feat: add support for HTTPS_PROXY

This commit adds support for the HTTPS_PROXY environment variable.
At the moment the NO_PROXY environment variable is ignored, please
be aware of that!

This should close fullstorydev#166

go.mod

@@ -7,6 +7,8 @@ require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/golang/protobuf v1.5.2
 	github.com/jhump/protoreflect v1.10.3
+	github.com/mwitkow/go-http-dialer v0.0.0-20161116154839-378f744fb2b8 // indirect
+	golang.org/x/net v0.0.0-20200822124328-c89045814202
 	golang.org/x/text v0.3.7 // indirect
 	google.golang.org/grpc v1.44.0
 	google.golang.org/protobuf v1.27.1

go.sum

@@ -116,6 +116,8 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/mwitkow/go-http-dialer v0.0.0-20161116154839-378f744fb2b8 h1:BhQQWYKJwXPtAhm12d4gQU4LKS9Yov22yOrDc2QA7ho=
+github.com/mwitkow/go-http-dialer v0.0.0-20161116154839-378f744fb2b8/go.mod h1:ntWhh7pzdiiRKBMxUB5iG+Q2gmZBxGxpX1KyK6N8kX8=
 github.com/nishanths/predeclared v0.0.0-20200524104333-86fad755b4d3/go.mod h1:nt3d53pc1VYcphSCIaYAJtnPYnr3Zyn8fMq2wvPGPso=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=

grpcurl.go

@@ -14,8 +14,11 @@ import (
 	"encoding/base64"
 	"errors"
 	"fmt"
+	http_dialer "github.com/mwitkow/go-http-dialer"
+	"golang.org/x/net/proxy"
 	"io/ioutil"
 	"net"
+	"net/url"
 	"os"
 	"regexp"
 	"sort"
@@ -638,7 +641,23 @@ func BlockingDial(ctx context.Context, network, address string, creds credential
 		// handshake). And that would mean that the library would send the
 		// wrong ":scheme" metaheader to servers: it would send "http" instead
 		// of "https" because it is unaware that TLS is actually in use.
-		conn, err := (&net.Dialer{}).DialContext(ctx, network, address)
+
+		// Use HTTPS_PROXY if it's set up:
+		if os.Getenv("HTTPS_PROXY") != "" {
+			proxyUrl, err := url.Parse(os.Getenv("HTTPS_PROXY"))
+			if err != nil {
+				panic("Invalid HTTPS_PROXY environment variable")
+			}
+
+			httpTunnel := http_dialer.New(proxyUrl)
+			conn, err := httpTunnel.Dial(network, address)
+			if err != nil {
+				writeResult(err)
+			}
+			return conn, err
+		}
+
+		conn, err := proxy.Dial(ctx, network, address)
 		if err != nil {
 			writeResult(err)
 		}