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Client-side of gRPC proxy (#511)

Browse Source 
* WIP: Client-side of gRPC proxy

* Add tests

* gofmt

* Implement OnShutdown; add a little logging

* Update for context in Exchange change

* go fmt

* Update README

* Review comments

* Compiling is good

* More README improvements
This commit is contained in:
John Belamaric
2017-02-14 22:20:20 -05:00
committed by GitHub
parent 98c86f3f9f
commit 061b3fc1bd
6 changed files with 353 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
middleware/proxy/README.md
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@@ -26,7 +26,7 @@ proxy FROM TO... {
health_check PATH:PORT [DURATION]
except IGNORED_NAMES...
spray
protocol [dns|https_google [bootstrap ADDRESS...]]
protocol [dns|https_google [bootstrap ADDRESS...]|grpc [insecure|CA-PEM|KEY-PEM CERT-PEM|KEY-PEM CERT-PEM CA-PEM]]
}
~~~
@@ -40,7 +40,8 @@ proxy FROM TO... {
* `spray` when all backends are unhealthy, randomly pick one to send the traffic to. (This is a failsafe.)
* `protocol` specifies what protocol to use to speak to an upstream, `dns` (the default) is plain old DNS, and
`https_google` uses `https://dns.google.com` and speaks a JSON DNS dialect. Note when using this
**TO** must be `dns.google.com`.
**TO** must be `dns.google.com`. The `grpc` option will talk to a server that has implemented the DnsService defined
in https://github.com/miekg/coredns/middleware/proxy/pb/dns.proto.
## Policies
@@ -82,6 +83,16 @@ example.org. 1799 IN SOA sns.dns.icann.org. noc.dns.icann.org. 2016110711 7200
;; ADDITIONAL SECTION:
. 0 CH TXT "Response from 199.43.133.53"
~~~
* `grpc`: options are used to control how the TLS connection is made to the gRPC server.
* None - No client authentication is used, and the system CAs are used to verify the server certificate.
* `insecure` - TLS is not used, the connection is made in plaintext (not good in production).
* CA-PEM - No client authentication is used, and the file CA-PEM is used to verify the server certificate.
* KEY-PEM CERT-PEM - Client authentication is used with the specified key/cert pair. The server certificate is verified
with the system CAs.
* KEY-PEM CERT-PEM CA-PEM - Client authentication is used with the specified key/cert pair. The server certificate is
verified using the CA-PEM file.
An out-of-tree middleware that implements the server side of this can be found at https://github.com/infobloxopen/coredns-grpc.
## Metrics

77
middleware/proxy/grpc.go Normal file
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@@ -0,0 +1,77 @@
package proxy
import (
"context"
"crypto/tls"
"log"
"github.com/miekg/coredns/middleware/proxy/pb"
"github.com/miekg/coredns/request"
"github.com/miekg/dns"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials"
)
type grpcClient struct {
dialOpt grpc.DialOption
clients map[string]pb.DnsServiceClient
conns []*grpc.ClientConn
upstream *staticUpstream
}
func newGrpcClient(tls *tls.Config, u *staticUpstream) *grpcClient {
g := &grpcClient{upstream: u}
if tls == nil {
g.dialOpt = grpc.WithInsecure()
} else {
g.dialOpt = grpc.WithTransportCredentials(credentials.NewTLS(tls))
}
g.clients = map[string]pb.DnsServiceClient{}
return g
}
func (g *grpcClient) Exchange(ctx context.Context, addr string, state request.Request) (*dns.Msg, error) {
msg, err := state.Req.Pack()
if err != nil {
return nil, err
}
reply, err := g.clients[addr].Query(ctx, &pb.DnsPacket{Msg: msg})
if err != nil {
return nil, err
}
d := new(dns.Msg)
err = d.Unpack(reply.Msg)
if err != nil {
return nil, err
}
return d, nil
}
func (g *grpcClient) Protocol() string { return "grpc" }
func (g *grpcClient) OnShutdown(p *Proxy) error {
for i, conn := range g.conns {
err := conn.Close()
if err != nil {
log.Printf("[WARNING] Error closing connection %d: %s\n", i, err)
}
}
return nil
}
func (g *grpcClient) OnStartup(p *Proxy) error {
for _, host := range g.upstream.Hosts {
conn, err := grpc.Dial(host.Name, g.dialOpt)
if err != nil {
log.Printf("[WARNING] Skipping gRPC host '%s' due to Dial error: %s\n", host.Name, err)
} else {
g.clients[host.Name] = pb.NewDnsServiceClient(conn)
g.conns = append(g.conns, conn)
}
}
return nil
}

140
middleware/proxy/pb/dns.pb.go Normal file
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@@ -0,0 +1,140 @@
// Code generated by protoc-gen-go.
// source: dns.proto
// DO NOT EDIT!
/*
Package pb is a generated protocol buffer package.
It is generated from these files:
dns.proto
It has these top-level messages:
DnsPacket
*/
package pb
import proto "github.com/golang/protobuf/proto"
import fmt "fmt"
import math "math"
import (
context "golang.org/x/net/context"
grpc "google.golang.org/grpc"
)
// Reference imports to suppress errors if they are not otherwise used.
var _ = proto.Marshal
var _ = fmt.Errorf
var _ = math.Inf
// This is a compile-time assertion to ensure that this generated file
// is compatible with the proto package it is being compiled against.
// A compilation error at this line likely means your copy of the
// proto package needs to be updated.
const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package
type DnsPacket struct {
Msg []byte `protobuf:"bytes,1,opt,name=msg,proto3" json:"msg,omitempty"`
}
func (m *DnsPacket) Reset() { *m = DnsPacket{} }
func (m *DnsPacket) String() string { return proto.CompactTextString(m) }
func (*DnsPacket) ProtoMessage() {}
func (*DnsPacket) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
func (m *DnsPacket) GetMsg() []byte {
if m != nil {
return m.Msg
}
return nil
}
func init() {
proto.RegisterType((*DnsPacket)(nil), "coredns.dns.DnsPacket")
}
// Reference imports to suppress errors if they are not otherwise used.
var _ context.Context
var _ grpc.ClientConn
// This is a compile-time assertion to ensure that this generated file
// is compatible with the grpc package it is being compiled against.
const _ = grpc.SupportPackageIsVersion4
// Client API for DnsService service
type DnsServiceClient interface {
Query(ctx context.Context, in *DnsPacket, opts ...grpc.CallOption) (*DnsPacket, error)
}
type dnsServiceClient struct {
cc *grpc.ClientConn
}
func NewDnsServiceClient(cc *grpc.ClientConn) DnsServiceClient {
return &dnsServiceClient{cc}
}
func (c *dnsServiceClient) Query(ctx context.Context, in *DnsPacket, opts ...grpc.CallOption) (*DnsPacket, error) {
out := new(DnsPacket)
err := grpc.Invoke(ctx, "/coredns.dns.DnsService/Query", in, out, c.cc, opts...)
if err != nil {
return nil, err
}
return out, nil
}
// Server API for DnsService service
type DnsServiceServer interface {
Query(context.Context, *DnsPacket) (*DnsPacket, error)
}
func RegisterDnsServiceServer(s *grpc.Server, srv DnsServiceServer) {
s.RegisterService(&_DnsService_serviceDesc, srv)
}
func _DnsService_Query_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
in := new(DnsPacket)
if err := dec(in); err != nil {
return nil, err
}
if interceptor == nil {
return srv.(DnsServiceServer).Query(ctx, in)
}
info := &grpc.UnaryServerInfo{
Server: srv,
FullMethod: "/coredns.dns.DnsService/Query",
}
handler := func(ctx context.Context, req interface{}) (interface{}, error) {
return srv.(DnsServiceServer).Query(ctx, req.(*DnsPacket))
}
return interceptor(ctx, in, info, handler)
}
var _DnsService_serviceDesc = grpc.ServiceDesc{
ServiceName: "coredns.dns.DnsService",
HandlerType: (*DnsServiceServer)(nil),
Methods: []grpc.MethodDesc{
{
MethodName: "Query",
Handler: _DnsService_Query_Handler,
},
},
Streams: []grpc.StreamDesc{},
Metadata: "dns.proto",
}
func init() { proto.RegisterFile("dns.proto", fileDescriptor0) }
var fileDescriptor0 = []byte{
// 120 bytes of a gzipped FileDescriptorProto
0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0xe2, 0xe2, 0x4c, 0xc9, 0x2b, 0xd6,
0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0xe2, 0x4e, 0xce, 0x2f, 0x4a, 0x05, 0x71, 0x53, 0xf2, 0x8a,
0x95, 0x64, 0xb9, 0x38, 0x5d, 0xf2, 0x8a, 0x03, 0x12, 0x93, 0xb3, 0x53, 0x4b, 0x84, 0x04, 0xb8,
0x98, 0x73, 0x8b, 0xd3, 0x25, 0x18, 0x15, 0x18, 0x35, 0x78, 0x82, 0x40, 0x4c, 0x23, 0x57, 0x2e,
0x2e, 0x97, 0xbc, 0xe2, 0xe0, 0xd4, 0xa2, 0xb2, 0xcc, 0xe4, 0x54, 0x21, 0x73, 0x2e, 0xd6, 0xc0,
0xd2, 0xd4, 0xa2, 0x4a, 0x21, 0x31, 0x3d, 0x24, 0x33, 0xf4, 0xe0, 0x06, 0x48, 0xe1, 0x10, 0x77,
0x62, 0x89, 0x62, 0x2a, 0x48, 0x4a, 0x62, 0x03, 0xdb, 0x6f, 0x0c, 0x08, 0x00, 0x00, 0xff, 0xff,
0xf5, 0xd1, 0x3f, 0x26, 0x8c, 0x00, 0x00, 0x00,
}

12
middleware/proxy/pb/dns.proto Normal file
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@@ -0,0 +1,12 @@
syntax = "proto3";
package coredns.dns;
option go_package = "pb";
message DnsPacket {
bytes msg = 1;
}
service DnsService {
rpc Query (DnsPacket) returns (DnsPacket);
}

11
middleware/proxy/upstream.go
View File

@@ -13,6 +13,7 @@ import (
"github.com/miekg/coredns/middleware"
"github.com/miekg/coredns/middleware/pkg/dnsutil"
"github.com/miekg/coredns/middleware/pkg/tls"
"github.com/mholt/caddy/caddyfile"
"github.com/miekg/dns"
@@ -197,6 +198,16 @@ func parseBlock(c *caddyfile.Dispenser, u *staticUpstream) error {
}
u.ex = newGoogle("", boot) // "" for default in google.go
case "grpc":
if len(encArgs) == 2 && encArgs[1] == "insecure" {
u.ex = newGrpcClient(nil, u)
return nil
}
tls, err := tls.NewTLSConfigFromArgs(encArgs[1:]...)
if err != nil {
return err
}
u.ex = newGrpcClient(tls, u)
default:
return fmt.Errorf("%s: %s", errInvalidProtocol, encArgs[0])
}

101
middleware/proxy/upstream_test.go
View File

@@ -8,6 +8,8 @@ import (
"testing"
"time"
"github.com/miekg/coredns/middleware/test"
"github.com/mholt/caddy"
)
@@ -96,6 +98,14 @@ func writeTmpFile(t *testing.T, data string) (string, string) {
}
func TestProxyParse(t *testing.T) {
rmFunc, cert, key, ca := getPEMFiles(t)
defer rmFunc()
grpc1 := "proxy . 8.8.8.8:53 {\n protocol grpc " + ca + "\n}"
grpc2 := "proxy . 8.8.8.8:53 {\n protocol grpc " + cert + " " + key + "\n}"
grpc3 := "proxy . 8.8.8.8:53 {\n protocol grpc " + cert + " " + key + " " + ca + "\n}"
grpc4 := "proxy . 8.8.8.8:53 {\n protocol grpc " + key + "\n}"
tests := []struct {
inputUpstreams string
shouldErr bool
@@ -174,8 +184,84 @@ proxy . 8.8.8.8:53 {
},
{
`
proxy . 8.8.8.8:53 {
protocol grpc
}`,
false,
},
{
`
proxy . 8.8.8.8:53 {
protocol grpc insecure
}`,
false,
},
{
`
proxy . 8.8.8.8:53 {
protocol grpc a b c d
}`,
true,
},
{
grpc1,
false,
},
{
grpc2,
false,
},
{
grpc3,
false,
},
{
grpc4,
true,
},
{
`
proxy . 8.8.8.8:53 {
protocol foobar
}`,
true,
},
{
`proxy`,
true,
},
{
`
proxy . 8.8.8.8:53 {
protocol foobar
}`,
true,
},
{
`
proxy . 8.8.8.8:53 {
policy
}`,
true,
},
{
`
proxy . 8.8.8.8:53 {
fail_timeout
}`,
true,
},
{
`
proxy . 8.8.8.8:53 {
fail_timeout junky
}`,
true,
},
{
`
proxy . 8.8.8.8:53 {
health_check
}`,
true,
},
@@ -184,7 +270,7 @@ proxy . 8.8.8.8:53 {
c := caddy.NewTestController("dns", test.inputUpstreams)
_, err := NewStaticUpstreams(&c.Dispenser)
if (err != nil) != test.shouldErr {
t.Errorf("Test %d expected no error, got %v", i+1, err)
t.Errorf("Test %d expected no error, got %v for %s", i+1, err, test.inputUpstreams)
}
}
}
@@ -264,3 +350,16 @@ junky resolve.conf
}
}
}
func getPEMFiles(t *testing.T) (rmFunc func(), cert, key, ca string) {
tempDir, rmFunc, err := test.WritePEMFiles("")
if err != nil {
t.Fatalf("Could not write PEM files: %s", err)
}
cert = filepath.Join(tempDir, "cert.pem")
key = filepath.Join(tempDir, "key.pem")
ca = filepath.Join(tempDir, "ca.pem")
return
}