Error stream parsing

[chris-rock]

Awesome project! We are using it heavily in InSpec and I would like to implement the following for Windows and InSpec:

# test stderr
describe powershell("Write-Error \"error\"") do
  its('stdout') { should eq '' }
  # this is an xml error for now, if the script is run via WinRM
  # @see https://github.com/WinRb/WinRM/issues/106
  # its('stderr') { should eq 'error' }
end

Since the error message is not parsed, I get the following error:

 Powershell stdout
     ✔  should eq ""
     ✖  should eq "error"\n
     expected: "error"
          got: "Write-Error \"error\" : error\n    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException\n    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException\n"

     (compared using ==)

     Diff:
     @@ -1,2 +1,4 @@
     -error
     +Write-Error "error" : error
     +    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
     +    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException

Do you have any good idea, how we can improve that?

[mwrock]

There was alot of work in winrm v2 to make powershell stderr MUCH better. For example, on v2 the above stderr would now be:

irb(main):009:0> puts shell.run("write-error 'error'").stderr
write-error 'error' : error
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException
=> nil
irb(main):010:0>

So no more crazy XML output.

[mwrock]

We tried to make stderr the same as what you would see in straight up powershell. We may have missed some edge cases so please file issues if you see unexpected results.

Definitely try out inspec/train#122 against inspec and see if that produces the desired output for the above spec.

[chris-rock]

I currently run the InSpec integration tests inspec/inspec#1018 with inspec/train#122

[mwrock]

Oh I should have included this too:

irb(main):010:0> puts shell.run("write-error 'error'").stdout

=> nil

So stdout is now empty.

[chris-rock]

@mwrock stdout is no issue. I was only discussing about stderr

[mwrock]

oh ok. Are these specs in inpec? I can take a look.

[chris-rock]

Those are included in https://github.com/chef/inspec/blob/master/test/integration/default/powershell_spec.rb#L38-L41. To test it, you would need the inspec/inspec#1018

[mwrock]

cool. will have a look now

[mwrock]

I should have read the spec above more closely. So it sounds like what you are looking for is to have stderr equal the message spit out from write-error. Currently, the WinRM::Output returned from run will return stderr matching what powershell would return. To get just error, you'd really need to do something like:

write-error 'error'
$err = $Error[0]
write-output $err.Exception.message

Then you'd see err from stdout

[chris-rock]

@mwrock Alright. Got you. I'll update the integration tests to expect the full error string.

[mwrock]

The :powershell shell does expose a send_pipeline_command which is so far undocumented. It returns an array of low level PSRP response messages that could be parsed for the specific error message.

[mwrock]

I think you could find the message that hase a type of WinRM::PSRP::Message::MESSAGE_TYPES[:error_record] and then look at message.parsed_data.exception[:message]