9ac3cab1b7
* Make CoreDNS a server type plugin for Caddy Remove code we don't need and port all middleware over. Fix all tests and rework the documentation. Also make `go generate` build a caddy binary which we then copy into our directory. This means `go build`-builds remain working as-is. And new etc instances in each etcd test for better isolation. Fix more tests and rework test.Server with the newer support Caddy offers. Fix Makefile to support new mode of operation. |
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| .. | ||
| cache.go | ||
| cache_test.go | ||
| handler.go | ||
| item.go | ||
| item_test.go | ||
| README.md | ||
| setup.go | ||
cache
cache enables a frontend cache.
Syntax
cache [ttl] [zones...]
ttlmax TTL in seconds, if not specified the TTL of the reply (SOA minimum or minimum TTL in the answer section) will be used.zoneszones it should 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, i.e. a proxy that retrieves answer, or to minimize backend queries for middleware like etcd. Using a cache with the file middleware essentially doubles the memory load with no concealable increase of query speed.
The minimum TTL allowed on resource records is 5 seconds.
If monitoring is enabled (prometheus directive) then the following 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 miek.nl
Proxy to Google Public DNS and only cache responses for miek.nl (or below).