add and source new PATHs

envpath/envpath.go

@@ -0,0 +1,378 @@
+package main
+
+import (
+	"fmt"
+	"io/ioutil"
+	"math/rand"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// ppsep is used as the replacement for slashes in path
+// ex: ~/bin => ~bin
+// ex: ~/bin => home~bin
+// ex: ~/.local/opt/foo/bin => ~.local»opt»foo»bin
+// other patterns considered:
+//   ~/.local/opt/foo/bin => ~.local·opt·foo·bin
+//   ~/.local/opt/foo/bin => home».local»opt»foo»bin
+//   ~/.local/opt/foo/bin => HOME•.local•opt•foo•bin
+//   ~/.local/opt/foo/bin => HOME_.local_opt_foo_bin
+//   ~/.local/opt/foo/bin => HOME·.local·opt·foo·bin
+const ppsep = "»"
+
+func usage() {
+	fmt.Fprintf(os.Stderr, "Usage: envpath show|add|append|remove <path>\n")
+}
+
+func main() {
+	// TODO --system to add to the system PATH rather than the user PATH
+
+	// Usage:
+	if len(os.Args) < 2 {
+		usage()
+		os.Exit(1)
+	}
+	action := os.Args[1]
+
+	paths, err := Paths()
+	if nil != err {
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+		os.Exit(2)
+	}
+
+	if "show" == action {
+		if len(os.Args) > 2 {
+			usage()
+		}
+		fmt.Println()
+		for i := range paths {
+			fmt.Println("\t" + paths[i])
+		}
+		fmt.Println()
+		return
+	}
+
+	if len(os.Args) < 3 {
+		usage()
+		os.Exit(1)
+	}
+
+	pathentry := os.Args[2]
+	if "remove" != action {
+		stat, err := os.Stat(pathentry)
+		if nil != err {
+			// TODO --force
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+			os.Exit(2)
+		}
+		if !stat.IsDir() {
+			fmt.Fprintf(os.Stderr, "%q is not a directory (folder)\n", pathentry)
+			os.Exit(2)
+		}
+	}
+
+	switch action {
+	default:
+		usage()
+		os.Exit(1)
+	case "append":
+		newpath, _, err := addPath(pathentry, appendOrder)
+		if nil != err {
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+			return
+		}
+		fmt.Println("New sessions will have " + pathentry + " in their PATH.")
+		fmt.Println("To update this session run\n")
+		//fmt.Println("\tsource", pathfile)
+		fmt.Printf(`%sexport PATH="$PATH:%s"%s`, "\t", newpath, "\n")
+	case "add":
+		_, pathfile, err := addPath(pathentry, prependOrder)
+		if nil != err {
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+			return
+		}
+		fmt.Println("\nRun this command (or open a new shell) to finish:\n")
+		fmt.Printf("\tsource %s\n\n", pathfile)
+		//fmt.Printf(`%sexport PATH="%s:$PATH"%s`, "\t", newpath, "\n\n")
+	case "remove":
+		_, err := removePath(pathentry)
+		if nil != err {
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+			return
+		}
+	}
+
+	// TODO support both of these usages:
+	// 1. export PATH="$(envpath append /opt/whatever/bin)"
+	// 2. envpath append /opt/whatever/bin
+	//    export PATH="$PATH:/opt/whatever/bin"
+}
+
+// Paths returns the slice of PATHs from the Environment
+func Paths() ([]string, error) {
+	// ":" on *nix
+	return strings.Split(os.Getenv("PATH"), string(os.PathListSeparator)), nil
+}
+
+func init() {
+	rand.Seed(time.Now().UnixNano())
+}
+
+type setOrder bool
+
+const prependOrder setOrder = true
+const appendOrder setOrder = false
+
+// returns newpath, error
+func addPath(oldpathentry string, order setOrder) (string, string, error) {
+	home, err := os.UserHomeDir()
+	if nil != err {
+		return "", "", err
+	}
+	home = filepath.ToSlash(home)
+
+	pathentry, fname, err := normalizeEntryAndFile(home, oldpathentry)
+	if nil != err {
+		return "", "", err
+	}
+
+	envpathd := filepath.Join(home, ".config/envpath/path.d")
+	err = os.MkdirAll(envpathd, 0755)
+	if nil != err {
+		return "", "", err
+	}
+
+	err = initializeShells(home)
+	if nil != err {
+		return "", "", err
+	}
+
+	nodes, err := ioutil.ReadDir(envpathd)
+	if nil != err {
+		return "", "", err
+	}
+
+	var priority int
+	if prependOrder == order {
+		// Counter-intuitively later PATHs, prepended are placed earlier
+		priority, err = getOrder(nodes, pathentry, fname, envpathd, sortForward)
+	} else {
+		// Counter-intuitively earlier PATHs are placed later
+		priority, err = getOrder(nodes, pathentry, fname, envpathd, sortBackward)
+	}
+	if nil != err {
+		return "", "", err
+	}
+
+	if err := ensureNotInPath(home, pathentry); nil != err {
+		return "", "", err
+	}
+
+	// ex: 100-opt»foo»bin.sh
+	// ex: 105-home»bar»bin.sh
+	pathfile := fmt.Sprintf("%03d-%s", priority, fname)
+
+	fullname := filepath.Join(envpathd, pathfile)
+	export := []byte(fmt.Sprintf("# Generated for envpath. Do not edit.\nexport PATH=\"%s:$PATH\"\n", pathentry))
+	err = ioutil.WriteFile(fullname, export, 0755)
+	if nil != err {
+		return "", "", err
+	}
+	// If we change from having the user source the path directory
+	// then we should uncomment this so the user knows where the path files are
+	//fmt.Printf("Wrote %s\n", fullname)
+
+	return pathentry, fullname, nil
+}
+
+// TODO don't check in parser before add/append functions actually run
+func ensureNotInPath(home, pathentry string) error {
+	paths, err := Paths()
+	if nil != err {
+		return err
+	}
+
+	index := -1
+	for i := range paths {
+		entry, _ := normalizePathEntry(home, paths[i])
+		if pathentry == entry {
+			index = i
+			break
+		}
+	}
+	if index >= 0 {
+		fmt.Fprintf(
+			os.Stderr,
+			"%q is in your PATH at position %d and must be removed manually to re-order\n",
+			pathentry,
+			index,
+		)
+		os.Exit(3)
+	}
+	return nil
+}
+
+func normalizeEntryAndFile(home, pathentry string) (string, string, error) {
+	var err error
+
+	pathentry, err = normalizePathEntry(home, pathentry)
+	if nil != err {
+		return "", "", err
+	}
+
+	// Now we split and rejoin the paths as a unique name
+	// ex: /opt/foo/bin/ => opt/foo/bin => [opt foo bin]
+	// ex: ~/bar/bin/ => bar/bin => [bar bin]
+	names := strings.Split(strings.Trim(filepath.ToSlash(pathentry), "/"), "/")
+	if strings.HasPrefix(pathentry, "$HOME/") {
+		// ~/bar/bin/ => [home bar bin]
+		names[0] = "home"
+	}
+
+	// ex: /opt/foo/bin/ => opt»foo»bin.sh
+	fname := strings.Join(names, ppsep) + ".sh"
+
+	return pathentry, fname, nil
+}
+
+func normalizePathEntry(home, pathentry string) (string, error) {
+	var err error
+
+	// We add the slashes so that we don't get false matches
+	// ex: foo should match foo/bar, but should NOT match foobar
+	home, err = filepath.Abs(home)
+	if nil != err {
+		// I'm not sure how it's possible to get an error with Abs...
+		return "", err
+	}
+	home += "/"
+	pathentry, err = filepath.Abs(pathentry)
+	if nil != err {
+		return "", err
+	}
+	pathentry += "/"
+
+	// Next we make the path relative to / or ~/
+	// ex: /Users/me/.local/bin/ => .local/bin/
+	if strings.HasPrefix(pathentry, home) {
+		pathentry = "$HOME/" + strings.TrimPrefix(pathentry, home)
+	}
+
+	return pathentry, nil
+}
+
+func sortForward(priority, n int) int {
+	// Pick a number such that 99 > newpriority > priority
+	if n >= priority {
+		m := n % 5
+		if 0 == m {
+			priority += 5
+		} else {
+			priority += (5 - m)
+		}
+	}
+
+	return priority
+}
+
+func sortBackward(priority, n int) int {
+	// Pick a number such that 0 < newpriority < priority
+	if n <= priority {
+		m := n % 5
+		if 0 == m {
+			m = 5
+		}
+		priority -= m
+	}
+
+	return priority
+}
+
+type sorter = func(int, int) int
+
+func getOrder(nodes []os.FileInfo, pathentry, fname, envpathd string, fn sorter) (int, error) {
+	// assuming people will append more often than prepend
+	// default the priority to less than halfway
+	priority := 100
+	for i := range nodes {
+		f := nodes[i]
+		name := f.Name()
+		if !strings.HasSuffix(name, ".sh") {
+			continue
+		}
+		if strings.HasSuffix(name, "-"+fname) {
+			return 0, fmt.Errorf(
+				"Error: %s already exports %s",
+				filepath.Join("~/.config/envpath/path.d", f.Name()),
+				pathentry,
+			)
+		}
+		n, err := strconv.Atoi(strings.Split(name, "-")[0])
+		if nil != err {
+			continue
+		}
+
+		priority = fn(priority, n)
+	}
+
+	return priority, nil
+}
+
+func removePath(oldpathentry string) (string, error) {
+	// TODO Show current PATH sans this item
+	/*
+		oldpaths := paths
+		paths = []string{}
+		for i := range oldpaths {
+			if i != index {
+				paths = append(paths, oldpaths[i])
+			}
+		}
+	*/
+
+	home, err := os.UserHomeDir()
+	if nil != err {
+		return "", err
+	}
+	home = filepath.ToSlash(home)
+
+	pathentry, fname, err := normalizeEntryAndFile(home, oldpathentry)
+	if nil != err {
+		return "", err
+	}
+
+	envpathd := filepath.Join(home, ".config/envpath/path.d")
+	err = os.MkdirAll(envpathd, 0755)
+	if nil != err {
+		return "", err
+	}
+
+	/*
+		err = ensureNotInPath(home, pathentry)
+		if nil != err {
+			return "", err
+		}
+	*/
+
+	nodes, err := ioutil.ReadDir(envpathd)
+	if nil != err {
+		return "", err
+	}
+
+	// TODO rename getOrder to getNext
+	_, err = getOrder(nodes, pathentry, fname, envpathd, sortForward)
+	if nil == err {
+		fmt.Fprintf(os.Stderr, "%q is not managed by envpath.\n", pathentry)
+	}
+
+	/*
+		if index < 0 {
+			fmt.Fprintf(os.Stderr, "%q is NOT in PATH.\n", pathentry)
+			os.Exit(3)
+		}
+	*/
+	return "", nil
+}

envpath/manager.go

@@ -0,0 +1,248 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+)
+
+type envConfig struct {
+	shell      string
+	shellDesc  string
+	home       string
+	rcFile     string
+	rcScript   string
+	loadFile   string
+	loadScript string
+}
+
+var confs []*envConfig
+
+func init() {
+	home, err := os.UserHomeDir()
+	if nil != err {
+		panic(err) // Must get home directory
+	}
+	home = filepath.ToSlash(home)
+
+	confs = []*envConfig{
+		&envConfig{
+			home:       home,
+			shell:      "bash",
+			shellDesc:  "bourne-compatible shell (bash)",
+			rcFile:     ".bashrc",
+			rcScript:   "[ -s \"$HOME/.config/envpath/load.sh\" ] && source \"$HOME/.config/envpath/load.sh\"\n",
+			loadFile:   ".config/envpath/load.sh",
+			loadScript: "for x in ~/.config/envpath/path.d/*.sh; do\n\tsource \"$x\"\ndone\n",
+		},
+		&envConfig{
+			home:       home,
+			shell:      "zsh",
+			shellDesc:  "bourne-compatible shell (zsh)",
+			rcFile:     ".zshrc",
+			rcScript:   "[ -s \"$HOME/.config/envpath/load.sh\" ] && source \"$HOME/.config/envpath/load.sh\"\n",
+			loadFile:   ".config/envpath/load.sh",
+			loadScript: "for x in ~/.config/envpath/path.d/*.sh; do\n\tsource \"$x\"\ndone\n",
+		},
+		&envConfig{
+			home:       home,
+			shell:      "fish",
+			shellDesc:  "fish shell",
+			rcFile:     ".config/fish/config.fish",
+			rcScript:   "test -s \"$HOME/.config/envpath/load.fish\"; and source \"$HOME/.config/envpath/load.fish\"\n",
+			loadFile:   ".config/envpath/load.fish",
+			loadScript: "for x in ~/.config/envpath/path.d/*.sh\n\tsource \"$x\"\nend\n",
+		},
+	}
+}
+
+func initializeShells(home string) error {
+	var hasRC bool
+	var nativeMatch *envConfig
+	for i := range confs {
+		c := confs[i]
+
+		if os.Getenv("SHELL") == c.shell {
+			nativeMatch = c
+		}
+
+		_, err := os.Stat(filepath.Join(home, c.rcFile))
+		if nil != err {
+			continue
+		}
+		hasRC = true
+	}
+
+	// ensure rc
+	if !hasRC {
+		if nil == nativeMatch {
+			return fmt.Errorf(
+				"%q is not a recognized shell and found none of .bashrc, .zshrc, .config/fish/config.fish",
+				os.Getenv("SHELL"),
+			)
+		}
+
+		// touch the rc file
+		f, err := os.OpenFile(filepath.Join(home, nativeMatch.rcFile), os.O_CREATE|os.O_WRONLY, 0644)
+		if nil != err {
+			return err
+		}
+		if err := f.Close(); nil != err {
+			return err
+		}
+	}
+
+	// MacOS is special. It *requires* .bash_profile in order to read .bashrc
+	if "darwin" == runtime.GOOS && "bash" == os.Getenv("SHELL") {
+		if err := ensureBashProfile(home); nil != err {
+			return err
+		}
+	}
+
+	//
+	// Bash (sh, dash, zsh, ksh)
+	//
+	// http://www.joshstaiger.org/archives/2005/07/bash_profile_vs.html
+	for i := range confs {
+		c := confs[i]
+		err := c.maybeInitializeShell()
+		if nil != err {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (c *envConfig) maybeInitializeShell() error {
+	if _, err := os.Stat(filepath.Join(c.home, c.rcFile)); nil != err {
+		if !os.IsNotExist(err) {
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+		}
+		return nil
+	}
+
+	changed, err := c.initializeShell()
+	if nil != err {
+		return err
+	}
+
+	if changed {
+		fmt.Printf(
+			"Detected %s shell and updated ~/%s\n",
+			c.shellDesc,
+			strings.TrimPrefix(c.rcFile, c.home),
+		)
+	}
+
+	return nil
+}
+
+func (c *envConfig) initializeShell() (bool, error) {
+	if err := c.ensurePathsLoader(); err != nil {
+		return false, err
+	}
+
+	// Get current config
+	// ex: ~/.bashrc
+	// ex: ~/.config/fish/config.fish
+	b, err := ioutil.ReadFile(filepath.Join(c.home, c.rcFile))
+	if nil != err {
+		return false, err
+	}
+
+	// For Windows, just in case
+	s := strings.Replace(string(b), "\r\n", "\n", -1)
+
+	// Looking to see if loader script has been added to rc file
+	lines := strings.Split(strings.TrimSpace(s), "\n")
+	for i := range lines {
+		line := lines[i]
+		if line == strings.TrimSpace(c.rcScript) {
+			// indicate that it was not neccesary to change the rc file
+			return false, nil
+		}
+	}
+
+	// Open rc file to append and write
+	f, err := os.OpenFile(filepath.Join(c.home, c.rcFile), os.O_APPEND|os.O_WRONLY, 0644)
+	if err != nil {
+		return false, err
+	}
+
+	// Generate our script
+	script := fmt.Sprintf("# Generated for envpath. Do not edit.\n%s\n", c.rcScript)
+
+	// If there's not a newline before our template,
+	// include it in the template. We want nice things.
+	n := len(lines)
+	if "" != strings.TrimSpace(lines[n-1]) {
+		script = "\n" + script
+	}
+
+	// Write and close the rc file
+	if _, err := f.Write([]byte(script)); err != nil {
+		return false, err
+	}
+	if err := f.Close(); err != nil {
+		return true, err
+	}
+
+	// indicate that we have changed the rc file
+	return true, nil
+}
+
+func (c *envConfig) ensurePathsLoader() error {
+	loadFile := filepath.Join(c.home, c.loadFile)
+
+	if _, err := os.Stat(loadFile); nil != err {
+		// Write the loop file. For example:
+		// $HOME/.config/envpath/load.sh
+		// $HOME/.config/envpath/load.fish
+		// TODO maybe don't write every time
+		if err := ioutil.WriteFile(
+			loadFile,
+			[]byte(fmt.Sprintf("# Generated for envpath. Do not edit.\n%s\n", c.loadScript)),
+			os.FileMode(0755),
+		); nil != err {
+			return err
+		}
+		fmt.Printf("Created %s\n", "~/"+c.loadFile)
+	}
+	return nil
+}
+
+// I think this issue only affects darwin users with bash as the default shell
+func ensureBashProfile(home string) error {
+	profileFile := filepath.Join(home, ".bash_profile")
+
+	// touch the profile file
+	f, err := os.OpenFile(profileFile, os.O_CREATE|os.O_WRONLY, 0644)
+	if nil != err {
+		return err
+	}
+	if err := f.Close(); nil != err {
+		return err
+	}
+
+	b, err := ioutil.ReadFile(profileFile)
+	if !bytes.Contains(b, []byte(".bashrc")) {
+		f, err := os.OpenFile(profileFile, os.O_APPEND|os.O_WRONLY, 0644)
+		if nil != err {
+			return err
+		}
+		sourceBashRC := "[ -s \"$HOME/.bashrc\" ] && source \"$HOME/.bashrc\"\n"
+		b := []byte(fmt.Sprintf("# Generated for MacOS bash. Do not edit.\n%s\n", sourceBashRC))
+		_, err = f.Write(b)
+		if nil != err {
+			return err
+		}
+		fmt.Printf("Updated ~/.bash_profile to source ~/.bashrc\n")
+	}
+
+	return nil
+}