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added transformAndPublish

This commit is contained in:
Kwitsch 2024-04-13 00:09:29 +00:00
parent 6a899075b6
commit 86071445e5
1 changed files with 43 additions and 40 deletions
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83
resolver/caching_resolver.go
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@ -2,7 +2,6 @@ package resolver
import (
"context"
"fmt"
"math"
"sync/atomic"
"time"
@ -119,28 +118,7 @@ func (r *CachingResolver) reloadCacheEntry(ctx context.Context, cacheKey string)
return nil, 0
}
if response.Res.Rcode == dns.RcodeSuccess {
respCopy := response.Res.Copy()
// don't cache any EDNS OPT records
util.RemoveEdns0Record(respCopy)
packed, err := respCopy.Pack()
if err != nil {
logger.Error("unable to pack response", err)
return nil, 0
}
if r.redisClient != nil {
res := *respCopy
r.redisClient.PublishCache(cacheKey, &res)
}
return &packed, r.adjustTTLs(response.Res.Answer)
}
return nil, 0
return r.transformAndPublish(ctx, cacheKey, response, true)
}
func (r *CachingResolver) redisSubscriber(ctx context.Context) {
@ -151,8 +129,7 @@ func (r *CachingResolver) redisSubscriber(ctx context.Context) {
case rc := <-r.redisClient.CacheChannel:
if rc != nil {
logger.Debug("Received key from redis: ", rc.Key)
ttl := r.adjustTTLs(rc.Response.Res.Answer)
r.putInCache(ctx, rc.Key, rc.Response, ttl, false)
r.putInCache(ctx, rc.Key, rc.Response, false)
}
case <-ctx.Done():
@ -205,8 +182,7 @@ func (r *CachingResolver) Resolve(ctx context.Context, request *model.Request) (
response, err = r.next.Resolve(ctx, request)
if err == nil {
cacheTTL := r.adjustTTLs(response.Res.Answer)
r.putInCache(ctx, cacheKey, response, cacheTTL, true)
r.putInCache(ctx, cacheKey, response, true)
}
}
@ -262,33 +238,60 @@ func isResponseCacheable(msg *dns.Msg) bool {
return !msg.Truncated && !msg.CheckingDisabled
}
func (r *CachingResolver) putInCache(
ctx context.Context, cacheKey string, response *model.Response, ttl time.Duration, publish bool,
) {
// transformAndPublish transforms the response to a byte array and publishes it to redis if publish is true
// and redis is enabled. Returns the byte array and the TTL of the response
func (r *CachingResolver) transformAndPublish(ctx context.Context, cacheKey string,
response *model.Response, publish bool,
) (*[]byte, time.Duration) {
if response.Res.Rcode == dns.RcodeSuccess && !isResponseCacheable(response.Res) {
return nil, 0
}
_, domainName := util.ExtractCacheKey(cacheKey)
_, logger := r.log(ctx)
respCopy := response.Res.Copy()
// don't cache any EDNS OPT records
util.RemoveEdns0Record(respCopy)
packed, err := respCopy.Pack()
util.LogOnError(ctx, "error on packing", err)
if err != nil {
logger.WithError(err).WithField("domain", domainName).Warn("cache prefetch failed")
if err == nil {
if response.Res.Rcode == dns.RcodeSuccess && isResponseCacheable(response.Res) {
// put value into cache
r.resultCache.Put(cacheKey, &packed, ttl)
} else if response.Res.Rcode == dns.RcodeNameError {
if r.cfg.CacheTimeNegative.IsAboveZero() {
// put negative cache if result code is NXDOMAIN
r.resultCache.Put(cacheKey, &packed, r.cfg.CacheTimeNegative.ToDuration())
}
return nil, 0
}
ttl := time.Duration(0)
if response.Res.Rcode == dns.RcodeSuccess {
ttl = r.adjustTTLs(response.Res.Answer)
} else if response.Res.Rcode == dns.RcodeNameError {
if r.cfg.CacheTimeNegative.IsAboveZero() {
ttl = r.cfg.CacheTimeNegative.ToDuration()
}
}
if publish && r.redisClient != nil {
res := *respCopy
for _, rr := range res.Answer {
rr.Header().Ttl = uint32(ttl.Seconds())
}
r.redisClient.PublishCache(cacheKey, &res)
}
return &packed, ttl
}
func (r *CachingResolver) putInCache(
ctx context.Context, cacheKey string, response *model.Response, publish bool,
) {
res, ttl := r.transformAndPublish(ctx, cacheKey, response, publish)
if res != nil {
r.resultCache.Put(cacheKey, res, ttl)
}
}
// adjustTTLs calculates and returns the min TTL (considers also the min and max cache time)