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Diffstat (limited to 'docs/pages/4 - Cask Actors.md')
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diff --git a/docs/pages/4 - Cask Actors.md b/docs/pages/4 - Cask Actors.md index 5d8d3c7..6845d08 100644 --- a/docs/pages/4 - Cask Actors.md +++ b/docs/pages/4 - Cask Actors.md @@ -347,4 +347,74 @@ does not enforce it. Similarly, it is generally good practice to avoid defining "auxiliary" mutable state `var`s in the body of a `StateMachineActor`. The library does not enforce that either, but doing so somewhat defeats the purpose of using a `StateMachineActor` to model your actor state in the first place, in -which case you might as well use `SimpleActor`.
\ No newline at end of file +which case you might as well use `SimpleActor`. + +### Debug Logging State Machines + +When using `StateMachineActor`, all your actor's internal state should be in the +single `state` variable. You can thus easily override `def run` to print the +state before and after each message is received: + +```scala +override def run(msg: Msg): Unit = { + println(s"$state + $msg -> ") + super.run(msg) + println(state) +} +``` + +If your `StateMachineActor` is misbehaving, this should hopefully make it easier +to trace what it is doing in response to each message, so you can figure out +exactly why it is misbehaving: + +```scala +logger.send(Text("I am cow")) +// Idle() + Text(I am cow) -> +// Buffering(Vector(I am cow)) +logger.send(Text("hear me moo")) +// Buffering(Vector(I am cow)) + Text(hear me moo) -> +// Buffering(Vector(I am cow, hear me moo)) +Thread.sleep(100) +// Buffering(Vector(I am cow, hear me moo)) + Debounced() -> +// Idle() +logger.send(Text("I weight twice as much as you")) +// Idle() + Text(I weight twice as much as you) -> +// Buffering(Vector(I weight twice as much as you)) +logger.send(Text("And I look good on the barbecue")) +// Buffering(Vector(I weight twice as much as you)) + Text(And I look good on the barbecue) -> +// Buffering(Vector(I weight twice as much as you, And I look good on the barbecue)) +Thread.sleep(100) +// Buffering(Vector(I weight twice as much as you, And I look good on the barbecue)) + Debounced() -> +// Idle() +logger.send(Text("Yoghurt curds cream cheese and butter")) +// Idle() + Text(Yoghurt curds cream cheese and butter) -> +// Buffering(Vector(Yoghurt curds cream cheese and butter)) +logger.send(Text("Comes from liquids from my udder")) +// Buffering(Vector(Yoghurt curds cream cheese and butter)) + +// Text(Comes from liquids from my udder) -> Buffering(Vector(Yoghurt curds cream cheese and butter, Comes from liquids from my udder)) +logger.send(Text("I am cow, I am cow")) +// Buffering(Vector(Yoghurt curds cream cheese and butter, Comes from liquids from my udder)) + Text(I am cow, I am cow) -> +// Buffering(Vector(Yoghurt curds cream cheese and butter, Comes from liquids from my udder, I am cow, I am cow)) +logger.send(Text("Hear me moo, moooo")) +// Buffering(Vector(Yoghurt curds cream cheese and butter, Comes from liquids from my udder, I am cow, I am cow)) + Text(Hear me moo, moooo) -> +// Buffering(Vector(Yoghurt curds cream cheese and butter, Comes from liquids from my udder, I am cow, I am cow, Hear me moo, moooo)) + +ac.waitForInactivity() +// Buffering(Vector(Yoghurt curds cream cheese and butter, Comes from liquids from my udder, I am cow, I am cow, Hear me moo, moooo)) + Debounced() -> +// Idle() +``` + +Logging every message received and processed by one or more Actors may get very +verbose in a large system with lots going on; you can use a conditional +`if(...)` in your `override def run` to specify exactly which state transitions +on which actors you care about (e.g. only actors handling a certain user ID) to +cut down on the noise: + + +```scala +override def run(msg: Msg): Unit = { + if (???) println(s"$state + $msg -> ") + super.run(msg) + if (???) println(state) +} +```
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