Revert "Revert "Disallow multiple build executions in parallel""
Bug: 36698966
Test: m -j & m -j # (run two builds at once)
This reverts commit be9cd1192bf8774f529a1ca6d2b8ee3876a80d02.
Change-Id: Ia15c0bf156a6de54da054eab8134f36bae0823ca
diff --git a/ui/build/Android.bp b/ui/build/Android.bp
index 8f5250b..25520da 100644
--- a/ui/build/Android.bp
+++ b/ui/build/Android.bp
@@ -30,6 +30,7 @@
"kati.go",
"make.go",
"ninja.go",
+ "proc_sync.go",
"signal.go",
"soong.go",
"util.go",
@@ -37,6 +38,7 @@
testSrcs: [
"environment_test.go",
"util_test.go",
+ "proc_sync_test.go",
],
darwin: {
srcs: [
diff --git a/ui/build/build.go b/ui/build/build.go
index 51dce05..83dbcb6 100644
--- a/ui/build/build.go
+++ b/ui/build/build.go
@@ -117,6 +117,10 @@
// Start getting java version as early as possible
getJavaVersions(ctx, config)
+ // Make sure that no other Soong process is running with the same output directory
+ buildLock := BecomeSingletonOrFail(ctx, config)
+ defer buildLock.Unlock()
+
SetupOutDir(ctx, config)
checkCaseSensitivity(ctx, config)
diff --git a/ui/build/proc_sync.go b/ui/build/proc_sync.go
new file mode 100644
index 0000000..857786d
--- /dev/null
+++ b/ui/build/proc_sync.go
@@ -0,0 +1,143 @@
+// Copyright 2017 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 build
+
+import (
+ "errors"
+ "fmt"
+ "math"
+ "os"
+ "path/filepath"
+ "syscall"
+ "time"
+
+ "android/soong/ui/logger"
+)
+
+// This file provides cross-process synchronization methods
+// i.e. making sure only one Soong process is running for a given output directory
+
+func BecomeSingletonOrFail(ctx Context, config Config) (lock *fileLock) {
+ lockingInfo, err := newLock(config.OutDir())
+ if err != nil {
+ ctx.Logger.Fatal(err)
+ }
+ err = lockSynchronous(*lockingInfo, newSleepWaiter(lockfilePollDuration, lockfileTimeout), ctx.Logger)
+ if err != nil {
+ ctx.Logger.Fatal(err)
+ }
+ return lockingInfo
+}
+
+var lockfileTimeout = time.Second * 10
+var lockfilePollDuration = time.Second
+
+type lockable interface {
+ tryLock() error
+ Unlock() error
+ description() string
+}
+
+var _ lockable = (*fileLock)(nil)
+
+type fileLock struct {
+ File *os.File
+}
+
+func (l fileLock) description() (path string) {
+ return l.File.Name()
+}
+func (l fileLock) tryLock() (err error) {
+ return syscall.Flock(int(l.File.Fd()), syscall.LOCK_EX|syscall.LOCK_NB)
+}
+func (l fileLock) Unlock() (err error) {
+ return l.File.Close()
+}
+
+func lockSynchronous(lock lockable, waiter waiter, logger logger.Logger) (err error) {
+
+ waited := false
+
+ for {
+ err = lock.tryLock()
+ if err == nil {
+ if waited {
+ // If we had to wait at all, then when the wait is done, we inform the user
+ logger.Printf("Acquired lock on %v; previous Soong process must have completed. Continuing...\n", lock.description())
+ }
+ return nil
+ }
+
+ waited = true
+
+ done, description := waiter.checkDeadline()
+
+ if done {
+ return fmt.Errorf("Tried to lock %s, but timed out %s . Make sure no other Soong process is using it",
+ lock.description(), waiter.summarize())
+ } else {
+ logger.Printf("Waiting up to %s to lock %v to ensure no other Soong process is running in the same output directory\n", description, lock.description())
+ waiter.wait()
+ }
+ }
+}
+
+func newLock(basedir string) (lock *fileLock, err error) {
+ lockPath := filepath.Join(basedir, ".lock")
+
+ os.MkdirAll(basedir, 0777)
+ lockfileDescriptor, err := os.OpenFile(lockPath, os.O_RDWR|os.O_CREATE, 0666)
+ if err != nil {
+ return nil, errors.New("failed to open " + lockPath)
+ }
+ lockingInfo := &fileLock{File: lockfileDescriptor}
+
+ return lockingInfo, nil
+}
+
+type waiter interface {
+ wait()
+ checkDeadline() (done bool, remainder string)
+ summarize() (summary string)
+}
+
+type sleepWaiter struct {
+ sleepInterval time.Duration
+ deadline time.Time
+
+ totalWait time.Duration
+}
+
+var _ waiter = (*sleepWaiter)(nil)
+
+func newSleepWaiter(interval time.Duration, duration time.Duration) (waiter *sleepWaiter) {
+ return &sleepWaiter{interval, time.Now().Add(duration), duration}
+}
+
+func (s sleepWaiter) wait() {
+ time.Sleep(s.sleepInterval)
+}
+func (s *sleepWaiter) checkDeadline() (done bool, remainder string) {
+ remainingSleep := s.deadline.Sub(time.Now())
+ numSecondsRounded := math.Floor(remainingSleep.Seconds()*10+0.5) / 10
+ if remainingSleep > 0 {
+ return false, fmt.Sprintf("%vs", numSecondsRounded)
+ } else {
+ return true, ""
+ }
+}
+func (s sleepWaiter) summarize() (summary string) {
+ return fmt.Sprintf("polling every %v until %v", s.sleepInterval, s.totalWait)
+}
diff --git a/ui/build/proc_sync_test.go b/ui/build/proc_sync_test.go
new file mode 100644
index 0000000..857bea3
--- /dev/null
+++ b/ui/build/proc_sync_test.go
@@ -0,0 +1,241 @@
+// Copyright 2017 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 build
+
+import (
+ "fmt"
+ "io/ioutil"
+ "os"
+ "os/exec"
+ "path/filepath"
+ "syscall"
+ "testing"
+
+ "android/soong/ui/logger"
+)
+
+// some util methods and data structures that aren't directly part of a test
+func makeLockDir() (path string, err error) {
+ return ioutil.TempDir("", "soong_lock_test")
+}
+func lockOrFail(t *testing.T) (lock fileLock) {
+ lockDir, err := makeLockDir()
+ var lockPointer *fileLock
+ if err == nil {
+ lockPointer, err = newLock(lockDir)
+ }
+ if err != nil {
+ os.RemoveAll(lockDir)
+ t.Fatalf("Failed to create lock: %v", err)
+ }
+
+ return *lockPointer
+}
+func removeTestLock(fileLock fileLock) {
+ lockdir := filepath.Dir(fileLock.File.Name())
+ os.RemoveAll(lockdir)
+}
+
+// countWaiter only exists for the purposes of testing lockSynchronous
+type countWaiter struct {
+ numWaitsElapsed int
+ maxNumWaits int
+}
+
+func newCountWaiter(count int) (waiter *countWaiter) {
+ return &countWaiter{0, count}
+}
+
+func (c *countWaiter) wait() {
+ c.numWaitsElapsed++
+}
+func (c *countWaiter) checkDeadline() (done bool, remainder string) {
+ numWaitsRemaining := c.maxNumWaits - c.numWaitsElapsed
+ if numWaitsRemaining < 1 {
+ return true, ""
+ }
+ return false, fmt.Sprintf("%v waits remain", numWaitsRemaining)
+}
+func (c countWaiter) summarize() (summary string) {
+ return fmt.Sprintf("waiting %v times", c.maxNumWaits)
+}
+
+// countLock only exists for the purposes of testing lockSynchronous
+type countLock struct {
+ nextIndex int
+ successIndex int
+}
+
+var _ lockable = (*countLock)(nil)
+
+// returns a countLock that succeeds on iteration <index>
+func testLockCountingTo(index int) (lock *countLock) {
+ return &countLock{nextIndex: 0, successIndex: index}
+}
+func (c *countLock) description() (message string) {
+ return fmt.Sprintf("counter that counts from %v to %v", c.nextIndex, c.successIndex)
+}
+func (c *countLock) tryLock() (err error) {
+ currentIndex := c.nextIndex
+ c.nextIndex++
+ if currentIndex == c.successIndex {
+ return nil
+ }
+ return fmt.Errorf("Lock busy: %s", c.description())
+}
+func (c *countLock) Unlock() (err error) {
+ if c.nextIndex == c.successIndex {
+ return nil
+ }
+ return fmt.Errorf("Not locked: %s", c.description())
+}
+
+// end of util methods
+
+// start of tests
+
+// simple test
+func TestGetLock(t *testing.T) {
+ lockfile := lockOrFail(t)
+ defer removeTestLock(lockfile)
+}
+
+// a more complicated test that spans multiple processes
+var lockPathVariable = "LOCK_PATH"
+var successStatus = 0
+var unexpectedError = 1
+var busyStatus = 2
+
+func TestTrylock(t *testing.T) {
+ lockpath := os.Getenv(lockPathVariable)
+ if len(lockpath) < 1 {
+ checkTrylockMainProcess(t)
+ } else {
+ getLockAndExit(lockpath)
+ }
+}
+
+// the portion of TestTrylock that runs in the main process
+func checkTrylockMainProcess(t *testing.T) {
+ var err error
+ lockfile := lockOrFail(t)
+ defer removeTestLock(lockfile)
+ lockdir := filepath.Dir(lockfile.File.Name())
+ otherAcquired, message, err := forkAndGetLock(lockdir)
+ if err != nil {
+ t.Fatalf("Unexpected error in subprocess trying to lock uncontested fileLock: %v. Subprocess output: %q", err, message)
+ }
+ if !otherAcquired {
+ t.Fatalf("Subprocess failed to lock uncontested fileLock. Subprocess output: %q", message)
+ }
+
+ err = lockfile.tryLock()
+ if err != nil {
+ t.Fatalf("Failed to lock fileLock: %v", err)
+ }
+
+ reacquired, message, err := forkAndGetLock(filepath.Dir(lockfile.File.Name()))
+ if err != nil {
+ t.Fatal(err)
+ }
+ if reacquired {
+ t.Fatalf("Permitted locking fileLock twice. Subprocess output: %q", message)
+ }
+
+ err = lockfile.Unlock()
+ if err != nil {
+ t.Fatalf("Error unlocking fileLock: %v", err)
+ }
+
+ reacquired, message, err = forkAndGetLock(filepath.Dir(lockfile.File.Name()))
+ if err != nil {
+ t.Fatal(err)
+ }
+ if !reacquired {
+ t.Fatalf("Subprocess failed to acquire lock after it was released by the main process. Subprocess output: %q", message)
+ }
+}
+func forkAndGetLock(lockDir string) (acquired bool, subprocessOutput []byte, err error) {
+ cmd := exec.Command(os.Args[0], "-test.run=TestTrylock")
+ cmd.Env = append(os.Environ(), fmt.Sprintf("%s=%s", lockPathVariable, lockDir))
+ subprocessOutput, err = cmd.CombinedOutput()
+ exitStatus := successStatus
+ if exitError, ok := err.(*exec.ExitError); ok {
+ if waitStatus, ok := exitError.Sys().(syscall.WaitStatus); ok {
+ exitStatus = waitStatus.ExitStatus()
+ }
+ }
+ if exitStatus == successStatus {
+ return true, subprocessOutput, nil
+ } else if exitStatus == busyStatus {
+ return false, subprocessOutput, nil
+ } else {
+ return false, subprocessOutput, fmt.Errorf("Unexpected status %v", exitStatus)
+ }
+}
+
+// This function runs in a different process. See TestTrylock
+func getLockAndExit(lockpath string) {
+ fmt.Printf("Will lock path %q\n", lockpath)
+ lockfile, err := newLock(lockpath)
+ exitStatus := unexpectedError
+ if err == nil {
+ err = lockfile.tryLock()
+ if err == nil {
+ exitStatus = successStatus
+ } else {
+ exitStatus = busyStatus
+ }
+ }
+ fmt.Printf("Tried to lock path %s. Received error %v. Exiting with status %v\n", lockpath, err, exitStatus)
+ os.Exit(exitStatus)
+}
+
+func TestLockFirstTrySucceeds(t *testing.T) {
+ noopLogger := logger.New(ioutil.Discard)
+ lock := testLockCountingTo(0)
+ waiter := newCountWaiter(0)
+ err := lockSynchronous(lock, waiter, noopLogger)
+ if err != nil {
+ t.Fatal(err)
+ }
+ if waiter.numWaitsElapsed != 0 {
+ t.Fatalf("Incorrect number of waits elapsed; expected 0, got %v", waiter.numWaitsElapsed)
+ }
+}
+func TestLockThirdTrySucceeds(t *testing.T) {
+ noopLogger := logger.New(ioutil.Discard)
+ lock := testLockCountingTo(2)
+ waiter := newCountWaiter(2)
+ err := lockSynchronous(lock, waiter, noopLogger)
+ if err != nil {
+ t.Fatal(err)
+ }
+ if waiter.numWaitsElapsed != 2 {
+ t.Fatalf("Incorrect number of waits elapsed; expected 2, got %v", waiter.numWaitsElapsed)
+ }
+}
+func TestLockTimedOut(t *testing.T) {
+ noopLogger := logger.New(ioutil.Discard)
+ lock := testLockCountingTo(3)
+ waiter := newCountWaiter(2)
+ err := lockSynchronous(lock, waiter, noopLogger)
+ if err == nil {
+ t.Fatalf("Appeared to have acquired lock on iteration %v which should not be available until iteration %v", waiter.numWaitsElapsed, lock.successIndex)
+ }
+ if waiter.numWaitsElapsed != waiter.maxNumWaits {
+ t.Fatalf("Waited an incorrect number of times; expected %v, got %v", waiter.maxNumWaits, waiter.numWaitsElapsed)
+ }
+}