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ServiceBackend interface (#369)

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* Add ServiceBackend interface

This adds a ServiceBackend interface that is shared between etcd/etcd3
(later) and kubernetes, leading to a massive reduction in code. When
returning the specific records from their backend.

Fixes #273
This commit is contained in:
Miek Gieben
2016-10-30 15:54:16 +00:00
committed by GitHub
parent 81d5baee28
commit 27d893cf33
15 changed files with 273 additions and 503 deletions
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58
middleware/etcd/etcd.go
View File

@@ -11,8 +11,10 @@ import (
"github.com/miekg/coredns/middleware/etcd/msg"
"github.com/miekg/coredns/middleware/pkg/singleflight"
"github.com/miekg/coredns/middleware/proxy"
"github.com/miekg/coredns/request"
etcdc "github.com/coreos/etcd/client"
"github.com/miekg/dns"
"golang.org/x/net/context"
)
@@ -26,17 +28,47 @@ type Etcd struct {
Ctx context.Context
Inflight *singleflight.Group
Stubmap *map[string]proxy.Proxy // list of proxies for stub resolving.
Debug bool // Do we allow debug queries.
Debugging bool // Do we allow debug queries.
endpoints []string // Stored here as well, to aid in testing.
}
// Records looks up records in etcd. If exact is true, it will lookup just
// this name. This is used when find matches when completing SRV lookups
// for instance.
// Services implements the ServiceBackend interface.
func (e *Etcd) Services(state request.Request, exact bool, opt middleware.Options) (services, debug []msg.Service, err error) {
services, err = e.Records(state.Name(), exact)
if err != nil {
return
}
if opt.Debug != "" {
debug = services
}
services = msg.Group(services)
return
}
// Lookup implements the ServiceBackend interface.
func (e *Etcd) Lookup(state request.Request, name string, typ uint16) (*dns.Msg, error) {
return e.Proxy.Lookup(state, name, typ)
}
// IsNameError implements the ServiceBackend interface.
func (e *Etcd) IsNameError(err error) bool {
if ee, ok := err.(etcdc.Error); ok && ee.Code == etcdc.ErrorCodeKeyNotFound {
return true
}
return false
}
// Debug implements the ServiceBackend interface.
func (e *Etcd) Debug() string {
return e.PathPrefix
}
// Records looks up records in etcd. If exact is true, it will lookup just this
// name. This is used when find matches when completing SRV lookups for instance.
func (e *Etcd) Records(name string, exact bool) ([]msg.Service, error) {
path, star := msg.PathWithWildcard(name, e.PathPrefix)
r, err := e.Get(path, true)
r, err := e.get(path, true)
if err != nil {
return nil, err
}
@@ -51,8 +83,8 @@ func (e *Etcd) Records(name string, exact bool) ([]msg.Service, error) {
}
}
// Get is a wrapper for client.Get that uses SingleInflight to suppress multiple outstanding queries.
func (e *Etcd) Get(path string, recursive bool) (*etcdc.Response, error) {
// get is a wrapper for client.Get that uses SingleInflight to suppress multiple outstanding queries.
func (e *Etcd) get(path string, recursive bool) (*etcdc.Response, error) {
resp, err := e.Inflight.Do(path, func() (interface{}, error) {
ctx, cancel := context.WithTimeout(e.Ctx, etcdTimeout)
defer cancel()
@@ -76,7 +108,7 @@ func (e *Etcd) Get(path string, recursive bool) (*etcdc.Response, error) {
// loopNodes recursively loops through the nodes and returns all the values. The nodes' keyname
// will be match against any wildcards when star is true.
func (e Etcd) loopNodes(ns []*etcdc.Node, nameParts []string, star bool, bx map[msg.Service]bool) (sx []msg.Service, err error) {
func (e *Etcd) loopNodes(ns []*etcdc.Node, nameParts []string, star bool, bx map[msg.Service]bool) (sx []msg.Service, err error) {
if bx == nil {
bx = make(map[msg.Service]bool)
}
@@ -145,18 +177,8 @@ func (e *Etcd) TTL(node *etcdc.Node, serv *msg.Service) uint32 {
return serv.TTL
}
// etcNameError checks if the error is ErrorCodeKeyNotFound from etcd.
func isEtcdNameError(err error) bool {
if e, ok := err.(etcdc.Error); ok && e.Code == etcdc.ErrorCodeKeyNotFound {
return true
}
return false
}
const (
priority = 10 // default priority when nothing is set
ttl = 300 // default ttl when nothing is set
minTTL = 60
hostmaster = "hostmaster"
etcdTimeout = 5 * time.Second
)