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middleware/proxy: absorb httpproxy (#481)

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* middleware/proxy: absorb httpproxy

Move the httproxy into proxy. This adds and Exchanger interface which
is used to exchange the messages with the upstream.

The https_google upstream will re-resolve itself and update the upstream
hosts used every 300s.

* Remove and add TODO
This commit is contained in:
Miek Gieben 2017-02-06 19:32:48 +00:00 • committed by GitHub
parent 77f957d443
commit 123a76c91e
21 changed files with 466 additions and 827 deletions
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24
middleware/proxy/proxy.go
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@ -21,8 +21,12 @@ var (
// Proxy represents a middleware instance that can proxy requests to another (DNS) server.
type Proxy struct {
Next middleware.Handler
Upstreams []Upstream
Next middleware.Handler
// Upstreams is a pointer to a slice, so we can update the upstream (used for Google)
// midway.
Upstreams *[]Upstream
}
// Upstream manages a pool of proxy upstream hosts. Select should return a
@ -34,8 +38,8 @@ type Upstream interface {
Select() *UpstreamHost
// Checks if subpdomain is not an ignored.
IsAllowedPath(string) bool
// Options returns the options set for this upstream
Options() Options
// Exchanger returns the exchanger to be used for this upstream.
Exchanger() Exchanger
}
// UpstreamHostDownFunc can be used to customize how Down behaves.
@ -50,7 +54,6 @@ type UpstreamHost struct {
Unhealthy bool
CheckDown UpstreamHostDownFunc
WithoutPathPrefix string
Exchanger
}
// Down checks whether the upstream host is down or not.
@ -70,11 +73,12 @@ func (uh *UpstreamHost) Down() bool {
var tryDuration = 60 * time.Second
// ServeDNS satisfies the middleware.Handler interface.
func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
var span, child ot.Span
span = ot.SpanFromContext(ctx)
state := request.Request{W: w, Req: r}
for _, upstream := range p.Upstreams {
for _, upstream := range *p.Upstreams {
start := time.Now()
// Since Select() should give us "up" hosts, keep retrying
@ -83,7 +87,7 @@ func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
host := upstream.Select()
if host == nil {
RequestDuration.WithLabelValues(state.Proto(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
RequestDuration.WithLabelValues(upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
return dns.RcodeServerFailure, errUnreachable
}
@ -95,7 +99,7 @@ func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
atomic.AddInt64(&host.Conns, 1)
reply, backendErr := host.Exchange(state)
reply, backendErr := upstream.Exchanger().Exchange(host.Name, state)
atomic.AddInt64(&host.Conns, -1)
@ -106,7 +110,7 @@ func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
if backendErr == nil {
w.WriteMsg(reply)
RequestDuration.WithLabelValues(state.Proto(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
RequestDuration.WithLabelValues(upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
return 0, nil
}
@ -121,7 +125,7 @@ func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
}(host, timeout)
}
RequestDuration.WithLabelValues(state.Proto(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
RequestDuration.WithLabelValues(upstream.Exchanger().Protocol(), upstream.From()).Observe(float64(time.Since(start) / time.Millisecond))
return dns.RcodeServerFailure, errUnreachable
}