actors: better facet stop tracing

src/syndicate/actors.nim

@@ -122,18 +122,17 @@ using
 
 proc labels(f: Facet): string =
   proc catLabels(f: Facet; labels: var string) =
-    labels.add ':'
     if not f.parent.isNil:
       catLabels(f.parent, labels)
       labels.add ':'
-    when tracing:
       labels.add $f.id
   result.add f.actor.name
   catLabels(f, result)
 
+proc `$`*(f: Facet): string =
+  "<Facet:" & f.labels & ">"
+
 when tracing:
-  proc `$`*(f: Facet): string =
-    "<Facet:" & f.labels & ">"
 
   proc `$`*(r: Cap): string =
     "<Ref:" & r.relay.labels & ">"
@@ -162,6 +161,13 @@ proc nextHandle(facet: Facet): Handle =
   result = succ(facet.actor.handleAllocator[])
   facet.actor.handleAllocator[] = result
 
+template recallFacet(turn: var Turn; body: untyped): untyped =
+  let facet = turn.facet
+  block:
+    body
+  assert facet.actor == turn.facet.actor
+  turn.facet = facet
+
 proc queueWork*(turn: var Turn; facet: Facet; act: TurnAction) =
   assert not facet.isNil
   turn.work.addLast((facet, act,))
@@ -401,18 +407,12 @@ proc isInert(facet): bool =
     noOutboundHandles = facet.outbound.len == 0
     isRootFacet = facet.parent.isNil
     noInertCheckPreventers = facet.inertCheckPreventers == 0
-  noKids and (noOutboundHandles or isRootFacet) and noInertCheckPreventers
+  result = noKids and (noOutboundHandles or isRootFacet) and noInertCheckPreventers
 
-proc preventInertCheck*(facet): (proc()) {.discardable.} =
-  var armed = true
-  inc facet.inertCheckPreventers
-  proc disarm() =
-    if armed:
-      armed = false
-      dec facet.inertCheckPreventers
-  result = disarm
+proc preventInertCheck*(turn: Turn) =
+  inc turn.facet.inertCheckPreventers
 
-proc terminate(actor; turn; reason: ref Exception)
+proc terminateActor(turn; reason: ref Exception)
 
 proc terminate(facet; turn: var Turn; orderly: bool) =
   if facet.isAlive:
@@ -432,37 +432,44 @@ proc terminate(facet; turn: var Turn; orderly: bool) =
           if parent.isInert:
             parent.terminate(turn, true)
         else:
-          terminate(facet.actor, turn, nil)
+          terminateActor(turn, nil)
     when tracing:
       var act = ActionDescription(orKind: ActionDescriptionKind.facetStop)
       act.facetstop.path = facet.path
       turn.desc.actions.add act
 
+proc inertCheck(turn: var Turn) =
+  if (not turn.facet.parent.isNil and
+        (not turn.facet.parent.isAlive)) or
+      turn.facet.isInert:
+    when tracing:
+      var act = ActionDescription(orKind: ActionDescriptionKind.facetStop)
+      act.facetstop.path = facet.path
+      act.facetstop.reason = FacetStopReason.inert
+      turn.desc.actions.add act
+    stop(turn)
+
 proc stopIfInertAfter(action: TurnAction): TurnAction =
-  # TODO: verify this
-  proc wrapper(turn: var Turn) =
-    action(turn)
-    queueEffect(turn, turn.facet) do (turn: var Turn):
-      if (not turn.facet.parent.isNil and
-            (not turn.facet.parent.isAlive)) or
-          turn.facet.isInert:
-        stop(turn)
-  wrapper
+  proc work(turn: var Turn) =
+    queueWork(turn, turn.facet, action)
+    queueEffect(turn, turn.facet, inertCheck)
+  work
 
 proc newFacet(turn: var Turn): Facet = newFacet(turn.facet.actor, turn.facet)
 
-proc inFacet*(turn: var Turn; bootProc: TurnAction): Facet =
+#[
+proc inFacet(turn: var Turn; bootProc: TurnAction): Facet =
   result = newFacet(turn)
-  let facet = turn.facet
-  turn.facet = result
-  when tracing:
-    var act = ActionDescription(orKind: ActionDescriptionKind.facetstart)
-    act.facetstart.path.add result.path
-    turn.desc.actions.add act
-  stopIfInertAfter(bootProc)(turn)
-  turn.facet = facet
+  recallFacet turn:
+    turn.facet = result
+    when tracing:
+      var act = ActionDescription(orKind: ActionDescriptionKind.facetstart)
+      act.facetstart.path.add result.path
+      turn.desc.actions.add act
+    stopIfInertAfter(bootProc)(turn)
+]#
 
-proc facet(turn: var Turn; bootProc: TurnAction): Facet {.deprecated.} = inFacet(turn, bootProc)
+# proc facet(turn: var Turn; bootProc: TurnAction): Facet {.deprecated.} = inFacet(turn, bootProc)
 
 proc newActor(name: string; parent: Facet): Actor =
   result = Actor(
@@ -539,7 +546,8 @@ proc newInertCap*(): Cap =
 
 proc atExit*(actor; action) = actor.exitHooks.add action
 
-proc terminate(actor; turn; reason: ref Exception) =
+proc terminateActor(turn; reason: ref Exception) =
+  let actor = turn.actor
   if not actor.exiting:
     actor.exiting = true
     actor.exitReason = reason
@@ -549,7 +557,13 @@ proc terminate(actor; turn; reason: ref Exception) =
         act.stop.status = ExitStatus(orKind: ExitStatusKind.Error)
         act.stop.status.error.message = reason.msg
       trace(actor, act)
-    for hook in actor.exitHooks: hook(turn)
+    while actor.exitHooks.len > 0:
+      var hook = actor.exitHooks.pop()
+      try: hook(turn)
+      except CatchableError as err:
+        if reason.isNil:
+          terminateActor(turn, err)
+          return
     proc finish(turn: var Turn) =
       assert not actor.root.isNil, actor.name
       actor.root.terminate(turn, reason.isNil)
@@ -558,14 +572,7 @@ proc terminate(actor; turn; reason: ref Exception) =
 
 proc terminate*(facet; e: ref Exception) =
   run(facet.actor.root) do (turn: var Turn):
-    facet.actor.terminate(turn, e)
-
-template recallFacet(turn: var Turn; body: untyped): untyped =
-  let facet = turn.facet
-  block:
-    body
-  assert facet.actor == turn.facet.actor
-  turn.facet = facet
+    terminateActor(turn, e)
 
 proc stopNow(turn: var Turn) =
   let caller = turn.facet
@@ -583,6 +590,11 @@ proc stop*(turn: var Turn, facet: Facet) =
   queueEffect(turn, facet, stopNow)
 
 proc stop*(turn: var Turn) =
+  when tracing:
+    var act = ActionDescription(orKind: ActionDescriptionKind.facetStop)
+    act.facetstop.path = facet.path
+    act.facetstop.reason = FacetStopReason.explicitAction
+    turn.desc.actions.add act
   stop(turn, turn.facet)
 
 proc onStop*(facet: Facet; act: TurnAction) =
@@ -596,7 +608,12 @@ proc onStop*(turn: var Turn; act: TurnAction) =
 proc stop*(actor: Actor) =
   queueTurn(actor.root) do (turn: var Turn):
     assert(not turn.facet.isNil)
-    stop(turn)
+    when tracing:
+      var act = ActionDescription(orKind: ActionDescriptionKind.facetStop)
+      act.facetstop.path = facet.path
+      act.facetstop.reason = FacetStopReason.actorStopping
+      turn.desc.actions.add act
+    stop(turn, turn.facet)
 
 proc stopActor*(facet: Facet) =
   stop(facet.actor)
@@ -655,9 +672,16 @@ proc run* =
     while turnQueue.len > 0:
       var turn = turnQueue.popFirst()
       # TODO: check if actor is still valid
-      run turn
+      try: run(turn)
+      except CatchableError as err:
+        stderr.writeLine("actor ", turn.actor.name, " threw an error during a turn")
+        terminateActor(turn, err)
     ioqueue.poll(ready)
     if ready.len == 0: break
     while ready.len > 0:
-      discard trampoline:
-        ready.pop()
+      try:
+        discard trampoline:
+          ready.pop()
+      except CatchableError as err:
+        stderr.writeLine "ioqueue continuation threw an error"
+        raise err

src/syndicate/dataspaces.nim

@@ -42,7 +42,7 @@ type DeprecatedBootProc = proc (ds: Cap; turn: var Turn) {.closure.}
 
 proc bootDataspace*(name: string; bootProc: BootProc): Actor =
   bootActor(name) do (turn: var Turn):
-    discard turn.facet.preventInertCheck()
+    turn.preventInertCheck()
     bootProc(turn, newDataspace(turn))
 
 proc bootDataspace*(name: string; bootProc: DeprecatedBootProc): Actor {.deprecated.} =

src/syndicate/relays.nim

@@ -262,12 +262,12 @@ type
 
 proc spawnRelay(name: string; turn: var Turn; opts: RelayActorOptions; setup: RelaySetup) =
   spawnLink(name, turn) do (turn: var Turn):
+    turn.preventInertCheck()
     let relay = Relay(
         facet: turn.facet,
         packetWriter: opts.packetWriter,
         wireBuf: newBufferedDecoder(0),
       )
-    discard relay.facet.preventInertCheck()
     if not opts.initialCap.isNil:
       var exported: seq[WireSymbol]
       discard rewriteCapOut(relay, opts.initialCap, exported)

syndicate.nimble

@@ -1,6 +1,6 @@
 # Package
 
-version = "20240311"
+version = "20240312"
 author        = "Emery Hemingway"
 description   = "Syndicated actors for conversational concurrency"
 license       = "Unlicense"