client/cmd/rpc: RPC CLI

client/cmd/rpc/call.go

Index: client/cmd/rpc/call.go
diff --git a/client/cmd/rpc/call.go b/client/cmd/rpc/call.go
new file mode 100644
index 0000000000000000000000000000000000000000..766893c269ddf873720fbdb9fffd4de60fdf6670
--- /dev/null
+++ b/client/cmd/rpc/call.go
@@ -0,0 +1,186 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"sort"
+	"strings"
+
+	"github.com/maruel/subcommands"
+	"golang.org/x/net/context"
+
+	"github.com/luci/luci-go/common/logging"
+)
+
+type format string
+
+const (
+	formatBinary format = "binary"
+	formatJSON   format = "json"
+	formatText   format = "text"
+)
+
+// TODO(nodir): support specifying message fields with options, e.g.
+//   rpc call :8080 helloworld.Greeter -name Lucy
+// It will be the default request format.
+
+var cmdCall = &subcommands.Command{
+	UsageLine: `call [flags] <server> <service>.<method>
+
+  server: scheme (http or https) and hostname, e.g. "https://example.com".

[iannucci, 2016/01/15 03:45:16]

can we ONLY support https?

...

Oh, dev_appserver.... Can we make localhost the only exception?

[nodir, 2016/01/15 18:17:19]

Done. Also simplified usage string and parsing function

+	A short syntax for "http://localhost:port" is ":port", e.g. ":8080".
+  service: full name of a service, e.g. "pkg.service"
+  method: name of the method.
+
+Flags:`,
+	ShortDesc: "calls a service method.",
+	LongDesc:  "Calls a service method.",
+	CommandRun: func() subcommands.CommandRun {
+		c := &callRun{}
+		c.registerBaseFlags()
+		c.Flags.StringVar(&c.format, "format", string(formatJSON), fmt.Sprintf(
+			"Request format, read from stdin. Valid values: %q, %q, %q.",
+			formatJSON, formatBinary, formatText,
+		))
+		return c
+	},
+}
+
+// callRun implements "call" subcommand.
+type callRun struct {
+	cmdRun
+	format  string
+	message string
+}
+
+func (r *callRun) Run(a subcommands.Application, args []string) int {
+	if len(args) != 2 {
+		return r.argErr("")
+	}
+	var req request
+	var err error
+	req.server, err = parseServer(args[0])
+	if err != nil {
+		return r.argErr("server: %s", err)
+	}
+	req.service, req.method, err = splitServiceAndMethod(args[1])
+	if err != nil {
+		return r.argErr("%s", err)
+	}
+
+	switch f := format(r.format); f {
+	case formatJSON, formatBinary, formatText:
+		req.format = f
+	default:
+		return r.argErr("invalid format %q", f)
+	}
+
+	var msg bytes.Buffer
+	if _, err := io.Copy(&msg, os.Stdin); err != nil {
+		return r.done(fmt.Errorf("could not read message from stdin: %s", err))
+	}
+	req.message = msg.Bytes()
+	return r.done(call(r.initContext(), &req, os.Stdout))
+}
+
+func splitServiceAndMethod(fullName string) (service string, method string, err error) {
+	lastDot := strings.LastIndex(fullName, ".")
+	if lastDot < 0 {
+		return "", "", fmt.Errorf("invalid full method name %q. It must contain a '.'", fullName)
+	}
+	service = fullName[:lastDot]
+	method = fullName[lastDot+1:]
+	return
+}
+
+// request is an RPC request.
+type request struct {
+	server  *url.URL
+	service string
+	method  string
+	format  format
+	message []byte
+}
+
+// call makes an RPC and writes response to out.
+func call(c context.Context, req *request, out io.Writer) error {
+	if req.format == "" {
+		return fmt.Errorf("format is not set")
+	}
+
+	// Create HTTP request.
+	methodURL := *req.server
+	methodURL.Path = fmt.Sprintf("/prpc/%s/%s", req.service, req.method)
+	hr, err := http.NewRequest("POST", methodURL.String(), bytes.NewBuffer(req.message))
+	if err != nil {
+		return err
+	}
+
+	// Set headers.
+	mediaType := "application/prpc; encoding=" + string(req.format)
+	if len(req.message) > 0 {
+		hr.Header.Set("Content-Type", mediaType)
+	}
+	hr.Header.Set("Accept", mediaType)
+	hr.Header.Set("User-Agent", userAgent)
+	hr.Header.Set("Content-Length", fmt.Sprintf("%d", len(req.message)))
+	// TODO(nodir): add "Accept-Encoding: gzip" when pRPC server supports it.
+
+	// Log request in curl style.
+	logRequest(c, hr)
+	logging.Infof(c, ">")
+
+	// Send the request.
+	var client http.Client
+	res, err := client.Do(hr)
+	if err != nil {
+		return fmt.Errorf("failed to send request: %s", err)
+	}
+	defer res.Body.Close()
+
+	// Log response in curl style.
+	logResponse(c, res)
+	logging.Infof(c, "<")

[iannucci, 2016/01/15 03:45:16]

do we log to stderr so that you can pipe the output to get valid
binary/json/text proto on stdout?

[nodir, 2016/01/15 18:17:19]

yes to stderr, see
https://chromiumcodereview.appspot.com/1587323003/diff/20001/client/cmd/rpc/m...

+
+	// Read response.
+	if _, err := io.Copy(out, res.Body); err != nil {
+		return fmt.Errorf("failed to read response: %s", err)
+	}
+	return err
+}
+
+// logRequest logs an HTTP request in curl style.
+func logRequest(c context.Context, r *http.Request) {
+	logging.Infof(c, "> %s %s %s", r.Method, r.URL.Path, r.Proto)
+	logging.Infof(c, "> Host: %s", r.URL.Host)
+	logHeaders(c, r.Header, "> ")
+}
+
+// logResponse logs an HTTP response in curl style.
+func logResponse(c context.Context, r *http.Response) {
+	logging.Infof(c, "< %s %s", r.Proto, r.Status)
+	logHeaders(c, r.Header, "< ")
+
+}
+
+// logHeaders logs all headers sorted.
+func logHeaders(c context.Context, header http.Header, prefix string) {
+	var names []string
+	for n := range header {
+		names = append(names, n)
+	}
+	sort.Strings(names)
+	for _, name := range names {
+		for _, v := range header[name] {
+			logging.Infof(c, "%s%s: %s", prefix, name, v)
+		}
+	}
+}