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tailscale/cmd/testwrapper/testwrapper.go

327 lines
8.6 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
// 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 (
"bufio"
"bytes"
"context"
"encoding/json"
"errors"
"flag"
"fmt"
"io"
"log"
"os"
"os/exec"
"sort"
"strings"
"time"
xmaps "golang.org/x/exp/maps"
"tailscale.com/cmd/testwrapper/flakytest"
)
const maxAttempts = 3
type testAttempt struct {
pkg string // "tailscale.com/types/key"
testName string // "TestFoo"
outcome string // "pass", "fail", "skip"
logs bytes.Buffer
isMarkedFlaky bool // set if the test is marked as flaky
pkgFinished bool
}
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") != ""
// runTests runs the tests in pt and sends the results on ch. It sends a
// testAttempt for each test and a final testAttempt per pkg with pkgFinished
// set to true. Package build errors will not emit a testAttempt (as no valid
// JSON is produced) but the [os/exec.ExitError] will be returned.
// It calls close(ch) when it's done.
func runTests(ctx context.Context, attempt int, pt *packageTests, otherArgs []string, ch chan<- *testAttempt) error {
defer close(ch)
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)
}
defer r.Close()
cmd.Stderr = os.Stderr
cmd.Env = os.Environ()
cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%d", flakytest.FlakeAttemptEnv, attempt))
if err := cmd.Start(); err != nil {
log.Printf("error starting test: %v", err)
os.Exit(1)
}
s := bufio.NewScanner(r)
resultMap := make(map[string]map[string]*testAttempt) // pkg -> test -> testAttempt
for s.Scan() {
var goOutput goTestOutput
if err := json.Unmarshal(s.Bytes(), &goOutput); err != nil {
if errors.Is(err, io.EOF) || errors.Is(err, os.ErrClosed) {
break
}
// `go test -json` outputs invalid JSON when a build fails.
// In that case, discard the the output and start reading again.
// The build error will be printed to stderr.
// See: https://github.com/golang/go/issues/35169
if _, ok := err.(*json.SyntaxError); ok {
fmt.Println(s.Text())
continue
}
panic(err)
}
pkg := goOutput.Package
pkgTests := resultMap[pkg]
if goOutput.Test == "" {
switch goOutput.Action {
case "fail", "pass", "skip":
for _, test := range pkgTests {
if test.outcome == "" {
test.outcome = "fail"
ch <- test
}
}
ch <- &testAttempt{
pkg: goOutput.Package,
outcome: goOutput.Action,
pkgFinished: true,
}
}
continue
}
if pkgTests == nil {
pkgTests = make(map[string]*testAttempt)
resultMap[pkg] = pkgTests
}
testName := goOutput.Test
if test, _, isSubtest := strings.Cut(goOutput.Test, "/"); isSubtest {
testName = test
if goOutput.Action == "output" {
resultMap[pkg][testName].logs.WriteString(goOutput.Output)
}
continue
}
switch goOutput.Action {
case "start":
// ignore
case "run":
pkgTests[testName] = &testAttempt{
pkg: pkg,
testName: testName,
}
case "skip", "pass", "fail":
pkgTests[testName].outcome = goOutput.Action
ch <- pkgTests[testName]
case "output":
if strings.TrimSpace(goOutput.Output) == flakytest.FlakyTestLogMessage {
pkgTests[testName].isMarkedFlaky = true
} else {
pkgTests[testName].logs.WriteString(goOutput.Output)
}
}
}
if err := cmd.Wait(); err != nil {
return err
}
if err := s.Err(); err != nil {
return fmt.Errorf("reading go test stdout: %w", err)
}
return nil
}
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:]
type nextRun struct {
tests []*packageTests
attempt int
}
toRun := []*nextRun{
{
tests: []*packageTests{{pattern: pattern}},
attempt: 1,
},
}
printPkgOutcome := func(pkg, outcome string, attempt int) {
if outcome == "skip" {
fmt.Printf("?\t%s [skipped/no tests] \n", pkg)
return
}
if outcome == "pass" {
outcome = "ok"
}
if outcome == "fail" {
outcome = "FAIL"
}
if attempt > 1 {
fmt.Printf("%s\t%s [attempt=%d]\n", outcome, pkg, attempt)
return
}
fmt.Printf("%s\t%s\n", outcome, pkg)
}
for len(toRun) > 0 {
var thisRun *nextRun
thisRun, toRun = toRun[0], toRun[1:]
if thisRun.attempt > maxAttempts {
fmt.Println("max attempts reached")
os.Exit(1)
}
if thisRun.attempt > 1 {
fmt.Printf("\n\nAttempt #%d: Retrying flaky tests:\n\n", thisRun.attempt)
}
toRetry := make(map[string][]string) // pkg -> tests to retry
for _, pt := range thisRun.tests {
ch := make(chan *testAttempt)
runErr := make(chan error, 1)
go func() {
defer close(runErr)
runErr <- runTests(ctx, thisRun.attempt, pt, otherArgs, ch)
}()
var failed bool
for tr := range ch {
// Go assigns the package name "command-line-arguments" when you
// `go test FILE` rather than `go test PKG`. It's more
// convenient for us to to specify files in tests, so fix tr.pkg
// so that subsequent testwrapper attempts run correctly.
if tr.pkg == "command-line-arguments" {
tr.pkg = pattern
}
if tr.pkgFinished {
if tr.outcome == "fail" && len(toRetry[tr.pkg]) == 0 {
// If a package fails and we don't have any tests to
// retry, then we should fail. This typically happens
// when a package times out.
failed = true
}
printPkgOutcome(tr.pkg, tr.outcome, thisRun.attempt)
continue
}
if *v || tr.outcome == "fail" {
io.Copy(os.Stdout, &tr.logs)
}
if tr.outcome != "fail" {
continue
}
if tr.isMarkedFlaky {
toRetry[tr.pkg] = append(toRetry[tr.pkg], tr.testName)
} else {
failed = true
}
}
if failed {
fmt.Println("\n\nNot retrying flaky tests because non-flaky tests failed.")
os.Exit(1)
}
// If there's nothing to retry and no non-retryable tests have
// failed then we've probably hit a build error.
if err := <-runErr; len(toRetry) == 0 && err != nil {
var exit *exec.ExitError
if errors.As(err, &exit) {
if code := exit.ExitCode(); code > -1 {
os.Exit(exit.ExitCode())
}
}
log.Printf("testwrapper: %s", err)
os.Exit(1)
}
}
if len(toRetry) == 0 {
continue
}
pkgs := xmaps.Keys(toRetry)
sort.Strings(pkgs)
nextRun := &nextRun{
attempt: thisRun.attempt + 1,
}
for _, pkg := range pkgs {
tests := toRetry[pkg]
sort.Strings(tests)
nextRun.tests = append(nextRun.tests, &packageTests{
pattern: pkg,
tests: tests,
})
}
toRun = append(toRun, nextRun)
}
}