Print stack trace of all goroutines when emergency halting if verbose

environment.go

@@ -41,6 +41,7 @@ type environment struct {
 		logDirectory string
 		configFile   string
 		verbose      bool
+		crash        bool
 	}
 
 	// running stores whether the environment is currently running.
@@ -136,11 +137,13 @@ func (this *environment) Del(ctx context.Context, actors ...Actor) error {
 	channels := []<- chan struct { } { }
 	for _, actor := range actors {
 		info := this.info(actor)
-		if info.done != nil {
+		if info.stopped != nil {
 			channels = append(channels, info.stopped)
 		}
+		info.done()
 	}
 	for _, channel := range channels {
+		if channel == nil { continue }
 		select {
 		case <- channel:
 		case <- ctx.Done():
@@ -249,7 +252,11 @@ func (this *environment) run(actor Actor) {
 	// contains context information
 	info := this.info(actor)
 	ctx := info.ctx
-	defer close(info.stopped)
+	defer func() {
+		if info.stopped != nil {
+			close(info.stopped)
+		}
+	}()
 	
 	switch actor := actor.(type) {
 	case Runnable:
@@ -282,7 +289,12 @@ func (this *environment) runRunnable(ctx context.Context, actor Runnable) (stopE
 	for {
 		// run actor
 		lastStart := time.Now()
-		err := panicWrapCtx(ctx, actor.Run)
+		var err error
+		if this.flags.crash {
+			err = actor.Run(ctx)
+		} else {
+			err = panicWrapCtx(ctx, actor.Run)
+		}
 
 		// detect context cancellation
 		if ctxErr := ctx.Err(); ctxErr != nil {

examples/panic/main.go

@@ -0,0 +1,35 @@
+// Example panic demonstrates how the environment can restart actors if they
+// fail.
+package main
+
+import "log"
+import "time"
+import "errors"
+import "context"
+import "math/rand"
+import "git.tebibyte.media/sashakoshka/camfish"
+
+func main() {
+	camfish.Run("panic",
+		"Example panic demonstrates how the environment can restart " +
+		"actors if they fail",
+		new(actor))
+}
+
+// actor is an incorrectly implemented actor that panics and errs randomly.
+type actor struct { }
+var _ camfish.Runnable = new(actor)
+func (this *actor) Type() string { return "panic" }
+
+func (this *actor) Run(ctx context.Context) error {
+	log.Println("(i) [panic] panicking in 10 seconds")
+	select {
+	case <- ctx.Done(): return ctx.Err()
+	case <- time.After(time.Second * 10):
+		if rand.Int() % 2 == 0 {
+			panic("this is a panic")
+		} else {
+			return errors.New("this is an error")
+		}
+	}
+}

phases.go

@@ -6,6 +6,7 @@ import "log"
 import "io/fs"
 import "errors"
 import "context"
+import "runtime"
 import "strings"
 import "path/filepath"
 import "git.tebibyte.media/sashakoshka/go-cli"
@@ -24,6 +25,7 @@ func (this *environment) phase10FlagParsing() bool {
 	flagLogDirectory  := set.Flag('l', "log-directory", "Write logs to the specified directory", cli.ValString)
 	flagConfigFile    := set.Flag('c', "config-file",   "Use this configuration file", cli.ValString)
 	flagVerbose       := set.Flag('v', "verbose",       "Enable verbose output/logging", nil)
+	flagCrash         := set.Flag(0,   "crash",         "Crash when an actor panics", nil)
 
 	// ask actors to add flags
 	actors, done := this.actors.RBorrow()
@@ -60,6 +62,9 @@ func (this *environment) phase10FlagParsing() bool {
 	if _, ok := flagVerbose.First(); ok {
 		this.flags.verbose = true
 	}
+	if _, ok := flagCrash.First(); ok {
+		this.flags.crash = true
+	}
 	return true
 }
 
@@ -128,6 +133,12 @@ func (this *environment) phase30ConfigurationParsing() bool {
 	if this.flags.configFile != "" {
 		paths = append(paths, this.flags.configFile)
 	}
+	if this.Verb() {
+		log.Println("(i) (30) have configuration files:")
+		for _, paths := range paths {
+			log.Println("(i) (30) -", paths)
+		}
+	}
 	// parse every config and merge them all
 	configs := make([]iniConfig, 0, len(paths))
 	for _, path := range paths {
@@ -263,6 +274,11 @@ func (this *environment) phase80Shutdown() bool {
 		<- ctx.Done()
 		if errors.Is(context.Cause(ctx), context.DeadlineExceeded) {
 			log.Println("XXX (80) shutdown timeout expired, performing emergency halt")
+			if Verb() {
+				dumpBuffer := make([]byte, 8192)
+				runtime.Stack(dumpBuffer, true)
+				log.Printf("XXX (80) stack trace of all goroutines:\n%s", dumpBuffer)
+			}
 			log.Printf("====== [%s] END =======", this.name)
 			os.Exit(1)
 		}

util.go

@@ -12,6 +12,19 @@ import "strings"
 import "context"
 import "sync/atomic"
 import "unicode/utf8"
+import "runtime/debug"
+
+func panicErr(message any, stack []byte) (err error) {
+	if panErr, ok := message.(error); ok {
+		err = panErr
+	} else {
+		err = errors.New(fmt.Sprint(message))
+	}
+	if stack != nil {
+		err = fmt.Errorf("%w: %s", err, stack)
+	}
+	return err
+}
 
 func defaul[T comparable](value, def T) T {
 	var zero T
@@ -22,11 +35,7 @@ func defaul[T comparable](value, def T) T {
 func panicWrap(f func() error) (err error) {
 	defer func () {
 		if pan := recover(); pan != nil {
-			if panErr, ok := pan.(error); ok {
-				err = panErr
-			} else {
-				err = errors.New(fmt.Sprint(pan))
-			}
+			err = panicErr(pan, debug.Stack())
 		}
 	} ()
 	
@@ -37,11 +46,7 @@ func panicWrap(f func() error) (err error) {
 func panicWrapCtx(ctx context.Context, f func(context.Context) error) (err error) {
 	defer func () {
 		if pan := recover(); pan != nil {
-			if panErr, ok := pan.(error); ok {
-				err = panErr
-			} else {
-				err = errors.New(fmt.Sprint(pan))
-			}
+			err = panicErr(pan, debug.Stack())
 		}
 	} ()