coredns/middleware/cache
Miek Gieben 090d1872e9 Golint2 (#280)
* Fix linter errors

* More linting fixes

* More docs and making members private that dont need to be public

* Fix linter errors

* More linting fixes

* More docs and making members private that dont need to be public

* More lint fixes

This leaves:

~~~
middleware/kubernetes/nametemplate/nametemplate.go:64:6: exported type NameTemplate should have comment or be unexported
middleware/kubernetes/nametemplate/nametemplate.go:71:1: exported method NameTemplate.SetTemplate should have comment or be unexported
middleware/kubernetes/nametemplate/nametemplate.go:108:1: exported method NameTemplate.GetZoneFromSegmentArray should have comment or be unexported
middleware/kubernetes/nametemplate/nametemplate.go:116:1: exported method NameTemplate.GetNamespaceFromSegmentArray should have comment or be unexported
middleware/kubernetes/nametemplate/nametemplate.go:120:1: exported method NameTemplate.GetServiceFromSegmentArray should have comment or be unexported
middleware/kubernetes/nametemplate/nametemplate.go:124:1: exported method NameTemplate.GetTypeFromSegmentArray should have comment or be unexported
middleware/kubernetes/nametemplate/nametemplate.go:135:1: exported method NameTemplate.GetSymbolFromSegmentArray should have comment or be unexported
middleware/kubernetes/nametemplate/nametemplate.go:167:1: exported method NameTemplate.IsValid should have comment or be unexported
middleware/kubernetes/nametemplate/nametemplate.go:182:6: exported type NameValues should have comment or be unexported
middleware/kubernetes/util/util.go:1:1: package comment should be of the form "Package util ..."
middleware/kubernetes/util/util.go:27:2: exported const WildcardStar should have comment (or a comment on this block) or be unexported
middleware/proxy/lookup.go:66:1: exported method Proxy.Forward should have comment or be unexported
middleware/proxy/proxy.go:24:6: exported type Client should have comment or be unexported
middleware/proxy/proxy.go:107:1: exported function Clients should have comment or be unexported
middleware/proxy/reverseproxy.go:10:6: exported type ReverseProxy should have comment or be unexported
middleware/proxy/reverseproxy.go:16:1: exported method ReverseProxy.ServeDNS should have comment or be unexported
middleware/proxy/upstream.go:42:6: exported type Options should have comment or be unexported
~~~

I plan on reworking the proxy anyway, so I'll leave that be.
2016-09-23 09:14:12 +01:00
..
cache.go Golint2 (#280) 2016-09-23 09:14:12 +01:00
cache_test.go Golint2 (#280) 2016-09-23 09:14:12 +01:00
handler.go Cleanup: put middleware helper functions in pkgs (#245) 2016-09-07 11:10:16 +01:00
item.go Golint2 (#280) 2016-09-23 09:14:12 +01:00
item_test.go Cache (#126) 2016-04-19 11:13:24 +01:00
README.md Update README.md 2016-08-22 13:51:54 -07:00
setup.go Run golint and go vet (#276) 2016-09-21 17:01:19 +01:00

cache

cache enables a frontend cache.

Syntax

cache [ttl] [zones...]
  • ttl max TTL in seconds. If not specified, the TTL of the reply (SOA minimum or minimum TTL in the answer section) will be used.
  • zones zones it should cache for. If empty, the zones from the configuration block are used.

Each element in the cache is cached according to its TTL. For the negative cache, the SOA's MinTTL value is used.

A cache mostly makes sense with a middleware that is potentially slow (e.g., a proxy that retrieves an answer), or to minimize backend queries for middleware like etcd. Using a cache with the file middleware essentially doubles the memory load with no conceivable increase of query speed.

The minimum TTL allowed on resource records is 5 seconds.

If monitoring is enabled (via the prometheus directive) then the following extra metrics are added:

  • coredns_cache_hit_count_total, and
  • coredns_cache_miss_count_total

They both work on a per-zone basis and just count the hit and miss counts for each query.

Examples

cache 10

Enable caching for all zones, but cap everything to a TTL of 10 seconds.

proxy . 8.8.8.8:53
cache example.org

Proxy to Google Public DNS and only cache responses for example.org (or below).