telegraf/internal/internal.go

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package internal
import (
"bufio"
"bytes"
"compress/gzip"
"context"
"crypto/rand"
"errors"
"fmt"
"io"
"math"
"math/big"
"os"
"os/exec"
"runtime"
"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
}
type Number struct {
Value float64
}
// 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
}
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// ProductToken returns a tag for Telegraf that can be used in user agents.
func ProductToken() string {
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return fmt.Sprintf("Telegraf/%s Go/%s",
Version(), strings.TrimPrefix(runtime.Version(), "go"))
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}
// 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
}
func (n *Number) UnmarshalTOML(b []byte) error {
value, err := strconv.ParseFloat(string(b), 64)
if err != nil {
return err
}
n.Value = value
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)
}
// 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.
// If the current time is aligned a 0 duration is returned.
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.
// If the current time is aligned the current time is returned.
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
}
// ParseTimestamp parses a Time according to the standard Telegraf options.
// These are generally displayed in the toml similar to:
// json_time_key= "timestamp"
// json_time_format = "2006-01-02T15:04:05Z07:00"
// json_timezone = "America/Los_Angeles"
//
// The format can be one of "unix", "unix_ms", "unix_us", "unix_ns", or a Go
// time layout suitable for time.Parse.
//
// When using the "unix" format, a optional fractional component is allowed.
// Specific unix time precisions cannot have a fractional component.
//
// Unix times may be an int64, float64, or string. When using a Go format
// string the timestamp must be a string.
//
// The location is a location string suitable for time.LoadLocation. Unix
// times do not use the location string, a unix time is always return in the
// UTC location.
func ParseTimestamp(format string, timestamp interface{}, location string) (time.Time, error) {
switch format {
case "unix", "unix_ms", "unix_us", "unix_ns":
return parseUnix(format, timestamp)
default:
if location == "" {
location = "UTC"
}
return parseTime(format, timestamp, location)
}
}
func parseUnix(format string, timestamp interface{}) (time.Time, error) {
integer, fractional, err := parseComponents(timestamp)
if err != nil {
return time.Unix(0, 0), err
}
switch strings.ToLower(format) {
case "unix":
return time.Unix(integer, fractional).UTC(), nil
case "unix_ms":
return time.Unix(0, integer*1e6).UTC(), nil
case "unix_us":
return time.Unix(0, integer*1e3).UTC(), nil
case "unix_ns":
return time.Unix(0, integer).UTC(), nil
default:
return time.Unix(0, 0), errors.New("unsupported type")
}
}
// Returns the integers before and after an optional decimal point. Both '.'
// and ',' are supported for the decimal point. The timestamp can be an int64,
// float64, or string.
// ex: "42.5" -> (42, 5, nil)
func parseComponents(timestamp interface{}) (int64, int64, error) {
switch ts := timestamp.(type) {
case string:
parts := strings.SplitN(ts, ".", 2)
if len(parts) == 2 {
return parseUnixTimeComponents(parts[0], parts[1])
}
parts = strings.SplitN(ts, ",", 2)
if len(parts) == 2 {
return parseUnixTimeComponents(parts[0], parts[1])
}
integer, err := strconv.ParseInt(ts, 10, 64)
if err != nil {
return 0, 0, err
}
return integer, 0, nil
case int64:
return ts, 0, nil
case float64:
integer, fractional := math.Modf(ts)
return int64(integer), int64(fractional * 1e9), nil
default:
return 0, 0, errors.New("unsupported type")
}
}
func parseUnixTimeComponents(first, second string) (int64, int64, error) {
integer, err := strconv.ParseInt(first, 10, 64)
if err != nil {
return 0, 0, err
}
// Convert to nanoseconds, dropping any greater precision.
buf := []byte("000000000")
copy(buf, second)
fractional, err := strconv.ParseInt(string(buf), 10, 64)
if err != nil {
return 0, 0, err
}
return integer, fractional, nil
}
// ParseTime parses a string timestamp according to the format string.
func parseTime(format string, timestamp interface{}, location string) (time.Time, error) {
switch ts := timestamp.(type) {
case string:
loc, err := time.LoadLocation(location)
if err != nil {
return time.Unix(0, 0), err
}
return time.ParseInLocation(format, ts, loc)
default:
return time.Unix(0, 0), errors.New("unsupported type")
}
}