telegraf/internal/internal.go

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package internal
import (
"bufio"
"crypto/rand"
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"io/ioutil"
"os"
"strings"
"time"
)
const alphanum string = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
// Duration just wraps time.Duration
type Duration struct {
Duration time.Duration
}
// UnmarshalTOML parses the duration from the TOML config file
func (d *Duration) UnmarshalTOML(b []byte) error {
dur, err := time.ParseDuration(string(b[1 : len(b)-1]))
if err != nil {
return err
}
d.Duration = dur
return nil
}
var NotImplementedError = errors.New("not implemented yet")
// 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)
}
// GetTLSConfig gets a tls.Config object from the given certs, key, and CA files.
// you must give the full path to the files.
// If all files are blank and InsecureSkipVerify=false, returns a nil pointer.
func GetTLSConfig(
SSLCert, SSLKey, SSLCA string,
InsecureSkipVerify bool,
) (*tls.Config, error) {
if SSLCert == "" && SSLKey == "" && SSLCA == "" && !InsecureSkipVerify {
return nil, nil
}
t := &tls.Config{
InsecureSkipVerify: InsecureSkipVerify,
}
if SSLCA != "" {
caCert, err := ioutil.ReadFile(SSLCA)
if err != nil {
return nil, errors.New(fmt.Sprintf("Could not load TLS CA: %s",
err))
}
caCertPool := x509.NewCertPool()
caCertPool.AppendCertsFromPEM(caCert)
t.RootCAs = caCertPool
}
if SSLCert != "" && SSLKey != "" {
cert, err := tls.LoadX509KeyPair(SSLCert, SSLKey)
if err != nil {
return nil, errors.New(fmt.Sprintf(
"Could not load TLS client key/certificate: %s",
err))
}
t.Certificates = []tls.Certificate{cert}
t.BuildNameToCertificate()
}
// will be nil by default if nothing is provided
return t, nil
}
// Glob will test a string pattern, potentially containing globs, against a
// subject string. The result is a simple true/false, determining whether or
// not the glob pattern matched the subject text.
//
// Adapted from https://github.com/ryanuber/go-glob/blob/master/glob.go
// thanks Ryan Uber!
func Glob(pattern, measurement string) bool {
// Empty pattern can only match empty subject
if pattern == "" {
return measurement == pattern
}
// If the pattern _is_ a glob, it matches everything
if pattern == "*" {
return true
}
parts := strings.Split(pattern, "*")
if len(parts) == 1 {
// No globs in pattern, so test for match
return pattern == measurement
}
leadingGlob := strings.HasPrefix(pattern, "*")
trailingGlob := strings.HasSuffix(pattern, "*")
end := len(parts) - 1
for i, part := range parts {
switch i {
case 0:
if leadingGlob {
continue
}
if !strings.HasPrefix(measurement, part) {
return false
}
case end:
if len(measurement) > 0 {
return trailingGlob || strings.HasSuffix(measurement, part)
}
default:
if !strings.Contains(measurement, part) {
return false
}
}
// Trim evaluated text from measurement as we loop over the pattern.
idx := strings.Index(measurement, part) + len(part)
measurement = measurement[idx:]
}
// All parts of the pattern matched
return true
}