1 files changed, 85 insertions, 0 deletions
diff --git a/examples/subprocess_shell.py b/examples/subprocess_shell.py
new file mode 100644
index 0000000..d0e5d65
--- /dev/null
+++ b/examples/subprocess_shell.py
@@ -0,0 +1,85 @@
+"""Example writing to and reading from a subprocess at the same time using
+tasks."""
+
+import asyncio
+import os
+from asyncio.subprocess import PIPE
+
+
+@asyncio.coroutine
+def send_input(writer, input):
+    try:
+        for line in input:
+            print('sending', len(line), 'bytes')
+            writer.write(line)
+            d = writer.drain()
+            if d:
+                print('pause writing')
+                yield from d
+                print('resume writing')
+        writer.close()
+    except BrokenPipeError:
+        print('stdin: broken pipe error')
+    except ConnectionResetError:
+        print('stdin: connection reset error')
+
+@asyncio.coroutine
+def log_errors(reader):
+    while True:
+        line = yield from reader.readline()
+        if not line:
+            break
+        print('ERROR', repr(line))
+
+@asyncio.coroutine
+def read_stdout(stdout):
+    while True:
+        line = yield from stdout.readline()
+        print('received', repr(line))
+        if not line:
+            break
+
+@asyncio.coroutine
+def start(cmd, input=None, **kwds):
+    kwds['stdout'] = PIPE
+    kwds['stderr'] = PIPE
+    if input is None and 'stdin' not in kwds:
+        kwds['stdin'] = None
+    else:
+        kwds['stdin'] = PIPE
+    proc = yield from asyncio.create_subprocess_shell(cmd, **kwds)
+
+    tasks = []
+    if input is not None:
+        tasks.append(send_input(proc.stdin, input))
+    else:
+        print('No stdin')
+    if proc.stderr is not None:
+        tasks.append(log_errors(proc.stderr))
+    else:
+        print('No stderr')
+    if proc.stdout is not None:
+        tasks.append(read_stdout(proc.stdout))
+    else:
+        print('No stdout')
+
+    if tasks:
+        # feed stdin while consuming stdout to avoid hang
+        # when stdin pipe is full
+        yield from asyncio.wait(tasks)
+
+    exitcode = yield from proc.wait()
+    print("exit code: %s" % exitcode)
+
+
+def main():
+    if os.name == 'nt':
+        loop = asyncio.ProactorEventLoop()
+        asyncio.set_event_loop(loop)
+    else:
+        loop = asyncio.get_event_loop()
+    loop.run_until_complete(start('sleep 2; wc', input=[b'foo bar baz\n'*300 for i in range(100)]))
+
+
+if __name__ == '__main__':
+    main()