Introduce GRPC_PROXY EnvVar Support

Introduce the ability to specify a dial context for GRPC connections.

Signed-off-by: Alexander Greene <greene.al1991@gmail.com>

go.mod

@@ -36,6 +36,7 @@ require (
  github.com/spf13/cobra v1.1.3
  github.com/spf13/pflag v1.0.5
  github.com/stretchr/testify v1.7.0
+ golang.org/x/net v0.0.0-20210520170846-37e1c6afe023
  golang.org/x/time v0.0.0-20210723032227-1f47c861a9ac
  google.golang.org/grpc v1.38.0
  gopkg.in/yaml.v2 v2.4.0

pkg/controller/registry/grpc/source.go

@@ -2,12 +2,17 @@ package grpc
 
 import (
  "context"
+ "net"
+ "net/url"
+ "os"
  "sync"
  "time"
 
  "github.com/operator-framework/operator-registry/pkg/client"
 
  "github.com/sirupsen/logrus"
+ "golang.org/x/net/http/httpproxy"
+ "golang.org/x/net/proxy"
  "google.golang.org/grpc"
  "google.golang.org/grpc/connectivity"
 
@@ -100,10 +105,70 @@ func (s *SourceStore) Get(key registry.CatalogKey) *SourceConn {
  return &source
 }
 
+func grpcProxyURL(addr string) (*url.URL, error) {
+ // Handle ip addresses
+ host, _, err := net.SplitHostPort(addr)
+ if err != nil {
+ return nil, err
+ }
+
+ url, err := url.Parse(host)
+ if err != nil {
+ return nil, err
+ }
+
+ // Hardcode fields required for proxy resolution
+ url.Host = addr
+ url.Scheme = "http"
+
+ // Override HTTPS_PROXY and HTTP_PROXY with GRPC_PROXY
+ proxyConfig := &httpproxy.Config{
+ HTTPProxy: getGRPCProxyEnv(),
+ HTTPSProxy: getGRPCProxyEnv(),
+ NoProxy: getEnvAny("NO_PROXY", "no_proxy"),
+ CGI: os.Getenv("REQUEST_METHOD") != "",
+ }
+
+ // Check if a proxy should be used based on environment variables
+ return proxyConfig.ProxyFunc()(url)
+}
+
+func getGRPCProxyEnv() string {
+ return getEnvAny("GRPC_PROXY", "grpc_proxy")
+}
+
+func getEnvAny(names ...string) string {
+ for _, n := range names {
+ if val := os.Getenv(n); val != "" {
+ return val
+ }
+ }
+ return ""
+}
+
+func grpcConnection(address string) (*grpc.ClientConn, error) {
+ proxyURL, err := grpcProxyURL(address)
+ if err != nil {
+ return nil, err
+ }
+
+ if proxyURL != nil {
+ return grpc.Dial(address, grpc.WithInsecure(), grpc.WithContextDialer(func(ctx context.Context, addr string) (net.Conn, error) {
+ dialer, err := proxy.FromURL(proxyURL, &net.Dialer{})
+ if err != nil {
+ return nil, err
+ }
+ return dialer.Dial("tcp", addr)
+ }))
+ }
+
+ return grpc.Dial(address, grpc.WithInsecure())
+}
+
 func (s *SourceStore) Add(key registry.CatalogKey, address string) (*SourceConn, error) {
  _ = s.Remove(key)
 
- conn, err := grpc.Dial(address, grpc.WithInsecure())
+ conn, err := grpcConnection(address)
  if err != nil {
  return nil, err
  }