Improved the API

experiment.py

@@ -45,12 +45,17 @@ async def main():
     print("Spawning countdown immediately, scheduling count for 4 secs from now")
     task = loop.spawn(countdown(8))
     task1 = loop.schedule(count(6, 2), 4)   # Schedules the task, it will be ran 4 seconds from now
-    await giambio.sleep(0)  # TODO: Fix this to avoid the need to use a checkpoint before cancelling
-    await task.cancel()
-#    result = await task.join()  # Would raise TaskError!
+    await giambio.sleep(2)  # TODO: Fix this to avoid the need to use a checkpoint before cancelling
+#    await task.cancel()
+    result = await task.join()  # Would raise TaskCancelled if the task was cancelled
     result = 'Task cancelled' if task.cancelled else task.result.val
     result1 = await task1.join()
     print(f"countdown returned: {result}\ncount returned: {result1}")
     print("All done")
+    print("PT. 2 Context Manager")
+    async with giambio.TaskManager(loop) as manager:
+        task2 = await manager.spawn(countdown(8))
+        task3 = await manager.schedule(count(16, 2), 4)
+    print(manager.values)
 
 loop.start(main)

giambio/abstractions.py

@@ -25,6 +25,7 @@ class Task:
         self.loop = loop  # The EventLoop object that spawned the task
         self.cancelled = False
         self.execution = "INIT"
+        self.steps = 0    # How many steps did the task do before ending, incremented while executing
 
     def run(self):
         self.status = True
@@ -40,8 +41,8 @@ class Task:
     async def cancel(self):
         return await cancel(self)
 
-    async def join(self):
-        return await join(self)
+    async def join(self, silent=False):
+        return await join(self, silent)
 
     def get_result(self):
         if self.result:

giambio/core.py

@@ -50,6 +50,7 @@ class EventLoop:
                 try:
                     method, *args = self.running.run()
                     getattr(self, method)(*args)   # Sneaky method call, thanks to David Beazley for this ;)
+                    self.running.steps += 1
                 except StopIteration as e:
                     self.running.execution = "FINISH"
                     self.running.result = Result(e.args[0] if e.args else None, None)  # Saves the return value

giambio/traps.py

@@ -34,17 +34,21 @@ def want_write(sock: socket.socket):
 
 
 @types.coroutine
-def join(task):
-    """'Tells' the scheduler that the desired task MUST be awaited for completion"""
+def join(task, silent=False):
+    """'Tells' the scheduler that the desired task MUST be awaited for completion
+        If silent is True, any exception in the child task will be discarded"""
 
     if task.cancelled:
-        raise TaskCancelled("Cannot join cancelled task!")
-    if task.execution == "FINISH":
-        raise TaskFinished("Cannot join already terminated task!")
+        raise TaskCancelled("cannot join cancelled task!")
     task.joined = True
     yield "want_join", task
-    return task.get_result()    # This raises an exception if the child task errored
-
+    if silent:
+        try:
+            return task.get_result()   # Exception silenced
+        except:
+            return None
+    else:
+        return task.get_result()   # Will raise
 
 @types.coroutine
 def cancel(task):
@@ -52,3 +56,13 @@ def cancel(task):
 
     yield "want_cancel", task
 
+@types.coroutine
+def join_unfinished(task):
+    """Same as join(), but it will raise a TaskFinished exception if the task already ended"""
+
+    if task.execution == "FINISH":
+        raise TaskFinished("task has already ended!")
+    yield "want_join", task
+    task.joined = True
+    return task.get_result()
+

giambio/util.py

@@ -6,17 +6,18 @@ class TaskManager(Task):
     """Class to be used inside context managers to spawn multiple tasks and be sure that they will all joined before the code exits the with block"""
 
 
-    def __init__(self, loop):
+    def __init__(self, loop, silent=False):
         self.tasks = deque()    # All tasks spawned
         self.values = {}   # Results OR exceptions of each task
         self.loop = loop
+        self.silent = silent
 
     async def __aenter__(self):
         return self
 
     async def __aexit__(self, *args):
         for task in self.tasks:
-            self.values[task.coroutine.__name__] = await task.join()
+            self.values[task.coroutine.__name__] = await task.join(self.silent)
 
     async def spawn(self, coro):
         task = self.loop.spawn(coro)