142 lines
3.5 KiB
Go
142 lines
3.5 KiB
Go
package main
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import (
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"crypto/sha256"
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"fmt"
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"io"
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"io/fs"
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"log"
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"os"
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"path/filepath"
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"time"
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flags "github.com/jessevdk/go-flags"
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)
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const VERSION string = "v0.4.1"
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type Options struct {
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Version bool `short:"v" long:"version" description:"Displays version info and exits"`
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Quiet bool `short:"q" long:"quiet" description:"Suppresses status messages (stderr lines beginning with '&')"`
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Files []string `short:"f" long:"file" description:"File(s) to listen to (watch)" value-name:"FILE"`
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Condition string `short:"w" long:"when" description:"If multiple files are specified, choose if any file or all files specified are needed to trigger COMMAND" default:"any" choice:"any" choice:"all"`
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NoChecksum bool `short:"x" long:"no-checksum" description:"Do not calculate checksum as an additional check for file changes (see MODES section in man page for more info)"`
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Interval string `short:"i" long:"interval" description:"Use this time interval (ex. 5m30s, 1s) between filesystem checks instead of watching kernel events. If the interval is effectively 0 (the default), kernel events are used" default:"0s"`
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RunFirst bool `short:"r" long:"run" description:"Runs COMMAND (if specified) before starting listen"`
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}
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func validateArgs(opts Options, commandLen int) error {
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// file checks
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if len(opts.Files) <= 0 {
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fmt.Println("listen: at least one file (-f) is required")
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return flags.ErrCommandRequired
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}
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for _, file := range opts.Files {
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info, err := os.Stat(file)
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if err != nil {
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fmt.Printf("listen: %s\n", err)
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return err
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}
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if info.IsDir() {
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fmt.Printf("listen: %s: not a file\n", file)
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return fs.ErrInvalid
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}
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_, err = os.Open(file)
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if err != nil {
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fmt.Printf("listen: %s\n", err)
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return err
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}
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}
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// interval checks
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if _, err := time.ParseDuration(opts.Interval); err != nil {
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fmt.Printf("listen: %s\n", err)
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return err
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}
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// run first check
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if commandLen < 1 && opts.RunFirst {
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fmt.Println("listen: -r cannot be specified without a command")
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return flags.ErrInvalidChoice
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}
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return nil
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}
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func setup(opts Options, command []string) int {
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var filesMap map[string]bool = make(map[string]bool)
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var cksumMap map[string][]byte = make(map[string][]byte)
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var intervalMap map[string]time.Time = make(map[string]time.Time)
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intervalDuration, _ := time.ParseDuration(opts.Interval)
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success := true
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for _, file := range opts.Files {
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hasher := sha256.New()
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f, err := os.Open(file)
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if err != nil {
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success = false
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break
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}
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defer f.Close()
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s, err := os.Stat(file)
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if err != nil {
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success = false
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break
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}
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if _, err := io.Copy(hasher, f); err != nil {
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log.Fatal(err)
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}
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abs, err := filepath.Abs(file)
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if err == nil {
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filesMap[abs] = false
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cksumMap[abs] = hasher.Sum(nil)
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intervalMap[abs] = s.ModTime()
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} else {
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success = false
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break
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}
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}
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if success {
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l := Listen{filesMap, cksumMap, intervalMap, opts.Condition, opts.NoChecksum, intervalDuration, command, opts.Quiet, opts.RunFirst}
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return l.Run()
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}
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return -1
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}
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func main() {
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ret := 0
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opts := Options{}
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parser := flags.NewParser(&opts, flags.Default)
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parser.Usage = "[OPTIONS] -- [COMMAND]"
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remaining, err := parser.Parse()
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defer func() {
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if err := recover(); err != nil {
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switch ret {
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case -1:
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os.Exit(5)
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default:
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os.Exit(ret)
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}
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}
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}()
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if err == nil {
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if opts.Version {
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fmt.Printf("listen %s\n", VERSION)
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} else if err := validateArgs(opts, len(remaining)); err == nil {
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ret = setup(opts, remaining)
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if ret != 0 {
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panic(ret)
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}
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}
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}
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}
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