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<li><a class="reference internal" href="#">Coroutines and Tasks</a><ul>
<li><a class="reference internal" href="#coroutines">Coroutines</a></li>
<li><a class="reference internal" href="#awaitables">Awaitables</a></li>
<li><a class="reference internal" href="#running-an-asyncio-program">Running an asyncio Program</a></li>
<li><a class="reference internal" href="#creating-tasks">Creating Tasks</a></li>
<li><a class="reference internal" href="#sleeping">Sleeping</a></li>
<li><a class="reference internal" href="#running-tasks-concurrently">Running Tasks Concurrently</a></li>
<li><a class="reference internal" href="#shielding-from-cancellation">Shielding From Cancellation</a></li>
<li><a class="reference internal" href="#timeouts">Timeouts</a></li>
<li><a class="reference internal" href="#waiting-primitives">Waiting Primitives</a></li>
<li><a class="reference internal" href="#running-in-threads">Running in Threads</a></li>
<li><a class="reference internal" href="#scheduling-from-other-threads">Scheduling From Other Threads</a></li>
<li><a class="reference internal" href="#introspection">Introspection</a></li>
<li><a class="reference internal" href="#task-object">Task Object</a></li>
<li><a class="reference internal" href="#generator-based-coroutines">Generator-based Coroutines</a></li>
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 <section id="coroutines-and-tasks">
<h1>Coroutines and Tasks<a class="headerlink" href="#coroutines-and-tasks" title="Permalink to this headline">¶</a></h1>
This section outlines high-level asyncio APIs to work with coroutines
and Tasks.
<div class="contents local topic" id="contents">
<ul class="simple">
<li><a class="reference internal" href="#coroutines" id="id1">Coroutines</a></li>
<li><a class="reference internal" href="#awaitables" id="id2">Awaitables</a></li>
<li><a class="reference internal" href="#running-an-asyncio-program" id="id3">Running an asyncio Program</a></li>
<li><a class="reference internal" href="#creating-tasks" id="id4">Creating Tasks</a></li>
<li><a class="reference internal" href="#sleeping" id="id5">Sleeping</a></li>
<li><a class="reference internal" href="#running-tasks-concurrently" id="id6">Running Tasks Concurrently</a></li>
<li><a class="reference internal" href="#shielding-from-cancellation" id="id7">Shielding From Cancellation</a></li>
<li><a class="reference internal" href="#timeouts" id="id8">Timeouts</a></li>
<li><a class="reference internal" href="#waiting-primitives" id="id9">Waiting Primitives</a></li>
<li><a class="reference internal" href="#running-in-threads" id="id10">Running in Threads</a></li>
<li><a class="reference internal" href="#scheduling-from-other-threads" id="id11">Scheduling From Other Threads</a></li>
<li><a class="reference internal" href="#introspection" id="id12">Introspection</a></li>
<li><a class="reference internal" href="#task-object" id="id13">Task Object</a></li>
<li><a class="reference internal" href="#generator-based-coroutines" id="id14">Generator-based Coroutines</a></li>
</ul>
</div>
<section id="coroutines">
<h2><a class="toc-backref" href="#id1">Coroutines</a><a class="headerlink" href="#coroutines" title="Permalink to this headline">¶</a></h2>
Source code: <a class="reference external" href="https://github.com/python/cpython/tree/3.10/Lib/asyncio/coroutines.py">Lib/asyncio/coroutines.py</a>
<hr class="docutils" />
<a class="reference internal" href="../glossary.html#term-coroutine">Coroutines</a> declared with the async/await syntax is the
preferred way of writing asyncio applications. For example, the following
snippet of code prints “hello”, waits 1 second,
and then prints “world”:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>&gt;&gt;&gt; import asyncio

&gt;&gt;&gt; async def main():
... print(&#39;hello&#39;)
... await asyncio.sleep(1)
... print(&#39;world&#39;)

&gt;&gt;&gt; asyncio.run(main())
hello
world
</pre></div>
</div>
Note that simply calling a coroutine will not schedule it to
be executed:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>&gt;&gt;&gt; main()
&lt;coroutine object main at 0x1053bb7c8&gt;
</pre></div>
</div>
To actually run a coroutine, asyncio provides three main mechanisms:
<ul>
<li>The <a class="reference internal" href="#asyncio.run" title="asyncio.run"><code class="xref py py-func docutils literal notranslate">asyncio.run()</code></a> function to run the top-level
entry point “main()” function (see the above example.)</li>
<li>Awaiting on a coroutine. The following snippet of code will
print “hello” after waiting for 1 second, and then print “world”
after waiting for another 2 seconds:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>import asyncio
import time

async def say_after(delay, what):
 await asyncio.sleep(delay)
 print(what)

async def main():
 print(f&quot;started at {time.strftime(&#39;%X&#39;)}&quot;)

await say_after(1, &#39;hello&#39;)
 await say_after(2, &#39;world&#39;)

asyncio.run(main())
</pre></div>
</div>
Expected output:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>started at 17:13:52
hello
world
finished at 17:13:55
</pre></div>
</div>
</li>
<li>The <a class="reference internal" href="#asyncio.create_task" title="asyncio.create_task"><code class="xref py py-func docutils literal notranslate">asyncio.create_task()</code></a> function to run coroutines
concurrently as asyncio <a class="reference internal" href="#asyncio.Task" title="asyncio.Task"><code class="xref py py-class docutils literal notranslate">Tasks</code></a>.
Let’s modify the above example and run two <code class="docutils literal notranslate">say_after</code> coroutines
concurrently:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>async def main():
 task1 = asyncio.create_task(
 say_after(1, &#39;hello&#39;))

task2 = asyncio.create_task(
 say_after(2, &#39;world&#39;))

print(f&quot;started at {time.strftime(&#39;%X&#39;)}&quot;)

# Wait until both tasks are completed (should take
 # around 2 seconds.)
 await task1
 await task2

print(f&quot;finished at {time.strftime(&#39;%X&#39;)}&quot;)
</pre></div>
</div>
Note that expected output now shows that the snippet runs
1 second faster than before:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>started at 17:14:32
hello
world
finished at 17:14:34
</pre></div>
</div>
</li>
</ul>
</section>
<section id="awaitables">
<h2><a class="toc-backref" href="#id2">Awaitables</a><a class="headerlink" href="#awaitables" title="Permalink to this headline">¶</a></h2>
We say that an object is an awaitable object if it can be used
in an <a class="reference internal" href="../reference/expressions.html#await"><code class="xref std std-keyword docutils literal notranslate">await</code></a> expression. Many asyncio APIs are designed to
accept awaitables.
There are three main types of awaitable objects:
coroutines, Tasks, and Futures.
Coroutines
Python coroutines are awaitables and therefore can be awaited from
other coroutines:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>import asyncio

async def nested():
 return 42

async def main():
 # Nothing happens if we just call &quot;nested()&quot;.
 # A coroutine object is created but not awaited,
 # so it *won&#39;t run at all*.
 nested()

# Let&#39;s do it differently now and await it:
 print(await nested()) # will print &quot;42&quot;.

asyncio.run(main())
</pre></div>
</div>
<div class="admonition important">
Important
In this documentation the term “coroutine” can be used for
two closely related concepts:
<ul class="simple">
<li>a coroutine function: an <a class="reference internal" href="../reference/compound_stmts.html#async-def"><code class="xref std std-keyword docutils literal notranslate">async def</code></a> function;</li>
<li>a coroutine object: an object returned by calling a
coroutine function.</li>
</ul>
</div>
asyncio also supports legacy <a class="reference internal" href="#asyncio-generator-based-coro">generator-based</a> coroutines.
Tasks
Tasks are used to schedule coroutines concurrently.
When a coroutine is wrapped into a Task with functions like
<a class="reference internal" href="#asyncio.create_task" title="asyncio.create_task"><code class="xref py py-func docutils literal notranslate">asyncio.create_task()</code></a> the coroutine is automatically
scheduled to run soon:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>import asyncio

async def nested():
 return 42

async def main():
 # Schedule nested() to run soon concurrently
 # with &quot;main()&quot;.
 task = asyncio.create_task(nested())

# &quot;task&quot; can now be used to cancel &quot;nested()&quot;, or
 # can simply be awaited to wait until it is complete:
 await task

asyncio.run(main())
</pre></div>
</div>
Futures
A <a class="reference internal" href="asyncio-future.html#asyncio.Future" title="asyncio.Future"><code class="xref py py-class docutils literal notranslate">Future</code></a> is a special low-level awaitable object that
represents an eventual result of an asynchronous operation.
When a Future object is awaited it means that the coroutine will
wait until the Future is resolved in some other place.
Future objects in asyncio are needed to allow callback-based code
to be used with async/await.
Normally there is no need to create Future objects at the
application level code.
Future objects, sometimes exposed by libraries and some asyncio
APIs, can be awaited:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>async def main():
 await function_that_returns_a_future_object()

# this is also valid:
 await asyncio.gather(
 function_that_returns_a_future_object(),
 some_python_coroutine()
 )
</pre></div>
</div>
A good example of a low-level function that returns a Future object
is <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.run_in_executor" title="asyncio.loop.run_in_executor"><code class="xref py py-meth docutils literal notranslate">loop.run_in_executor()</code></a>.
</section>
<section id="running-an-asyncio-program">
<h2><a class="toc-backref" href="#id3">Running an asyncio Program</a><a class="headerlink" href="#running-an-asyncio-program" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.run">
asyncio.run(coro, *, debug=False)<a class="headerlink" href="#asyncio.run" title="Permalink to this definition">¶</a></dt>
<dd>Execute the <a class="reference internal" href="../glossary.html#term-coroutine">coroutine</a> coro and return the result.
This function runs the passed coroutine, taking care of
managing the asyncio event loop, finalizing asynchronous
generators, and closing the threadpool.
This function cannot be called when another asyncio event loop is
running in the same thread.
If debug is <code class="docutils literal notranslate">True</code>, the event loop will be run in debug mode.
This function always creates a new event loop and closes it at
the end. It should be used as a main entry point for asyncio
programs, and should ideally only be called once.
Example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>async def main():
 await asyncio.sleep(1)
 print(&#39;hello&#39;)

asyncio.run(main())
</pre></div>
</div>
<div class="versionadded">
New in version 3.7.
</div>
<div class="versionchanged">
Changed in version 3.9: Updated to use <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.shutdown_default_executor" title="asyncio.loop.shutdown_default_executor"><code class="xref py py-meth docutils literal notranslate">loop.shutdown_default_executor()</code></a>.
</div>
<div class="admonition note">
Note
The source code for <code class="docutils literal notranslate">asyncio.run()</code> can be found in
<a class="reference external" href="https://github.com/python/cpython/tree/3.10/Lib/asyncio/runners.py">Lib/asyncio/runners.py</a>.
</div>
</dd></dl>

</section>
<section id="creating-tasks">
<h2><a class="toc-backref" href="#id4">Creating Tasks</a><a class="headerlink" href="#creating-tasks" title="Permalink to this headline">¶</a></h2>
Source code: <a class="reference external" href="https://github.com/python/cpython/tree/3.10/Lib/asyncio/tasks.py">Lib/asyncio/tasks.py</a>
<hr class="docutils" />
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.create_task">
asyncio.create_task(coro, *, name=None)<a class="headerlink" href="#asyncio.create_task" title="Permalink to this definition">¶</a></dt>
<dd>Wrap the coro <a class="reference internal" href="#coroutine">coroutine</a> into a <a class="reference internal" href="#asyncio.Task" title="asyncio.Task"><code class="xref py py-class docutils literal notranslate">Task</code></a>
and schedule its execution. Return the Task object.
If name is not <code class="docutils literal notranslate">None</code>, it is set as the name of the task using
<a class="reference internal" href="#asyncio.Task.set_name" title="asyncio.Task.set_name"><code class="xref py py-meth docutils literal notranslate">Task.set_name()</code></a>.
The task is executed in the loop returned by <a class="reference internal" href="asyncio-eventloop.html#asyncio.get_running_loop" title="asyncio.get_running_loop"><code class="xref py py-func docutils literal notranslate">get_running_loop()</code></a>,
<a class="reference internal" href="exceptions.html#RuntimeError" title="RuntimeError"><code class="xref py py-exc docutils literal notranslate">RuntimeError</code></a> is raised if there is no running loop in
current thread.
<div class="admonition important">
Important
Save a reference to the result of this function, to avoid
a task disappearing mid-execution. The event loop only keeps
weak references to tasks. A task that isn’t referenced elsewhere
may get garbage collected at any time, even before it’s done.
For reliable “fire-and-forget” background tasks, gather them in
a collection:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>background_tasks = set()

for i in range(10):
 task = asyncio.create_task(some_coro(param=i))

# Add task to the set. This creates a strong reference.
 background_tasks.add(task)

# To prevent keeping references to finished tasks forever,
 # make each task remove its own reference from the set after
 # completion:
 task.add_done_callback(background_tasks.discard)
</pre></div>
</div>
</div>
<div class="versionadded">
New in version 3.7.
</div>
<div class="versionchanged">
Changed in version 3.8: Added the name parameter.
</div>
</dd></dl>

</section>
<section id="sleeping">
<h2><a class="toc-backref" href="#id5">Sleeping</a><a class="headerlink" href="#sleeping" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.sleep">
coroutine asyncio.sleep(delay, result=None)<a class="headerlink" href="#asyncio.sleep" title="Permalink to this definition">¶</a></dt>
<dd>Block for delay seconds.
If result is provided, it is returned to the caller
when the coroutine completes.
<code class="docutils literal notranslate">sleep()</code> always suspends the current task, allowing other tasks
to run.
Setting the delay to 0 provides an optimized path to allow other
tasks to run. This can be used by long-running functions to avoid
blocking the event loop for the full duration of the function call.
<div class="deprecated-removed">
Deprecated since version 3.8, removed in version 3.10: The <code class="docutils literal notranslate">loop</code> parameter. This function has been implicitly getting the
current running loop since 3.7. See
<a class="reference internal" href="../whatsnew/3.10.html#whatsnew310-removed">What’s New in 3.10’s Removed section</a>
for more information.
</div>
Example of coroutine displaying the current date every second
for 5 seconds:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>import asyncio
import datetime

async def display_date():
 loop = asyncio.get_running_loop()
 end_time = loop.time() + 5.0
 while True:
 print(datetime.datetime.now())
 if (loop.time() + 1.0) &gt;= end_time:
 break
 await asyncio.sleep(1)

asyncio.run(display_date())
</pre></div>
</div>
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
</dd></dl>

</section>
<section id="running-tasks-concurrently">
<h2><a class="toc-backref" href="#id6">Running Tasks Concurrently</a><a class="headerlink" href="#running-tasks-concurrently" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.gather">
awaitable asyncio.gather(*aws, return_exceptions=False)<a class="headerlink" href="#asyncio.gather" title="Permalink to this definition">¶</a></dt>
<dd>Run <a class="reference internal" href="#asyncio-awaitables">awaitable objects</a> in the aws
sequence concurrently.
If any awaitable in aws is a coroutine, it is automatically
scheduled as a Task.
If all awaitables are completed successfully, the result is an
aggregate list of returned values. The order of result values
corresponds to the order of awaitables in aws.
If return_exceptions is <code class="docutils literal notranslate">False</code> (default), the first
raised exception is immediately propagated to the task that
awaits on <code class="docutils literal notranslate">gather()</code>. Other awaitables in the aws sequence
won’t be cancelled and will continue to run.
If return_exceptions is <code class="docutils literal notranslate">True</code>, exceptions are treated the
same as successful results, and aggregated in the result list.
If <code class="docutils literal notranslate">gather()</code> is cancelled, all submitted awaitables
(that have not completed yet) are also cancelled.
If any Task or Future from the aws sequence is cancelled, it is
treated as if it raised <a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate">CancelledError</code></a> – the <code class="docutils literal notranslate">gather()</code>
call is not cancelled in this case. This is to prevent the
cancellation of one submitted Task/Future to cause other
Tasks/Futures to be cancelled.
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
Example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>import asyncio

async def factorial(name, number):
 f = 1
 for i in range(2, number + 1):
 print(f&quot;Task {name}: Compute factorial({number}), currently i={i}...&quot;)
 await asyncio.sleep(1)
 f *= i
 print(f&quot;Task {name}: factorial({number}) = {f}&quot;)
 return f

async def main():
 # Schedule three calls *concurrently*:
 L = await asyncio.gather(
 factorial(&quot;A&quot;, 2),
 factorial(&quot;B&quot;, 3),
 factorial(&quot;C&quot;, 4),
 )
 print(L)

asyncio.run(main())

# Expected output:
#
# Task A: Compute factorial(2), currently i=2...
# Task B: Compute factorial(3), currently i=2...
# Task C: Compute factorial(4), currently i=2...
# Task A: factorial(2) = 2
# Task B: Compute factorial(3), currently i=3...
# Task C: Compute factorial(4), currently i=3...
# Task B: factorial(3) = 6
# Task C: Compute factorial(4), currently i=4...
# Task C: factorial(4) = 24
# [2, 6, 24]
</pre></div>
</div>
<div class="admonition note">
Note
If return_exceptions is False, cancelling gather() after it
has been marked done won’t cancel any submitted awaitables.
For instance, gather can be marked done after propagating an
exception to the caller, therefore, calling <code class="docutils literal notranslate">gather.cancel()</code>
after catching an exception (raised by one of the awaitables) from
gather won’t cancel any other awaitables.
</div>
<div class="versionchanged">
Changed in version 3.7: If the gather itself is cancelled, the cancellation is
propagated regardless of return_exceptions.
</div>
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
<div class="deprecated">
Deprecated since version 3.10: Deprecation warning is emitted if no positional arguments are provided
or not all positional arguments are Future-like objects
and there is no running event loop.
</div>
</dd></dl>

</section>
<section id="shielding-from-cancellation">
<h2><a class="toc-backref" href="#id7">Shielding From Cancellation</a><a class="headerlink" href="#shielding-from-cancellation" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.shield">
awaitable asyncio.shield(aw)<a class="headerlink" href="#asyncio.shield" title="Permalink to this definition">¶</a></dt>
<dd>Protect an <a class="reference internal" href="#asyncio-awaitables">awaitable object</a>
from being <a class="reference internal" href="#asyncio.Task.cancel" title="asyncio.Task.cancel"><code class="xref py py-meth docutils literal notranslate">cancelled</code></a>.
If aw is a coroutine it is automatically scheduled as a Task.
The statement:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>task = asyncio.create_task(something())
res = await shield(task)
</pre></div>
</div>
is equivalent to:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>res = await something()
</pre></div>
</div>
except that if the coroutine containing it is cancelled, the
Task running in <code class="docutils literal notranslate">something()</code> is not cancelled. From the point
of view of <code class="docutils literal notranslate">something()</code>, the cancellation did not happen.
Although its caller is still cancelled, so the “await” expression
still raises a <a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate">CancelledError</code></a>.
If <code class="docutils literal notranslate">something()</code> is cancelled by other means (i.e. from within
itself) that would also cancel <code class="docutils literal notranslate">shield()</code>.
If it is desired to completely ignore cancellation (not recommended)
the <code class="docutils literal notranslate">shield()</code> function should be combined with a try/except
clause, as follows:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>task = asyncio.create_task(something())
try:
 res = await shield(task)
except CancelledError:
 res = None
</pre></div>
</div>
<div class="admonition important">
Important
Save a reference to tasks passed to this function, to avoid
a task disappearing mid-execution. The event loop only keeps
weak references to tasks. A task that isn’t referenced elsewhere
may get garbage collected at any time, even before it’s done.
</div>
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
<div class="deprecated">
Deprecated since version 3.10: Deprecation warning is emitted if aw is not Future-like object
and there is no running event loop.
</div>
</dd></dl>

</section>
<section id="timeouts">
<h2><a class="toc-backref" href="#id8">Timeouts</a><a class="headerlink" href="#timeouts" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.wait_for">
coroutine asyncio.wait_for(aw, timeout)<a class="headerlink" href="#asyncio.wait_for" title="Permalink to this definition">¶</a></dt>
<dd>Wait for the aw <a class="reference internal" href="#asyncio-awaitables">awaitable</a>
to complete with a timeout.
If aw is a coroutine it is automatically scheduled as a Task.
timeout can either be <code class="docutils literal notranslate">None</code> or a float or int number of seconds
to wait for. If timeout is <code class="docutils literal notranslate">None</code>, block until the future
completes.
If a timeout occurs, it cancels the task and raises
<a class="reference internal" href="asyncio-exceptions.html#asyncio.TimeoutError" title="asyncio.TimeoutError"><code class="xref py py-exc docutils literal notranslate">asyncio.TimeoutError</code></a>.
To avoid the task <a class="reference internal" href="#asyncio.Task.cancel" title="asyncio.Task.cancel"><code class="xref py py-meth docutils literal notranslate">cancellation</code></a>,
wrap it in <a class="reference internal" href="#asyncio.shield" title="asyncio.shield"><code class="xref py py-func docutils literal notranslate">shield()</code></a>.
The function will wait until the future is actually cancelled,
so the total wait time may exceed the timeout. If an exception
happens during cancellation, it is propagated.
If the wait is cancelled, the future aw is also cancelled.
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
Example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>async def eternity():
 # Sleep for one hour
 await asyncio.sleep(3600)
 print(&#39;yay!&#39;)

async def main():
 # Wait for at most 1 second
 try:
 await asyncio.wait_for(eternity(), timeout=1.0)
 except asyncio.TimeoutError:
 print(&#39;timeout!&#39;)

asyncio.run(main())

# Expected output:
#
# timeout!
</pre></div>
</div>
<div class="versionchanged">
Changed in version 3.7: When aw is cancelled due to a timeout, <code class="docutils literal notranslate">wait_for</code> waits
for aw to be cancelled. Previously, it raised
<a class="reference internal" href="asyncio-exceptions.html#asyncio.TimeoutError" title="asyncio.TimeoutError"><code class="xref py py-exc docutils literal notranslate">asyncio.TimeoutError</code></a> immediately.
</div>
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
</dd></dl>

</section>
<section id="waiting-primitives">
<h2><a class="toc-backref" href="#id9">Waiting Primitives</a><a class="headerlink" href="#waiting-primitives" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.wait">
coroutine asyncio.wait(aws, *, timeout=None, return_when=ALL_COMPLETED)<a class="headerlink" href="#asyncio.wait" title="Permalink to this definition">¶</a></dt>
<dd>Run <a class="reference internal" href="#asyncio-awaitables">awaitable objects</a> in the aws
iterable concurrently and block until the condition specified
by return_when.
The aws iterable must not be empty.
Returns two sets of Tasks/Futures: <code class="docutils literal notranslate">(done, pending)</code>.
Usage:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>done, pending = await asyncio.wait(aws)
</pre></div>
</div>
timeout (a float or int), if specified, can be used to control
the maximum number of seconds to wait before returning.
Note that this function does not raise <a class="reference internal" href="asyncio-exceptions.html#asyncio.TimeoutError" title="asyncio.TimeoutError"><code class="xref py py-exc docutils literal notranslate">asyncio.TimeoutError</code></a>.
Futures or Tasks that aren’t done when the timeout occurs are simply
returned in the second set.
return_when indicates when this function should return. It must
be one of the following constants:
<table class="docutils align-default">
<colgroup>
<col style="width: 42%" />
<col style="width: 58%" />
</colgroup>
<thead>
<tr class="row-odd"><th class="head">Constant</th>
<th class="head">Description</th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><code class="xref py py-const docutils literal notranslate">FIRST_COMPLETED</code></td>
<td>The function will return when any
future finishes or is cancelled.</td>
</tr>
<tr class="row-odd"><td><code class="xref py py-const docutils literal notranslate">FIRST_EXCEPTION</code></td>
<td>The function will return when any
future finishes by raising an
exception. If no future raises an
exception then it is equivalent to
<code class="xref py py-const docutils literal notranslate">ALL_COMPLETED</code>.</td>
</tr>
<tr class="row-even"><td><code class="xref py py-const docutils literal notranslate">ALL_COMPLETED</code></td>
<td>The function will return when all
futures finish or are cancelled.</td>
</tr>
</tbody>
</table>
Unlike <a class="reference internal" href="#asyncio.wait_for" title="asyncio.wait_for"><code class="xref py py-func docutils literal notranslate">wait_for()</code></a>, <code class="docutils literal notranslate">wait()</code> does not cancel the
futures when a timeout occurs.
<div class="deprecated">
Deprecated since version 3.8: If any awaitable in aws is a coroutine, it is automatically
scheduled as a Task. Passing coroutines objects to
<code class="docutils literal notranslate">wait()</code> directly is deprecated as it leads to
<a class="reference internal" href="#asyncio-example-wait-coroutine">confusing behavior</a>.
</div>
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
<div class="admonition note" id="asyncio-example-wait-coroutine">
Note
<code class="docutils literal notranslate">wait()</code> schedules coroutines as Tasks automatically and later
returns those implicitly created Task objects in <code class="docutils literal notranslate">(done, pending)</code>
sets. Therefore the following code won’t work as expected:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>async def foo():
 return 42

coro = foo()
done, pending = await asyncio.wait({coro})

if coro in done:
 # This branch will never be run!
</pre></div>
</div>
Here is how the above snippet can be fixed:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>async def foo():
 return 42

task = asyncio.create_task(foo())
done, pending = await asyncio.wait({task})

if task in done:
 # Everything will work as expected now.
</pre></div>
</div>
</div>
<div class="deprecated-removed">
Deprecated since version 3.8, will be removed in version 3.11: Passing coroutine objects to <code class="docutils literal notranslate">wait()</code> directly is
deprecated.
</div>
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="asyncio.as_completed">
asyncio.as_completed(aws, *, timeout=None)<a class="headerlink" href="#asyncio.as_completed" title="Permalink to this definition">¶</a></dt>
<dd>Run <a class="reference internal" href="#asyncio-awaitables">awaitable objects</a> in the aws
iterable concurrently. Return an iterator of coroutines.
Each coroutine returned can be awaited to get the earliest next
result from the iterable of the remaining awaitables.
Raises <a class="reference internal" href="asyncio-exceptions.html#asyncio.TimeoutError" title="asyncio.TimeoutError"><code class="xref py py-exc docutils literal notranslate">asyncio.TimeoutError</code></a> if the timeout occurs before
all Futures are done.
Example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>for coro in as_completed(aws):
 earliest_result = await coro
 # ...
</pre></div>
</div>
<div class="versionchanged">
Changed in version 3.10: Removed the loop parameter.
</div>
<div class="deprecated">
Deprecated since version 3.10: Deprecation warning is emitted if not all awaitable objects in the aws
iterable are Future-like objects and there is no running event loop.
</div>
</dd></dl>

</section>
<section id="running-in-threads">
<h2><a class="toc-backref" href="#id10">Running in Threads</a><a class="headerlink" href="#running-in-threads" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.to_thread">
coroutine asyncio.to_thread(func, /, *args, **kwargs)<a class="headerlink" href="#asyncio.to_thread" title="Permalink to this definition">¶</a></dt>
<dd>Asynchronously run function func in a separate thread.
Any *args and **kwargs supplied for this function are directly passed
to func. Also, the current <a class="reference internal" href="contextvars.html#contextvars.Context" title="contextvars.Context"><code class="xref py py-class docutils literal notranslate">contextvars.Context</code></a> is propagated,
allowing context variables from the event loop thread to be accessed in the
separate thread.
Return a coroutine that can be awaited to get the eventual result of func.
This coroutine function is primarily intended to be used for executing
IO-bound functions/methods that would otherwise block the event loop if
they were ran in the main thread. For example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>def blocking_io():
 print(f&quot;start blocking_io at {time.strftime(&#39;%X&#39;)}&quot;)
 # Note that time.sleep() can be replaced with any blocking
 # IO-bound operation, such as file operations.
 time.sleep(1)
 print(f&quot;blocking_io complete at {time.strftime(&#39;%X&#39;)}&quot;)

async def main():
 print(f&quot;started main at {time.strftime(&#39;%X&#39;)}&quot;)

await asyncio.gather(
 asyncio.to_thread(blocking_io),
 asyncio.sleep(1))

print(f&quot;finished main at {time.strftime(&#39;%X&#39;)}&quot;)

asyncio.run(main())

# Expected output:
#
# started main at 19:50:53
# start blocking_io at 19:50:53
# blocking_io complete at 19:50:54
# finished main at 19:50:54
</pre></div>
</div>
Directly calling <code class="docutils literal notranslate">blocking_io()</code> in any coroutine would block the event loop
for its duration, resulting in an additional 1 second of run time. Instead,
by using <code class="docutils literal notranslate">asyncio.to_thread()</code>, we can run it in a separate thread without
blocking the event loop.
<div class="admonition note">
Note
Due to the <a class="reference internal" href="../glossary.html#term-GIL">GIL</a>, <code class="docutils literal notranslate">asyncio.to_thread()</code> can typically only be used
to make IO-bound functions non-blocking. However, for extension modules
that release the GIL or alternative Python implementations that don’t
have one, <code class="docutils literal notranslate">asyncio.to_thread()</code> can also be used for CPU-bound functions.
</div>
<div class="versionadded">
New in version 3.9.
</div>
</dd></dl>

</section>
<section id="scheduling-from-other-threads">
<h2><a class="toc-backref" href="#id11">Scheduling From Other Threads</a><a class="headerlink" href="#scheduling-from-other-threads" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.run_coroutine_threadsafe">
asyncio.run_coroutine_threadsafe(coro, loop)<a class="headerlink" href="#asyncio.run_coroutine_threadsafe" title="Permalink to this definition">¶</a></dt>
<dd>Submit a coroutine to the given event loop. Thread-safe.
Return a <a class="reference internal" href="concurrent.futures.html#concurrent.futures.Future" title="concurrent.futures.Future"><code class="xref py py-class docutils literal notranslate">concurrent.futures.Future</code></a> to wait for the result
from another OS thread.
This function is meant to be called from a different OS thread
than the one where the event loop is running. Example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre># Create a coroutine
coro = asyncio.sleep(1, result=3)

# Submit the coroutine to a given loop
future = asyncio.run_coroutine_threadsafe(coro, loop)

# Wait for the result with an optional timeout argument
assert future.result(timeout) == 3
</pre></div>
</div>
If an exception is raised in the coroutine, the returned Future
will be notified. It can also be used to cancel the task in
the event loop:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>try:
 result = future.result(timeout)
except concurrent.futures.TimeoutError:
 print(&#39;The coroutine took too long, cancelling the task...&#39;)
 future.cancel()
except Exception as exc:
 print(f&#39;The coroutine raised an exception: {exc!r}&#39;)
else:
 print(f&#39;The coroutine returned: {result!r}&#39;)
</pre></div>
</div>
See the <a class="reference internal" href="asyncio-dev.html#asyncio-multithreading">concurrency and multithreading</a>
section of the documentation.
Unlike other asyncio functions this function requires the loop
argument to be passed explicitly.
<div class="versionadded">
New in version 3.5.1.
</div>
</dd></dl>

</section>
<section id="introspection">
<h2><a class="toc-backref" href="#id12">Introspection</a><a class="headerlink" href="#introspection" title="Permalink to this headline">¶</a></h2>
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.current_task">
asyncio.current_task(loop=None)<a class="headerlink" href="#asyncio.current_task" title="Permalink to this definition">¶</a></dt>
<dd>Return the currently running <a class="reference internal" href="#asyncio.Task" title="asyncio.Task"><code class="xref py py-class docutils literal notranslate">Task</code></a> instance, or <code class="docutils literal notranslate">None</code> if
no task is running.
If loop is <code class="docutils literal notranslate">None</code> <a class="reference internal" href="asyncio-eventloop.html#asyncio.get_running_loop" title="asyncio.get_running_loop"><code class="xref py py-func docutils literal notranslate">get_running_loop()</code></a> is used to get
the current loop.
<div class="versionadded">
New in version 3.7.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="asyncio.all_tasks">
asyncio.all_tasks(loop=None)<a class="headerlink" href="#asyncio.all_tasks" title="Permalink to this definition">¶</a></dt>
<dd>Return a set of not yet finished <a class="reference internal" href="#asyncio.Task" title="asyncio.Task"><code class="xref py py-class docutils literal notranslate">Task</code></a> objects run by
the loop.
If loop is <code class="docutils literal notranslate">None</code>, <a class="reference internal" href="asyncio-eventloop.html#asyncio.get_running_loop" title="asyncio.get_running_loop"><code class="xref py py-func docutils literal notranslate">get_running_loop()</code></a> is used for getting
current loop.
<div class="versionadded">
New in version 3.7.
</div>
</dd></dl>

</section>
<section id="task-object">
<h2><a class="toc-backref" href="#id13">Task Object</a><a class="headerlink" href="#task-object" title="Permalink to this headline">¶</a></h2>
<dl class="py class">
<dt class="sig sig-object py" id="asyncio.Task">
class asyncio.Task(coro, *, loop=None, name=None)<a class="headerlink" href="#asyncio.Task" title="Permalink to this definition">¶</a></dt>
<dd>A <a class="reference internal" href="asyncio-future.html#asyncio.Future" title="asyncio.Future"><code class="xref py py-class docutils literal notranslate">Future-like</code></a> object that runs a Python
<a class="reference internal" href="#coroutine">coroutine</a>. Not thread-safe.
Tasks are used to run coroutines in event loops.
If a coroutine awaits on a Future, the Task suspends
the execution of the coroutine and waits for the completion
of the Future. When the Future is done, the execution of
the wrapped coroutine resumes.
Event loops use cooperative scheduling: an event loop runs
one Task at a time. While a Task awaits for the completion of a
Future, the event loop runs other Tasks, callbacks, or performs
IO operations.
Use the high-level <a class="reference internal" href="#asyncio.create_task" title="asyncio.create_task"><code class="xref py py-func docutils literal notranslate">asyncio.create_task()</code></a> function to create
Tasks, or the low-level <a class="reference internal" href="asyncio-eventloop.html#asyncio.loop.create_task" title="asyncio.loop.create_task"><code class="xref py py-meth docutils literal notranslate">loop.create_task()</code></a> or
<a class="reference internal" href="asyncio-future.html#asyncio.ensure_future" title="asyncio.ensure_future"><code class="xref py py-func docutils literal notranslate">ensure_future()</code></a> functions. Manual instantiation of Tasks
is discouraged.
To cancel a running Task use the <a class="reference internal" href="#asyncio.Task.cancel" title="asyncio.Task.cancel"><code class="xref py py-meth docutils literal notranslate">cancel()</code></a> method. Calling it
will cause the Task to throw a <a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate">CancelledError</code></a> exception into
the wrapped coroutine. If a coroutine is awaiting on a Future
object during cancellation, the Future object will be cancelled.
<a class="reference internal" href="#asyncio.Task.cancelled" title="asyncio.Task.cancelled"><code class="xref py py-meth docutils literal notranslate">cancelled()</code></a> can be used to check if the Task was cancelled.
The method returns <code class="docutils literal notranslate">True</code> if the wrapped coroutine did not
suppress the <a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate">CancelledError</code></a> exception and was actually
cancelled.
<a class="reference internal" href="#asyncio.Task" title="asyncio.Task"><code class="xref py py-class docutils literal notranslate">asyncio.Task</code></a> inherits from <a class="reference internal" href="asyncio-future.html#asyncio.Future" title="asyncio.Future"><code class="xref py py-class docutils literal notranslate">Future</code></a> all of its
APIs except <a class="reference internal" href="asyncio-future.html#asyncio.Future.set_result" title="asyncio.Future.set_result"><code class="xref py py-meth docutils literal notranslate">Future.set_result()</code></a> and
<a class="reference internal" href="asyncio-future.html#asyncio.Future.set_exception" title="asyncio.Future.set_exception"><code class="xref py py-meth docutils literal notranslate">Future.set_exception()</code></a>.
Tasks support the <a class="reference internal" href="contextvars.html#module-contextvars" title="contextvars: Context Variables"><code class="xref py py-mod docutils literal notranslate">contextvars</code></a> module. When a Task
is created it copies the current context and later runs its
coroutine in the copied context.
<div class="versionchanged">
Changed in version 3.7: Added support for the <a class="reference internal" href="contextvars.html#module-contextvars" title="contextvars: Context Variables"><code class="xref py py-mod docutils literal notranslate">contextvars</code></a> module.
</div>
<div class="versionchanged">
Changed in version 3.8: Added the name parameter.
</div>
<div class="deprecated">
Deprecated since version 3.10: Deprecation warning is emitted if loop is not specified
and there is no running event loop.
</div>
<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.cancel">
cancel(msg=None)<a class="headerlink" href="#asyncio.Task.cancel" title="Permalink to this definition">¶</a></dt>
<dd>Request the Task to be cancelled.
This arranges for a <a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate">CancelledError</code></a> exception to be thrown
into the wrapped coroutine on the next cycle of the event loop.
The coroutine then has a chance to clean up or even deny the
request by suppressing the exception with a <a class="reference internal" href="../reference/compound_stmts.html#try"><code class="xref std std-keyword docutils literal notranslate">try</code></a> …
… <code class="docutils literal notranslate">except CancelledError</code> … <a class="reference internal" href="../reference/compound_stmts.html#finally"><code class="xref std std-keyword docutils literal notranslate">finally</code></a> block.
Therefore, unlike <a class="reference internal" href="asyncio-future.html#asyncio.Future.cancel" title="asyncio.Future.cancel"><code class="xref py py-meth docutils literal notranslate">Future.cancel()</code></a>, <a class="reference internal" href="#asyncio.Task.cancel" title="asyncio.Task.cancel"><code class="xref py py-meth docutils literal notranslate">Task.cancel()</code></a> does
not guarantee that the Task will be cancelled, although
suppressing cancellation completely is not common and is actively
discouraged.
<div class="versionchanged">
Changed in version 3.9: Added the msg parameter.
</div>
The following example illustrates how coroutines can intercept
the cancellation request:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>async def cancel_me():
 print(&#39;cancel_me(): before sleep&#39;)

try:
 # Wait for 1 hour
 await asyncio.sleep(3600)
 except asyncio.CancelledError:
 print(&#39;cancel_me(): cancel sleep&#39;)
 raise
 finally:
 print(&#39;cancel_me(): after sleep&#39;)

async def main():
 # Create a &quot;cancel_me&quot; Task
 task = asyncio.create_task(cancel_me())

# Wait for 1 second
 await asyncio.sleep(1)

task.cancel()
 try:
 await task
 except asyncio.CancelledError:
 print(&quot;main(): cancel_me is cancelled now&quot;)

asyncio.run(main())

# Expected output:
#
# cancel_me(): before sleep
# cancel_me(): cancel sleep
# cancel_me(): after sleep
# main(): cancel_me is cancelled now
</pre></div>
</div>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.cancelled">
cancelled()<a class="headerlink" href="#asyncio.Task.cancelled" title="Permalink to this definition">¶</a></dt>
<dd>Return <code class="docutils literal notranslate">True</code> if the Task is cancelled.
The Task is cancelled when the cancellation was requested with
<a class="reference internal" href="#asyncio.Task.cancel" title="asyncio.Task.cancel"><code class="xref py py-meth docutils literal notranslate">cancel()</code></a> and the wrapped coroutine propagated the
<a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate">CancelledError</code></a> exception thrown into it.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.done">
done()<a class="headerlink" href="#asyncio.Task.done" title="Permalink to this definition">¶</a></dt>
<dd>Return <code class="docutils literal notranslate">True</code> if the Task is done.
A Task is done when the wrapped coroutine either returned
a value, raised an exception, or the Task was cancelled.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.result">
result()<a class="headerlink" href="#asyncio.Task.result" title="Permalink to this definition">¶</a></dt>
<dd>Return the result of the Task.
If the Task is done, the result of the wrapped coroutine
is returned (or if the coroutine raised an exception, that
exception is re-raised.)
If the Task has been cancelled, this method raises
a <a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate">CancelledError</code></a> exception.
If the Task’s result isn’t yet available, this method raises
a <a class="reference internal" href="asyncio-exceptions.html#asyncio.InvalidStateError" title="asyncio.InvalidStateError"><code class="xref py py-exc docutils literal notranslate">InvalidStateError</code></a> exception.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.exception">
exception()<a class="headerlink" href="#asyncio.Task.exception" title="Permalink to this definition">¶</a></dt>
<dd>Return the exception of the Task.
If the wrapped coroutine raised an exception that exception
is returned. If the wrapped coroutine returned normally
this method returns <code class="docutils literal notranslate">None</code>.
If the Task has been cancelled, this method raises a
<a class="reference internal" href="asyncio-exceptions.html#asyncio.CancelledError" title="asyncio.CancelledError"><code class="xref py py-exc docutils literal notranslate">CancelledError</code></a> exception.
If the Task isn’t done yet, this method raises an
<a class="reference internal" href="asyncio-exceptions.html#asyncio.InvalidStateError" title="asyncio.InvalidStateError"><code class="xref py py-exc docutils literal notranslate">InvalidStateError</code></a> exception.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.add_done_callback">
add_done_callback(callback, *, context=None)<a class="headerlink" href="#asyncio.Task.add_done_callback" title="Permalink to this definition">¶</a></dt>
<dd>Add a callback to be run when the Task is done.
This method should only be used in low-level callback-based code.
See the documentation of <a class="reference internal" href="asyncio-future.html#asyncio.Future.add_done_callback" title="asyncio.Future.add_done_callback"><code class="xref py py-meth docutils literal notranslate">Future.add_done_callback()</code></a>
for more details.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.remove_done_callback">
remove_done_callback(callback)<a class="headerlink" href="#asyncio.Task.remove_done_callback" title="Permalink to this definition">¶</a></dt>
<dd>Remove callback from the callbacks list.
This method should only be used in low-level callback-based code.
See the documentation of <a class="reference internal" href="asyncio-future.html#asyncio.Future.remove_done_callback" title="asyncio.Future.remove_done_callback"><code class="xref py py-meth docutils literal notranslate">Future.remove_done_callback()</code></a>
for more details.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.get_stack">
get_stack(*, limit=None)<a class="headerlink" href="#asyncio.Task.get_stack" title="Permalink to this definition">¶</a></dt>
<dd>Return the list of stack frames for this Task.
If the wrapped coroutine is not done, this returns the stack
where it is suspended. If the coroutine has completed
successfully or was cancelled, this returns an empty list.
If the coroutine was terminated by an exception, this returns
the list of traceback frames.
The frames are always ordered from oldest to newest.
Only one stack frame is returned for a suspended coroutine.
The optional limit argument sets the maximum number of frames
to return; by default all available frames are returned.
The ordering of the returned list differs depending on whether
a stack or a traceback is returned: the newest frames of a
stack are returned, but the oldest frames of a traceback are
returned. (This matches the behavior of the traceback module.)
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.print_stack">
print_stack(*, limit=None, file=None)<a class="headerlink" href="#asyncio.Task.print_stack" title="Permalink to this definition">¶</a></dt>
<dd>Print the stack or traceback for this Task.
This produces output similar to that of the traceback module
for the frames retrieved by <a class="reference internal" href="#asyncio.Task.get_stack" title="asyncio.Task.get_stack"><code class="xref py py-meth docutils literal notranslate">get_stack()</code></a>.
The limit argument is passed to <a class="reference internal" href="#asyncio.Task.get_stack" title="asyncio.Task.get_stack"><code class="xref py py-meth docutils literal notranslate">get_stack()</code></a> directly.
The file argument is an I/O stream to which the output
is written; by default output is written to <a class="reference internal" href="sys.html#sys.stdout" title="sys.stdout"><code class="xref py py-data docutils literal notranslate">sys.stdout</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.get_coro">
get_coro()<a class="headerlink" href="#asyncio.Task.get_coro" title="Permalink to this definition">¶</a></dt>
<dd>Return the coroutine object wrapped by the <a class="reference internal" href="#asyncio.Task" title="asyncio.Task"><code class="xref py py-class docutils literal notranslate">Task</code></a>.
<div class="versionadded">
New in version 3.8.
</div>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.get_name">
get_name()<a class="headerlink" href="#asyncio.Task.get_name" title="Permalink to this definition">¶</a></dt>
<dd>Return the name of the Task.
If no name has been explicitly assigned to the Task, the default
asyncio Task implementation generates a default name during
instantiation.
<div class="versionadded">
New in version 3.8.
</div>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="asyncio.Task.set_name">
set_name(value)<a class="headerlink" href="#asyncio.Task.set_name" title="Permalink to this definition">¶</a></dt>
<dd>Set the name of the Task.
The value argument can be any object, which is then
converted to a string.
In the default Task implementation, the name will be visible
in the <a class="reference internal" href="functions.html#repr" title="repr"><code class="xref py py-func docutils literal notranslate">repr()</code></a> output of a task object.
<div class="versionadded">
New in version 3.8.
</div>
</dd></dl>

</dd></dl>

</section>
<section id="generator-based-coroutines">
<h2><a class="toc-backref" href="#id14">Generator-based Coroutines</a><a class="headerlink" href="#generator-based-coroutines" title="Permalink to this headline">¶</a></h2>
<div class="admonition note">
Note
Support for generator-based coroutines is deprecated and
is removed in Python 3.11.
</div>
Generator-based coroutines predate async/await syntax. They are
Python generators that use <code class="docutils literal notranslate">yield from</code> expressions to await
on Futures and other coroutines.
Generator-based coroutines should be decorated with
<a class="reference internal" href="#asyncio.coroutine" title="asyncio.coroutine"><code class="xref py py-func docutils literal notranslate">&#64;asyncio.coroutine</code></a>, although this is not
enforced.
<dl class="py function">
<dt class="sig sig-object py" id="asyncio.coroutine">
&#64;asyncio.coroutine<a class="headerlink" href="#asyncio.coroutine" title="Permalink to this definition">¶</a></dt>
<dd>Decorator to mark generator-based coroutines.
This decorator enables legacy generator-based coroutines to be
compatible with async/await code:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>@asyncio.coroutine
def old_style_coroutine():
 yield from asyncio.sleep(1)

async def main():
 await old_style_coroutine()
</pre></div>
</div>
This decorator should not be used for <a class="reference internal" href="../reference/compound_stmts.html#async-def"><code class="xref std std-keyword docutils literal notranslate">async def</code></a>
coroutines.
<div class="deprecated-removed">
Deprecated since version 3.8, will be removed in version 3.11: Use <a class="reference internal" href="../reference/compound_stmts.html#async-def"><code class="xref std std-keyword docutils literal notranslate">async def</code></a> instead.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="asyncio.iscoroutine">
asyncio.iscoroutine(obj)<a class="headerlink" href="#asyncio.iscoroutine" title="Permalink to this definition">¶</a></dt>
<dd>Return <code class="docutils literal notranslate">True</code> if obj is a <a class="reference internal" href="#coroutine">coroutine object</a>.
This method is different from <a class="reference internal" href="inspect.html#inspect.iscoroutine" title="inspect.iscoroutine"><code class="xref py py-func docutils literal notranslate">inspect.iscoroutine()</code></a> because
it returns <code class="docutils literal notranslate">True</code> for generator-based coroutines.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="asyncio.iscoroutinefunction">
asyncio.iscoroutinefunction(func)<a class="headerlink" href="#asyncio.iscoroutinefunction" title="Permalink to this definition">¶</a></dt>
<dd>Return <code class="docutils literal notranslate">True</code> if func is a <a class="reference internal" href="#coroutine">coroutine function</a>.
This method is different from <a class="reference internal" href="inspect.html#inspect.iscoroutinefunction" title="inspect.iscoroutinefunction"><code class="xref py py-func docutils literal notranslate">inspect.iscoroutinefunction()</code></a>
because it returns <code class="docutils literal notranslate">True</code> for generator-based coroutine functions
decorated with <a class="reference internal" href="#asyncio.coroutine" title="asyncio.coroutine"><code class="xref py py-func docutils literal notranslate">&#64;coroutine</code></a>.
</dd></dl>

</section>
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<li><a class="reference internal" href="#">Coroutines and Tasks</a><ul>
<li><a class="reference internal" href="#coroutines">Coroutines</a></li>
<li><a class="reference internal" href="#awaitables">Awaitables</a></li>
<li><a class="reference internal" href="#running-an-asyncio-program">Running an asyncio Program</a></li>
<li><a class="reference internal" href="#creating-tasks">Creating Tasks</a></li>
<li><a class="reference internal" href="#sleeping">Sleeping</a></li>
<li><a class="reference internal" href="#running-tasks-concurrently">Running Tasks Concurrently</a></li>
<li><a class="reference internal" href="#shielding-from-cancellation">Shielding From Cancellation</a></li>
<li><a class="reference internal" href="#timeouts">Timeouts</a></li>
<li><a class="reference internal" href="#waiting-primitives">Waiting Primitives</a></li>
<li><a class="reference internal" href="#running-in-threads">Running in Threads</a></li>
<li><a class="reference internal" href="#scheduling-from-other-threads">Scheduling From Other Threads</a></li>
<li><a class="reference internal" href="#introspection">Introspection</a></li>
<li><a class="reference internal" href="#task-object">Task Object</a></li>
<li><a class="reference internal" href="#generator-based-coroutines">Generator-based Coroutines</a></li>
</ul>
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