CommandLine.PrintDefaults()
fmt.Println()
fmt.Println("examples:")
fmt.Println("\ttestwrapper -v ./... -count=1")
fmt.Println("\ttestwrapper ./pkg/foo -run TestBar -count=1")
fmt.Println()
fmt.Println("Unlike 'go test', testwrapper requires a package pattern as the first positional argument and only supports a single pattern.")
}
flag.Parse()
args := flag.Args()
if len(args) < 1 || strings.HasPrefix(args[0], "-") {
fmt.Println("no pattern specified")
flag.Usage()
os.Exit(1)
} else if len(args) > 1 && !strings.HasPrefix(args[1], "-") {
fmt.Println("expected single pattern")
flag.Usage()
os.Exit(1)
}
pattern, otherArgs := args[0], args[1:]
toRun := []*packageTests{ // packages still to test
{pattern: pattern},
}
var exitErr *exec.ExitError
if !errors.As(err, &exitErr) {
if debug {
log.Printf("error isn't an ExitError")
pkgAttempts := make(map[string]int) // tracks how many times we've tried a package
attempt := 0
for len(toRun) > 0 {
attempt++
var pt *packageTests
pt, toRun = toRun[0], toRun[1:]
toRetry := make(map[string][]string) // pkg -> tests to retry
failed := false
for _, tr := range runTests(ctx, attempt, pt, otherArgs) {
if *v || tr.outcome == "fail" {
io.Copy(os.Stderr, &tr.logs)
}
if tr.outcome != "fail" {
continue
}
if tr.isMarkedFlaky {
toRetry[tr.name.pkg] = append(toRetry[tr.name.pkg], tr.name.name)
} else {
failed = true
}
}
if failed {
os.Exit(1)
}
if code := exitErr.ExitCode(); code != retryStatus {
if debug {
log.Printf("code (%d) != retryStatus (%d)", code, retryStatus)
pkgs := maps.Keys(toRetry)
sort.Strings(pkgs)
for _, pkg := range pkgs {
tests := toRetry[pkg]
sort.Strings(tests)
pkgAttempts[pkg]++
if pkgAttempts[pkg] >= maxAttempts {
fmt.Println("Too many attempts for flaky tests:", pkg, tests)
continue
}
os.Exit(code)
fmt.Println("\nRetrying flaky tests:", pkg, tests)
toRun = append(toRun, &packageTests{
pattern: pkg,
tests: tests,
})
}
}
log.Printf("test did not pass in %d iterations", maxIterations)
os.Exit(1)
for _, a := range pkgAttempts {
if a >= maxAttempts {
os.Exit(1)
}
}
fmt.Println("PASS")
}

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