Pipelining is a *significant* performance benefit, because each task can
be completed with a single SSH connection (vs. one ssh connection at the
start to mkdir, plus one sftp and one ssh per task).
Pipelining is disabled by default in Ansible because it conflicts with
the use of sudo if 'Defaults requiretty' is set in /etc/sudoers (as it
is on Red Hat) and su (which always requires a tty).
We can (and already do) make sudo/su happy by using "ssh -t" to allocate
a tty, but then the python interpreter goes into interactive mode and is
unhappy with module source being written to its stdin, per the following
comment from connections/ssh.py:
# we can only use tty when we are not pipelining the modules.
# piping data into /usr/bin/python inside a tty automatically
# invokes the python interactive-mode but the modules are not
# compatible with the interactive-mode ("unexpected indent"
# mainly because of empty lines)
Instead of the (current) drastic solution of turning off pipelining when
we use a tty, we can instead use a tty but suppress the behaviour of the
Python interpreter to switch to interactive mode. The easiest way to do
this is to make its stdin *not* be a tty, e.g. with cat|python.
This works, but there's a problem: ssh will ignore -t if its input isn't
really a tty. So we could open a pseudo-tty and use that as ssh's stdin,
but if we then write Python source into it, it's all echoed back to us
(because we're a tty). So we have to use -tt to force tty allocation; in
that case, however, ssh puts the tty into "raw" mode (~ICANON), so there
is no good way for the process on the other end to detect EOF on stdin.
So if we do:
echo -e "print('hello world')\n"|ssh -tt someho.st "cat|python"
…it hangs forever, because cat keeps on reading input even after we've
closed our pipe into ssh's stdin. We can get around this by writing a
special __EOF__ marker after writing in_data, and doing this:
echo -e "print('hello world')\n__EOF__\n"|ssh -tt someho.st "sed -ne '/__EOF__/q' -e p|python"
This works fine, but in fact I use a clever python one-liner by mgedmin
to achieve the same effect without depending on sed (at the expense of a
much longer command line, alas; Python really isn't one-liner-friendly).
We also enable pipelining by default as a consequence.
* Add exception handling when running PowerShell modules to provide exception message and stack trace.
* Enable strict mode for all PowerShell modules and internal commands.
* Update common PowerShell code to fix strict mode errors.
* Fix an issue with Set-Attr where it would not replace an existing property if already set.
* Add tests for exception handling using modified win_ping modules.
* Add exception handling when running PowerShell modules to provide exception message and stack trace.
* Enable strict mode for all PowerShell modules and internal commands.
* Update common PowerShell code to fix strict mode errors.
* Fix an issue with Set-Attr where it would not replace an existing property if already set.
* Add tests for exception handling using modified win_ping modules.
- Add support for inserting module args into PowerShell modules. Fixes#11661.
- Support Windows paths containing spaces. Applies changes from #10727 to v2. Fixes#9999. Should also fixansible/ansible-modules-core#944 and ansible/ansible-modules-core#1007.
- Change how execution policy is set for running remote scripts. Applies changes from #11092 to v2. Also fixesansible/ansible-modules-core#1776.
- Use codepage 65001 (UTF-8) for WinRM connection instead of default (CP437), convert command to UTF-8 and results from UTF-8. Replaces changes from #10024. Fixes#11198.
- Close WinRM connection when task completes.
- Use win_stat, win_file and win_copy modules instead of stat, file and copy when called from within other action plugins (only when using WinRM+PowerShell).
- Unquote Windows path arguments before passing to win_stat, win_file, win_copy and slurp modules (only when using WinRM/PowerShell).
- Check for win_ping module to determine if core modules are missing (only when using WinRM/PowerShell).
- Add stdout_lines to result from running low level commands (so stdout_lines is available when using raw/script).
- Update copy action plugin to use shell functions for joining paths and checking for trailing slash.
- Update fetch action plugin to unquote source path when using Windows paths.
- Add win_copy and win_template action plugins that inherit from copy and template.
- Support running .bat and .cmd scripts using default system encoding instead of UTF-8.
- Always send PowerShell commands as base64-encoded blobs to allow for running simple PowerShell commands via raw.
- Support running modules on Windows with interpreters other than PowerShell.
- Update integration tests to support above changes and test unicode fixes.
- Add test for win_user error from ansible/ansible-modules-core#1241 (fixed by ansible/ansible-modules-core#1774).
- Add test for additional win_stat output values (implemented by ansible/ansible-modules-core#1473).
- Add test for OS architecture and name from setup.ps1 (implemented by ansible/ansible-modules-core#1100).
All WinRM integration tests pass for me with these changes.
Abhijit Menon-Sen
Toshio Kuratomi
James Cammarata
Chris Church