Merge pull request #224 from safing/fix/metrics-modules-api

Fix metrics, modules, api

api/authentication.go

@@ -151,7 +151,7 @@ func authenticateRequest(w http.ResponseWriter, r *http.Request, targetHandler h
 	switch requiredPermission { //nolint:exhaustive
 	case NotFound:
 		// Not found.
-		tracer.Trace("api: authenticated handler reported: not found")
+		tracer.Debug("api: no API endpoint registered for this path")
 		http.Error(w, "Not found.", http.StatusNotFound)
 		return nil
 	case NotSupported:

api/router.go

@@ -235,6 +235,7 @@ func (mh *mainHandler) handle(w http.ResponseWriter, r *http.Request) error {
 		http.Error(lrw, "Method not allowed.", http.StatusMethodNotAllowed)
 		return nil
 	default:
+		tracer.Debug("api: no handler registered for this path")
 		http.Error(lrw, "Not found.", http.StatusNotFound)
 		return nil
 	}

metrics/api.go

@@ -11,7 +11,6 @@ import (
 	"github.com/safing/portbase/api"
 	"github.com/safing/portbase/config"
 	"github.com/safing/portbase/log"
-	"github.com/safing/portbase/utils"
 )
 
 func registerAPI() error {
@@ -140,11 +139,7 @@ func writeMetricsTo(ctx context.Context, url string) error {
 	)
 }
 
-var metricsPusherDone = utils.NewBroadcastFlag()
-
 func metricsWriter(ctx context.Context) error {
-	defer metricsPusherDone.NotifyAndReset()
-
 	pushURL := pushOption()
 	ticker := module.NewSleepyTicker(1*time.Minute, 0)
 	defer ticker.Stop()

metrics/metrics_host.go

@@ -16,7 +16,7 @@ import (
 
 const hostStatTTL = 1 * time.Second
 
-func registeHostMetrics() (err error) {
+func registerHostMetrics() (err error) {
 	// Register load average metrics.
 	_, err = NewGauge("host/load/avg/1", nil, getFloat64HostStat(LoadAvg1), &Options{Name: "Host Load Avg 1min", Permission: api.PermitUser})
 	if err != nil {

metrics/metrics_info.go

@@ -3,10 +3,13 @@ package metrics
 import (
 	"runtime"
 	"strings"
+	"sync/atomic"
 
 	"github.com/safing/portbase/info"
 )
 
+var reportedStart atomic.Bool
+
 func registerInfoMetric() error {
 	meta := info.GetInfo()
 	_, err := NewGauge(
@@ -26,6 +29,10 @@ func registerInfoMetric() error {
 			"comment":       commentOption(),
 		},
 		func() float64 {
+			// Report as 0 the first time in order to detect (re)starts.
+			if reportedStart.CompareAndSwap(false, true) {
+				return 0
+			}
 			return 1
 		},
 		nil,

metrics/metrics_logs.go

@@ -5,7 +5,7 @@ import (
 	"github.com/safing/portbase/log"
 )
 
-func registeLogMetrics() (err error) {
+func registerLogMetrics() (err error) {
 	_, err = NewFetchingCounter(
 		"logs/warning/total",
 		nil,

metrics/module.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"sort"
 	"sync"
-	"time"
 
 	"github.com/safing/portbase/modules"
 )
@@ -59,11 +58,11 @@ func start() error {
 		return err
 	}
 
-	if err := registeHostMetrics(); err != nil {
+	if err := registerHostMetrics(); err != nil {
 		return err
 	}
 
-	if err := registeLogMetrics(); err != nil {
+	if err := registerLogMetrics(); err != nil {
 		return err
 	}
 
@@ -82,16 +81,13 @@ func stop() error {
 	// Wait until the metrics pusher is done, as it may have started reporting
 	// and may report a higher number than we store to disk. For persistent
 	// metrics it can then happen that the first report is lower than the
-	// previous report, making prometheus think that al that happened since the
+	// previous report, making prometheus think that all that happened since the
 	// last report, due to the automatic restart detection.
-	done := metricsPusherDone.NewFlag()
+
-	done.Refresh()
+	// The registry is read locked when writing metrics.
-	if !done.IsSet() {
+	// Write lock the registry to make sure all writes are finished.
-		select {
+	registryLock.Lock()
-		case <-done.Signal():
+	registryLock.Unlock() //nolint:staticcheck
-		case <-time.After(10 * time.Second):
-		}
-	}
 
 	storePersistentMetrics()
 
@@ -120,6 +116,10 @@ func register(m Metric) error {
 	// Set flag that first metric is now registered.
 	firstMetricRegistered = true
 
+	if module.Status() < modules.StatusStarting {
+		return fmt.Errorf("registering metric %q too early", m.ID())
+	}
+
 	return nil
 }
 

metrics/persistence.go

@@ -25,7 +25,7 @@ var (
 	})
 
 	// ErrAlreadyInitialized is returned when trying to initialize an option
-	// more than once.
+	// more than once or if the time window for initializing is over.
 	ErrAlreadyInitialized = errors.New("already initialized")
 )
 
@@ -55,7 +55,7 @@ func EnableMetricPersistence(key string) error {
 
 	// Load metrics from storage.
 	var err error
-	storage, err = getMetricsStorage(key)
+	storage, err = getMetricsStorage(storageKey)
 	switch {
 	case err == nil:
 		// Continue.

modules/modules.go

@@ -60,6 +60,7 @@ type Module struct { //nolint:maligned
 	Ctx           context.Context
 	cancelCtx     func()
 	stopFlag      *abool.AtomicBool
+	stopCompleted *abool.AtomicBool
 	stopComplete  chan struct{}
 
 	// workers/tasks
@@ -255,12 +256,10 @@ func (m *Module) checkIfStopComplete() {
 		atomic.LoadInt32(m.taskCnt) == 0 &&
 		atomic.LoadInt32(m.microTaskCnt) == 0 {
 
+		if m.stopCompleted.SetToIf(false, true) {
 			m.Lock()
 			defer m.Unlock()
-
-		if m.stopComplete != nil {
 			close(m.stopComplete)
-			m.stopComplete = nil
 		}
 	}
 }
@@ -283,61 +282,57 @@ func (m *Module) stop(reports chan *report) {
 	// Reset start/stop signal channels.
 	m.startComplete = make(chan struct{})
 	m.stopComplete = make(chan struct{})
+	m.stopCompleted.SetTo(false)
 
-	// Make a copy of the stop channel.
+	// Set status.
-	stopComplete := m.stopComplete
-
-	// Set status and cancel context.
 	m.status = StatusStopping
+
+	go m.stopAllTasks(reports)
+}
+
+func (m *Module) stopAllTasks(reports chan *report) {
+	// Manually set the control function flag in order to stop completion by race
+	// condition before stop function has even started.
+	m.ctrlFuncRunning.Set()
+
+	// Set stop flag for everyone checking this flag before we activate any stop trigger.
 	m.stopFlag.Set()
+
+	// Cancel the context to notify all workers and tasks.
 	m.cancelCtx()
 
-	go m.stopAllTasks(reports, stopComplete)
+	// Start stop function.
-}
+	stopFnError := m.startCtrlFn("stop module", m.stopFn)
-
-func (m *Module) stopAllTasks(reports chan *report, stopComplete chan struct{}) {
-	// start shutdown function
-	var stopFnError error
-	stopFuncRunning := abool.New()
-	if m.stopFn != nil {
-		stopFuncRunning.Set()
-		go func() {
-			stopFnError = m.runCtrlFn("stop module", m.stopFn)
-			stopFuncRunning.UnSet()
-			m.checkIfStopComplete()
-		}()
-	} else {
-		m.checkIfStopComplete()
-	}
 
 	// wait for results
 	select {
-	case <-stopComplete:
+	case <-m.stopComplete:
-	// case <-time.After(moduleStopTimeout):
+		// Complete!
 	case <-time.After(moduleStopTimeout):
 		log.Warningf(
-			"%s: timed out while waiting for stopfn/workers/tasks to finish: stopFn=%v/%v workers=%d tasks=%d microtasks=%d, continuing shutdown...",
+			"%s: timed out while waiting for stopfn/workers/tasks to finish: stopFn=%v workers=%d tasks=%d microtasks=%d, continuing shutdown...",
 			m.Name,
-			stopFuncRunning.IsSet(), m.ctrlFuncRunning.IsSet(),
+			m.ctrlFuncRunning.IsSet(),
 			atomic.LoadInt32(m.workerCnt),
 			atomic.LoadInt32(m.taskCnt),
 			atomic.LoadInt32(m.microTaskCnt),
 		)
 	}
 
-	// collect error
+	// Check for stop fn status.
 	var err error
-	if stopFuncRunning.IsNotSet() && stopFnError != nil {
+	select {
-		err = stopFnError
+	case err = <-stopFnError:
-	}
-	// set status
 		if err != nil {
+			// Set error as module error.
 			m.Error(
 				fmt.Sprintf("%s:stop-failed", m.Name),
 				fmt.Sprintf("Stopping module %s failed", m.Name),
 				fmt.Sprintf("Failed to stop module: %s", err.Error()),
 			)
 		}
+	default:
+	}
 
 	// Always set to offline in order to let other modules shutdown in order.
 	m.Lock()
@@ -384,7 +379,7 @@ func initNewModule(name string, prep, start, stop func() error, dependencies ...
 		Name:                name,
 		enabled:             abool.NewBool(false),
 		enabledAsDependency: abool.NewBool(false),
-		sleepMode:           abool.NewBool(true),
+		sleepMode:           abool.NewBool(true), // Change (for init) is triggered below.
 		sleepWaitingChannel: make(chan time.Time),
 		prepFn:              prep,
 		startFn:             start,
@@ -393,6 +388,7 @@ func initNewModule(name string, prep, start, stop func() error, dependencies ...
 		Ctx:                 ctx,
 		cancelCtx:           cancelCtx,
 		stopFlag:            abool.NewBool(false),
+		stopCompleted:       abool.NewBool(true),
 		ctrlFuncRunning:     abool.NewBool(false),
 		workerCnt:           &workerCnt,
 		taskCnt:             &taskCnt,
@@ -401,7 +397,7 @@ func initNewModule(name string, prep, start, stop func() error, dependencies ...
 		depNames:            dependencies,
 	}
 
-	// Sleep mode is disabled by default
+	// Sleep mode is disabled by default.
 	newModule.Sleep(false)
 
 	return newModule

modules/worker.go

@@ -53,6 +53,7 @@ func (m *Module) RunWorker(name string, fn func(context.Context) error) error {
 }
 
 // StartServiceWorker starts a generic worker, which is automatically restarted in case of an error. A call to StartServiceWorker runs the service-worker in a new goroutine and returns immediately. `backoffDuration` specifies how to long to wait before restarts, multiplied by the number of failed attempts. Pass `0` for the default backoff duration. For custom error remediation functionality, build your own error handling procedure using calls to RunWorker.
+// Returning nil error or context.Canceled will stop the service worker.
 func (m *Module) StartServiceWorker(name string, backoffDuration time.Duration, fn func(context.Context) error) {
 	if m == nil {
 		log.Errorf(`modules: cannot start service worker "%s" with nil module`, name)
@@ -81,34 +82,36 @@ func (m *Module) runServiceWorker(name string, backoffDuration time.Duration, fn
 		}
 
 		err := m.runWorker(name, fn)
-		if err != nil {
+		switch {
-			if !errors.Is(err, ErrRestartNow) {
+		case err == nil:
-				// reset fail counter if running without error for some time
+			// No error means that the worker is finished.
+			return
+
+		case errors.Is(err, context.Canceled):
+			// A canceled context also means that the worker is finished.
+			return
+
+		case errors.Is(err, ErrRestartNow):
+			// Worker requested a restart - silently continue with loop.
+
+		default:
+			// Any other errors triggers a restart with backoff.
+
+			// Reset fail counter if running without error for some time.
 			if time.Now().Add(-5 * time.Minute).After(lastFail) {
 				failCnt = 0
 			}
-				// increase fail counter and set last failed time
+			// Increase fail counter and set last failed time.
 			failCnt++
 			lastFail = time.Now()
-				// log error
+			// Log error and back off for some time.
 			sleepFor := time.Duration(failCnt) * backoffDuration
-				if errors.Is(err, context.Canceled) {
-					log.Debugf("%s: service-worker %s was canceled (%d): %s - restarting in %s", m.Name, name, failCnt, err, sleepFor)
-				} else {
 			log.Errorf("%s: service-worker %s failed (%d): %s - restarting in %s", m.Name, name, failCnt, err, sleepFor)
-				}
 			select {
 			case <-time.After(sleepFor):
 			case <-m.Ctx.Done():
 				return
 			}
-				// loop to restart
-			} else {
-				log.Infof("%s: service-worker %s %s - restarting now", m.Name, name, err)
-			}
-		} else {
-			// finish
-			return
 		}
 	}
 }
@@ -132,10 +135,7 @@ func (m *Module) runWorker(name string, fn func(context.Context) error) (err err
 }
 
 func (m *Module) runCtrlFnWithTimeout(name string, timeout time.Duration, fn func() error) error {
-	stopFnError := make(chan error)
+	stopFnError := m.startCtrlFn(name, fn)
-	go func() {
-		stopFnError <- m.runCtrlFn(name, fn)
-	}()
 
 	// wait for results
 	select {
@@ -146,26 +146,44 @@ func (m *Module) runCtrlFnWithTimeout(name string, timeout time.Duration, fn fun
 	}
 }
 
-func (m *Module) runCtrlFn(name string, fn func() error) (err error) {
+func (m *Module) startCtrlFn(name string, fn func() error) chan error {
+	ctrlFnError := make(chan error, 1)
+
+	// If no function is given, still act as if it was run.
 	if fn == nil {
-		return
+		// Signal finish.
+		m.ctrlFuncRunning.UnSet()
+		m.checkIfStopComplete()
+
+		// Report nil error and return.
+		ctrlFnError <- nil
+		return ctrlFnError
 	}
 
-	if m.ctrlFuncRunning.SetToIf(false, true) {
+	// Signal that a control function is running.
-		defer m.ctrlFuncRunning.SetToIf(true, false)
+	m.ctrlFuncRunning.Set()
-	}
 
+	// Start control function in goroutine.
+	go func() {
+		// Recover from panic and reset control function signal.
 		defer func() {
 			// recover from panic
 			panicVal := recover()
 			if panicVal != nil {
 				me := m.NewPanicError(name, "module-control", panicVal)
 				me.Report()
-			err = me
+				ctrlFnError <- fmt.Errorf("panic: %s", panicVal)
 			}
+
+			// Signal finish.
+			m.ctrlFuncRunning.UnSet()
+			m.checkIfStopComplete()
 		}()
 
-	// run
+		// Run control function and report error.
-	err = fn()
+		err := fn()
-	return
+		ctrlFnError <- err
+	}()
+
+	return ctrlFnError
 }