Activate xDS support in grpcurl (#137)

* use wrapped TransportCredentials instead of handling handshake in Dialer, so that grpc library will use correct :scheme
* support -authority for TLS conns; now effectively supercedes -servername flag

.travis.yml

@@ -3,17 +3,17 @@ sudo: false
 
 matrix:
   include:
-    - go: "1.9"
-    - go: "1.10"
-    - go: "1.11"
+    - go: 1.9.x
+    - go: 1.10.x
+    - go: 1.11.x
       env:
       - GO111MODULE=off
       - VET=1
-    - go: "1.11"
+    - go: 1.11.x
       env: GO111MODULE=on
-    - go: "1.12"
+    - go: 1.12.x
       env: GO111MODULE=off
-    - go: "1.12"
+    - go: 1.12.x
       env: GO111MODULE=on
     - go: tip
 

cmd/grpcurl/grpcurl.go

@@ -23,6 +23,9 @@ import (
 	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 	reflectpb "google.golang.org/grpc/reflection/grpc_reflection_v1alpha"
+
+	// Register gzip compressor so compressed responses will work:
+	_ "google.golang.org/grpc/encoding/gzip"
 )
 
 var version = "dev build <no version set>"
@@ -52,15 +55,27 @@ var (
 	key = flags.String("key", "", prettify(`
 		File containing client private key, to present to the server. Not valid
 		with -plaintext option. Must also provide -cert option.`))
-	protoset    multiString
-	protoFiles  multiString
-	importPaths multiString
-	addlHeaders multiString
-	rpcHeaders  multiString
-	reflHeaders multiString
-	authority   = flags.String("authority", "", prettify(`
-		Value of :authority pseudo-header to be use with underlying HTTP/2
-		requests. It defaults to the given address.`))
+	protoset      multiString
+	protoFiles    multiString
+	importPaths   multiString
+	addlHeaders   multiString
+	rpcHeaders    multiString
+	reflHeaders   multiString
+	expandHeaders = flags.Bool("expand-headers", false, prettify(`
+		If set, headers may use '${NAME}' syntax to reference environment
+		variables. These will be expanded to the actual environment variable
+		value before sending to the server. For example, if there is an
+		environment variable defined like FOO=bar, then a header of
+		'key: ${FOO}' would expand to 'key: bar'. This applies to -H,
+		-rpc-header, and -reflect-header options. No other expansion/escaping is
+		performed. This can be used to supply credentials/secrets without having
+		to put them in command-line arguments.`))
+	authority = flags.String("authority", "", prettify(`
+		The authoritative name of the remote server. This value is passed as the
+		value of the ":authority" pseudo-header in the HTTP/2 protocol. When TLS
+		is used, this will also be used as the server name when verifying the
+		server's certificate. It defaults to the address that is provided in the
+		positional arguments.`))
 	data = flags.String("d", "", prettify(`
 		Data for request contents. If the value is '@' then the request contents
 		are read from stdin. For calls that accept a stream of requests, the
@@ -93,12 +108,24 @@ var (
 		will accept. If not specified, defaults to 4,194,304 (4 megabytes).`))
 	emitDefaults = flags.Bool("emit-defaults", false, prettify(`
 		Emit default values for JSON-encoded responses.`))
+	protosetOut = flags.String("protoset-out", "", prettify(`
+		The name of a file to be written that will contain a FileDescriptorSet
+		proto. With the list and describe verbs, the listed or described
+		elements and their transitive dependencies will be written to the named
+		file if this option is given. When invoking an RPC and this option is
+		given, the method being invoked and its transitive dependencies will be
+		included in the output file.`))
 	msgTemplate = flags.Bool("msg-template", false, prettify(`
 		When describing messages, show a template of input data.`))
 	verbose = flags.Bool("v", false, prettify(`
 		Enable verbose output.`))
 	serverName = flags.String("servername", "", prettify(`
-		Override server name when validating TLS certificate.`))
+		Override server name when validating TLS certificate. This flag is
+		ignored if -plaintext or -insecure is used.
+		NOTE: Prefer -authority. This flag may be removed in the future. It is
+		an error to use both -authority and -servername (though this will be
+		permitted if they are both set to the same value, to increase backwards
+		compatibility with earlier releases that allowed both to be set).`))
 )
 
 func init() {
@@ -286,9 +313,6 @@ func main() {
 		if *maxMsgSz > 0 {
 			opts = append(opts, grpc.WithDefaultCallOptions(grpc.MaxCallRecvMsgSize(*maxMsgSz)))
 		}
-		if *authority != "" {
-			opts = append(opts, grpc.WithAuthority(*authority))
-		}
 		var creds credentials.TransportCredentials
 		if !*plaintext {
 			var err error
@@ -296,11 +320,27 @@ func main() {
 			if err != nil {
 				fail(err, "Failed to configure transport credentials")
 			}
-			if *serverName != "" {
-				if err := creds.OverrideServerName(*serverName); err != nil {
-					fail(err, "Failed to override server name as %q", *serverName)
+
+			// can use either -servername or -authority; but not both
+			if *serverName != "" && *authority != "" {
+				if *serverName == *authority {
+					warn("Both -servername and -authority are present; prefer only -authority.")
+				} else {
+					fail(nil, "Cannot specify different values for -servername and -authority.")
 				}
 			}
+			overrideName := *serverName
+			if overrideName == "" {
+				overrideName = *authority
+			}
+
+			if overrideName != "" {
+				if err := creds.OverrideServerName(overrideName); err != nil {
+					fail(err, "Failed to override server name as %q", overrideName)
+				}
+			}
+		} else if *authority != "" {
+			opts = append(opts, grpc.WithAuthority(*authority))
 		}
 		network := "tcp"
 		if isUnixSocket != nil && isUnixSocket() {
@@ -313,6 +353,22 @@ func main() {
 		return cc
 	}
 
+	if *expandHeaders {
+		var err error
+		addlHeaders, err = grpcurl.ExpandHeaders(addlHeaders)
+		if err != nil {
+			fail(err, "Failed to expand additional headers")
+		}
+		rpcHeaders, err = grpcurl.ExpandHeaders(rpcHeaders)
+		if err != nil {
+			fail(err, "Failed to expand rpc headers")
+		}
+		reflHeaders, err = grpcurl.ExpandHeaders(reflHeaders)
+		if err != nil {
+			fail(err, "Failed to expand reflection headers")
+		}
+	}
+
 	var cc *grpc.ClientConn
 	var descSource grpcurl.DescriptorSource
 	var refClient *grpcreflect.Client
@@ -367,6 +423,9 @@ func main() {
 					fmt.Printf("%s\n", svc)
 				}
 			}
+			if err := writeProtoset(descSource, svcs...); err != nil {
+				fail(err, "Failed to write protoset to %s", *protosetOut)
+			}
 		} else {
 			methods, err := grpcurl.ListMethods(descSource, symbol)
 			if err != nil {
@@ -379,6 +438,9 @@ func main() {
 					fmt.Printf("%s\n", m)
 				}
 			}
+			if err := writeProtoset(descSource, symbol); err != nil {
+				fail(err, "Failed to write protoset to %s", *protosetOut)
+			}
 		}
 
 	} else if describe {
@@ -479,6 +541,9 @@ func main() {
 				fmt.Println(str)
 			}
 		}
+		if err := writeProtoset(descSource, symbols...); err != nil {
+			fail(err, "Failed to write protoset to %s", *protosetOut)
+		}
 
 	} else {
 		// Invoke an RPC
@@ -595,3 +660,15 @@ func fail(err error, msg string, args ...interface{}) {
 		exit(2)
 	}
 }
+
+func writeProtoset(descSource grpcurl.DescriptorSource, symbols ...string) error {
+	if *protosetOut == "" {
+		return nil
+	}
+	f, err := os.Create(*protosetOut)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	return grpcurl.WriteProtoset(f, descSource, symbols...)
+}

desc_source.go

@@ -3,6 +3,7 @@ package grpcurl
 import (
 	"errors"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"sync"
 
@@ -251,3 +252,53 @@ func reflectionSupport(err error) error {
 	}
 	return err
 }
+
+// WriteProtoset will use the given descriptor source to resolve all of the given
+// symbols and write a proto file descriptor set with their definitions to the
+// given output. The output will include descriptors for all files in which the
+// symbols are defined as well as their transitive dependencies.
+func WriteProtoset(out io.Writer, descSource DescriptorSource, symbols ...string) error {
+	// compute set of file descriptors
+	filenames := make([]string, 0, len(symbols))
+	fds := make(map[string]*desc.FileDescriptor, len(symbols))
+	for _, sym := range symbols {
+		d, err := descSource.FindSymbol(sym)
+		if err != nil {
+			return fmt.Errorf("failed to find descriptor for %q: %v", sym, err)
+		}
+		fd := d.GetFile()
+		if _, ok := fds[fd.GetName()]; !ok {
+			fds[fd.GetName()] = fd
+			filenames = append(filenames, fd.GetName())
+		}
+	}
+	// now expand that to include transitive dependencies in topologically sorted
+	// order (such that file always appears after its dependencies)
+	expandedFiles := make(map[string]struct{}, len(fds))
+	allFilesSlice := make([]*descpb.FileDescriptorProto, 0, len(fds))
+	for _, filename := range filenames {
+		allFilesSlice = addFilesToSet(allFilesSlice, expandedFiles, fds[filename])
+	}
+	// now we can serialize to file
+	b, err := proto.Marshal(&descpb.FileDescriptorSet{File: allFilesSlice})
+	if err != nil {
+		return fmt.Errorf("failed to serialize file descriptor set: %v", err)
+	}
+	if _, err := out.Write(b); err != nil {
+		return fmt.Errorf("failed to write file descriptor set: %v", err)
+	}
+	return nil
+}
+
+func addFilesToSet(allFiles []*descpb.FileDescriptorProto, expanded map[string]struct{}, fd *desc.FileDescriptor) []*descpb.FileDescriptorProto {
+	if _, ok := expanded[fd.GetName()]; ok {
+		// already seen this one
+		return allFiles
+	}
+	expanded[fd.GetName()] = struct{}{}
+	// add all dependencies first
+	for _, dep := range fd.GetDependencies() {
+		allFiles = addFilesToSet(allFiles, expanded, dep)
+	}
+	return append(allFiles, fd.AsFileDescriptorProto())
+}

desc_source_test.go

@@ -0,0 +1,62 @@
+package grpcurl
+
+import (
+	"bytes"
+	"io/ioutil"
+	"testing"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/golang/protobuf/protoc-gen-go/descriptor"
+)
+
+func TestWriteProtoset(t *testing.T) {
+	exampleProtoset, err := loadProtoset("./testing/example.protoset")
+	if err != nil {
+		t.Fatalf("failed to load example.protoset: %v", err)
+	}
+	testProtoset, err := loadProtoset("./testing/test.protoset")
+	if err != nil {
+		t.Fatalf("failed to load test.protoset: %v", err)
+	}
+
+	mergedProtoset := &descriptor.FileDescriptorSet{
+		File: append(exampleProtoset.File, testProtoset.File...),
+	}
+
+	descSrc, err := DescriptorSourceFromFileDescriptorSet(mergedProtoset)
+	if err != nil {
+		t.Fatalf("failed to create descriptor source: %v", err)
+	}
+
+	checkWriteProtoset(t, descSrc, exampleProtoset, "TestService")
+	checkWriteProtoset(t, descSrc, testProtoset, "grpc.testing.TestService")
+	checkWriteProtoset(t, descSrc, mergedProtoset, "TestService", "grpc.testing.TestService")
+}
+
+func loadProtoset(path string) (*descriptor.FileDescriptorSet, error) {
+	b, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	var protoset descriptor.FileDescriptorSet
+	if err := proto.Unmarshal(b, &protoset); err != nil {
+		return nil, err
+	}
+	return &protoset, nil
+}
+
+func checkWriteProtoset(t *testing.T, descSrc DescriptorSource, protoset *descriptor.FileDescriptorSet, symbols ...string) {
+	var buf bytes.Buffer
+	if err := WriteProtoset(&buf, descSrc, symbols...); err != nil {
+		t.Fatalf("failed to write protoset: %v", err)
+	}
+
+	var result descriptor.FileDescriptorSet
+	if err := proto.Unmarshal(buf.Bytes(), &result); err != nil {
+		t.Fatalf("failed to unmarshal written protoset: %v", err)
+	}
+
+	if !proto.Equal(protoset, &result) {
+		t.Fatalf("written protoset not equal to input:\nExpecting: %s\nActual: %s", protoset, &result)
+	}
+}

go.mod

@@ -1,8 +1,8 @@
 module github.com/fullstorydev/grpcurl
 
 require (
-	github.com/golang/protobuf v1.3.1
-	github.com/jhump/protoreflect v1.4.4
+	github.com/golang/protobuf v1.3.5
+	github.com/jhump/protoreflect v1.5.0
 	golang.org/x/net v0.0.0-20190311183353-d8887717615a
-	google.golang.org/grpc v1.21.0
+	google.golang.org/grpc v1.28.0
 )

go.sum

@@ -1,30 +1,58 @@
 cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
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+github.com/envoyproxy/go-control-plane v0.9.0/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
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 google.golang.org/genproto v0.0.0-20180817151627-c66870c02cf8/go.mod h1:JiN7NxoALGmiZfu7CAH4rXhgtRTLTxftemlI0sWmxmc=
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+google.golang.org/genproto v0.0.0-20190819201941-24fa4b261c55/go.mod h1:DMBHOl98Agz4BDEuKkezgsaosCRResVns1a3J2ZsMNc=
 google.golang.org/grpc v1.8.0/go.mod h1:yo6s7OP7yaDglbqo1J04qKzAhqBH6lvTonzMVmEdcZw=
-google.golang.org/grpc v1.21.0 h1:G+97AoqBnmZIT91cLG/EkCoK9NSelj64P8bOHHNmGn0=
-google.golang.org/grpc v1.21.0/go.mod h1:oYelfM1adQP15Ek0mdvEgi9Df8B9CZIaU1084ijfRaM=
+google.golang.org/grpc v1.19.0/go.mod h1:mqu4LbDTu4XGKhr4mRzUsmM4RtVoemTSY81AxZiDr8c=
+google.golang.org/grpc v1.23.0/go.mod h1:Y5yQAOtifL1yxbo5wqy6BxZv8vAUGQwXBOALyacEbxg=
+google.golang.org/grpc v1.25.1/go.mod h1:c3i+UQWmh7LiEpx4sFZnkU36qjEYZ0imhYfXVyQciAY=
+google.golang.org/grpc v1.28.0 h1:bO/TA4OxCOummhSf10siHuG7vJOiwh7SpRpFZDkOgl4=
+google.golang.org/grpc v1.28.0/go.mod h1:rpkK4SK4GF4Ach/+MFLZUBavHOvF2JJB5uozKKal+60=
 honnef.co/go/tools v0.0.0-20190102054323-c2f93a96b099/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=
+honnef.co/go/tools v0.0.0-20190523083050-ea95bdfd59fc/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=

grpcurl.go

@@ -15,6 +15,8 @@ import (
 	"fmt"
 	"io/ioutil"
 	"net"
+	"os"
+	"regexp"
 	"sort"
 	"strings"
 
@@ -30,6 +32,7 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/metadata"
+	_ "google.golang.org/grpc/xds/experimental"
 )
 
 // ListServices uses the given descriptor source to return a sorted list of fully-qualified
@@ -161,6 +164,36 @@ func MetadataFromHeaders(headers []string) metadata.MD {
 	return md
 }
 
+var envVarRegex = regexp.MustCompile(`\${\w+}`)
+
+// ExpandHeaders expands environment variables contained in the header string.
+// If no corresponding environment variable is found an error is returned.
+// TODO: Add escaping for `${`
+func ExpandHeaders(headers []string) ([]string, error) {
+	expandedHeaders := make([]string, len(headers))
+	for idx, header := range headers {
+		if header == "" {
+			continue
+		}
+		results := envVarRegex.FindAllString(header, -1)
+		if len(results) == 0 {
+			expandedHeaders[idx] = headers[idx]
+			continue
+		}
+		expandedHeader := header
+		for _, result := range results {
+			envVarName := result[2 : len(result)-1] // strip leading `${` and trailing `}`
+			envVarValue, ok := os.LookupEnv(envVarName)
+			if !ok {
+				return nil, fmt.Errorf("header %q refers to missing environment variable %q", header, envVarName)
+			}
+			expandedHeader = strings.Replace(expandedHeader, result, envVarValue, -1)
+		}
+		expandedHeaders[idx] = expandedHeader
+	}
+	return expandedHeaders, nil
+}
+
 var base64Codecs = []*base64.Encoding{base64.StdEncoding, base64.URLEncoding, base64.RawStdEncoding, base64.RawURLEncoding}
 
 func decode(val string) (string, error) {
@@ -573,33 +606,44 @@ func BlockingDial(ctx context.Context, network, address string, creds credential
 		}
 	}
 
+	// custom credentials and dialer will notify on error via the
+	// writeResult function
+	if creds != nil {
+		creds = &errSignalingCreds{
+			TransportCredentials: creds,
+			writeResult:          writeResult,
+		}
+	}
 	dialer := func(ctx context.Context, address string) (net.Conn, error) {
+		// NB: We *could* handle the TLS handshake ourselves, in the custom
+		// dialer (instead of customizing both the dialer and the credentials).
+		// But that requires using WithInsecure dial option (so that the gRPC
+		// library doesn't *also* try to do a 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)
 		if err != nil {
 			writeResult(err)
-			return nil, err
 		}
-		if creds != nil {
-			conn, _, err = creds.ClientHandshake(ctx, address, conn)
-			if err != nil {
-				writeResult(err)
-				return nil, err
-			}
-		}
-		return conn, nil
+		return conn, err
 	}
 
 	// Even with grpc.FailOnNonTempDialError, this call will usually timeout in
 	// the face of TLS handshake errors. So we can't rely on grpc.WithBlock() to
 	// know when we're done. So we run it in a goroutine and then use result
-	// channel to either get the channel or fail-fast.
+	// channel to either get the connection or fail-fast.
 	go func() {
 		opts = append(opts,
 			grpc.WithBlock(),
 			grpc.FailOnNonTempDialError(true),
 			grpc.WithContextDialer(dialer),
-			grpc.WithInsecure(), // we are handling TLS, so tell grpc not to
 		)
+		if creds == nil {
+			opts = append(opts, grpc.WithInsecure())
+		} else {
+			opts = append(opts, grpc.WithTransportCredentials(creds))
+		}
 		conn, err := grpc.DialContext(ctx, address, opts...)
 		var res interface{}
 		if err != nil {
@@ -620,3 +664,18 @@ func BlockingDial(ctx context.Context, network, address string, creds credential
 		return nil, ctx.Err()
 	}
 }
+
+// errSignalingCreds is a wrapper around a TransportCredentials value, but
+// it will use the writeResult function to notify on error.
+type errSignalingCreds struct {
+	credentials.TransportCredentials
+	writeResult func(res interface{})
+}
+
+func (c *errSignalingCreds) ClientHandshake(ctx context.Context, addr string, rawConn net.Conn) (net.Conn, credentials.AuthInfo, error) {
+	conn, auth, err := c.TransportCredentials.ClientHandshake(ctx, addr, rawConn)
+	if err != nil {
+		c.writeResult(err)
+	}
+	return conn, auth, err
+}

grpcurl_test.go

@@ -300,6 +300,33 @@ func TestGetAllFiles(t *testing.T) {
 	}
 }
 
+func TestExpandHeaders(t *testing.T) {
+	inHeaders := []string{"key1: ${value}", "key2: bar", "key3: ${woo", "key4: woo}", "key5: ${TEST}",
+		"key6: ${TEST_VAR}", "${TEST}: ${TEST_VAR}", "key8: ${EMPTY}"}
+	os.Setenv("value", "value")
+	os.Setenv("TEST", "value5")
+	os.Setenv("TEST_VAR", "value6")
+	os.Setenv("EMPTY", "")
+	expectedHeaders := map[string]bool{"key1: value": true, "key2: bar": true, "key3: ${woo": true, "key4: woo}": true,
+		"key5: value5": true, "key6: value6": true, "value5: value6": true, "key8: ": true}
+
+	outHeaders, err := ExpandHeaders(inHeaders)
+	if err != nil {
+		t.Errorf("The ExpandHeaders function generated an unexpected error %s", err)
+	}
+	for _, expandedHeader := range outHeaders {
+		if _, ok := expectedHeaders[expandedHeader]; !ok {
+			t.Errorf("The ExpandHeaders function has returned an unexpected header. Received unexpected header %s", expandedHeader)
+		}
+	}
+
+	badHeaders := []string{"key: ${DNE}"}
+	_, err = ExpandHeaders(badHeaders)
+	if err == nil {
+		t.Errorf("The ExpandHeaders function should return an error for missing environment variables %q", badHeaders)
+	}
+}
+
 func fileNames(files []*desc.FileDescriptor) []string {
 	names := make([]string, len(files))
 	for i, f := range files {