Allow disabling shared configuration check from hosting bundle.

[jkotalik]

Issue: #4451

Description

When installing the 2.2 Windows Hosting Bundle, today, we block the use of shared applicationHost.config redirection. This was a change made in the time period between 2.2-preview3 and 2.2. However, some customers relied on this behavior when installing the hosting bundle to update a shared configuration file on the same machine. More importantly, there was no way to disable the check in the new hosting bundle.

The fix is to allow users to specify the parameter "OPT_NO_SHARED_CONFIG_CHECK" to disable the shared configuration check.

Usage:

dotnet-hosting-2.2.x.exe OPT_NO_SHARED_CONFIG_CHECK=1

Regression?

Regression from 2.1 hosting bundle.

Risk

Very low. Default scenario are still the same and this only skips a check for shared configuration.

[jkotalik]

cc @muratg @DamianEdwards

[muratg]

We'll review this on Thursday's shiproom.

[jamshedd]

Approved for 2.2.2.

[muratg]

@jkotalik @pakrym Before this is checked in -- what was the reason the block was introduced in the first place? Who made that?

[jkotalik]

This was introduced because a majority of the time, when IIS is redirecting configuration, it is pointing to a location where the current user doesn't have write permissions to. When the hosting bundle runs, it will fail to install with no warning/ error (just says it fails to install). There was a few customers complaining about this, and I found that many other IIS installers (UrlRewrite, ARR, etc) had a check for if there was a shared configuration used, and if so fail to install. I added this check to the ANCM msis, but then we realized there was no way to revert this behavior.

[dougbu]

Not sure if this change affects the ANCM packages. If it does, please update the 2.2.2 section of eng/PatchConfig.props: https://github.com/aspnet/Extensions/blob/d8407116d183debaadb801c0cbc41d65927999d6/eng/PatchConfig.props#L7-L10

[jkotalik]

This change will not affect ANCM packages, just the hosting bundle.

[jkotalik]

@pakrym @joeloff updated based on feedback. The shared config check will now only run on install.

[muratg]

Where are we with this one? Is this ready to check-in?

cc @mikaelm12 @dougbu FYI.

[pakrym]

I'd like https://github.com/aspnet/AspNetCore/pull/6498/files/3b658e8022aa260b361d202139cea338e70d399d#diff-f870277bc9a67c26e59bc002457cece7R255 to be approved by @joeloff otherwise LGTM

[muratg]

FYI I believe @joeloff is OOF today.

[mikaelm12]

Any updates here? This is the last thing we have for 2.2.2

[joeloff]

I posted a comment this morning about the uninstall check. Update them to be REMOVE="ALL"

[jkotalik]

Verified the installers work with this change.