LineInFile: New resource proposal

[wildmichael]

Description

Many file formats do not match the pre-made assumptions of this module. E.g. the KeyValuePairFile resource almost matches my current requirement, however in my case the key and value should be separated by a colon, not an equal sign. This resource would be more general as it would allow the user to specify the line contents (Text) and a regex to determine whether the line is already present. The proposal is modeled after the lineinfile module in Ansible, however in a simplified form. More options (like InsertBefore, InsertAfter, FirstMatch, Backrefs, Backup, etc) could be added if deemed necessary.

Proposed properties

• Path: The file to modify.
• Create: Whether the file should be created if not present (if Ensure = 'Present').
• Text: The line to insert (if Ensure = 'Present')
• Regex: The regular expression to find the line to modify. If Ensure = 'Present' the regular expression should match the state before and after modification to ensure idempotence. If Ensure = 'Absent' it will be used to determine whether the line needs to be removed. Only the last found instance will be modified.

Special considerations or limitations

None that I could see.

[johlju]

What would be the key(s) in this resource?

Maybe we should add a property for the InsertType where it in a first iteration can only have single InsertAfter value? But rather they are all considered so we can find potential limitations.

Also, maybe we could add a optional property Line which could be an array of numbers, to just say that it should insert the text at a specific line(s)?

[wildmichael]

Line numbers are a fickle thing. I would rather make InsertAfter and InsertBefore regular expressions, that should cover most cases. What do you mean by keys (sorry if this is a stupid question, I'm quite new to DSC)?

[johlju]

I meant that both line numbers and regular expression could be used (mutually exclusively).

There are no such question, all questions are welcome! :)
If you look at this schema.mof (link below), there are two properties that has the type qualifier Key. There can only be one instance of a configuration with the same key’s that uniquely separates it from another configuration, so that two configuration instances can’t change the same thing.
I hope I explained it well enough 😄

https://github.com/PlagueHO/FileContentDsc/blob/dev/DSCResources/DSR_KeyValuePairFile/DSR_KeyValuePairFile.schema.mof