fix: fetch GCP metadata from 169.254.169.254 directly

[nettrino]

• Followed the steps in the contributor's guide: https://crashoverride.com/docs/other/contributing#filing-the-pull-request
• PR title uses semantic commit messages
• Filled out the template to a useful degree
• Updated CHANGELOG.md if necessary

Issue

Fixes #292

[ee7]

LGTM. We already used 169.254.169.254 for AWS and Azure:

chalk/src/plugins/cloudMetadata.nim

Line 14 in ca217bd

awsBaseUri = "http://169.254.169.254/latest/"

chalk/src/plugins/cloudMetadata.nim

Line 237 in ca217bd

let resultOpt = hitProviderEndpoint("http://169.254.169.254/metadata/instance?api-version=2021-02-01", newHttpHeaders([("Metadata", "true")]))

We should probably define 169.254.169.254 as a const in this file and use that everywhere, but I don't mind leaving that till later.

[nettrino]

We should probably define 169.254.169.254 as a const in this file and use that everywhere, but I don't mind leaving that till later.

Agreed - not sure though if there are lists of IPs that differ slightly per provider? this plugin could be split / refactored in the future so left it as such for now as I treated it as a nit as well

[ee7]

not sure though if there are lists of IPs that differ slightly per provider

For this particular case, I think we'd be pretty safe even if we added more cloud providers. My understanding is that 169.254.0.0/16 is reserved for link-local addressing, and it's pretty standard for the instance metadata service to be available via 169.254.169.254. At least also for:

• IBM Cloud
• Oracle Cloud
• DigitalOcean

[thc202]

Alibaba Cloud uses a different address: https://www.alibabacloud.com/help/en/ecs/user-guide/view-instance-metadata (not arguing against or for, just providing an example).

[ee7]

Cool, thanks.

Yeah, I've got no context for Alibaba Cloud. Looks like it's different for Tencent Cloud too.

[ee7]

I suggest merging with the edited shorter PR title - commit title would be longer than 72 chars otherwise, which overflows e.g. GitHub's commit view.