implement replica exec

This implements the execution of commands in deplo.io application replicas. If there are multiple replicas, the first replica will be used.

api/util/release.go

@@ -0,0 +1,26 @@
+package util
+
+import (
+	"sort"
+
+	apps "github.com/ninech/apis/apps/v1alpha1"
+)
+
+// OrderReleaseList orders the given list of releases, moving the latest
+// release to the beginning of the list
+func OrderReleaseList(releaseList *apps.ReleaseList) {
+	if len(releaseList.Items) <= 1 {
+		return
+	}
+
+	sort.Slice(releaseList.Items, func(i, j int) bool {
+		applicationNameI := releaseList.Items[i].ObjectMeta.Labels[ApplicationNameLabel]
+		applicationNameJ := releaseList.Items[j].ObjectMeta.Labels[ApplicationNameLabel]
+
+		if applicationNameI != applicationNameJ {
+			return applicationNameI < applicationNameJ
+		}
+
+		return releaseList.Items[i].CreationTimestampNano < releaseList.Items[j].CreationTimestampNano
+	})
+}

exec/application.go

@@ -0,0 +1,254 @@
+package exec
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	b64 "encoding/base64"
+
+	dockerterm "github.com/moby/term"
+	apps "github.com/ninech/apis/apps/v1alpha1"
+	infrastructure "github.com/ninech/apis/infrastructure/v1alpha1"
+	meta "github.com/ninech/apis/meta/v1alpha1"
+	"github.com/ninech/nctl/api"
+	"github.com/ninech/nctl/api/util"
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/client-go/kubernetes"
+	"k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/remotecommand"
+	"k8s.io/kubectl/pkg/scheme"
+	"k8s.io/kubectl/pkg/util/term"
+	runtimeclient "sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+const (
+	appBuildTypeBuildpack  appBuildType = "buildpack"
+	appBuildTypeDockerfile appBuildType = "dockerfile"
+	buildpackEntrypoint                 = "launcher"
+	defaultShellBuildpack               = "/bin/bash"
+	defaultShellDockerfile              = "/bin/sh"
+)
+
+// appBuildType describes the way how the app was build (buildpack/dockerfile)
+type appBuildType string
+
+type remoteCommandParameters struct {
+	replicaName      string
+	replicaNamespace string
+	command          []string
+	tty              bool
+	enableStdin      bool
+	stdin            io.Reader
+	stdout           io.Writer
+	stderr           io.Writer
+	restConfig       *rest.Config
+}
+
+type applicationCmd struct {
+	resourceCmd
+	Stdin   bool     `name:"stdin" short:"i" help:"Pass stdin to the application" default:"true"`
+	Tty     bool     `name:"tty" short:"t" help:"Stdin is a TTY" default:"true"`
+	Command []string `arg:"" help:"command to execute" optional:""`
+}
+
+// Help displays examples for the application exec command
+func (ac applicationCmd) Help() string {
+	return `Examples:
+  # Open a shell in a buildpack/dockerfile built application. The dockerfile
+  # built application needs a valid "/bin/sh" shell to be installed.
+  nctl exec app myapp
+
+  # Get output from running the 'date' command in an application replica.
+  nctl exec app myapp -- date
+
+  # Use redirection to execute a comand.
+  echo date | nctl exec app myapp
+
+  # In certain situations it might be needed to not redirect stdin. This can be
+  # achieved by using the "stdin" flag:
+  nctl exec app --stdin=false myapp -- <command>
+  `
+}
+
+func (cmd *applicationCmd) Run(ctx context.Context, client *api.Client, exec *Cmd) error {
+	replicaName, buildType, err := cmd.getReplica(ctx, client)
+	if err != nil {
+		return fmt.Errorf("error when searching for replica to connect: %w", err)
+	}
+	config, err := deploioRestConfig(ctx, client)
+	if err != nil {
+		return fmt.Errorf("can not create deplo.io cluster rest config: %w", err)
+	}
+	// use dockerterm to gather the std io streams (windows supported)
+	stdin, stdout, stderr := dockerterm.StdStreams()
+	return executeRemoteCommand(
+		ctx,
+		remoteCommandParameters{
+			replicaName:      replicaName,
+			replicaNamespace: client.Project,
+			command:          replicaCommand(buildType, cmd.Command),
+			tty:              cmd.Tty,
+			enableStdin:      cmd.Stdin,
+			stdin:            stdin,
+			stdout:           stdout,
+			stderr:           stderr,
+			restConfig:       config,
+		})
+}
+
+func latestAvailableRelease(releases *apps.ReleaseList) *apps.Release {
+	util.OrderReleaseList(releases)
+	for _, release := range releases.Items {
+		if release.Status.AtProvider.ReleaseStatus == apps.ReleaseProcessStatusAvailable {
+			return &release
+		}
+	}
+	return nil
+}
+
+// getReplica finds a replica of the latest available release
+func (cmd *applicationCmd) getReplica(ctx context.Context, client *api.Client) (string, appBuildType, error) {
+	releases := &apps.ReleaseList{}
+	if err := client.List(
+		ctx,
+		releases,
+		runtimeclient.InNamespace(client.Project),
+		runtimeclient.MatchingLabels{util.ApplicationNameLabel: cmd.Name},
+	); err != nil {
+		return "", "", err
+	}
+
+	if len(releases.Items) == 0 {
+		return "", "", fmt.Errorf("no releases found for application %s", cmd.Name)
+	}
+	latestAvailableRelease := latestAvailableRelease(releases)
+	if latestAvailableRelease == nil {
+		return "", "", fmt.Errorf("no ready release found for application %s", cmd.Name)
+	}
+	buildType := appBuildTypeBuildpack
+	if latestAvailableRelease.Spec.ForProvider.DockerfileBuild {
+		buildType = appBuildTypeDockerfile
+	}
+	if len(latestAvailableRelease.Status.AtProvider.ReplicaObservation) == 0 {
+		return "", buildType, fmt.Errorf("no replica information found for release %s", latestAvailableRelease.Name)
+	}
+	if replica := readyReplica(latestAvailableRelease.Status.AtProvider.ReplicaObservation); replica != "" {
+		return replica, buildType, nil
+	}
+	return "", buildType, fmt.Errorf("no ready replica found for release %s", latestAvailableRelease.Name)
+}
+
+func readyReplica(replicaObs []apps.ReplicaObservation) string {
+	for _, obs := range replicaObs {
+		if obs.Status == apps.ReplicaStatusReady {
+			return obs.ReplicaName
+		}
+	}
+	return ""
+}
+
+// setupTTY sets up a TTY for command execution
+func setupTTY(params *remoteCommandParameters) term.TTY {
+	t := term.TTY{
+		Out: params.stdout,
+	}
+	if !params.enableStdin {
+		return t
+	}
+	t.In = params.stdin
+	if !params.tty {
+		return t
+	}
+	if !t.IsTerminalIn() {
+		// if this is not a suitable TTY, we don't request one in the
+		// exec call and don't set the terminal into RAW mode either
+		params.tty = false
+		return t
+	}
+	// if we get to here, the user wants to attach stdin, wants a TTY, and
+	// os.Stdin is a terminal, so we can safely set t.Raw to true
+	t.Raw = true
+	return t
+}
+
+func executeRemoteCommand(ctx context.Context, params remoteCommandParameters) error {
+	coreClient, err := kubernetes.NewForConfig(params.restConfig)
+	if err != nil {
+		return err
+	}
+
+	tty := setupTTY(&params)
+	var sizeQueue remotecommand.TerminalSizeQueue
+	if tty.Raw {
+		// this call spawns a goroutine to monitor/update the terminal size
+		sizeQueue = tty.MonitorSize(tty.GetSize())
+
+		// unset stderr if it was previously set because both stdout
+		// and stderr go over params.stdout when tty is
+		// true
+		params.stderr = nil
+	}
+	fn := func() error {
+		request := coreClient.CoreV1().RESTClient().
+			Post().
+			Namespace(params.replicaNamespace).
+			Resource("pods").
+			Name(params.replicaName).
+			SubResource("exec").
+			VersionedParams(&corev1.PodExecOptions{
+				Command: params.command,
+				Stdin:   params.enableStdin,
+				Stdout:  params.stdout != nil,
+				Stderr:  params.stderr != nil,
+				TTY:     params.tty,
+			}, scheme.ParameterCodec)
+
+		exec, err := remotecommand.NewSPDYExecutor(params.restConfig, "POST", request.URL())
+		if err != nil {
+			return err
+		}
+		return exec.StreamWithContext(ctx, remotecommand.StreamOptions{
+			Stdin:             tty.In,
+			Stdout:            params.stdout,
+			Stderr:            params.stderr,
+			Tty:               params.tty,
+			TerminalSizeQueue: sizeQueue,
+		})
+
+	}
+	return tty.Safe(fn)
+}
+
+func deploioRestConfig(ctx context.Context, client *api.Client) (*rest.Config, error) {
+	config := rest.CopyConfig(client.Config)
+	deploioClusterData := &infrastructure.ClusterData{}
+	if err := client.Get(ctx, types.NamespacedName{Name: meta.ClusterDataDeploioName}, deploioClusterData); err != nil {
+		return nil, fmt.Errorf("can not gather deplo.io cluster connection details: %w", err)
+	}
+	config.Host = deploioClusterData.Status.AtProvider.APIEndpoint
+	var err error
+	if config.CAData, err = b64.StdEncoding.DecodeString(deploioClusterData.Status.AtProvider.APICACert); err != nil {
+		return nil, fmt.Errorf("can not decode deplo.io cluster CA certificate: %w", err)
+	}
+	return config, nil
+}
+
+func replicaCommand(buildType appBuildType, command []string) []string {
+	switch buildType {
+	case appBuildTypeBuildpack:
+		execute := append([]string{buildpackEntrypoint}, command...)
+		if len(command) == 0 {
+			execute = []string{buildpackEntrypoint, defaultShellBuildpack}
+		}
+		return execute
+	case appBuildTypeDockerfile:
+		if len(command) == 0 {
+			return []string{defaultShellDockerfile}
+		}
+		return command
+	default:
+		return command
+	}
+}