Add 'keto get config' functionality

bin/keto_test_e2e_exec.sh

@@ -10,12 +10,6 @@ set +e
 WORKINGDIR="${GOPATH}/src/github.com/UKHomeOffice/keto"
 KETO_ASSETS_DIR=${KETO_ASSETS_DIR:-${PWD}}
 
-function generate_kube_config() {
-    API_ADDR="https://$(aws cloudformation describe-stacks --stack-name keto-${CLUSTER_NAME}-elb --query "Stacks[0].Outputs[?OutputKey=='ELBDNS'].OutputValue" --output text)"
-    mkdir -p ~/.kube/
-    kubeadm alpha phase kubeconfig client-certs --client-name kubernetes-admin --organization system:masters --server ${API_ADDR} --cert-dir ${KETO_ASSETS_DIR} > ~/.kube/config
-}
-
 function cleanup() {
     echo "[INFO] Attempting to delete keto cluster '${CLUSTER_NAME}'"
     keto --cloud ${KETO_CLOUD_PROVIDER} delete cluster ${CLUSTER_NAME}
@@ -33,7 +27,8 @@ function run_e2e_test() {
 
     # TODO: Modify once Keto adds capability to auto generate config using the client cli
     echo "[INFO] Generating Kubernetes config"
-    generate_kube_config || return
+    mkdir -p ~/.kube
+    keto get config --cloud aws --cluster ${CLUSTER_NAME} --assets-dir ${KETO_ASSETS_DIR} --output-file ~/.kube/config || return
 
     echo "[INFO] Executing kuberang test to validate cluster health"
     ${WORKINGDIR}/bin/kuberang.sh 180 || return

bin/keto_test_e2e_setup.sh

@@ -13,9 +13,6 @@ glide install
 # cfssl for cert generation
 go get -u github.com/cloudflare/cfssl/cmd/...
 
-# TODO: This can be removed when keto implements the capability to locally generate the kube config
-curl -LO https://bootstrap.pypa.io/get-pip.py && python get-pip.py && pip install awscli
-
 # Get kubectl, kubeadm, kuberang
 curl -LO https://storage.googleapis.com/kubernetes-release/release/${KUBE_VERSION}/bin/linux/amd64/kubectl
 chmod +x kubectl && mv kubectl /usr/local/bin/kubectl && kubectl help

pkg/cloudprovider/cloud.go

@@ -54,6 +54,8 @@ type Clusters interface {
 	GetMasterPersistentIPs(clusterName string) (map[string]string, error)
 	// PushAssets pushes assets to cloud provider specific implementation.
 	PushAssets(clusterName string, a model.Assets) error
+	// GetKubeAPIURL retrieves the API URL for a given cluster
+	GetKubeAPIURL(clusterName string) (string, error)
 }
 
 // NodePooler is an abstract interface for node pools.

pkg/cloudprovider/providers/aws/aws.go

@@ -181,8 +181,8 @@ func (c *Cloud) DescribeCluster(name string) error {
 	return ErrNotImplemented
 }
 
-// getKubeAPIURL returns a full Kubernetes API URL from an ELB stack.
-func (c Cloud) getKubeAPIURL(clusterName string) (string, error) {
+// GetKubeAPIURL returns a full Kubernetes API URL from an ELB stack.
+func (c Cloud) GetKubeAPIURL(clusterName string) (string, error) {
 	stack, err := c.getStack(makeELBStackName(clusterName))
 	if err != nil {
 		return "", err
@@ -202,7 +202,7 @@ func formatKubeAPIURL(host string) string {
 	return "https://" + strings.ToLower(host)
 }
 
-// getELBName returns an ELB name from the ELB stack for a given given cluster.
+// getELBName returns an ELB name from the ELB stack for a given cluster.
 func (c Cloud) getELBName(clusterName string) (string, error) {
 	res, err := c.getStackResources(makeELBStackName(clusterName))
 	if err != nil {
@@ -428,7 +428,7 @@ func (c *Cloud) CreateMasterPool(p model.MasterPool) error {
 		return err
 	}
 
-	kubeAPIURL, err := c.getKubeAPIURL(p.ClusterName)
+	kubeAPIURL, err := c.GetKubeAPIURL(p.ClusterName)
 	if err != nil {
 		return err
 	}
@@ -485,7 +485,7 @@ func (c *Cloud) CreateComputePool(p model.ComputePool) error {
 	if err != nil {
 		return err
 	}
-	kubeAPIURL, err := c.getKubeAPIURL(p.ClusterName)
+	kubeAPIURL, err := c.GetKubeAPIURL(p.ClusterName)
 	if err != nil {
 		return err
 	}

pkg/cloudprovider/providers/aws/aws_test.go

@@ -441,7 +441,7 @@ func TestGetKubeAPIURL(t *testing.T) {
 			},
 		}, nil).Once()
 
-	result, err := c.getKubeAPIURL(clusterName)
+	result, err := c.GetKubeAPIURL(clusterName)
 	if err != nil {
 		t.Error(err)
 	}

pkg/controller/controller.go

@@ -19,6 +19,9 @@ package controller
 import (
 	"errors"
 	"fmt"
+	"os/exec"
+	"regexp"
+	"strings"
 
 	"github.com/UKHomeOffice/keto/pkg/cloudprovider"
 	"github.com/UKHomeOffice/keto/pkg/constants"
@@ -356,6 +359,45 @@ func (c *Controller) DeleteCluster(names ...string) error {
 	return nil
 }
 
+// GetClusterConfig retrieves the kubernetes config for a cluster
+func (c *Controller) GetClusterConfig(clusterName string, assetsDir string) (string, error) {
+	cl, impl := c.Cloud.Clusters()
+	if !impl {
+		return "", ErrNotImplemented
+	}
+
+	apiURL, err := cl.GetKubeAPIURL(clusterName)
+	if err != nil {
+		return "", err
+	}
+
+	var validURL = regexp.MustCompile(`^https:\/\/.+$`)
+	if !validURL.MatchString(apiURL) {
+		return "", fmt.Errorf(
+			"unable to retrieve valid API URL for cluster name %q and cloud provider %q. URL: %q",
+			clusterName,
+			c.Cloud.ProviderName(),
+			apiURL,
+		)
+	}
+
+	c.Logger.Printf("Generating kubernetes config for cluster: %q", clusterName)
+
+	cmdName := "kubeadm"
+	var cmdOut []byte
+	cmdArgs := []string{
+		"alpha", "phase", "kubeconfig", "client-certs", "--client-name",
+		"kubernetes-admin", "--organization", "system:masters",
+		"--server", apiURL, "--cert-dir", assetsDir,
+	}
+	c.Logger.Printf("Running: %v %v", cmdName, strings.Join(cmdArgs, " "))
+	cmdOut, err = exec.Command(cmdName, cmdArgs...).CombinedOutput()
+	if err != nil {
+		return "", err
+	}
+	return string(cmdOut[:]), nil
+}
+
 // DeleteMasterPool deletes a master node pool.
 func (c *Controller) DeleteMasterPool(clusterName string) error {
 	pooler, impl := c.Cloud.NodePooler()

pkg/keto/cmd/get.go

@@ -17,8 +17,14 @@ limitations under the License.
 package cmd
 
 import (
+	"bytes"
+	"fmt"
 	"os"
+	"os/exec"
+	"path"
+	"runtime"
 
+	"github.com/UKHomeOffice/keto/pkg/constants"
 	"github.com/UKHomeOffice/keto/pkg/keto"
 
 	"github.com/spf13/cobra"
@@ -129,16 +135,117 @@ func listClusters(cli *cli, names ...string) error {
 	return keto.PrintClusters(keto.GetPrinter(os.Stdout), clusters, true)
 }
 
+var getClusterConfigCmd = &cobra.Command{
+	Use:          "config --cluster [NAME]",
+	Aliases:      clusterConfigCmdAliases,
+	Short:        "Get cluster kubernetes config",
+	Long:         "Get cluster kubernetes config",
+	SilenceUsage: true,
+	PreRunE: func(c *cobra.Command, args []string) error {
+		return validateGetConfigPrecursors(c, args)
+	},
+	RunE: func(c *cobra.Command, args []string) error {
+		return getClusterConfigCmdFunc(c, args)
+	},
+}
+
+func validateGetConfigPrecursors(c *cobra.Command, args []string) error {
+	if !c.Flags().Changed("cluster") {
+		return fmt.Errorf("cluster name must be set: --cluster [NAME]")
+	}
+
+	_, err := exec.LookPath("kubeadm")
+	if err != nil {
+		var binaryDownloadLink bytes.Buffer
+		binaryDownloadLink.WriteString("https://storage.googleapis.com/kubernetes-release/release/")
+		binaryDownloadLink.WriteString(constants.DefaultKubeVersion)
+		binaryDownloadLink.WriteString("/bin/")
+		binaryDownloadLink.WriteString(runtime.GOOS + "/")
+		binaryDownloadLink.WriteString(runtime.GOARCH)
+		binaryDownloadLink.WriteString("/kubeadm")
+
+		return fmt.Errorf(`the executable 'kubeadm' was not found. Retrieve it using the following command:
+curl -Lo %q /usr/local/bin/kubeadm && chmod +x /usr/local/bin/kubeadm
+Note: If the 'kubeadm' binary is not built for your distribution the above link may not work.`, binaryDownloadLink.String())
+	}
+
+	_, err = c.Flags().GetString("cluster")
+	if err != nil {
+		return err
+	}
+
+	assetsDir, err := c.Flags().GetString("assets-dir")
+	if err != nil {
+		return err
+	}
+	if assetsDir == "" {
+		assetsDir, err = os.Getwd()
+		if err != nil {
+			return err
+		}
+	}
+
+	// Check if assets exist, create symlinks from 'kube_ca' files if necessary
+	certName := "ca.crt"
+	keyName := "ca.key"
+
+	if !fileExists(assetsDir) {
+		return fmt.Errorf("assets directory %q does not exist", assetsDir)
+	}
+	if !fileExists(path.Join(assetsDir, certName)) {
+		if !fileExists(path.Join(assetsDir, "kube_" + certName)) {
+			return fmt.Errorf("%q does not exist (kube ca certificate)", path.Join(assetsDir, certName))
+		}
+		os.Symlink(path.Join(assetsDir, "kube_" + certName), path.Join(assetsDir, certName))
+	}
+	if !fileExists(path.Join(assetsDir, keyName)) {
+		if !fileExists(path.Join(assetsDir, "kube_" + keyName)) {
+			return fmt.Errorf("%q does not exist (kube ca private key)", path.Join(assetsDir, keyName))
+		}
+		os.Symlink(path.Join(assetsDir, "kube_" + keyName), path.Join(assetsDir, keyName))
+	}
+
+	return nil
+}
+
+func getClusterConfigCmdFunc(c *cobra.Command, args []string) error {
+	clusterName, _ := c.Flags().GetString("cluster")
+	assetsDir, _ := c.Flags().GetString("assets-dir")
+	outputFile, _ := c.Flags().GetString("output-file")
+
+	cli, err := newCLI(c)
+	if err != nil {
+		return err
+	}
+
+	config, err := cli.ctrl.GetClusterConfig(clusterName, assetsDir)
+	if err != nil {
+		return err
+	}
+
+	return keto.PrintClusterConfig(keto.GetPrinter(os.Stdout), config, outputFile)
+}
+
 func init() {
 	getCmd.AddCommand(
 		getClusterCmd,
 		getMasterPoolCmd,
 		getComputePoolCmd,
+		getClusterConfigCmd,
 	)
 
 	// Add flags that are relevant to different subcommands.
 	addClusterFlag(
 		getMasterPoolCmd,
 		getComputePoolCmd,
+		getClusterConfigCmd,
+	)
+
+	addAssetsDirFlag(
+		getClusterConfigCmd,
+	)
+
+	addConfigOutputFileFlag(
+		getClusterConfigCmd,
 	)
 }

pkg/keto/cmd/keto.go

@@ -51,9 +51,10 @@ var (
 	}
 
 	// subcommand aliases
-	clusterCmdAliases     = []string{"cl", "clusters"}
-	masterPoolCmdAliases  = []string{"mp", "master", "masters", "masterpools"}
-	computePoolCmdAliases = []string{"cp", "compute", "computes", "computepools"}
+	clusterCmdAliases       = []string{"cl", "clusters"}
+	masterPoolCmdAliases    = []string{"mp", "master", "masters", "masterpools"}
+	computePoolCmdAliases   = []string{"cp", "compute", "computes", "computepools"}
+	clusterConfigCmdAliases = []string{"conf", "configuration"}
 )
 
 // Execute adds all child commands to the root command sets flags appropriately.
@@ -260,3 +261,10 @@ func addSchedulerExtraArgsFlag(c ...*cobra.Command) {
 		i.Flags().String("scheduler-extra-args", "", "Kubernetes scheduler extra arguments")
 	}
 }
+
+// addConfigOutputFileFlag adds an output file flag
+func addConfigOutputFileFlag(c ...*cobra.Command) {
+	for _, i := range c {
+		i.Flags().String("output-file", "", "Write config output to a file")
+	}
+}

pkg/keto/resource_printer.go

@@ -19,6 +19,7 @@ package keto
 import (
 	"fmt"
 	"io"
+	"os"
 	"strings"
 	"text/tabwriter"
 
@@ -89,6 +90,28 @@ func PrintComputePool(w *tabwriter.Writer, pools []*model.ComputePool, headers b
 	return w.Flush()
 }
 
+func PrintClusterConfig(w *tabwriter.Writer, config string, outputFile string) error {
+	if len(outputFile) < 1 {
+		fmt.Fprintln(w, config)
+		return w.Flush()
+	}
+
+	_, err := os.Stat(outputFile)
+	if !os.IsNotExist(err) {
+		return err
+	}
+
+	file, err := os.Create(outputFile)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	_, err = file.WriteString(config)
+	file.Sync()
+	return w.Flush()
+}
+
 // formatData formats data of slices of string slices ready for tabwriter.
 func formatData(data [][]string) string {
 	rows := []string{}