mirror of
https://github.com/coredns/coredns.git
synced 2025-10-30 01:34:21 -04:00
16504234e5
* plugin/forward: on demand healtchecking Only start doing health checks when we encouner an error (any error). This uses the new pluing/pkg/up package to abstract away the actual checking. This reduces the LOC quite a bit; does need more testing, unit testing and tcpdumping a bit. * fix tests * Fix readme * Use pkg/up for healthchecks * remove unused channel * more cleanups * update readme * * Again do go generate and go build; still referencing the wrong forward repo? Anyway fixed. * Use pkg/up for doing the healtchecks to cut back on unwanted queries * Change up.Func to return an error instead of a boolean. * Drop the string target argument as it doesn't make sense. * Add healthcheck test on failing to get an upstream answer. TODO(miek): double check Forward and Lookup and how they interact with HC, and if we correctly call close() on those * actual test * Tests here * more tests * try getting rid of host * Get rid of the host indirection * Finish removing hosts * moar testing * import fmt * field is not used * docs * move some stuff * bring back health_check * maxfails=0 test * git and merging, bah * review
93 lines
2.1 KiB
Go
93 lines
2.1 KiB
Go
package forward
|
|
|
|
import (
|
|
"crypto/tls"
|
|
"sync/atomic"
|
|
"time"
|
|
|
|
"github.com/coredns/coredns/plugin/pkg/up"
|
|
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
// Proxy defines an upstream host.
|
|
type Proxy struct {
|
|
addr string
|
|
client *dns.Client
|
|
|
|
// Connection caching
|
|
expire time.Duration
|
|
transport *transport
|
|
|
|
// health checking
|
|
probe *up.Probe
|
|
fails uint32
|
|
}
|
|
|
|
// NewProxy returns a new proxy.
|
|
func NewProxy(addr string, tlsConfig *tls.Config) *Proxy {
|
|
p := &Proxy{
|
|
addr: addr,
|
|
fails: 0,
|
|
probe: up.New(),
|
|
transport: newTransport(addr, tlsConfig),
|
|
}
|
|
p.client = dnsClient(tlsConfig)
|
|
return p
|
|
}
|
|
|
|
// dnsClient returns a client used for health checking.
|
|
func dnsClient(tlsConfig *tls.Config) *dns.Client {
|
|
c := new(dns.Client)
|
|
c.Net = "udp"
|
|
// TODO(miek): this should be half of hcDuration?
|
|
c.ReadTimeout = 1 * time.Second
|
|
c.WriteTimeout = 1 * time.Second
|
|
|
|
if tlsConfig != nil {
|
|
c.Net = "tcp-tls"
|
|
c.TLSConfig = tlsConfig
|
|
}
|
|
return c
|
|
}
|
|
|
|
// SetTLSConfig sets the TLS config in the lower p.transport.
|
|
func (p *Proxy) SetTLSConfig(cfg *tls.Config) { p.transport.SetTLSConfig(cfg) }
|
|
|
|
// SetExpire sets the expire duration in the lower p.transport.
|
|
func (p *Proxy) SetExpire(expire time.Duration) { p.transport.SetExpire(expire) }
|
|
|
|
// Dial connects to the host in p with the configured transport.
|
|
func (p *Proxy) Dial(proto string) (*dns.Conn, error) { return p.transport.Dial(proto) }
|
|
|
|
// Yield returns the connection to the pool.
|
|
func (p *Proxy) Yield(c *dns.Conn) { p.transport.Yield(c) }
|
|
|
|
// Healthcheck kicks of a round of health checks for this proxy.
|
|
func (p *Proxy) Healthcheck() { p.probe.Do(p.Check) }
|
|
|
|
// Down returns true if this proxy is down, i.e. has *more* fails than maxfails.
|
|
func (p *Proxy) Down(maxfails uint32) bool {
|
|
if maxfails == 0 {
|
|
return false
|
|
}
|
|
|
|
fails := atomic.LoadUint32(&p.fails)
|
|
return fails > maxfails
|
|
}
|
|
|
|
// close stops the health checking goroutine.
|
|
func (p *Proxy) close() {
|
|
p.probe.Stop()
|
|
p.transport.Stop()
|
|
}
|
|
|
|
// start starts the proxy's healthchecking.
|
|
func (p *Proxy) start(duration time.Duration) { p.probe.Start(duration) }
|
|
|
|
const (
|
|
dialTimeout = 4 * time.Second
|
|
timeout = 2 * time.Second
|
|
hcDuration = 500 * time.Millisecond
|
|
)
|