[Bug]: `occ maintenance:install` fails on read-only htdocs directory

[Pilzinsel64]

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Since Nextcloud 27.1.5 and Nextcloud 28.0.0 the occ command for manual install requires write-access to the htdocs directory. This were not the case before and allowed Nextcloud to be deployed via the SNAP environment.

Ref: nextcloud-snap/nextcloud-snap#2631 (comment)

This prevents us from updating our snap packges at the moment as the snap environment is read-only for security reasons.

Is there a workaround for this to execute manual install without the need for write-access?

Steps to reproduce

1. Create a read-only webspace.
2. Install Nextcloud 27.1.5 or 28.0.0 there.
3. Execute the installation process via the command occ maintenance:install.
4. The command will fail because it requires write-access to the htdocs direcotry.

Expected behavior

Do not require write-access on occ maintenance:install or at least try-catch and skip the steps that would write to the htdocs directory, so the command will execute successfully - like in v27.1.4 and earlier.

Installation method

Community SNAP package

Nextcloud Server version

27

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.1

Web server

Apache (supported)

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

Fresh Nextcloud Server install

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

No response

List of activated Apps

No response

Nextcloud Signing status

No response

Nextcloud Logs

No response

Additional info

No response

[joshtrichards]

The first error in the linked issue is the result of a recently added check to make sure there's enough disk space available before writing out the config.php. This is important since avoids truncating the existing config.php. It was added in #41544 and the code is as follows:

server/lib/private/Setup.php

Lines 562 to 573 in cd32db6

	if ($content !== '') {
	// Never write file back if disk space should be too low
	if (function_exists('disk_free_space')) {
	$df = disk_free_space(\OC::$SERVERROOT);
	$size = strlen($content) + 10240;
	if ($df !== false && $df < (float)$size) {
	throw new \Exception(\OC::$SERVERROOT . " does not have enough space for writing the htaccess file! Not writing it back!");
	}
	}
	//suppress errors in case we don't have permissions for it
	return (bool)@file_put_contents($setupHelper->pathToHtaccess(), $htaccessContent . $content . "\n");
	}

As for occ maintenance:install I don't see anything significant that's changed lately in regards to write related behavior. The only change made for NC28 was increased verbosity. Which might help you uncover what's going on if you activate it.

The code for the command is here:

https://github.com/nextcloud/server/blob/master/core/Command/Maintenance/Install.php

[solracsf]

Problem is at line 568.
To handle these (SNAP) cases, it should just return false, but it actually throws.
@szaimen any objections here?

[szaimen]

I think we should rather chevk if the dir is read only and then return false...

[kyrofa]

Yes, the snap is a squashfs image, which is by definition 100% full and read-only.

[kyrofa]

The first error in the linked issue is the result of a recently added check to make sure there's enough disk space available before writing out the config.php

Remember that config.php could be held entirely out of the webroot. Read-only webroots are not uncommon.

[solracsf]

PR at #42298

[kyrofa]

Thank you, @solracsf!