Add Kubernetes operator webook server as DNS target (#10404)

This PR adds a DNS target that ensures to update an entry
into Kubernetes operator when a bucket is created or deleted.

See minio/operator#264 for details.

Co-authored-by: Harshavardhana <harsha@minio.io>

cmd/config/constants.go

@@ -33,6 +33,7 @@ const (
 	EnvPublicIPs    = "MINIO_PUBLIC_IPS"
 	EnvFSOSync      = "MINIO_FS_OSYNC"
 	EnvArgs         = "MINIO_ARGS"
+	EnvDNSWebhook   = "MINIO_DNS_WEBHOOK_ENDPOINT"
 
 	EnvUpdate = "MINIO_UPDATE"
 

cmd/config/etcd/dns/operator_dns.go

@@ -0,0 +1,200 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * 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 dns
+
+import (
+	"context"
+	"crypto/tls"
+	"crypto/x509"
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+	"net/url"
+	"time"
+
+	"github.com/dgrijalva/jwt-go"
+	"github.com/minio/minio/cmd/config"
+)
+
+var (
+	defaultOperatorContextTimeout = 10 * time.Second
+	// ErrNotImplemented - Indicates no entries were found for the given key (directory)
+	ErrNotImplemented = errors.New("The method is not implemented")
+	globalRootCAs     *x509.CertPool
+)
+
+// RegisterGlobalCAs register the global root CAs
+func RegisterGlobalCAs(CAs *x509.CertPool) {
+	globalRootCAs = CAs
+}
+
+func (c *OperatorDNS) addAuthHeader(r *http.Request) (*http.Request, error) {
+	claims := &jwt.StandardClaims{
+		ExpiresAt: int64(15 * time.Minute),
+		Issuer:    c.Username,
+		Subject:   config.EnvDNSWebhook,
+	}
+
+	token := jwt.NewWithClaims(jwt.SigningMethodHS512, claims)
+	ss, err := token.SignedString([]byte(c.Password))
+	if err != nil {
+		return r, err
+	}
+
+	r.Header.Set("Authorization", "Bearer "+ss)
+	return r, nil
+}
+
+func (c *OperatorDNS) endpoint(bucket string, delete bool) (string, error) {
+	u, err := url.Parse(c.Endpoint)
+	if err != nil {
+		return "", err
+	}
+	q := u.Query()
+	q.Add("bucket", bucket)
+	if delete {
+		q.Add("delete", "true")
+	} else {
+		q.Add("delete", "false")
+	}
+	u.RawQuery = q.Encode()
+	return u.String(), nil
+}
+
+// Put - Adds DNS entries into operator webhook server
+func (c *OperatorDNS) Put(bucket string) error {
+	ctx, cancel := context.WithTimeout(context.Background(), defaultOperatorContextTimeout)
+	defer cancel()
+	e, err := c.endpoint(bucket, false)
+	if err != nil {
+		return err
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, e, nil)
+	if err != nil {
+		return err
+	}
+	req, err = c.addAuthHeader(req)
+	if err != nil {
+		return err
+	}
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		if err := c.Delete(bucket); err != nil {
+			return err
+		}
+	}
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("request to create the service for bucket %s, failed with status %s", bucket, resp.Status)
+	}
+	return nil
+}
+
+// Delete - Removes DNS entries added in Put().
+func (c *OperatorDNS) Delete(bucket string) error {
+	ctx, cancel := context.WithTimeout(context.Background(), defaultOperatorContextTimeout)
+	defer cancel()
+	e, err := c.endpoint(bucket, true)
+	if err != nil {
+		return err
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, e, nil)
+	if err != nil {
+		return err
+	}
+	req, err = c.addAuthHeader(req)
+	if err != nil {
+		return err
+	}
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return err
+	}
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("request to delete the service for bucket %s, failed with status %s", bucket, resp.Status)
+	}
+	return nil
+}
+
+// DeleteRecord - Removes a specific DNS entry
+// No Op for Operator because operator deals on with bucket entries
+func (c *OperatorDNS) DeleteRecord(record SrvRecord) error {
+	return ErrNotImplemented
+}
+
+// Close closes the internal http client
+func (c *OperatorDNS) Close() error {
+	c.httpClient.CloseIdleConnections()
+	return nil
+}
+
+// List - Retrieves list of DNS entries for the domain.
+// This is a No Op for Operator because, there is no intent to enforce global
+// namespace at MinIO level with this DNS entry. The global namespace in
+// enforced by the Kubernetes Operator
+func (c *OperatorDNS) List() (srvRecords map[string][]SrvRecord, err error) {
+	return nil, ErrNotImplemented
+}
+
+// Get - Retrieves DNS records for a bucket.
+// This is a No Op for Operator because, there is no intent to enforce global
+// namespace at MinIO level with this DNS entry. The global namespace in
+// enforced by the Kubernetes Operator
+func (c *OperatorDNS) Get(bucket string) (srvRecords []SrvRecord, err error) {
+	return nil, ErrNotImplemented
+}
+
+// OperatorDNS - represents dns config for MinIO k8s operator.
+type OperatorDNS struct {
+	httpClient *http.Client
+	Endpoint   string
+	Username   string
+	Password   string
+}
+
+// NewOperatorDNS - initialize a new K8S Operator DNS set/unset values.
+func NewOperatorDNS(endpoint, user, pwd string) (Store, error) {
+	if endpoint == "" || user == "" || pwd == "" {
+		return nil, errors.New("invalid argument")
+	}
+	args := &OperatorDNS{
+		Username: user,
+		Password: pwd,
+		Endpoint: endpoint,
+		httpClient: &http.Client{
+			Transport: &http.Transport{
+				Proxy: http.ProxyFromEnvironment,
+				DialContext: (&net.Dialer{
+					Timeout:   3 * time.Second,
+					KeepAlive: 5 * time.Second,
+				}).DialContext,
+				ResponseHeaderTimeout: 3 * time.Second,
+				TLSHandshakeTimeout:   3 * time.Second,
+				ExpectContinueTimeout: 3 * time.Second,
+				TLSClientConfig: &tls.Config{
+					RootCAs: globalRootCAs,
+				},
+				// Go net/http automatically unzip if content-type is
+				// gzip disable this feature, as we are always interested
+				// in raw stream.
+				DisableCompression: true,
+			},
+		},
+	}
+
+	return args, nil
+}