(#2854) Add helper to read config values

[TheCakeIsNaOH]

Description Of Changes

This adds a PowerShell helper to get config values from the Chocolatey configuration file. This helper is intended to be used to allow hook scripts to access configuration values set in the config.

Motivation and Context

See #2854 and chocolatey-community/chocolatey-hooks#6 (comment)

Testing

1. Create a package called getconfig with a chocolateyInstall.ps1 with these contents:

$ErrorActionPreference = 'Stop'

$val1 = Get-ChocolateyConfigValue -configKey "addedTextValue"
Write-Host "Should have 'validAddedValue' output: '$val1'"

$val2 = Get-ChocolateyConfigValue -configKey "addedNumberValue"
Write-Host "Should have '123456' output: '$val2'"

$val3 = Get-ChocolateyConfigValue -configKey "commandExecutionTimeoutSeconds"
Write-Host "Should have '2700' output: '$val3'"

$val4 = Get-ChocolateyConfigValue -configKey "cacheLocation"
Write-Host "Should have empty output:  '$val4'"

$val5 = Get-ChocolateyConfigValue -configKey "nonExistentKey"
Write-Host "Should have empty output:  '$val5'"

2. Run .\choco.exe config set --name="addedTextValue" --value="validAddedValue"
3. Run .\choco.exe config set --name="addedNumberValue" --value="123456"
4. Run `.\choco.exe install getconfig --source=".\getconfig" --yes
5. Validate that the Write-Host calls output the correct values.

Operating Systems Testing

• Windows 10 22H2

Change Types Made

• Bug fix (non-breaking change).
• Feature / Enhancement (non-breaking change).
• Breaking change (fix or feature that could cause existing functionality to change).
• Documentation changes.
• PowerShell code changes.

Change Checklist

• Requires a change to the documentation.
• Documentation has been updated.
• Tests to cover my changes, have been added.
• All new and existing tests passed?
• PowerShell code changes: PowerShell v2 compatibility checked?

Related Issue

Fixes #2854

[corbob]

A couple of suggestions. As well, we would do well to either add some Pester tests that exercises these, or open an issue to track adding pester tests.

Some tests that I see above and beyond the testing listed in the PR description would be to change the config values, and ensure that the changed values are read. As well as adding non-standard values and ensure that they too can be read. (Edit: The first sentence was written before I had looked again at the testing instructions. That was already covered there.)

[TheCakeIsNaOH]

As well, we would do well to either add some Pester tests that exercises these, or open an issue to track adding pester tests.

Agreed. I don't really have a good setup to iterate on the Pester tests, so a separate issue, or waiting until the behavior is nailed down is the way to go.

[pauby]

we would do well to either add some Pester tests that exercises these, or open an issue to track adding pester tests.

Let's get some tests added as part of this PR before we merge it. If we're adding code line this, we need to be adding tests too.

[corbob]

Let's get some tests added as part of this PR before we merge it. If we're adding code line this, we need to be adding tests too.

@TheCakeIsNaOH as you're not in a position to test the pester tests here, I'll get these tests added to the PR.

[gep13]

LGTM!

[gep13]

@corbob thanks for getting this over the line, and thanks to @TheCakeIsNaOH for the initial implementation!

[TheCakeIsNaOH]

Thanks @corbob for creating the tests.