eb9bb8285d
Automatic merge from submit-queue (batch tested with PRs 51480, 49616, 50123, 50846, 50404) Kubectl to use http caching to cache openapi responses from the server **What this PR does / why we need it**: This PR is trying to address the problems raised in #50254 > * uses a disk-based cache that is not safe between processes (does not use atomic fs operations) > * writes get/list responses to disk that should not be cached (like kubectl get secrets) > * is vulnerable to partially written cache responses being used as responses to future requests > * breaks uses of the client transport that make use of websockets > * defaults to enabling the cache for any client builder using RecommendedConfigOverrideFlags or DefaultClientConfig which affects more components than just kubectl All of these points are addressed by this pull-request: 1. It now uses atomic fs operations 2. Doesn't cache by default, only if requested by the client (and it's only done by openapi client) 3. Fixed because of atomic fs operations 4. Found the reason for the bug: Cache wrapper couldn't be unwrapped. I implemented the `WrappedRoundTripper` interface. 5. Since 2. is fixed, I think that should be fine @smarterclayton @liggitt **Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #50254 **Special notes for your reviewer**: **Release note**: ```release-note Allows kubectl to use http caching mechanism for the OpenAPI schema. The cache directory can be configured through `--cache-dir` command line flag to kubectl. If set to empty string, caching will be disabled. ``` Kubernetes-commit: 0f2c2bd847ca7a66035b2289e83359ef4c923617 |
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README.md
httpcache
Package httpcache provides a http.RoundTripper implementation that works as a mostly RFC-compliant cache for http responses.
It is only suitable for use as a 'private' cache (i.e. for a web-browser or an API-client and not for a shared proxy).
Cache Backends
- The built-in 'memory' cache stores responses in an in-memory map.
github.com/gregjones/httpcache/diskcacheprovides a filesystem-backed cache using the diskv library.github.com/gregjones/httpcache/memcacheprovides memcache implementations, for both App Engine and 'normal' memcache servers.sourcegraph.com/sourcegraph/s3cacheuses Amazon S3 for storage.github.com/gregjones/httpcache/leveldbcacheprovides a filesystem-backed cache using leveldb.github.com/die-net/lrucacheprovides an in-memory cache that will evict least-recently used entries.github.com/die-net/lrucache/twotierallows caches to be combined, for example to use lrucache above with a persistent disk-cache.