Stdin write (#257)

* Added handling EAGAIN on stdin streams for run_command host output
* Updated changelog
* Updated docs

Author: pkittenis

Changelog.rst

@@ -10,7 +10,8 @@ Changes
 * Added interactive shell support to single and parallel clients - see `documentation <https://parallel-ssh.readthedocs.io/en/latest/advanced.html#interactive-shells>`_.
 * Added ``pssh.utils.enable_debug_logger`` function.
 * ``ParallelSSHClient`` timeout parameter is now also applied to *starting* remote commands via ``run_command``.
-* Assigning to ``ParallelSSHClient.hosts`` cleans up clients of hosts no longer in host list - #220
+* ``HostOutput.stdin`` now handles EAGAIN automatically when writing - #165.
+* Assigning to ``ParallelSSHClient.hosts`` cleans up clients of hosts no longer in host list - #220.
 
 Fixes
 -----

pssh/clients/base/single.py

@@ -43,6 +43,38 @@
 logger = logging.getLogger(__name__)
 
 
+class Stdin(object):
+    """Stdin stream for a channel.
+
+    Handles EAGAIN.
+
+    Provides ``write`` and ``flush`` only.
+    """
+    __slots__ = ('_channel', '_client')
+
+    def __init__(self, channel, client):
+        """
+        :param channel: The channel the stdin stream is from.
+        :type channel: IO object
+        :param client: The SSH client the channel is from.
+        :type client: ``BaseSSHClient``
+        """
+        self._channel = channel
+        self._client = client
+
+    def write(self, data):
+        """Write to stdin.
+
+        :param data: Data to write.
+        :type data: str
+        """
+        return self._client._eagain(self._channel.write, data)
+
+    def flush(self):
+        """Flush pending data written to stdin."""
+        return self._client._eagain(self._channel.flush)
+
+
 class InteractiveShell(object):
     """
     Run commands on an interactive shell.
@@ -304,9 +336,8 @@ def _make_host_output(self, channel, encoding, read_timeout):
         _buffers = HostOutputBuffers(
             stdout=BufferData(rw_buffer=_stdout_buffer, reader=_stdout_reader),
             stderr=BufferData(rw_buffer=_stderr_buffer, reader=_stderr_reader))
-        stdin = channel
         host_out = HostOutput(
-            host=self.host, channel=channel, stdin=stdin,
+            host=self.host, channel=channel, stdin=Stdin(channel, self),
             client=self, encoding=encoding, read_timeout=read_timeout,
             buffers=_buffers,
         )

tests/native/test_single_client.py

@@ -94,6 +94,14 @@ def test_stderr(self):
         self.assertListEqual(expected, stderr)
         self.assertTrue(len(output) == 0)
 
+    def test_stdin(self):
+        host_out = self.client.run_command('read line; echo $line')
+        host_out.stdin.write('a line\n')
+        host_out.stdin.flush()
+        self.client.wait_finished(host_out)
+        stdout = list(host_out.stdout)
+        self.assertListEqual(stdout, ['a line'])
+
     def test_long_running_cmd(self):
         host_out = self.client.run_command('sleep 2; exit 2')
         self.assertRaises(ValueError, self.client.wait_finished, host_out.channel)