revised spinner

wang-engineer · wang-engineer · commit 12d1bb34bd5c · 2023-02-13T20:16:59.000-05:00
diff --git a/17-it-generator/sentence_gen2.py b/17-it-generator/sentence_gen2.py
@@ -22,3 +22,4 @@ def __iter__(self):
             yield match.group()  # <3>
 
 # end::SENTENCE_GEN2[]
+
diff --git a/19-concurrency/spinner_async.py b/19-concurrency/spinner_async.py
@@ -7,6 +7,7 @@
 # tag::SPINNER_ASYNC_TOP[]
 import asyncio
 import itertools
+import time
 
 async def spin(msg: str) -> None:  # <1>
     for char in itertools.cycle(r'\|/-'):
diff --git a/19-concurrency/spinner_async_experiment.py b/19-concurrency/spinner_async_experiment.py
@@ -20,13 +20,15 @@ async def spin(msg: str) -> None:
 
 # tag::SPINNER_ASYNC_EXPERIMENT[]
 async def slow() -> int:
+    print("start waiting")
     time.sleep(3)  # <4>
     return 42
 
 async def supervisor() -> int:
     spinner = asyncio.create_task(spin('thinking!'))  # <1>
     print(f'spinner object: {spinner}')  # <2>
-    result = await slow()  # <3>
+    result = await slow()  # <3>\
+    print("End waiting")
     spinner.cancel()  # <5>
     return result
 # end::SPINNER_ASYNC_EXPERIMENT[]
diff --git a/19-concurrency/spinner_async_slow.py b/19-concurrency/spinner_async_slow.py
@@ -0,0 +1,51 @@
+# spinner_async.py
+
+# credits: Example by Luciano Ramalho inspired by
+# Michele Simionato's multiprocessing example in the python-list:
+# https://mail.python.org/pipermail/python-list/2009-February/675659.html
+
+# tag::SPINNER_ASYNC_TOP[]
+import asyncio
+import itertools
+import time
+
+
+async def spin(msg: str) -> None:  # <1>
+    print("start spinning")
+    for char in itertools.cycle(r'\|/-'):
+        status = f'{char} {msg}'
+        print(status)
+        try:
+            await asyncio.sleep(0.5)  # <2>
+        except asyncio.CancelledError:  # <3>
+            print("spinner will be broken ...")
+            break
+    blanks = ' ' * len(status)
+    print(f'\r{blanks}\r', end='')
+async def slow() -> int:
+    print("start slow process")
+    await asyncio.sleep(3)  # <4>
+    return 42
+# end::SPINNER_ASYNC_TOP[]
+
+# tag::SPINNER_ASYNC_START[]
+def main() -> None:  # <1>
+    result = asyncio.run(supervisor())  # <2>
+    print(f'Answer: {result}')
+
+async def supervisor() -> int:  # <3>
+    spinner = asyncio.create_task(spin('thinking!'))  # <4>
+    print(f'spinner object: {spinner}')  # <5>
+    result = await slow()  # <6>
+
+    print("0.8 wait starts")
+    await asyncio.sleep(0.8)
+    print("0.8 wait ends")
+    print("start cancel spinning")
+    spinner.cancel() # <7>
+
+    return result
+
+if __name__ == '__main__':
+    main()
+# end::SPINNER_ASYNC_START[]

Original file line number	Diff line number	Diff line change
`@@ -22,3 +22,4 @@ def __iter__(self):`
`22`	`22`	`yield match.group() # <3>`
`23`	`23`
`24`	`24`	`# end::SENTENCE_GEN2[]`
	`25`	`+`