github.com/DFWallet/tendermint-cosmos@v0.0.2/libs/os/os.go (about)

     1  package os
     2  
     3  import (
     4  	"errors"
     5  	"fmt"
     6  	"io"
     7  	"io/ioutil"
     8  	"os"
     9  	"os/signal"
    10  	"syscall"
    11  )
    12  
    13  type logger interface {
    14  	Info(msg string, keyvals ...interface{})
    15  }
    16  
    17  // TrapSignal catches the SIGTERM/SIGINT and executes cb function. After that it exits
    18  // with code 0.
    19  func TrapSignal(logger logger, cb func()) {
    20  	c := make(chan os.Signal, 1)
    21  	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
    22  	go func() {
    23  		for sig := range c {
    24  			logger.Info(fmt.Sprintf("captured %v, exiting...", sig))
    25  			if cb != nil {
    26  				cb()
    27  			}
    28  			os.Exit(0)
    29  		}
    30  	}()
    31  }
    32  
    33  // Kill the running process by sending itself SIGTERM.
    34  func Kill() error {
    35  	p, err := os.FindProcess(os.Getpid())
    36  	if err != nil {
    37  		return err
    38  	}
    39  	return p.Signal(syscall.SIGTERM)
    40  }
    41  
    42  func Exit(s string) {
    43  	fmt.Printf(s + "\n")
    44  	os.Exit(1)
    45  }
    46  
    47  // EnsureDir ensures the given directory exists, creating it if necessary.
    48  // Errors if the path already exists as a non-directory.
    49  func EnsureDir(dir string, mode os.FileMode) error {
    50  	err := os.MkdirAll(dir, mode)
    51  	if err != nil {
    52  		return fmt.Errorf("could not create directory %q: %w", dir, err)
    53  	}
    54  	return nil
    55  }
    56  
    57  func FileExists(filePath string) bool {
    58  	_, err := os.Stat(filePath)
    59  	return !os.IsNotExist(err)
    60  }
    61  
    62  func ReadFile(filePath string) ([]byte, error) {
    63  	return ioutil.ReadFile(filePath)
    64  }
    65  
    66  func MustReadFile(filePath string) []byte {
    67  	fileBytes, err := ioutil.ReadFile(filePath)
    68  	if err != nil {
    69  		Exit(fmt.Sprintf("MustReadFile failed: %v", err))
    70  		return nil
    71  	}
    72  	return fileBytes
    73  }
    74  
    75  func WriteFile(filePath string, contents []byte, mode os.FileMode) error {
    76  	return ioutil.WriteFile(filePath, contents, mode)
    77  }
    78  
    79  func MustWriteFile(filePath string, contents []byte, mode os.FileMode) {
    80  	err := WriteFile(filePath, contents, mode)
    81  	if err != nil {
    82  		Exit(fmt.Sprintf("MustWriteFile failed: %v", err))
    83  	}
    84  }
    85  
    86  // CopyFile copies a file. It truncates the destination file if it exists.
    87  func CopyFile(src, dst string) error {
    88  	srcfile, err := os.Open(src)
    89  	if err != nil {
    90  		return err
    91  	}
    92  	defer srcfile.Close()
    93  
    94  	info, err := srcfile.Stat()
    95  	if err != nil {
    96  		return err
    97  	}
    98  	if info.IsDir() {
    99  		return errors.New("cannot read from directories")
   100  	}
   101  
   102  	// create new file, truncate if exists and apply same permissions as the original one
   103  	dstfile, err := os.OpenFile(dst, os.O_RDWR|os.O_CREATE|os.O_TRUNC, info.Mode().Perm())
   104  	if err != nil {
   105  		return err
   106  	}
   107  	defer dstfile.Close()
   108  
   109  	_, err = io.Copy(dstfile, srcfile)
   110  	return err
   111  }