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go-micro/util/kubernetes/client/util.go

103 lines
2.7 KiB
Go

package client
import (
"crypto/x509"
"encoding/pem"
"errors"
"fmt"
"io"
"io/ioutil"
"strings"
"text/template"
)
// renderTemplateFile renders template for a given resource into writer w
func renderTemplate(resource string, w io.Writer, data interface{}) error {
t := template.Must(template.New("kubernetes").Parse(templates[resource]))
if err := t.Execute(w, data); err != nil {
return err
}
return nil
}
// COPIED FROM
// https://github.com/kubernetes/kubernetes/blob/7a725418af4661067b56506faabc2d44c6d7703a/pkg/util/crypto/crypto.go
// CertPoolFromFile returns an x509.CertPool containing the certificates in the given PEM-encoded file.
// Returns an error if the file could not be read, a certificate could not be parsed, or if the file does not contain any certificates
func CertPoolFromFile(filename string) (*x509.CertPool, error) {
certs, err := certificatesFromFile(filename)
if err != nil {
return nil, err
}
pool := x509.NewCertPool()
for _, cert := range certs {
pool.AddCert(cert)
}
return pool, nil
}
// certificatesFromFile returns the x509.Certificates contained in the given PEM-encoded file.
// Returns an error if the file could not be read, a certificate could not be parsed, or if the file does not contain any certificates
func certificatesFromFile(file string) ([]*x509.Certificate, error) {
if len(file) == 0 {
return nil, errors.New("error reading certificates from an empty filename")
}
pemBlock, err := ioutil.ReadFile(file)
if err != nil {
return nil, err
}
certs, err := CertsFromPEM(pemBlock)
if err != nil {
return nil, fmt.Errorf("error reading %s: %s", file, err)
}
return certs, nil
}
// CertsFromPEM returns the x509.Certificates contained in the given PEM-encoded byte array
// Returns an error if a certificate could not be parsed, or if the data does not contain any certificates
func CertsFromPEM(pemCerts []byte) ([]*x509.Certificate, error) {
ok := false
certs := []*x509.Certificate{}
for len(pemCerts) > 0 {
var block *pem.Block
block, pemCerts = pem.Decode(pemCerts)
if block == nil {
break
}
// Only use PEM "CERTIFICATE" blocks without extra headers
if block.Type != "CERTIFICATE" || len(block.Headers) != 0 {
continue
}
cert, err := x509.ParseCertificate(block.Bytes)
if err != nil {
return certs, err
}
certs = append(certs, cert)
ok = true
}
if !ok {
return certs, errors.New("could not read any certificates")
}
return certs, nil
}
// Format is used to format a string value into a k8s valid name
func Format(v string) string {
// to lower case
v = strings.ToLower(v)
// dots to dashes
v = strings.ReplaceAll(v, ".", "-")
// limit to 253 chars
if len(v) > 253 {
v = v[:253]
}
// return new name
return v
}