Feature request - Parameter property to bypass any extra processing of the value

SUMMARY

Sometimes it's required to pass data to an action as is, with no processing from st2 whatsoever. Currently, Stackstorm seems to be passes data thru jinja2 renderer, causing (and sometimes even breaking) undesirable transformation of the values.

For example, if a string contains {{.XYZ}} combination of characters, it's just impossible to pass such string to an action without prior modification. Sometimes it's not doable as data can be large and complex, produced by other actions. It is also applicable to data passed as object, e.g. {"data": "{{.XYZ}}"}

$ st2 run core.local cmd="echo {{.blah}}"
ERROR: 500 Server Error: Internal Server Error
MESSAGE: unexpected '.' for url: https://l...

So, this is a request to add another property to parameters (we already have properties like secret, required, etc), which would disable any extra processing from the stackstorm side and just take the value as is.

ISSUE TYPE

• Feature Idea

STACKSTORM VERSION

Paste the output of st2 --version:

st2 2.10.3, on Python 2.7.10

OS / ENVIRONMENT / INSTALL METHOD

CentOS 6. Custom install from one-liner :)

STEPS TO REPRODUCE

$ st2 run core.local cmd="echo \"{{.blah}}\""
ERROR: 500 Server Error: Internal Server Error
MESSAGE: unexpected '.' for url: https://l...

EXPECTED RESULTS

If cmd parameter had the proposed property set to true, we'd see:

$ st2 run core.local cmd="echo \"{{.blah}}\""
.
id: 5c88789e7afb5b004209d064
status: succeeded
parameters: 
  cmd: echo "{{.blah}}"
result: 
  failed: false
  return_code: 0
  stderr: ''
  stdout: '{{.blah}}'
  succeeded: true

ACTUAL RESULTS

$ st2 run core.local cmd="echo \"{{.blah}}\""
ERROR: 500 Server Error: Internal Server Error
MESSAGE: unexpected '.' for url: https://l...

Start with the provided st2 run core.local reproduction using a value containing {{.blah}}, and compare the current error with the expected unchanged parameter and successful action result. Trace where action parameters are processed to determine the scope of a property that bypasses processing; done means the value is passed through unchanged without breaking existing parameter behavior.