Support tmpfs and a server queue for C++ compilers (#10)

This PR drops an option -working-dir, adding two new instead:
* -cpp-dir {string}, Directory for incoming C++ files and src cache
* -obj-dir {string}, Directory for resulting obj files and obj cache
The directory passed as -cpp-dir can be placed in tmpfs.

Also, nocc-server now managers C++ compiler launches with a waiting queue. 
The purpose of a waiting queue is not to over-utilize server resources at peak times.

Makefile

@@ -1,4 +1,4 @@
-RELEASE = v1.1.2
+RELEASE = v1.2
 BUILD_COMMIT := $(shell git rev-parse --short HEAD)
 DATE := $(shell date -u '+%F %X UTC')
 VERSION := ${RELEASE}, rev ${BUILD_COMMIT}, compiled at ${DATE}

cmd/nocc-daemon/main.go

@@ -91,17 +91,20 @@ func main() {
 	}
 
 	if *checkServersAndExit {
-		if len(remoteNoccHosts) == 0 {
-			failedStart("no remote hosts set; you should set NOCC_SERVERS or NOCC_SERVERS_FILENAME")
-		}
 		if len(os.Args) == 3 { // nocc -check-servers {remoteHostPort}
 			remoteNoccHosts = []string{os.Args[2]}
 		}
+		if len(remoteNoccHosts) == 0 {
+			failedStart("no remote hosts set; you should set NOCC_SERVERS or NOCC_SERVERS_FILENAME")
+		}
 		client.RequestRemoteStatus(remoteNoccHosts)
 		os.Exit(0)
 	}
 
 	if *dumpServerLogsAndExit {
+		if len(os.Args) == 3 { // nocc -dump-server-logs {remoteHostPort}
+			remoteNoccHosts = []string{os.Args[2]}
+		}
 		if len(remoteNoccHosts) == 0 {
 			failedStart("no remote hosts set; you should set NOCC_SERVERS or NOCC_SERVERS_FILENAME")
 		}

cmd/nocc-server/main.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"net"
 	"os"
-	"path"
+	"runtime"
 	"time"
 
 	"github.com/VKCOM/nocc/internal/common"
@@ -18,24 +18,29 @@ func failedStart(message string, err error) {
 	os.Exit(1)
 }
 
-// cleanupWorkingDir ensures that workingDir exists and is empty
+// prepareEmptyDir ensures that serverDir exists and is empty
 // it's executed on server launch
 // as a consequence, all file caches are lost on restart
-func cleanupWorkingDir(workingDir string) error {
-	oldWorkingDir := workingDir + ".old"
-
-	if err := os.RemoveAll(oldWorkingDir); err != nil {
-		failedStart("can't remove old working dir", err)
-	}
-	if _, err := os.Stat(workingDir); err == nil {
-		if err := os.Rename(workingDir, oldWorkingDir); err != nil {
-			failedStart("can't rename working dir %s to .old", err)
+func prepareEmptyDir(parentDir *string, subdir string) string {
+	// if /tmp/nocc/cpp/src-cache already exists, it means, that it contains files from a previous launch
+	// to start up as quickly as possible, do the following:
+	// 1) rename it to /tmp/nocc/cpp/src-cache.old
+	// 2) clear it recursively in the background
+	serverDir := *parentDir + "/" + subdir
+	if _, err := os.Stat(serverDir); err == nil {
+		oldDirRenamed := fmt.Sprintf("%s.old.%d", serverDir, time.Now().Unix())
+		if err := os.Rename(serverDir, oldDirRenamed); err != nil {
+			failedStart("can't rename "+serverDir, err)
 		}
+		go func() {
+			_ = os.RemoveAll(oldDirRenamed)
+		}()
 	}
-	if err := os.MkdirAll(workingDir, os.ModePerm); err != nil {
-		return err
+
+	if err := os.MkdirAll(serverDir, os.ModePerm); err != nil {
+		failedStart("can't create "+serverDir, err)
 	}
-	return nil
+	return serverDir
 }
 
 // printDockerContainerIP is a dev/debug function called only when build special for local Docker, for local testing.
@@ -58,8 +63,10 @@ func main() {
 		"host", "")
 	listenPort := common.CmdEnvInt("Listening port, default 43210.", 43210,
 		"port", "")
-	workingDir := common.CmdEnvString("Directory for saving incoming files, default /tmp/nocc-server.", "/tmp/nocc-server",
-		"working-dir", "")
+	cppStoreDir := common.CmdEnvString("Directory for incoming C++ files and src cache, default /tmp/nocc/cpp.\nIt can be placed in tmpfs to speed up compilation", "/tmp/nocc/cpp",
+		"cpp-dir", "")
+	objStoreDir := common.CmdEnvString("Directory for resulting obj files and obj cache, default /tmp/nocc/obj.", "/tmp/nocc/obj",
+		"obj-dir", "")
 	logFileName := common.CmdEnvString("A filename to log, by default use stderr.", "",
 		"log-filename", "")
 	logVerbosity := common.CmdEnvInt("Logger verbosity level for INFO (-1 off, default 0, max 2).\nErrors are logged always.", 0,
@@ -70,6 +77,8 @@ func main() {
 		"obj-cache-limit", "")
 	statsdHostPort := common.CmdEnvString("Statsd udp address (host:port), omitted by default.\nIf omitted, stats won't be written.", "",
 		"statsd", "")
+	maxParallelCxx := common.CmdEnvInt("Max amount of C++ compiler processes launched in parallel, other ready sessions are waiting in a queue.\nBy default, it's a number of CPUs on the current machine.", int64(runtime.NumCPU()),
+		"max-parallel-cxx", "")
 
 	common.ParseCmdFlagsCombiningWithEnv()
 
@@ -78,10 +87,6 @@ func main() {
 		os.Exit(0)
 	}
 
-	if err = cleanupWorkingDir(*workingDir); err != nil {
-		failedStart("Can't create working directory "+*workingDir, err)
-	}
-
 	if err = server.MakeLoggerServer(*logFileName, *logVerbosity); err != nil {
 		failedStart("Can't init logger", err)
 	}
@@ -95,12 +100,12 @@ func main() {
 		failedStart("Failed to connect to statsd", err)
 	}
 
-	s.ActiveClients, err = server.MakeClientsStorage(path.Join(*workingDir, "clients"))
+	s.ActiveClients, err = server.MakeClientsStorage(prepareEmptyDir(cppStoreDir, "clients"))
 	if err != nil {
 		failedStart("Failed to init clients hashtable", err)
 	}
 
-	s.CxxLauncher, err = server.MakeCxxLauncher()
+	s.CxxLauncher, err = server.MakeCxxLauncher(*maxParallelCxx)
 	if err != nil {
 		failedStart("Failed to init cxx launcher", err)
 	}
@@ -110,17 +115,17 @@ func main() {
 		failedStart("Failed to init system headers hashtable", err)
 	}
 
-	s.SrcFileCache, err = server.MakeSrcFileCache(path.Join(*workingDir, "src-cache"), *srcCacheLimit)
+	s.SrcFileCache, err = server.MakeSrcFileCache(prepareEmptyDir(cppStoreDir, "src-cache"), *srcCacheLimit)
 	if err != nil {
 		failedStart("Failed to init src file cache", err)
 	}
 
-	s.ObjFileCache, err = server.MakeObjFileCache(path.Join(*workingDir, "obj-cache"), *objCacheLimit)
+	s.ObjFileCache, err = server.MakeObjFileCache(prepareEmptyDir(objStoreDir, "obj-cache"), prepareEmptyDir(objStoreDir, "cxx-out"), *objCacheLimit)
 	if err != nil {
 		failedStart("Failed to init obj file cache", err)
 	}
 
-	s.PchCompilation, err = server.MakePchCompilation(path.Join(*workingDir, "pch"))
+	s.PchCompilation, err = server.MakePchCompilation(prepareEmptyDir(cppStoreDir, "pch"))
 	if err != nil {
 		failedStart("Failed to init pch compilation", err)
 	}

cmd/nocc.cpp

@@ -44,7 +44,7 @@ char *format_time_to_log() {
   static char time_buf[64];
   time_t ts = time(nullptr);
   tm *now = localtime(&ts);
-  sprintf(time_buf, "%d/%02d/%02d %02d:%02d:%02d", 1900 + now->tm_year, 1 + now->tm_mon, now->tm_mday, now->tm_hour, now->tm_min, now->tm_sec);
+  sprintf(time_buf, "%d-%02d-%02d %02d:%02d:%02d", 1900 + now->tm_year, 1 + now->tm_mon, now->tm_mday, now->tm_hour, now->tm_min, now->tm_sec);
   return time_buf;
 }
 
@@ -97,13 +97,6 @@ void __attribute__((noreturn)) execute_cxx_locally(const char *errToPrint, int e
   exit(1);
 }
 
-void __attribute__((noreturn)) execute_distcc_locally() {
-  ARGV[0] = strdup("distcc");
-  execvp("distcc", ARGV + 0);
-  printf("could not run `distcc`, exit(1)\n");
-  exit(1);
-}
-
 void __attribute__((noreturn)) execute_go_nocc_instead_of_cpp() {
   execv(NOCC_GO_EXECUTABLE, ARGV);
   printf("could not run %s, exit(1)\n", NOCC_GO_EXECUTABLE);
@@ -279,13 +272,6 @@ int main(int argc, char *argv[]) {
     exit(1);
   }
 
-  // this possible fallback will be available for some time just in case
-  char *env_fallback_to_distcc = getenv("NOCC_FALLBACK_TO_DISTCC");
-  bool fallback_to_distcc = env_fallback_to_distcc != nullptr && env_fallback_to_distcc[0] == '1';
-  if (fallback_to_distcc) {
-    execute_distcc_locally();
-  }
-
   if (ARGC == 2 && !strcmp(ARGV[1], "start")) {
     int sockfd = connect_to_go_daemon_or_start_a_new_one();
     exit(sockfd == -1 ? 1 : 0);

docs/configuration.md

@@ -34,16 +34,18 @@ When you launch lots of jobs like `make -j 600`, then `nocc-daemon` has to maint
 All configuration on a server-side is done using command-line arguments.
 For a server, they are more reliable than environment variables.
 
-| Cmd argument             | Description                                                                             |
-|--------------------------|-----------------------------------------------------------------------------------------|
-| `-host {string}`         | Binding address, default 0.0.0.0.                                                       |
-| `-port {int}`            | Listening port, default 43210.                                                          |
-| `-working-dir {string}`  | Directory for saving incoming files, default */tmp/nocc-server*.                        |
-| `-log-filename {string}` | A filename to log, by default use stderr.                                               |
-| `-log-verbosity {int}`   | Logger verbosity level for INFO (-1 off, default 0, max 2). Errors are logged always.   |
-| `-src-cache-limit {int}` | Header and source cache limit, in bytes, default 4G.                                    |
-| `-obj-cache-limit {int}` | Compiled obj cache limit, in bytes, default 16G.                                        |
-| `-statsd {string}`       | Statsd udp address (host:port), omitted by default. If omitted, stats won't be written. |
+| Cmd argument              | Description                                                                             |
+|---------------------------|-----------------------------------------------------------------------------------------|
+| `-host {string}`          | Binding address, default 0.0.0.0.                                                       |
+| `-port {int}`             | Listening port, default 43210.                                                          |
+| `-cpp-dir {string}`       | Directory for incoming C++ files and src cache, default */tmp/nocc/cpp*.                |
+| `-obj-dir {string}`       | Directory for resulting obj files and obj cache, default */tmp/nocc/obj*.               |
+| `-log-filename {string}`  | A filename to log, by default use stderr.                                               |
+| `-log-verbosity {int}`    | Logger verbosity level for INFO (-1 off, default 0, max 2). Errors are logged always.   |
+| `-src-cache-limit {int}`  | Header and source cache limit, in bytes, default 4G.                                    |
+| `-obj-cache-limit {int}`  | Compiled obj cache limit, in bytes, default 16G.                                        |
+| `-statsd {string}`        | Statsd udp address (host:port), omitted by default. If omitted, stats won't be written. |
+| `-max-parallel-cxx {int}` | Max amount of C++ compiler processes launched in parallel, default *nCPU*.              |
 
 All file caches are lost on restart, as references to files are kept in memory. 
 There is also an LRU expiration mechanism to fit cache limits.
@@ -75,6 +77,26 @@ A list of all written stats could be obtained [inside statsd.go](../internal/ser
 They are quite intuitive, that's why we don't duplicate them here. 
 
 
+<p><br></p>
+
+## Configuring nocc + tmpfs
+
+The directory passed as `-cpp-dir` can be placed in **tmpfs**. 
+All operations with cpp files are performed in that directory: 
+* incoming files (h/cpp/etc.) are saved there mirroring client's file structure;
+* src-cache is placed there;
+* pch files are placed there;
+* tmp files for preventing race conditions are also there, not in sys tmp dir.
+
+So, if that directory is placed in tmpfs, the C++ compiler will take all files from memory (except for system headers),
+which noticeably speeds up compilation.
+
+When setting up limits to tmpfs in a system, ensure that it will fit `-src-cache-limit` plus some extra space.
+
+Note, that placing `-obj-dir` in tmpfs is not recommended, because obj files are usually much heavier,
+and they are just transparently streamed back from a hard disk in chunks.
+
+
 <p><br></p>
 
 ## Other commands from a client

internal/client/compile-remotely.go

@@ -52,7 +52,7 @@ func CompileCppRemotely(daemon *Daemon, cwd string, invocation *Invocation, remo
 		return 0, nil, nil, err
 	}
 
-	logClient.Info(1, "remote", remote.remoteHostPort, "sessionID", invocation.sessionID, "waiting", len(fileIndexesToUpload), "uploads", invocation.cppInFile)
+	logClient.Info(1, "remote", remote.remoteHost, "sessionID", invocation.sessionID, "waiting", len(fileIndexesToUpload), "uploads", invocation.cppInFile)
 	logClient.Info(2, "checked", len(requiredFiles), "files whether upload is needed or they exist on remote")
 	invocation.summary.AddTiming("remote_session")
 
@@ -75,7 +75,7 @@ func CompileCppRemotely(daemon *Daemon, cwd string, invocation *Invocation, remo
 
 	// Now, we have a resulting .o file placed in a path determined by -o from command line.
 	if exitCode != 0 {
-		logClient.Info(0, "remote C++ compiler exited with code", exitCode, "sessionID", invocation.sessionID, invocation.cppInFile, remote.remoteHostPort)
+		logClient.Info(0, "remote C++ compiler exited with code", exitCode, "sessionID", invocation.sessionID, invocation.cppInFile, remote.remoteHost)
 		logClient.Info(1, "cxxExitCode:", exitCode, "sessionID", invocation.sessionID, "\ncxxStdout:", strings.TrimSpace(string(invocation.cxxStdout)), "\ncxxStderr:", strings.TrimSpace(string(invocation.cxxStderr)))
 	} else {
 		logClient.Info(2, "saved obj file to", invocation.objOutFile)

internal/client/daemon.go

@@ -19,7 +19,7 @@ import (
 )
 
 const (
-	timeoutForceInterruptInvocation = 5 * time.Minute
+	timeoutForceInterruptInvocation = 8 * time.Minute
 )
 
 // Daemon is created once, in a separate process `nocc-daemon`, which is listening for connections via unix socket.
@@ -37,6 +37,7 @@ type Daemon struct {
 
 	listener          *DaemonUnixSockListener
 	remoteConnections []*RemoteConnection
+	allRemotesDelim   string
 	localCxxThrottle  chan struct{}
 
 	disableObjCache    bool
@@ -77,31 +78,55 @@ func detectHostUserName() string {
 	return curUser.Username
 }
 
-func MakeDaemon(remoteNoccHosts []string, disableObjCache bool, disableOwnIncludes bool, localCxxQueueSize int64) (*Daemon, error) {
+func MakeDaemon(remoteNoccHosts []string, disableObjCache bool, disableOwnIncludes bool, maxLocalCxxProcesses int64) (*Daemon, error) {
+	// send env NOCC_SERVERS on connect everywhere
+	// this is for debugging purpose: in production, all clients should have the same servers list
+	// to ensure this, just grep server logs: only one unique string should appear
+	allRemotesDelim := ""
+	for _, remoteHostPort := range remoteNoccHosts {
+		if allRemotesDelim != "" {
+			allRemotesDelim += ","
+		}
+		allRemotesDelim += ExtractRemoteHostWithoutPort(remoteHostPort)
+	}
+
 	// env NOCC_SERVERS and others are supposed to be the same between `nocc` invocations
 	// (in practice, this is true, as the first `nocc` invocation has no precedence over any other in a bunch)
 	daemon := &Daemon{
 		startTime:          time.Now(),
 		quitChan:           make(chan int),
 		clientID:           detectClientID(),
 		hostUserName:       detectHostUserName(),
-		remoteConnections:  make([]*RemoteConnection, 0, len(remoteNoccHosts)),
-		localCxxThrottle:   make(chan struct{}, localCxxQueueSize),
+		remoteConnections:  make([]*RemoteConnection, len(remoteNoccHosts)),
+		allRemotesDelim:    allRemotesDelim,
+		localCxxThrottle:   make(chan struct{}, maxLocalCxxProcesses),
 		disableOwnIncludes: disableOwnIncludes,
 		disableObjCache:    disableObjCache,
-		disableLocalCxx:    localCxxQueueSize == 0,
+		disableLocalCxx:    maxLocalCxxProcesses == 0,
 		activeInvocations:  make(map[uint32]*Invocation, 300),
 		includesCache:      make(map[string]*IncludesCache, 1),
 	}
 
-	for _, remoteHostPort := range remoteNoccHosts {
-		remote, err := MakeRemoteConnection(daemon, remoteHostPort, 1, 1)
-		if err != nil {
-			remote.isUnavailable = true
-			logClient.Error("error connecting to", remoteHostPort, err)
-		}
-		daemon.remoteConnections = append(daemon.remoteConnections, remote)
+	// connect to all remotes in parallel
+	wg := sync.WaitGroup{}
+	wg.Add(len(remoteNoccHosts))
+
+	ctxConnect, cancelFunc := context.WithTimeout(context.Background(), 5000*time.Millisecond)
+	defer cancelFunc()
+
+	for index, remoteHostPort := range remoteNoccHosts {
+		go func(index int, remoteHostPort string) {
+			remote, err := MakeRemoteConnection(daemon, remoteHostPort, ctxConnect)
+			if err != nil {
+				remote.isUnavailable = true
+				logClient.Error("error connecting to", remoteHostPort, err)
+			}
+
+			daemon.remoteConnections[index] = remote
+			wg.Done()
+		}(index, remoteHostPort)
 	}
+	wg.Wait()
 
 	return daemon, nil
 }
@@ -202,10 +227,10 @@ func (daemon *Daemon) HandleInvocation(req DaemonSockRequest) DaemonSockResponse
 		}
 
 		remote := daemon.chooseRemoteConnectionForCppCompilation(invocation.cppInFile)
-		invocation.summary.remoteHostPort = remote.remoteHostPort
+		invocation.summary.remoteHost = remote.remoteHost
 
 		if remote.isUnavailable {
-			return daemon.FallbackToLocalCxx(req, fmt.Errorf("remote %s is unavailable", remote.remoteHostPort))
+			return daemon.FallbackToLocalCxx(req, fmt.Errorf("remote %s is unavailable", remote.remoteHost))
 		}
 
 		daemon.mu.Lock()
@@ -292,7 +317,7 @@ func (daemon *Daemon) PeriodicallyInterruptHangedInvocations() {
 			daemon.mu.Lock()
 			for _, invocation := range daemon.activeInvocations {
 				if time.Since(invocation.createTime) > timeoutForceInterruptInvocation {
-					invocation.ForceInterrupt(fmt.Errorf("interrupt sessionID %d after %d sec timeout", invocation.sessionID, int(time.Since(invocation.createTime).Seconds())))
+					invocation.ForceInterrupt(fmt.Errorf("interrupt sessionID %d (%s) after %d sec timeout", invocation.sessionID, invocation.summary.remoteHost, int(time.Since(invocation.createTime).Seconds())))
 				}
 			}
 			daemon.mu.Unlock()

internal/client/files-receiving.go

@@ -153,7 +153,7 @@ func receiveObjFileByChunks(stream pb.CompilationService_RecvCompiledObjStreamCl
 		return errWrite, false
 	}
 
-	fileTmp, errWrite := common.OpenTempFile(objOutFile, false)
+	fileTmp, errWrite := common.OpenTempFile(objOutFile)
 	if errWrite == nil {
 		_, errWrite = fileTmp.Write(firstChunk.ChunkBody)
 	}

internal/client/invocation-summary.go

@@ -17,7 +17,7 @@ type invocationTimingItem struct {
 // It's mostly for developing/debugging purposes: multiple nocc invocations are appended to a single log file,
 // from which we can compute statistics, average and percentiles, either in total or partitioned by hosts.
 type InvocationSummary struct {
-	remoteHostPort string
+	remoteHost string
 
 	nIncludes      int
 	nFilesSent     int
@@ -44,7 +44,7 @@ func (s *InvocationSummary) ToLogString(invocation *Invocation) string {
 
 	b := strings.Builder{}
 	fmt.Fprintf(&b, "cppInFile=%q, remote=%s, sessionID=%d, nIncludes=%d, nFilesSent=%d, nBytesSent=%d, nBytesReceived=%d, cxxDuration=%dms",
-		invocation.cppInFile, s.remoteHostPort, invocation.sessionID, s.nIncludes, s.nFilesSent, s.nBytesSent, s.nBytesReceived, invocation.cxxDuration)
+		invocation.cppInFile, s.remoteHost, invocation.sessionID, s.nIncludes, s.nFilesSent, s.nBytesSent, s.nBytesReceived, invocation.cxxDuration)
 
 	prevTime := invocation.createTime
 	fmt.Fprintf(&b, ", started=0ms")