Implement upload/download for connections

[thheinen]

Adds default upload/download methods to transfer files. Also adds a content= method for remote file manipulation.

Description

While the SSH and the WinRM transport plugin already implemented the upload/download methods, those were not part of the general plugin API.

Offering these two methods and general file manipulation capabilities greatly extends any tool built on Train (e.g. Chef Target Mode).

On base_connection, the upload method iterates using the new content= method which uses base64 en-/decoding on Unix/Windows platforms. The local transport got simple local file manipulations for this, the cisco_ios_connectionwill throw an error. Can't test QNX/AIX, sorry.

I actually prepared both a Test Kitchen "train" transport and a remote shell utility based on this and it's working fine with my Linux/Windows systems. So I suppose the same goes for any other transport (AWS Systems Manager, VMware GOM etc).

Related Issue

none

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New content (non-breaking change)
• Breaking change (a content change which would break existing functionality or processes)

Checklist:

• I have read the CONTRIBUTING document.

[chef-expeditor]

Hello tecracer-theinen! Thanks for the pull request!

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Thank you for contributing!

[thheinen]

Definitively need help with the content= test in lib/train/transports/mock.rb - I don't understand that one 😅

[clintoncwolfe]

I found that if you rename the method to be set_content, you can avoid the name issue, but then you encounter arity issues in that all of the other data fields are expected to be called with no arguments. If the new method is omitted from the DATA_FIELDS list - it is not really a data field, it is a setter - and instead treated as an abstract method, the tests pass.

[thheinen]

That was an easy fix. Thank you!