fix(gatsby): open lmdb instances in writeable locations in generated ssr/dsg function

[pieh]

Description

This makes caches-lmdb AND gatsby-core-utils getStorage open lmdb cache/storage instances in writeable location (in case CWD in lambda environment is not writeable). The FS rewrites we have there now doesn't apply to LMDB (fs handling of lmdb is not in Node.js land) so we have to explicitly deal with "fs rewrite" when LMDB is concerned. We were already addressing this for main LMDB instance (datastore), but this expands it to cache and storage usage of lmdb as well.

gatsby-core-utils is already using global.__GATSBY.root -

gatsby/packages/gatsby-core-utils/src/utils/get-storage.ts

Lines 29 to 32 in 47ec2ac

	export function getDatabaseDir(): string {
	const rootDir = global.__GATSBY?.root ?? process.cwd()
	return path.join(rootDir, `.cache`, `data`, `gatsby-core-utils`)
	}

This PR adds similar usage to lmdb cache usage, as well as actually sets the root to writeable location in lambda

Documentation

Tests

This is example showing segfault problem caused by trying to open LMDB in non-writeable location - https://6527cb3ca4fc76285774d547--exquisite-pavlova-cc785c.netlify.app/

https://6527d2acfad30e0085a57db2--exquisite-pavlova-cc785c.netlify.app/ this one is using changes from this PR showing it fixing the problem.

Related Issues

Fixes FRA-10
https://github.com/netlify/pillar-support/issues/724

[pieh]

This is unrelated to rest of changes, just noticed this was logged even if LMDB wasn't excluded from the bundle (so when it shouldn't be logged)

[MarcL]

👍🏻

[madhums]

@pieh Can we do a release for this fix? Having this issue in production version of code hosted on netlify

[pieh]

gatsby@5.12.7 was released with this change

cc @madhums