[chef] Re: Re: Powershell LWRP, returns attribute, and idempotency

["Moser, Kevin" < >]

This is a quirk about how the powershell provider wraps the powershell 
commands in a temporary ps1 file and then calls that ps1 file via the execute 
resource.  What mixlib-shellout ends up getting back from that is essentially 
the $? powershell variable which is true or false and not the exit code.  You 
can see that this is happening in this line:

C:\Windows\sysnative\WindowsPowershell\v1.0\powershell.exe
-NoLogo -NonInteractive -NoProfile -ExecutionPolicy RemoteSigned -InputFormat 
No
ne -Command 
"C:\Users\bryans\AppData\Local\Temp\2\chef-script20130515-3228-kvs9u
h.ps1"

If you were to run that in cmd.exe and looked at %errorlevel% you would see 
you get returned 1 because the script quit with a non-zero return code.

However if you were to do:

C:\Windows\sysnative\WindowsPowershell\v1.0\powershell.exe
-NoLogo -NonInteractive -NoProfile -ExecutionPolicy RemoteSigned -InputFormat 
No
ne -Command "exit 42"

You would see that %errorlevel% is 42 or the actual exit code.

If you are trying to key off of the return code in your LWRP to drive 
behavior of your LWRP (last updated, do something else, etc) then I would 
also recommend, as Daniel points out, to use the powershell_out mixin that 
came in v 1.0.8 of the powershell cookbook.  This puts you in the context of 
the powershell shell itself and therefore would let you get the exit status 
from your process.

The code would look something like this…

Note: Put a depends "powershell" in your metadata, assuming you already have 
this since you are using the provider

include Chef::Mixin::PowershellOut
cmd = powershell_out("exit 42")
if cmd.exitstatus == 42
  # Do something interesting
end

Multi-line example

include Chef::Mixin::PowershellOut
script =<<-EOH
Write-Host "Nothing Interesting"
Exit 42
EOH
cmd = powershell_out(script)
if cmd.exitstatus == 42
  # Do something interesting
end

You can also get to cmd.stderr and cmd.stdout just like you can in shell_out. 
 You also can pass any of the options hash just like you can in shell_out, 
simply add a that hash of options as the second parameter to the 
powershell_out method call.  The allowed options are the same as in shell_out 
as they are just passed along down the pipe to it.

Thanks

Kevin

From: Daniel DeLeo 
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Date: Wednesday, May 15, 2013 10:06 AM
To: 
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Subject: [chef] Re: Powershell LWRP, returns attribute, and idempotency



On Wednesday, May 15, 2013 at 9:13 AM, Bryan Stenson wrote:

Ohai!

I'm trying to catch exit codes from my powershell code block to determine 
whether my provider has affected change (to correctly set 
updated_by_last_action).

I think I should be able to do this using the "returns" attribute of the 
Powershell LWRP, but I'm having trouble getting it to work (and I haven't 
found many good examples).  I can see the "returns" attribute should be 
either an Array or Integer of acceptable exit codes, and I've set it to my 
expected values.

However, no matter what my code block returns, Chef gets an exit code of "1" 
for all non-zero return codes from Mixlib::ShellOut::ShellCommandFailed.

Here's my sample recipe, and chef-client run error: 
https://gist.github.com/stensonb/5585093

Even if I successfully get a non-one error code response, how do I access 
this return code?

I'm hoping I'm just using it wrong.  Anybody have an example?

Bryan

Chef's design makes it difficult to get data about what happens in a provider 
back out to a resource, so your LWRP is better off using the powershell 
library code directly.

https://github.com/opscode-cookbooks/powershell/blob/master/libraries/powershell_out.rb

I don't have any experience using it so I can't say what the issue with exit 
codes might be.

--
Daniel DeLeo