Add Viewer mode

[robintw]

🧰 Issue

#610

🚀 Overview:

Adds a new Pepys Viewer app, which only provides access to the View Data commands within Pepys Admin. This can be called from the command-line using --viewer, or from two new Start Menu shortcuts: Pepys Viewer and Pepys Viewer (training mode).

🤔 Reason:

For some users, we wish to let them use Pepys-Admin to view data, but not to have access (or require training in) the rest of the Admin operations.

🔨Work carried out:

• Added --viewer shortcut, and made it load just the viewing interface
• Added Windows Start Menu shortcuts
• Tests pass

🖥️ Screenshot

Confirmations

• I have chosen reviewers for my PR.
• I have chosen an appropriate label for the PR.
• I have completed the mandatory sections of this document.
• I have deleted any unused sections.

📝 Developer Notes:

This depends on #624, and that should be merged first. I have already merged in the branch for #624 into this branch, as they were both modifying lots of the same files and I needed to sort out all the conflicts. Hopefully Github will do the sensible thing and only show the new commits here, once #624 is merged.

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Codecov Report

Merging #642 (c809a63) into develop (1d48e6f) will decrease coverage by 0.03%.
The diff coverage is 87.50%.

@@             Coverage Diff             @@
##           develop     #642      +/-   ##
===========================================
- Coverage    99.10%   99.07%   -0.04%     
===========================================
  Files           64       64              
  Lines         6054     6071      +17     
===========================================
+ Hits          6000     6015      +15     
- Misses          54       56       +2     

Impacted Files	Coverage Δ
pepys_admin/view_data_cli.py	94.65% <70.00%> (-2.15%)	⬇️
pepys_admin/cli.py	92.68% <100.00%> (+6.01%)	⬆️

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[IanMayo]

Thanks @robintw - could you have a think about what changes should be made to read the docs please?

I'm pretty sure we should include the new command line parameters, but there may be a need for some higher level content - such as introducing the concept of the viewer.

[IanMayo]

@robintw - it looks like there is an issue with Create Deployment. Maybe prompt_toolkit has moved.

[robintw]

This create_deployment issue seemed to be an issue with installing black using the latest version of pip. Pip have released a new version (20.3) today, which switches to a new package resolver which is a lot more strict than the previous version. Pip was checking the metadata for the black package it had downloaded and raised an error as some of the metadata versions didn't match. This only seems to occur on the embedded version of Python we use in the Windows deployment, not on a normal Windows Python.

This has been temporarily solved by pinning black to an older version in requirements_dev.txt. This older version (only two versions ago) has a Python wheel available on PyPI which means pip can just download that and use it, without needing to build it itself - skipping the part that causes problems.

I've raised an issue on the black Github repo at psf/black#1847. I have a suspicion they're going to tell me it's pip's problem, so I might end up raising an issue for pip too. I'll keep an eye on it all and let you know what happens.

As part of investigating this, I've noticed that failures in running the actual create_deployment.bat script aren't being picked up properly by Github Actions as a failure - I think the return codes from the various scripts aren't propagating properly. I'll add a separate issue to fix that.

[robintw]

Argh, ignore that - pinning to an older black version means black wants to reformat all of our files! I'll work on this more tomorrow.

[IanMayo]

I ❤️ the viewer logo.