Instance UserData string configuration option

[smathews]

Is your feature request related to a problem? Please describe.

Currently the only option for userdata is vsi_user_data_file, which requires a file path containing userdata. This forces the use of a static userdata script.

Describe the solution you'd like

Add a new configuration variable vsi_user_data for string userdata input, allowing dynamic userdata when using the packer function templatefile.

Describe alternatives you've considered

Running an initialization script before running packer to generate the userdata:

• Not generic enough
• Would not have access to packer variables

Create a custom data source:

• Fair amount of custom code and implementation to avoid an option that should be part of the base plugin
• Default behavior of the API is being overridden by the file path "helper" configuration variable `

Additional context

See use of templatefile

[BShrivastav]

Thanks, We will soon be supporting this feature request, wip.