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-rw-r--r--vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go52
-rw-r--r--vendor/google.golang.org/grpc/resolver/resolver.go8
2 files changed, 40 insertions, 20 deletions
diff --git a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
index 048fde6..084bdbf 100644
--- a/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
+++ b/vendor/google.golang.org/grpc/resolver/dns/dns_resolver.go
@@ -33,6 +33,7 @@ import (
"golang.org/x/net/context"
"google.golang.org/grpc/grpclog"
+ "google.golang.org/grpc/internal/backoff"
"google.golang.org/grpc/internal/grpcrand"
"google.golang.org/grpc/resolver"
)
@@ -51,17 +52,23 @@ const (
)
var (
- errMissingAddr = errors.New("missing address")
+ errMissingAddr = errors.New("dns resolver: missing address")
+
+ // Addresses ending with a colon that is supposed to be the separator
+ // between host and port is not allowed. E.g. "::" is a valid address as
+ // it is an IPv6 address (host only) and "[::]:" is invalid as it ends with
+ // a colon as the host and port separator
+ errEndsWithColon = errors.New("dns resolver: missing port after port-separator colon")
)
// NewBuilder creates a dnsBuilder which is used to factory DNS resolvers.
func NewBuilder() resolver.Builder {
- return &dnsBuilder{freq: defaultFreq}
+ return &dnsBuilder{minFreq: defaultFreq}
}
type dnsBuilder struct {
- // frequency of polling the DNS server.
- freq time.Duration
+ // minimum frequency of polling the DNS server.
+ minFreq time.Duration
}
// Build creates and starts a DNS resolver that watches the name resolution of the target.
@@ -92,7 +99,8 @@ func (b *dnsBuilder) Build(target resolver.Target, cc resolver.ClientConn, opts
// DNS address (non-IP).
ctx, cancel := context.WithCancel(context.Background())
d := &dnsResolver{
- freq: b.freq,
+ freq: b.minFreq,
+ backoff: backoff.Exponential{MaxDelay: b.minFreq},
host: host,
port: port,
ctx: ctx,
@@ -148,12 +156,14 @@ func (i *ipResolver) watcher() {
// dnsResolver watches for the name resolution update for a non-IP target.
type dnsResolver struct {
- freq time.Duration
- host string
- port string
- ctx context.Context
- cancel context.CancelFunc
- cc resolver.ClientConn
+ freq time.Duration
+ backoff backoff.Exponential
+ retryCount int
+ host string
+ port string
+ ctx context.Context
+ cancel context.CancelFunc
+ cc resolver.ClientConn
// rn channel is used by ResolveNow() to force an immediate resolution of the target.
rn chan struct{}
t *time.Timer
@@ -192,8 +202,15 @@ func (d *dnsResolver) watcher() {
case <-d.rn:
}
result, sc := d.lookup()
- // Next lookup should happen after an interval defined by d.freq.
- d.t.Reset(d.freq)
+ // Next lookup should happen within an interval defined by d.freq. It may be
+ // more often due to exponential retry on empty address list.
+ if len(result) == 0 {
+ d.retryCount++
+ d.t.Reset(d.backoff.Backoff(d.retryCount))
+ } else {
+ d.retryCount = 0
+ d.t.Reset(d.freq)
+ }
d.cc.NewServiceConfig(sc)
d.cc.NewAddress(result)
}
@@ -297,7 +314,6 @@ func formatIP(addr string) (addrIP string, ok bool) {
// target: "ipv4-host:80" returns host: "ipv4-host", port: "80"
// target: "[ipv6-host]" returns host: "ipv6-host", port: "443"
// target: ":80" returns host: "localhost", port: "80"
-// target: ":" returns host: "localhost", port: "443"
func parseTarget(target string) (host, port string, err error) {
if target == "" {
return "", "", errMissingAddr
@@ -307,15 +323,15 @@ func parseTarget(target string) (host, port string, err error) {
return target, defaultPort, nil
}
if host, port, err = net.SplitHostPort(target); err == nil {
+ if port == "" {
+ // If the port field is empty (target ends with colon), e.g. "[::1]:", this is an error.
+ return "", "", errEndsWithColon
+ }
// target has port, i.e ipv4-host:port, [ipv6-host]:port, host-name:port
if host == "" {
// Keep consistent with net.Dial(): If the host is empty, as in ":80", the local system is assumed.
host = "localhost"
}
- if port == "" {
- // If the port field is empty(target ends with colon), e.g. "[::1]:", defaultPort is used.
- port = defaultPort
- }
return host, port, nil
}
if host, port, err = net.SplitHostPort(target + ":" + defaultPort); err == nil {
diff --git a/vendor/google.golang.org/grpc/resolver/resolver.go b/vendor/google.golang.org/grpc/resolver/resolver.go
index 506afac..145cf47 100644
--- a/vendor/google.golang.org/grpc/resolver/resolver.go
+++ b/vendor/google.golang.org/grpc/resolver/resolver.go
@@ -49,8 +49,12 @@ func Get(scheme string) Builder {
return nil
}
-// SetDefaultScheme sets the default scheme that will be used.
-// The default default scheme is "passthrough".
+// SetDefaultScheme sets the default scheme that will be used. The default
+// default scheme is "passthrough".
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. The scheme set last overrides
+// previously set values.
func SetDefaultScheme(scheme string) {
defaultScheme = scheme
}