4 files changed, 413 insertions, 0 deletions

diff --git a/vendor/google.golang.org/grpc/naming/dns_resolver.go b/vendor/google.golang.org/grpc/naming/dns_resolver.go
new file mode 100644
index 0000000..efd37e3
--- /dev/null
+++ b/vendor/google.golang.org/grpc/naming/dns_resolver.go
@@ -0,0 +1,292 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package naming
+
+import (
+        "errors"
+        "fmt"
+        "net"
+        "strconv"
+        "time"
+
+        "golang.org/x/net/context"
+        "google.golang.org/grpc/grpclog"
+)
+
+const (
+        defaultPort = "443"
+        defaultFreq = time.Minute * 30
+)
+
+var (
+        errMissingAddr  = errors.New("missing address")
+        errWatcherClose = errors.New("watcher has been closed")
+)
+
+// NewDNSResolverWithFreq creates a DNS Resolver that can resolve DNS names, and
+// create watchers that poll the DNS server using the frequency set by freq.
+func NewDNSResolverWithFreq(freq time.Duration) (Resolver, error) {
+        return &dnsResolver{freq: freq}, nil
+}
+
+// NewDNSResolver creates a DNS Resolver that can resolve DNS names, and create
+// watchers that poll the DNS server using the default frequency defined by defaultFreq.
+func NewDNSResolver() (Resolver, error) {
+        return NewDNSResolverWithFreq(defaultFreq)
+}
+
+// dnsResolver handles name resolution for names following the DNS scheme
+type dnsResolver struct {
+        // frequency of polling the DNS server that the watchers created by this resolver will use.
+        freq time.Duration
+}
+
+// formatIP returns ok = false if addr is not a valid textual representation of an IP address.
+// If addr is an IPv4 address, return the addr and ok = true.
+// If addr is an IPv6 address, return the addr enclosed in square brackets and ok = true.
+func formatIP(addr string) (addrIP string, ok bool) {
+        ip := net.ParseIP(addr)
+        if ip == nil {
+                return "", false
+        }
+        if ip.To4() != nil {
+                return addr, true
+        }
+        return "[" + addr + "]", true
+}
+
+// parseTarget takes the user input target string, returns formatted host and port info.
+// If target doesn't specify a port, set the port to be the defaultPort.
+// If target is in IPv6 format and host-name is enclosed in sqarue brackets, brackets
+// are strippd when setting the host.
+// examples:
+// target: "www.google.com" returns host: "www.google.com", port: "443"
+// 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
+        }
+
+        if ip := net.ParseIP(target); ip != nil {
+                // target is an IPv4 or IPv6(without brackets) address
+                return target, defaultPort, nil
+        }
+        if host, port, err := net.SplitHostPort(target); err == nil {
+                // 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 {
+                // target doesn't have port
+                return host, port, nil
+        }
+        return "", "", fmt.Errorf("invalid target address %v", target)
+}
+
+// Resolve creates a watcher that watches the name resolution of the target.
+func (r *dnsResolver) Resolve(target string) (Watcher, error) {
+        host, port, err := parseTarget(target)
+        if err != nil {
+                return nil, err
+        }
+
+        if net.ParseIP(host) != nil {
+                ipWatcher := &ipWatcher{
+                        updateChan: make(chan *Update, 1),
+                }
+                host, _ = formatIP(host)
+                ipWatcher.updateChan <- &Update{Op: Add, Addr: host + ":" + port}
+                return ipWatcher, nil
+        }
+
+        ctx, cancel := context.WithCancel(context.Background())
+        return &dnsWatcher{
+                r:      r,
+                host:   host,
+                port:   port,
+                ctx:    ctx,
+                cancel: cancel,
+                t:      time.NewTimer(0),
+        }, nil
+}
+
+// dnsWatcher watches for the name resolution update for a specific target
+type dnsWatcher struct {
+        r    *dnsResolver
+        host string
+        port string
+        // The latest resolved address list
+        curAddrs []*Update
+        ctx      context.Context
+        cancel   context.CancelFunc
+        t        *time.Timer
+}
+
+// ipWatcher watches for the name resolution update for an IP address.
+type ipWatcher struct {
+        updateChan chan *Update
+}
+
+// Next returns the adrress resolution Update for the target. For IP address,
+// the resolution is itself, thus polling name server is unncessary. Therefore,
+// Next() will return an Update the first time it is called, and will be blocked
+// for all following calls as no Update exisits until watcher is closed.
+func (i *ipWatcher) Next() ([]*Update, error) {
+        u, ok := <-i.updateChan
+        if !ok {
+                return nil, errWatcherClose
+        }
+        return []*Update{u}, nil
+}
+
+// Close closes the ipWatcher.
+func (i *ipWatcher) Close() {
+        close(i.updateChan)
+}
+
+// AddressType indicates the address type returned by name resolution.
+type AddressType uint8
+
+const (
+        // Backend indicates the server is a backend server.
+        Backend AddressType = iota
+        // GRPCLB indicates the server is a grpclb load balancer.
+        GRPCLB
+)
+
+// AddrMetadataGRPCLB contains the information the name resolver for grpclb should provide. The
+// name resolver used by the grpclb balancer is required to provide this type of metadata in
+// its address updates.
+type AddrMetadataGRPCLB struct {
+        // AddrType is the type of server (grpc load balancer or backend).
+        AddrType AddressType
+        // ServerName is the name of the grpc load balancer. Used for authentication.
+        ServerName string
+}
+
+// compileUpdate compares the old resolved addresses and newly resolved addresses,
+// and generates an update list
+func (w *dnsWatcher) compileUpdate(newAddrs []*Update) []*Update {
+        update := make(map[Update]bool)
+        for _, u := range newAddrs {
+                update[*u] = true
+        }
+        for _, u := range w.curAddrs {
+                if _, ok := update[*u]; ok {
+                        delete(update, *u)
+                        continue
+                }
+                update[Update{Addr: u.Addr, Op: Delete, Metadata: u.Metadata}] = true
+        }
+        res := make([]*Update, 0, len(update))
+        for k := range update {
+                tmp := k
+                res = append(res, &tmp)
+        }
+        return res
+}
+
+func (w *dnsWatcher) lookupSRV() []*Update {
+        var newAddrs []*Update
+        _, srvs, err := lookupSRV(w.ctx, "grpclb", "tcp", w.host)
+        if err != nil {
+                grpclog.Infof("grpc: failed dns SRV record lookup due to %v.\n", err)
+                return nil
+        }
+        for _, s := range srvs {
+                lbAddrs, err := lookupHost(w.ctx, s.Target)
+                if err != nil {
+                        grpclog.Warningf("grpc: failed load banlacer address dns lookup due to %v.\n", err)
+                        continue
+                }
+                for _, a := range lbAddrs {
+                        a, ok := formatIP(a)
+                        if !ok {
+                                grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
+                                continue
+                        }
+                        newAddrs = append(newAddrs, &Update{Addr: a + ":" + strconv.Itoa(int(s.Port)),
+                                Metadata: AddrMetadataGRPCLB{AddrType: GRPCLB, ServerName: s.Target}})
+                }
+        }
+        return newAddrs
+}
+
+func (w *dnsWatcher) lookupHost() []*Update {
+        var newAddrs []*Update
+        addrs, err := lookupHost(w.ctx, w.host)
+        if err != nil {
+                grpclog.Warningf("grpc: failed dns A record lookup due to %v.\n", err)
+                return nil
+        }
+        for _, a := range addrs {
+                a, ok := formatIP(a)
+                if !ok {
+                        grpclog.Errorf("grpc: failed IP parsing due to %v.\n", err)
+                        continue
+                }
+                newAddrs = append(newAddrs, &Update{Addr: a + ":" + w.port})
+        }
+        return newAddrs
+}
+
+func (w *dnsWatcher) lookup() []*Update {
+        newAddrs := w.lookupSRV()
+        if newAddrs == nil {
+                // If failed to get any balancer address (either no corresponding SRV for the
+                // target, or caused by failure during resolution/parsing of the balancer target),
+                // return any A record info available.
+                newAddrs = w.lookupHost()
+        }
+        result := w.compileUpdate(newAddrs)
+        w.curAddrs = newAddrs
+        return result
+}
+
+// Next returns the resolved address update(delta) for the target. If there's no
+// change, it will sleep for 30 mins and try to resolve again after that.
+func (w *dnsWatcher) Next() ([]*Update, error) {
+        for {
+                select {
+                case <-w.ctx.Done():
+                        return nil, errWatcherClose
+                case <-w.t.C:
+                }
+                result := w.lookup()
+                // Next lookup should happen after an interval defined by w.r.freq.
+                w.t.Reset(w.r.freq)
+                if len(result) > 0 {
+                        return result, nil
+                }
+        }
+}
+
+func (w *dnsWatcher) Close() {
+        w.cancel()
+}
diff --git a/vendor/google.golang.org/grpc/naming/go17.go b/vendor/google.golang.org/grpc/naming/go17.go
new file mode 100644
index 0000000..a537b08
--- /dev/null
+++ b/vendor/google.golang.org/grpc/naming/go17.go
@@ -0,0 +1,34 @@
+// +build go1.6, !go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package naming
+
+import (
+        "net"
+
+        "golang.org/x/net/context"
+)
+
+var (
+        lookupHost = func(ctx context.Context, host string) ([]string, error) { return net.LookupHost(host) }
+        lookupSRV  = func(ctx context.Context, service, proto, name string) (string, []*net.SRV, error) {
+                return net.LookupSRV(service, proto, name)
+        }
+)
diff --git a/vendor/google.golang.org/grpc/naming/go18.go b/vendor/google.golang.org/grpc/naming/go18.go
new file mode 100644
index 0000000..b5a0f84
--- /dev/null
+++ b/vendor/google.golang.org/grpc/naming/go18.go
@@ -0,0 +1,28 @@
+// +build go1.8
+
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package naming
+
+import "net"
+
+var (
+        lookupHost = net.DefaultResolver.LookupHost
+        lookupSRV  = net.DefaultResolver.LookupSRV
+)
diff --git a/vendor/google.golang.org/grpc/naming/naming.go b/vendor/google.golang.org/grpc/naming/naming.go
new file mode 100644
index 0000000..1af7e32
--- /dev/null
+++ b/vendor/google.golang.org/grpc/naming/naming.go
@@ -0,0 +1,59 @@
+/*
+ *
+ * Copyright 2014 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package naming defines the naming API and related data structures for gRPC.
+// The interface is EXPERIMENTAL and may be suject to change.
+package naming
+
+// Operation defines the corresponding operations for a name resolution change.
+type Operation uint8
+
+const (
+        // Add indicates a new address is added.
+        Add Operation = iota
+        // Delete indicates an exisiting address is deleted.
+        Delete
+)
+
+// Update defines a name resolution update. Notice that it is not valid having both
+// empty string Addr and nil Metadata in an Update.
+type Update struct {
+        // Op indicates the operation of the update.
+        Op Operation
+        // Addr is the updated address. It is empty string if there is no address update.
+        Addr string
+        // Metadata is the updated metadata. It is nil if there is no metadata update.
+        // Metadata is not required for a custom naming implementation.
+        Metadata interface{}
+}
+
+// Resolver creates a Watcher for a target to track its resolution changes.
+type Resolver interface {
+        // Resolve creates a Watcher for target.
+        Resolve(target string) (Watcher, error)
+}
+
+// Watcher watches for the updates on the specified target.
+type Watcher interface {
+        // Next blocks until an update or error happens. It may return one or more
+        // updates. The first call should get the full set of the results. It should
+        // return an error if and only if Watcher cannot recover.
+        Next() ([]*Update, error)
+        // Close closes the Watcher.
+        Close()
+}