github.com/mook-as/cf-cli@v7.0.0-beta.28.0.20200120190804-b91c115fae48+incompatible/util/configv3/write_config.go (about)

     1  package configv3
     2  
     3  import (
     4  	"encoding/json"
     5  	"io/ioutil"
     6  	"os"
     7  	"os/signal"
     8  	"syscall"
     9  )
    10  
    11  // WriteConfig creates the .cf directory and then writes the config.json. The
    12  // location of .cf directory is written in the same way LoadConfig reads .cf
    13  // directory.
    14  func (c *Config) WriteConfig() error {
    15  	rawConfig, err := json.MarshalIndent(c.ConfigFile, "", "  ")
    16  	if err != nil {
    17  		return err
    18  	}
    19  
    20  	dir := configDirectory()
    21  	err = os.MkdirAll(dir, 0700)
    22  	if err != nil {
    23  		return err
    24  	}
    25  
    26  	// Developer Note: The following is untested! Change at your own risk.
    27  	// Setup notifications of termination signals to channel sig, create a process to
    28  	// watch for these signals so we can remove transient config temp files.
    29  	sig := make(chan os.Signal, 10)
    30  	signal.Notify(sig, syscall.SIGHUP, syscall.SIGINT, syscall.SIGQUIT, syscall.SIGTERM, os.Interrupt)
    31  	defer signal.Stop(sig)
    32  
    33  	tempConfigFile, err := ioutil.TempFile(dir, "temp-config")
    34  	if err != nil {
    35  		return err
    36  	}
    37  	tempConfigFile.Close()
    38  	tempConfigFileName := tempConfigFile.Name()
    39  
    40  	go catchSignal(sig, tempConfigFileName)
    41  
    42  	err = ioutil.WriteFile(tempConfigFileName, rawConfig, 0600)
    43  	if err != nil {
    44  		return err
    45  	}
    46  
    47  	return os.Rename(tempConfigFileName, ConfigFilePath())
    48  }
    49  
    50  // catchSignal tries to catch SIGHUP, SIGINT, SIGKILL, SIGQUIT and SIGTERM, and
    51  // Interrupt for removing temporarily created config files before the program
    52  // ends.  Note:  we cannot intercept a `kill -9`, so a well-timed `kill -9`
    53  // will allow a temp config file to linger.
    54  func catchSignal(sig chan os.Signal, tempConfigFileName string) {
    55  	<-sig
    56  	_ = os.Remove(tempConfigFileName)
    57  	os.Exit(2)
    58  }