Move runtime/kubernetes/client to util/kubernetes/client

util/kubernetes/client/util.go

@@ -0,0 +1,102 @@
+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
+}