package internal import ( "bufio" "bytes" "compress/gzip" "context" "crypto/rand" "errors" "io" "log" "math/big" "os" "os/exec" "strconv" "strings" "syscall" "time" "unicode" "github.com/alecthomas/units" ) const alphanum string = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz" var ( TimeoutErr = errors.New("Command timed out.") NotImplementedError = errors.New("not implemented yet") VersionAlreadySetError = errors.New("version has already been set") ) // Set via the main module var version string // Duration just wraps time.Duration type Duration struct { Duration time.Duration } // Size just wraps an int64 type Size struct { Size int64 } // SetVersion sets the telegraf agent version func SetVersion(v string) error { if version != "" { return VersionAlreadySetError } version = v return nil } // Version returns the telegraf agent version func Version() string { return version } // UnmarshalTOML parses the duration from the TOML config file func (d *Duration) UnmarshalTOML(b []byte) error { var err error b = bytes.Trim(b, `'`) // see if we can directly convert it d.Duration, err = time.ParseDuration(string(b)) if err == nil { return nil } // Parse string duration, ie, "1s" if uq, err := strconv.Unquote(string(b)); err == nil && len(uq) > 0 { d.Duration, err = time.ParseDuration(uq) if err == nil { return nil } } // First try parsing as integer seconds sI, err := strconv.ParseInt(string(b), 10, 64) if err == nil { d.Duration = time.Second * time.Duration(sI) return nil } // Second try parsing as float seconds sF, err := strconv.ParseFloat(string(b), 64) if err == nil { d.Duration = time.Second * time.Duration(sF) return nil } return nil } func (s *Size) UnmarshalTOML(b []byte) error { var err error b = bytes.Trim(b, `'`) val, err := strconv.ParseInt(string(b), 10, 64) if err == nil { s.Size = val return nil } uq, err := strconv.Unquote(string(b)) if err != nil { return err } val, err = units.ParseStrictBytes(uq) if err != nil { return err } s.Size = val return nil } // ReadLines reads contents from a file and splits them by new lines. // A convenience wrapper to ReadLinesOffsetN(filename, 0, -1). func ReadLines(filename string) ([]string, error) { return ReadLinesOffsetN(filename, 0, -1) } // ReadLines reads contents from file and splits them by new line. // The offset tells at which line number to start. // The count determines the number of lines to read (starting from offset): // n >= 0: at most n lines // n < 0: whole file func ReadLinesOffsetN(filename string, offset uint, n int) ([]string, error) { f, err := os.Open(filename) if err != nil { return []string{""}, err } defer f.Close() var ret []string r := bufio.NewReader(f) for i := 0; i < n+int(offset) || n < 0; i++ { line, err := r.ReadString('\n') if err != nil { break } if i < int(offset) { continue } ret = append(ret, strings.Trim(line, "\n")) } return ret, nil } // RandomString returns a random string of alpha-numeric characters func RandomString(n int) string { var bytes = make([]byte, n) rand.Read(bytes) for i, b := range bytes { bytes[i] = alphanum[b%byte(len(alphanum))] } return string(bytes) } // SnakeCase converts the given string to snake case following the Golang format: // acronyms are converted to lower-case and preceded by an underscore. func SnakeCase(in string) string { runes := []rune(in) length := len(runes) var out []rune for i := 0; i < length; i++ { if i > 0 && unicode.IsUpper(runes[i]) && ((i+1 < length && unicode.IsLower(runes[i+1])) || unicode.IsLower(runes[i-1])) { out = append(out, '_') } out = append(out, unicode.ToLower(runes[i])) } return string(out) } // CombinedOutputTimeout runs the given command with the given timeout and // returns the combined output of stdout and stderr. // If the command times out, it attempts to kill the process. func CombinedOutputTimeout(c *exec.Cmd, timeout time.Duration) ([]byte, error) { var b bytes.Buffer c.Stdout = &b c.Stderr = &b if err := c.Start(); err != nil { return nil, err } err := WaitTimeout(c, timeout) return b.Bytes(), err } // RunTimeout runs the given command with the given timeout. // If the command times out, it attempts to kill the process. func RunTimeout(c *exec.Cmd, timeout time.Duration) error { if err := c.Start(); err != nil { return err } return WaitTimeout(c, timeout) } // WaitTimeout waits for the given command to finish with a timeout. // It assumes the command has already been started. // If the command times out, it attempts to kill the process. func WaitTimeout(c *exec.Cmd, timeout time.Duration) error { timer := time.AfterFunc(timeout, func() { err := c.Process.Kill() if err != nil { log.Printf("E! FATAL error killing process: %s", err) return } }) err := c.Wait() isTimeout := timer.Stop() if err != nil { return err } else if isTimeout == false { return TimeoutErr } return err } // RandomSleep will sleep for a random amount of time up to max. // If the shutdown channel is closed, it will return before it has finished // sleeping. func RandomSleep(max time.Duration, shutdown chan struct{}) { if max == 0 { return } maxSleep := big.NewInt(max.Nanoseconds()) var sleepns int64 if j, err := rand.Int(rand.Reader, maxSleep); err == nil { sleepns = j.Int64() } t := time.NewTimer(time.Nanosecond * time.Duration(sleepns)) select { case <-t.C: return case <-shutdown: t.Stop() return } } // RandomDuration returns a random duration between 0 and max. func RandomDuration(max time.Duration) time.Duration { if max == 0 { return 0 } var sleepns int64 maxSleep := big.NewInt(max.Nanoseconds()) if j, err := rand.Int(rand.Reader, maxSleep); err == nil { sleepns = j.Int64() } return time.Duration(sleepns) } // SleepContext sleeps until the context is closed or the duration is reached. func SleepContext(ctx context.Context, duration time.Duration) error { if duration == 0 { return nil } t := time.NewTimer(duration) select { case <-t.C: return nil case <-ctx.Done(): t.Stop() return ctx.Err() } } // AlignDuration returns the duration until next aligned interval. func AlignDuration(tm time.Time, interval time.Duration) time.Duration { return AlignTime(tm, interval).Sub(tm) } // AlignTime returns the time of the next aligned interval. func AlignTime(tm time.Time, interval time.Duration) time.Time { truncated := tm.Truncate(interval) if truncated == tm { return tm } return truncated.Add(interval) } // Exit status takes the error from exec.Command // and returns the exit status and true // if error is not exit status, will return 0 and false func ExitStatus(err error) (int, bool) { if exiterr, ok := err.(*exec.ExitError); ok { if status, ok := exiterr.Sys().(syscall.WaitStatus); ok { return status.ExitStatus(), true } } return 0, false } // CompressWithGzip takes an io.Reader as input and pipes // it through a gzip.Writer returning an io.Reader containing // the gzipped data. // An error is returned if passing data to the gzip.Writer fails func CompressWithGzip(data io.Reader) (io.Reader, error) { pipeReader, pipeWriter := io.Pipe() gzipWriter := gzip.NewWriter(pipeWriter) var err error go func() { _, err = io.Copy(gzipWriter, data) gzipWriter.Close() // subsequent reads from the read half of the pipe will // return no bytes and the error err, or EOF if err is nil. pipeWriter.CloseWithError(err) }() return pipeReader, err }