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Add configuration flag to set if RecursionDesired should be set on health checkers in Forward-plugin (#3679)

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* Make the RD-flag in health-checks in the Forward-plugin configurable

Introduces a new configuration flag; `health_check_non_recursive`. This
flag makes the health-checker do non-recursive requests when checking
the health of upstream servers.

Signed-off-by: Geir Haugom <ghagit@haugom.org>
Signed-off-by: Christian Tryti <ctryti@gmail.com>

* Changes after feedback from reviewer

* Better tests of health-checks with and without recursion
* Removed the health_check_non_recursive configuration in favor of
extending the existing health_check configuration. Now supports an
optional `no_rec` argument.

Signed-off-by: Christian Tryti <ctryti@gmail.com>

* Add new test that checks setup of health_check.

Signed-off-by: Christian Tryti <ctryti@gmail.com>
This commit is contained in:
Christian Tryti
2020-03-06 11:52:43 +01:00
committed by GitHub
parent a74a209129
commit 116bda4d27
7 changed files with 135 additions and 26 deletions
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21
plugin/forward/health.go
View File

@@ -14,13 +14,18 @@ import (
type HealthChecker interface {
Check(*Proxy) error
SetTLSConfig(*tls.Config)
SetRecursionDesired(bool)
GetRecursionDesired() bool
}
// dnsHc is a health checker for a DNS endpoint (DNS, and DoT).
type dnsHc struct{ c *dns.Client }
type dnsHc struct {
c *dns.Client
recursionDesired bool
}
// NewHealthChecker returns a new HealthChecker based on transport.
func NewHealthChecker(trans string) HealthChecker {
func NewHealthChecker(trans string, recursionDesired bool) HealthChecker {
switch trans {
case transport.DNS, transport.TLS:
c := new(dns.Client)
@@ -28,7 +33,7 @@ func NewHealthChecker(trans string) HealthChecker {
c.ReadTimeout = 1 * time.Second
c.WriteTimeout = 1 * time.Second
return &dnsHc{c: c}
return &dnsHc{c: c, recursionDesired: recursionDesired}
}
log.Warningf("No healthchecker for transport %q", trans)
@@ -40,7 +45,14 @@ func (h *dnsHc) SetTLSConfig(cfg *tls.Config) {
h.c.TLSConfig = cfg
}
// For HC we send to . IN NS +norec message to the upstream. Dial timeouts and empty
func (h *dnsHc) SetRecursionDesired(recursionDesired bool) {
h.recursionDesired = recursionDesired
}
func (h *dnsHc) GetRecursionDesired() bool {
return h.recursionDesired
}
// For HC we send to . IN NS +[no]rec message to the upstream. Dial timeouts and empty
// replies are considered fails, basically anything else constitutes a healthy upstream.
// Check is used as the up.Func in the up.Probe.
@@ -59,6 +71,7 @@ func (h *dnsHc) Check(p *Proxy) error {
func (h *dnsHc) send(addr string) error {
ping := new(dns.Msg)
ping.SetQuestion(".", dns.TypeNS)
ping.MsgHdr.RecursionDesired = h.recursionDesired
m, _, err := h.c.Exchange(ping, addr)
// If we got a header, we're alright, basically only care about I/O errors 'n stuff.