Bug 1727800: Icon Subresource for PackageManifest

[alecmerdler]

Description

Adds packagemanifests/icon subresource, which serves logo icons for a given PackageManifest.

Caching will be accomplished in this way:

1. Console requests /packagemanifests/<pkg>/icon?resourceVersion=<pkg>.<channel>.<csvName>
2. Server gets bundle from gRPC operator-registry and sends the image data with an ETag header
3. Next time browser requests the icon endpoint, sends If-None-Match header containing the ETag
4. Server checks the existence of ETag and sends HTTP 304
5. When new ClusterServiceVersion is added to the package, console will change the resourceVersion in the request URL and therefore not send an If-None-Match header.
6. User can always perform hard refresh or clear cache to retrieve fresh icons.

Resources Used

• https://sourcegraph.com/github.com/kubernetes/kubernetes/-/blob/pkg/registry/core/pod/storage/storage.go#L69
• https://sourcegraph.com/github.com/kubernetes/kubernetes@master/-/blob/pkg/registry/core/rest/storage_core.go#L234
• https://sourcegraph.com/github.com/kubernetes/kubernetes/-/blob/pkg/registry/core/pod/rest/subresources.go#L134

Implements #985
Addresses https://jira.coreos.com/browse/OLM-1211

[openshift-ci-robot]

@alecmerdler: This pull request references a valid Bugzilla bug. The bug has been moved to the POST state. The bug has been updated to refer to the pull request using the external bug tracker.

In response to this:

Bug 1727800: Icon Subresource for PackageManifest

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[dinhxuanvu]

lgtm

[alecmerdler]

@ecordell Is this good to merge?

[openshift-ci-robot]

@alecmerdler: This pull request references Bugzilla bug 1727800, which is valid.

In response to this:

Bug 1727800: Icon Subresource for PackageManifest

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[ecordell]

/lgtm

[openshift-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: alecmerdler, ecordell

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[openshift-ci-robot]

@alecmerdler: All pull requests linked via external trackers have merged. Bugzilla bug 1727800 has been moved to the MODIFIED state.

In response to this:

Bug 1727800: Icon Subresource for PackageManifest

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.