Implement Kubeconfig endpoint in DCM

The /kubeconfig API path allows a client to retrieve a kubeconfig
file for a specified cluster reference of a logical cloud.
- includes CA cert, address, user private key and signed cert.

This commit includes the "lazy-loading" implementation of certificate
retrieval per cluster from Rsync (which happens when clients call).

The certificate is read from the cluster status in appcontext.
Thus, Monitor and Rsync need to be configured and running.

Issue-ID: MULTICLOUD-1143
Change-Id: Ie94cd128e14c8a944861eced2bdc886d95fab6ed
Signed-off-by: Igor D.C <igor.duarte.cardoso@intel.com>

2 files changed, 218 insertions, 3 deletions

diff --git a/src/dcm/pkg/module/cluster.go b/src/dcm/pkg/module/cluster.go
index 85b20117..6cb18539 100644
--- a/src/dcm/pkg/module/cluster.go
+++ b/src/dcm/pkg/module/cluster.go
@@ -17,7 +17,15 @@
 package module
 
 import (
+	"encoding/base64"
+	"encoding/json"
+	"strings"
+
+	clm "github.com/onap/multicloud-k8s/src/clm/pkg/cluster"
+	rb "github.com/onap/multicloud-k8s/src/monitor/pkg/apis/k8splugin/v1alpha1"
+	log "github.com/onap/multicloud-k8s/src/orchestrator/pkg/infra/logutils"
 	pkgerrors "github.com/pkg/errors"
+	"gopkg.in/yaml.v2"
 )
 
 // Cluster contains the parameters needed for a Cluster
@@ -37,6 +45,7 @@ type ClusterSpec struct {
 	ClusterProvider string `json:"cluster-provider"`
 	ClusterName     string `json:"cluster-name"`
 	LoadBalancerIP  string `json:"loadbalancer-ip"`
+	Certificate     string `json:"certificate"`
 }
 
 type ClusterKey struct {
@@ -45,6 +54,48 @@ type ClusterKey struct {
 	ClusterReference string `json:"clname"`
 }
 
+type KubeConfig struct {
+	ApiVersion     string            `yaml:"apiVersion"`
+	Kind           string            `yaml:"kind"`
+	Clusters       []KubeCluster     `yaml:"clusters"`
+	Contexts       []KubeContext     `yaml:"contexts"`
+	CurrentContext string            `yaml:"current-context`
+	Preferences    map[string]string `yaml:"preferences"`
+	Users          []KubeUser        `yaml:"users"`
+}
+
+type KubeCluster struct {
+	ClusterDef  KubeClusterDef `yaml:"cluster"`
+	ClusterName string         `yaml:"name"`
+}
+
+type KubeClusterDef struct {
+	CertificateAuthorityData string `yaml:"certificate-authority-data"`
+	Server                   string `yaml:"server"`
+}
+
+type KubeContext struct {
+	ContextDef  KubeContextDef `yaml:"context"`
+	ContextName string         `yaml:"name"`
+}
+
+type KubeContextDef struct {
+	Cluster   string `yaml:"cluster"`
+	Namespace string `yaml:"namespace,omitempty"`
+	User      string `yaml:"user"`
+}
+
+type KubeUser struct {
+	UserName string      `yaml:"name"`
+	UserDef  KubeUserDef `yaml:"user"`
+}
+
+type KubeUserDef struct {
+	ClientCertificateData string `yaml:"client-certificate-data"`
+	ClientKeyData         string `yaml:"client-key-data"`
+	// client-certificate and client-key are NOT implemented
+}
+
 // ClusterManager is an interface that exposes the connection
 // functionality
 type ClusterManager interface {
@@ -53,6 +104,7 @@ type ClusterManager interface {
 	GetAllClusters(project, logicalCloud string) ([]Cluster, error)
 	DeleteCluster(project, logicalCloud, name string) error
 	UpdateCluster(project, logicalCloud, name string, c Cluster) (Cluster, error)
+	GetClusterConfig(project, logicalcloud, name string) (string, error)
 }
 
 // ClusterClient implements the ClusterManager
@@ -204,3 +256,165 @@ func (v *ClusterClient) UpdateCluster(project, logicalCloud, clusterReference st
 	}
 	return c, nil
 }
+
+// Get returns Cluster's kubeconfig for corresponding cluster reference
+func (v *ClusterClient) GetClusterConfig(project, logicalCloud, clusterReference string) (string, error) {
+	lcClient := NewLogicalCloudClient()
+	context, ctxVal, err := lcClient.GetLogicalCloudContext(logicalCloud)
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Error getting logical cloud context.")
+	}
+	if ctxVal == "" {
+		return "", pkgerrors.New("Logical Cloud hasn't been applied yet")
+	}
+
+	// private key comes from logical cloud
+	lckey := LogicalCloudKey{
+		Project:          project,
+		LogicalCloudName: logicalCloud,
+	}
+	// get logical cloud resource
+	lc, err := lcClient.Get(project, logicalCloud)
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Failed getting logical cloud")
+	}
+	// get user's private key
+	privateKeyData, err := v.util.DBFind(v.storeName, lckey, "privatekey")
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Failed getting private key from logical cloud")
+	}
+
+	// get cluster from dcm (need provider/name)
+	cluster, err := v.GetCluster(project, logicalCloud, clusterReference)
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Failed getting cluster")
+	}
+
+	// before attempting to generate a kubeconfig,
+	// check if certificate has been issued and copy it from etcd to mongodb
+	if cluster.Specification.Certificate == "" {
+		log.Info("Certificate not yet in MongoDB, checking etcd.", log.Fields{})
+
+		// access etcd
+		clusterName := strings.Join([]string{cluster.Specification.ClusterProvider, "+", cluster.Specification.ClusterName}, "")
+
+		// get the app context handle for the status of this cluster (which should contain the certificate inside, if already issued)
+		statusHandle, err := context.GetClusterStatusHandle("logical-cloud", clusterName)
+
+		if err != nil {
+			return "", pkgerrors.New("The cluster doesn't contain status, please check if all services are up and running.")
+		}
+		statusRaw, err := context.GetValue(statusHandle)
+		if err != nil {
+			return "", pkgerrors.Wrap(err, "An error occurred while reading the cluster status.")
+		}
+
+		var rbstatus rb.ResourceBundleStatus
+		err = json.Unmarshal([]byte(statusRaw.(string)), &rbstatus)
+		if err != nil {
+			return "", pkgerrors.Wrap(err, "An error occurred while parsing the cluster status.")
+		}
+
+		// validate that we indeed obtained a certificate before persisting it in the database:
+		approved := false
+		for _, c := range rbstatus.CsrStatuses[0].Status.Conditions {
+			if c.Type == "Denied" {
+				return "", pkgerrors.Wrap(err, "Certificate was denied!")
+			}
+			if c.Type == "Failed" {
+				return "", pkgerrors.Wrap(err, "Certificate issue failed.")
+			}
+			if c.Type == "Approved" {
+				approved = true
+			}
+		}
+		if approved {
+			//just double-check certificate field contents aren't empty:
+			cert := rbstatus.CsrStatuses[0].Status.Certificate
+			if len(cert) > 0 {
+				cluster.Specification.Certificate = base64.StdEncoding.EncodeToString([]byte(cert))
+			} else {
+				return "", pkgerrors.Wrap(err, "Certificate issued was invalid.")
+			}
+		}
+
+		// copy key to MongoDB
+		// func (v *ClusterClient)
+		// UpdateCluster(project, logicalCloud, clusterReference string, c Cluster) (Cluster, error) {
+		_, err = v.UpdateCluster(project, logicalCloud, clusterReference, cluster)
+		if err != nil {
+			return "", pkgerrors.Wrap(err, "An error occurred while storing the certificate.")
+		}
+	} else {
+		// certificate is already in MongoDB so just hand it over to create the API response
+		log.Info("Certificate already in MongoDB, pass it to API.", log.Fields{})
+	}
+
+	// contact clm about admins cluster kubeconfig (to retrieve CA cert)
+	clusterContent, err := clm.NewClusterClient().GetClusterContent(cluster.Specification.ClusterProvider, cluster.Specification.ClusterName)
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Failed getting cluster content from CLM")
+	}
+	adminConfig, err := base64.StdEncoding.DecodeString(clusterContent.Kubeconfig)
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Failed decoding CLM kubeconfig from base64")
+	}
+
+	// unmarshall clm kubeconfig into struct
+	adminKubeConfig := KubeConfig{}
+	err = yaml.Unmarshal(adminConfig, &adminKubeConfig)
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Failed parsing CLM kubeconfig yaml")
+	}
+
+	// all data needed for final kubeconfig:
+	privateKey := string(privateKeyData[0])
+	signedCert := cluster.Specification.Certificate
+	clusterCert := adminKubeConfig.Clusters[0].ClusterDef.CertificateAuthorityData
+	clusterAddr := adminKubeConfig.Clusters[0].ClusterDef.Server
+	namespace := lc.Specification.NameSpace
+	userName := lc.Specification.User.UserName
+	contextName := userName + "@" + clusterReference
+
+	kubeconfig := KubeConfig{
+		ApiVersion: "v1",
+		Kind:       "Config",
+		Clusters: []KubeCluster{
+			KubeCluster{
+				ClusterName: clusterReference,
+				ClusterDef: KubeClusterDef{
+					CertificateAuthorityData: clusterCert,
+					Server:                   clusterAddr,
+				},
+			},
+		},
+		Contexts: []KubeContext{
+			KubeContext{
+				ContextName: contextName,
+				ContextDef: KubeContextDef{
+					Cluster:   clusterReference,
+					Namespace: namespace,
+					User:      userName,
+				},
+			},
+		},
+		CurrentContext: contextName,
+		Preferences:    map[string]string{},
+		Users: []KubeUser{
+			KubeUser{
+				UserName: userName,
+				UserDef: KubeUserDef{
+					ClientCertificateData: signedCert,
+					ClientKeyData:         privateKey,
+				},
+			},
+		},
+	}
+
+	yaml, err := yaml.Marshal(&kubeconfig)
+	if err != nil {
+		return "", pkgerrors.Wrap(err, "Failed marshaling user kubeconfig into yaml")
+	}
+
+	return string(yaml), nil
+}
diff --git a/src/dcm/pkg/module/logicalcloud.go b/src/dcm/pkg/module/logicalcloud.go
index 61d7b7a5..83ff153f 100644
--- a/src/dcm/pkg/module/logicalcloud.go
+++ b/src/dcm/pkg/module/logicalcloud.go
@@ -103,9 +103,10 @@ type DBService struct{}
 func NewLogicalCloudClient() *LogicalCloudClient {
 	service := DBService{}
 	return &LogicalCloudClient{
-		storeName: "orchestrator",
-		tagMeta:   "logicalcloud",
-		util:      service,
+		storeName:  "orchestrator",
+		tagMeta:    "logicalcloud",
+		tagContext: "lccontext",
+		util:       service,
 	}
 }