From 240f5912340bc9bfacef46cb252d6af8619e937e Mon Sep 17 00:00:00 2001
From: Tyler Goodlet <jgbt@protonmail.com>
Date: Sat, 31 Jul 2021 12:10:25 -0400
Subject: [PATCH] Add 2-way streaming example to readme and scripts

---
 docs/README.rst                 | 95 ++++++++++++++++++++++++++++++++-
 examples/rpc_bidir_streaming.py | 72 +++++++++++++++++++++++++
 tests/test_docs_examples.py     |  8 ++-
 3 files changed, 172 insertions(+), 3 deletions(-)
 create mode 100644 examples/rpc_bidir_streaming.py

diff --git a/docs/README.rst b/docs/README.rst
index bd7b6af..18afd26 100644
--- a/docs/README.rst
+++ b/docs/README.rst
@@ -127,7 +127,8 @@ Zombie safe: self-destruct a process tree
             print('This process tree will self-destruct in 1 sec...')
             await trio.sleep(1)
 
-            # you could have done this yourself
+            # raise an error in root actor/process and trigger
+            # reaping of all minions
             raise Exception('Self Destructed')
 
 
@@ -197,6 +198,98 @@ And, yes, there's a built-in crash handling mode B)
 We're hoping to add a respawn-from-repl system soon!
 
 
+SC compatible bi-directional streaming
+--------------------------------------
+Yes, you saw it here first; we provide 2-way streams
+with reliable, transitive setup/teardown semantics.
+
+Our nascent api is remniscent of ``trio.Nursery.start()``
+style invocation:
+
+.. code:: python
+
+    import trio
+    import tractor
+
+
+    @tractor.context
+    async def simple_rpc(
+
+        ctx: tractor.Context,
+        data: int,
+
+    ) -> None:
+        '''Test a small ping-pong 2-way streaming server.
+
+        '''
+        # signal to parent that we're up much like
+        # ``trio_typing.TaskStatus.started()``
+        await ctx.started(data + 1)
+
+        async with ctx.open_stream() as stream:
+
+            count = 0
+            async for msg in stream:
+
+                assert msg == 'ping'
+                await stream.send('pong')
+                count += 1
+
+            else:
+                assert count == 10
+
+
+    async def main() -> None:
+
+        async with tractor.open_nursery() as n:
+
+            portal = await n.start_actor(
+                'rpc_server',
+                enable_modules=[__name__],
+            )
+
+            # XXX: this syntax requires py3.9
+            async with (
+
+                portal.open_context(
+                    simple_rpc,
+                    data=10,
+                ) as (ctx, sent),
+
+                ctx.open_stream() as stream,
+            ):
+
+                assert sent == 11
+
+                count = 0
+                # receive msgs using async for style
+                await stream.send('ping')
+
+                async for msg in stream:
+                    assert msg == 'pong'
+                    await stream.send('ping')
+                    count += 1
+
+                    if count >= 9:
+                        break
+
+
+            # explicitly teardown the daemon-actor
+            await portal.cancel_actor()
+
+
+    if __name__ == '__main__':
+        trio.run(main)
+
+
+See original proposal and discussion in `#53`_ as well
+as follow up improvements in `#223`_ that we'd love to
+hear your thoughts on!
+
+.. _#53: https://github.com/goodboy/tractor/issues/53
+.. _#223: https://github.com/goodboy/tractor/issues/223
+
+
 Worker poolz are easy peasy
 ---------------------------
 The initial ask from most new users is *"how do I make a worker
diff --git a/examples/rpc_bidir_streaming.py b/examples/rpc_bidir_streaming.py
new file mode 100644
index 0000000..7320081
--- /dev/null
+++ b/examples/rpc_bidir_streaming.py
@@ -0,0 +1,72 @@
+import trio
+import tractor
+
+
+@tractor.context
+async def simple_rpc(
+
+    ctx: tractor.Context,
+    data: int,
+
+) -> None:
+    '''Test a small ping-pong 2-way streaming server.
+
+    '''
+    # signal to parent that we're up much like
+    # ``trio_typing.TaskStatus.started()``
+    await ctx.started(data + 1)
+
+    async with ctx.open_stream() as stream:
+
+        count = 0
+        async for msg in stream:
+
+            assert msg == 'ping'
+            await stream.send('pong')
+            count += 1
+
+        else:
+            assert count == 10
+
+
+async def main() -> None:
+
+    async with tractor.open_nursery() as n:
+
+        portal = await n.start_actor(
+            'rpc_server',
+            enable_modules=[__name__],
+        )
+
+        # XXX: syntax requires py3.9
+        async with (
+
+            portal.open_context(
+                simple_rpc,  # taken from pytest parameterization
+                data=10,
+
+            ) as (ctx, sent),
+
+            ctx.open_stream() as stream,
+        ):
+
+            assert sent == 11
+
+            count = 0
+            # receive msgs using async for style
+            await stream.send('ping')
+
+            async for msg in stream:
+                assert msg == 'pong'
+                await stream.send('ping')
+                count += 1
+
+                if count >= 9:
+                    break
+
+        # explicitly teardown the daemon-actor
+        await portal.cancel_actor()
+
+
+if __name__ == '__main__':
+    trio.run(main)
diff --git a/tests/test_docs_examples.py b/tests/test_docs_examples.py
index 632d85c..5f47419 100644
--- a/tests/test_docs_examples.py
+++ b/tests/test_docs_examples.py
@@ -84,8 +84,8 @@ def run_example_in_subproc(loglevel, testdir, arb_addr):
 
         if '__' not in f
         and f[0] != '_'
-        and 'debugging' not in p[0]
-    ],
+        and 'debugging' not in p[0]],
+
     ids=lambda t: t[1],
 )
 def test_example(run_example_in_subproc, example_script):
@@ -98,6 +98,10 @@ def test_example(run_example_in_subproc, example_script):
     test_example``.
     """
     ex_file = os.path.join(*example_script)
+
+    if 'rpc_bidir_streaming' in ex_file and sys.version_info < (3, 9):
+        pytest.skip("2-way streaming example requires py3.9 async with syntax")
+
     with open(ex_file, 'r') as ex:
         code = ex.read()