[RFC-0010] Add aws auth library

[matheuscscp]

This PR introduces the aws library from RFC-0010.

Part of: fluxcd/flux2#5022

PR Stack:

• azure
• gcp
• aws <---
• core

[matheuscscp]

Copied from here:

pkg/oci/auth/aws/auth.go

Lines 40 to 53 in f7fc565

	// This regex is sourced from the AWS ECR Credential Helper (https://github.com/awslabs/amazon-ecr-credential-helper).
	// It covers both public AWS partitions like amazonaws.com, China partitions like amazonaws.com.cn, and non-public partitions.
	var registryPartRe = regexp.MustCompile(`([0-9+]*).dkr.ecr(?:-fips)?\.([^/.]*)\.(amazonaws\.com[.cn]*|sc2s\.sgov\.gov|c2s\.ic\.gov|cloud\.adc-e\.uk|csp\.hci\.ic\.gov)`)
	// ParseRegistry returns the AWS account ID and region and `true` if
	// the image registry/repository is hosted in AWS's Elastic Container Registry,
	// otherwise empty strings and `false`.
	func ParseRegistry(registry string) (accountId, awsEcrRegion string, ok bool) {
	registryParts := registryPartRe.FindAllStringSubmatch(registry, -1)
	if len(registryParts) < 1 || len(registryParts[0]) < 3 {
	return "", "", false
	}
	return registryParts[0][1], registryParts[0][2], true
	}

[matheuscscp]

Copied from here:

pkg/oci/auth/aws/auth_test.go

Lines 37 to 125 in f7fc565

	func TestParseRegistry(t *testing.T) {
	tests := []struct {
	registry string
	wantAccountID string
	wantRegion string
	wantOK bool
	}{
	{
	registry: "012345678901.dkr.ecr.us-east-1.amazonaws.com/foo:v1",
	wantAccountID: "012345678901",
	wantRegion: "us-east-1",
	wantOK: true,
	},
	{
	registry: "012345678901.dkr.ecr.us-east-1.amazonaws.com/foo",
	wantAccountID: "012345678901",
	wantRegion: "us-east-1",
	wantOK: true,
	},
	{
	registry: "012345678901.dkr.ecr.us-east-1.amazonaws.com",
	wantAccountID: "012345678901",
	wantRegion: "us-east-1",
	wantOK: true,
	},
	{
	registry: "https://012345678901.dkr.ecr.us-east-1.amazonaws.com/v2/part/part",
	wantAccountID: "012345678901",
	wantRegion: "us-east-1",
	wantOK: true,
	},
	{
	registry: "012345678901.dkr.ecr.cn-north-1.amazonaws.com.cn/foo",
	wantAccountID: "012345678901",
	wantRegion: "cn-north-1",
	wantOK: true,
	},
	{
	registry: "012345678901.dkr.ecr-fips.us-gov-west-1.amazonaws.com",
	wantAccountID: "012345678901",
	wantRegion: "us-gov-west-1",
	wantOK: true,
	},
	{
	registry: "012345678901.dkr.ecr.us-secret-region.sc2s.sgov.gov",
	wantAccountID: "012345678901",
	wantRegion: "us-secret-region",
	wantOK: true,
	},
	{
	registry: "012345678901.dkr.ecr-fips.us-ts-region.c2s.ic.gov",
	wantAccountID: "012345678901",
	wantRegion: "us-ts-region",
	wantOK: true,
	},
	{
	registry: "012345678901.dkr.ecr.uk-region.cloud.adc-e.uk",
	wantAccountID: "012345678901",
	wantRegion: "uk-region",
	wantOK: true,
	},
	{
	registry: "012345678901.dkr.ecr.us-ts-region.csp.hci.ic.gov",
	wantAccountID: "012345678901",
	wantRegion: "us-ts-region",
	wantOK: true,
	},
	// TODO: Fix: this invalid registry is allowed by the regex.
	// {
	// registry: ".dkr.ecr.error.amazonaws.com",
	// wantOK: false,
	// },
	{
	registry: "gcr.io/foo/bar:baz",
	wantOK: false,
	},
	}
	for _, tt := range tests {
	t.Run(tt.registry, func(t *testing.T) {
	g := NewWithT(t)
	accId, region, ok := ParseRegistry(tt.registry)
	g.Expect(ok).To(Equal(tt.wantOK), "unexpected OK")
	g.Expect(accId).To(Equal(tt.wantAccountID), "unexpected account IDs")
	g.Expect(region).To(Equal(tt.wantRegion), "unexpected regions")
	})
	}
	}

[stefanprodan]

LGTM

Thanks @matheuscscp 🏅