cmd/geth: added 'geth bug' command (#3684)

* cmd/geth: added 'geth bug' command

Added bug command to geth, which will open a browser window
with an issue template and some additional system information.

* cmd/geth: update bug with better infos

* cmd/geth: added browser fallback

* cmd/geth: govet yo momma

3 files changed, 155 insertions, 0 deletions

diff --git a/cmd/geth/bugcmd.go b/cmd/geth/bugcmd.go
new file mode 100644
index 000000000..f21880501
--- /dev/null
+++ b/cmd/geth/bugcmd.go
@@ -0,0 +1,108 @@
+// Copyright 2017 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/url"
+	"os/exec"
+	"runtime"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/cmd/internal/browser"
+	"github.com/ethereum/go-ethereum/params"
+
+	cli "gopkg.in/urfave/cli.v1"
+)
+
+var bugCommand = cli.Command{
+	Action:    reportBug,
+	Name:      "bug",
+	Usage:     "opens a window to report a bug on the geth repo",
+	ArgsUsage: " ",
+	Category:  "MISCELLANEOUS COMMANDS",
+}
+
+const issueUrl = "https://github.com/ethereum/go-ethereum/issues/new"
+
+// reportBug reports a bug by opening a new URL to the go-ethereum GH issue
+// tracker and setting default values as the issue body.
+func reportBug(ctx *cli.Context) error {
+	// execute template and write contents to buff
+	var buff bytes.Buffer
+
+	fmt.Fprintln(&buff, header)
+	fmt.Fprintln(&buff, "Version:", params.Version)
+	fmt.Fprintln(&buff, "Go Version:", runtime.Version())
+	fmt.Fprintln(&buff, "OS:", runtime.GOOS)
+	printOSDetails(&buff)
+
+	// open a new GH issue
+	if !browser.Open(issueUrl + "?body=" + url.QueryEscape(buff.String())) {
+		fmt.Printf("Please file a new issue at %s using this template:\n%s", issueUrl, buff.String())
+	}
+	return nil
+}
+
+// copied from the Go source. Copyright 2017 The Go Authors
+func printOSDetails(w io.Writer) {
+	switch runtime.GOOS {
+	case "darwin":
+		printCmdOut(w, "uname -v: ", "uname", "-v")
+		printCmdOut(w, "", "sw_vers")
+	case "linux":
+		printCmdOut(w, "uname -sr: ", "uname", "-sr")
+		printCmdOut(w, "", "lsb_release", "-a")
+	case "openbsd", "netbsd", "freebsd", "dragonfly":
+		printCmdOut(w, "uname -v: ", "uname", "-v")
+	case "solaris":
+		out, err := ioutil.ReadFile("/etc/release")
+		if err == nil {
+			fmt.Fprintf(w, "/etc/release: %s\n", out)
+		} else {
+			fmt.Printf("failed to read /etc/release: %v\n", err)
+		}
+	}
+}
+
+// printCmdOut prints the output of running the given command.
+// It ignores failures; 'go bug' is best effort.
+//
+// copied from the Go source. Copyright 2017 The Go Authors
+func printCmdOut(w io.Writer, prefix, path string, args ...string) {
+	cmd := exec.Command(path, args...)
+	out, err := cmd.Output()
+	if err != nil {
+		fmt.Printf("%s %s: %v\n", path, strings.Join(args, " "), err)
+		return
+	}
+	fmt.Fprintf(w, "%s%s\n", prefix, bytes.TrimSpace(out))
+}
+
+const header = `Please answer these questions before submitting your issue. Thanks!
+
+#### What did you do?
+ 
+#### What did you expect to see?
+ 
+#### What did you see instead?
+ 
+#### System details
+`
diff --git a/cmd/geth/main.go b/cmd/geth/main.go
index c19770bfa..7d98f6bb2 100644
--- a/cmd/geth/main.go
+++ b/cmd/geth/main.go
@@ -81,6 +81,7 @@ func init() {
 		// See misccmd.go:
 		makedagCommand,
 		versionCommand,
+		bugCommand,
 		licenseCommand,
 	}
 
diff --git a/cmd/internal/browser/browser.go b/cmd/internal/browser/browser.go
new file mode 100644
index 000000000..897086f47
--- /dev/null
+++ b/cmd/internal/browser/browser.go
@@ -0,0 +1,46 @@
+// Copyright 2016 The Go 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 browser provides utilities for interacting with users' browsers.
+package browser
+
+import (
+	"os"
+	"os/exec"
+	"runtime"
+)
+
+// Commands returns a list of possible commands to use to open a url.
+func Commands() [][]string {
+	var cmds [][]string
+	if exe := os.Getenv("BROWSER"); exe != "" {
+		cmds = append(cmds, []string{exe})
+	}
+	switch runtime.GOOS {
+	case "darwin":
+		cmds = append(cmds, []string{"/usr/bin/open"})
+	case "windows":
+		cmds = append(cmds, []string{"cmd", "/c", "start"})
+	default:
+		cmds = append(cmds, []string{"xdg-open"})
+	}
+	cmds = append(cmds,
+		[]string{"chrome"},
+		[]string{"google-chrome"},
+		[]string{"chromium"},
+		[]string{"firefox"},
+	)
+	return cmds
+}
+
+// Open tries to open url in a browser and reports whether it succeeded.
+func Open(url string) bool {
+	for _, args := range Commands() {
+		cmd := exec.Command(args[0], append(args[1:], url)...)
+		if cmd.Start() == nil {
+			return true
+		}
+	}
+	return false
+}