(feat) Add auto-discovery in k8s | Adarsh

vendor/k8s.io/client-go/util/cert/io.go

@@ -0,0 +1,98 @@
+/*
+Copyright 2014 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cert
+
+import (
+	"crypto/x509"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+)
+
+// CanReadCertAndKey returns true if the certificate and key files already exists,
+// otherwise returns false. If lost one of cert and key, returns error.
+func CanReadCertAndKey(certPath, keyPath string) (bool, error) {
+	certReadable := canReadFile(certPath)
+	keyReadable := canReadFile(keyPath)
+
+	if certReadable == false && keyReadable == false {
+		return false, nil
+	}
+
+	if certReadable == false {
+		return false, fmt.Errorf("error reading %s, certificate and key must be supplied as a pair", certPath)
+	}
+
+	if keyReadable == false {
+		return false, fmt.Errorf("error reading %s, certificate and key must be supplied as a pair", keyPath)
+	}
+
+	return true, nil
+}
+
+// If the file represented by path exists and
+// readable, returns true otherwise returns false.
+func canReadFile(path string) bool {
+	f, err := os.Open(path)
+	if err != nil {
+		return false
+	}
+
+	defer f.Close()
+
+	return true
+}
+
+// WriteCert writes the pem-encoded certificate data to certPath.
+// The certificate file will be created with file mode 0644.
+// If the certificate file already exists, it will be overwritten.
+// The parent directory of the certPath will be created as needed with file mode 0755.
+func WriteCert(certPath string, data []byte) error {
+	if err := os.MkdirAll(filepath.Dir(certPath), os.FileMode(0755)); err != nil {
+		return err
+	}
+	return ioutil.WriteFile(certPath, data, os.FileMode(0644))
+}
+
+// NewPool 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 NewPool(filename string) (*x509.CertPool, error) {
+	certs, err := CertsFromFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	pool := x509.NewCertPool()
+	for _, cert := range certs {
+		pool.AddCert(cert)
+	}
+	return pool, nil
+}
+
+// CertsFromFile 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 CertsFromFile(file string) ([]*x509.Certificate, error) {
+	pemBlock, err := ioutil.ReadFile(file)
+	if err != nil {
+		return nil, err
+	}
+	certs, err := ParseCertsPEM(pemBlock)
+	if err != nil {
+		return nil, fmt.Errorf("error reading %s: %s", file, err)
+	}
+	return certs, nil
+}