generate systemd

Implement `podman generate systemd` for Podman v2 and enable associated
tests.

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

cmd/podman/generate/generate.go

@@ -0,0 +1,27 @@
+package pods
+
+import (
+	"github.com/containers/libpod/cmd/podman/registry"
+	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/containers/libpod/pkg/util"
+	"github.com/spf13/cobra"
+)
+
+var (
+	// Command: podman _generate_
+	generateCmd = &cobra.Command{
+		Use:              "generate",
+		Short:            "Generate structured data based on containers and pods.",
+		Long:             "Generate structured data (e.g., Kubernetes yaml or systemd units) based on containers and pods.",
+		TraverseChildren: true,
+		RunE:             registry.SubCommandExists,
+	}
+	containerConfig = util.DefaultContainerConfig()
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode},
+		Command: generateCmd,
+	})
+}

cmd/podman/generate/systemd.go

@@ -0,0 +1,57 @@
+package pods
+
+import (
+	"fmt"
+
+	"github.com/containers/libpod/cmd/podman/registry"
+	"github.com/containers/libpod/cmd/podman/utils"
+	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/spf13/cobra"
+)
+
+var (
+	systemdTimeout     uint
+	systemdOptions     = entities.GenerateSystemdOptions{}
+	systemdDescription = `Generate systemd units for a pod or container.
+  The generated units can later be controlled via systemctl(1).`
+
+	systemdCmd = &cobra.Command{
+		Use:   "systemd [flags] CTR|POD",
+		Short: "Generate systemd units.",
+		Long:  systemdDescription,
+		RunE:  systemd,
+		Args:  cobra.MinimumNArgs(1),
+		Example: `podman generate systemd CTR
+  podman generate systemd --new --time 10 CTR
+  podman generate systemd --files --name POD`,
+	}
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Mode:    []entities.EngineMode{entities.ABIMode, entities.TunnelMode},
+		Command: systemdCmd,
+		Parent:  generateCmd,
+	})
+	flags := systemdCmd.Flags()
+	flags.BoolVarP(&systemdOptions.Name, "name", "n", false, "Use container/pod names instead of IDs")
+	flags.BoolVarP(&systemdOptions.Files, "files", "f", false, "Generate .service files instead of printing to stdout")
+	flags.UintVarP(&systemdTimeout, "time", "t", containerConfig.Engine.StopTimeout, "Stop timeout override")
+	flags.StringVar(&systemdOptions.RestartPolicy, "restart-policy", "on-failure", "Systemd restart-policy")
+	flags.BoolVarP(&systemdOptions.New, "new", "", false, "Create a new container instead of starting an existing one")
+	flags.SetNormalizeFunc(utils.AliasFlags)
+}
+
+func systemd(cmd *cobra.Command, args []string) error {
+	if cmd.Flags().Changed("time") {
+		systemdOptions.StopTimeout = &systemdTimeout
+	}
+
+	report, err := registry.ContainerEngine().GenerateSystemd(registry.GetContext(), args[0], systemdOptions)
+	if err != nil {
+		return err
+	}
+
+	fmt.Println(report.Output)
+	return nil
+}

cmd/podman/main.go

@@ -4,6 +4,7 @@ import (
 	"os"
 
 	_ "github.com/containers/libpod/cmd/podman/containers"
+	_ "github.com/containers/libpod/cmd/podman/generate"
 	_ "github.com/containers/libpod/cmd/podman/healthcheck"
 	_ "github.com/containers/libpod/cmd/podman/images"
 	_ "github.com/containers/libpod/cmd/podman/manifest"

pkg/domain/entities/engine_container.go

@@ -41,6 +41,7 @@ type ContainerEngine interface {
 	ContainerUnpause(ctx context.Context, namesOrIds []string, options PauseUnPauseOptions) ([]*PauseUnpauseReport, error)
 	ContainerWait(ctx context.Context, namesOrIds []string, options WaitOptions) ([]WaitReport, error)
 	Events(ctx context.Context, opts EventsOptions) error
+	GenerateSystemd(ctx context.Context, nameOrID string, opts GenerateSystemdOptions) (*GenerateSystemdReport, error)
 	HealthCheckRun(ctx context.Context, nameOrId string, options HealthCheckOptions) (*define.HealthCheckResults, error)
 	Info(ctx context.Context) (*define.Info, error)
 	PodCreate(ctx context.Context, opts PodCreateOptions) (*PodCreateReport, error)

pkg/domain/entities/generate.go

@@ -0,0 +1,22 @@
+package entities
+
+// GenerateSystemdOptions control the generation of systemd unit files.
+type GenerateSystemdOptions struct {
+	// Files - generate files instead of printing to stdout.
+	Files bool
+	// Name - use container/pod name instead of its ID.
+	Name bool
+	// New - create a new container instead of starting a new one.
+	New bool
+	// RestartPolicy - systemd restart policy.
+	RestartPolicy string
+	// StopTimeout - time when stopping the container.
+	StopTimeout *uint
+}
+
+// GenerateSystemdReport
+type GenerateSystemdReport struct {
+	// Output of the generate process. Either the generated files or their
+	// entire content.
+	Output string
+}

pkg/domain/infra/abi/generate.go

@@ -0,0 +1,174 @@
+package abi
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/containers/libpod/libpod"
+	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/containers/libpod/pkg/systemd/generate"
+	"github.com/pkg/errors"
+)
+
+func (ic *ContainerEngine) GenerateSystemd(ctx context.Context, nameOrID string, options entities.GenerateSystemdOptions) (*entities.GenerateSystemdReport, error) {
+	opts := generate.Options{
+		Files: options.Files,
+		New:   options.New,
+	}
+
+	// First assume it's a container.
+	if info, found, err := ic.generateSystemdgenContainerInfo(nameOrID, nil, options); found && err != nil {
+		return nil, err
+	} else if found && err == nil {
+		output, err := generate.CreateContainerSystemdUnit(info, opts)
+		if err != nil {
+			return nil, err
+		}
+		return &entities.GenerateSystemdReport{Output: output}, nil
+	}
+
+	// --new does not support pods.
+	if options.New {
+		return nil, errors.Errorf("error generating systemd unit files: cannot generate generic files for a pod")
+	}
+
+	// We're either having a pod or garbage.
+	pod, err := ic.Libpod.LookupPod(nameOrID)
+	if err != nil {
+		return nil, err
+	}
+
+	// Error out if the pod has no infra container, which we require to be the
+	// main service.
+	if !pod.HasInfraContainer() {
+		return nil, fmt.Errorf("error generating systemd unit files: Pod %q has no infra container", pod.Name())
+	}
+
+	// Generate a systemdgen.ContainerInfo for the infra container. This
+	// ContainerInfo acts as the main service of the pod.
+	infraID, err := pod.InfraContainerID()
+	if err != nil {
+		return nil, nil
+	}
+	podInfo, _, err := ic.generateSystemdgenContainerInfo(infraID, pod, options)
+	if err != nil {
+		return nil, err
+	}
+
+	// Compute the container-dependency graph for the Pod.
+	containers, err := pod.AllContainers()
+	if err != nil {
+		return nil, err
+	}
+	if len(containers) == 0 {
+		return nil, fmt.Errorf("error generating systemd unit files: Pod %q has no containers", pod.Name())
+	}
+	graph, err := libpod.BuildContainerGraph(containers)
+	if err != nil {
+		return nil, err
+	}
+
+	// Traverse the dependency graph and create systemdgen.ContainerInfo's for
+	// each container.
+	containerInfos := []*generate.ContainerInfo{podInfo}
+	for ctr, dependencies := range graph.DependencyMap() {
+		// Skip the infra container as we already generated it.
+		if ctr.ID() == infraID {
+			continue
+		}
+		ctrInfo, _, err := ic.generateSystemdgenContainerInfo(ctr.ID(), nil, options)
+		if err != nil {
+			return nil, err
+		}
+		// Now add the container's dependencies and at the container as a
+		// required service of the infra container.
+		for _, dep := range dependencies {
+			if dep.ID() == infraID {
+				ctrInfo.BoundToServices = append(ctrInfo.BoundToServices, podInfo.ServiceName)
+			} else {
+				_, serviceName := generateServiceName(dep, nil, options)
+				ctrInfo.BoundToServices = append(ctrInfo.BoundToServices, serviceName)
+			}
+		}
+		podInfo.RequiredServices = append(podInfo.RequiredServices, ctrInfo.ServiceName)
+		containerInfos = append(containerInfos, ctrInfo)
+	}
+
+	// Now generate the systemd service for all containers.
+	builder := strings.Builder{}
+	for i, info := range containerInfos {
+		if i > 0 {
+			builder.WriteByte('\n')
+		}
+		out, err := generate.CreateContainerSystemdUnit(info, opts)
+		if err != nil {
+			return nil, err
+		}
+		builder.WriteString(out)
+	}
+
+	return &entities.GenerateSystemdReport{Output: builder.String()}, nil
+}
+
+// generateSystemdgenContainerInfo is a helper to generate a
+// systemdgen.ContainerInfo for `GenerateSystemd`.
+func (ic *ContainerEngine) generateSystemdgenContainerInfo(nameOrID string, pod *libpod.Pod, options entities.GenerateSystemdOptions) (*generate.ContainerInfo, bool, error) {
+	ctr, err := ic.Libpod.LookupContainer(nameOrID)
+	if err != nil {
+		return nil, false, err
+	}
+
+	timeout := ctr.StopTimeout()
+	if options.StopTimeout != nil {
+		timeout = *options.StopTimeout
+	}
+
+	config := ctr.Config()
+	conmonPidFile := config.ConmonPidFile
+	if conmonPidFile == "" {
+		return nil, true, errors.Errorf("conmon PID file path is empty, try to recreate the container with --conmon-pidfile flag")
+	}
+
+	createCommand := []string{}
+	if config.CreateCommand != nil {
+		createCommand = config.CreateCommand
+	} else if options.New {
+		return nil, true, errors.Errorf("cannot use --new on container %q: no create command found", nameOrID)
+	}
+
+	name, serviceName := generateServiceName(ctr, pod, options)
+	info := &generate.ContainerInfo{
+		ServiceName:       serviceName,
+		ContainerName:     name,
+		RestartPolicy:     options.RestartPolicy,
+		PIDFile:           conmonPidFile,
+		StopTimeout:       timeout,
+		GenerateTimestamp: true,
+		CreateCommand:     createCommand,
+	}
+
+	return info, true, nil
+}
+
+// generateServiceName generates the container name and the service name for systemd service.
+func generateServiceName(ctr *libpod.Container, pod *libpod.Pod, options entities.GenerateSystemdOptions) (string, string) {
+	var kind, name, ctrName string
+	if pod == nil {
+		kind = "container"
+		name = ctr.ID()
+		if options.Name {
+			name = ctr.Name()
+		}
+		ctrName = name
+	} else {
+		kind = "pod"
+		name = pod.ID()
+		ctrName = ctr.ID()
+		if options.Name {
+			name = pod.Name()
+			ctrName = ctr.Name()
+		}
+	}
+	return ctrName, fmt.Sprintf("%s-%s", kind, name)
+}

pkg/domain/infra/tunnel/generate.go

@@ -0,0 +1,12 @@
+package tunnel
+
+import (
+	"context"
+
+	"github.com/containers/libpod/pkg/domain/entities"
+	"github.com/pkg/errors"
+)
+
+func (ic *ContainerEngine) GenerateSystemd(ctx context.Context, nameOrID string, options entities.GenerateSystemdOptions) (*entities.GenerateSystemdReport, error) {
+	return nil, errors.New("not implemented for tunnel")
+}

pkg/specgen/generate/container_create.go

@@ -76,6 +76,7 @@ func MakeContainer(ctx context.Context, rt *libpod.Runtime, s *specgen.SpecGener
 	}
 
 	options := []libpod.CtrCreateOption{}
+	options = append(options, libpod.WithCreateCommand())
 
 	var newImage *image.Image
 	if s.Rootfs != "" {

test/e2e/generate_systemd_test.go

@@ -18,7 +18,6 @@ var _ = Describe("Podman generate systemd", func() {
 	)
 
 	BeforeEach(func() {
-		Skip(v2fail)
 		tempdir, err = CreateTempDirInTempDir()
 		if err != nil {
 			os.Exit(1)

test/system/250-generate-systemd.bats

@@ -10,6 +10,8 @@ SERVICE_NAME="podman_test_$(random_string)"
 UNIT_DIR="$HOME/.config/systemd/user"
 UNIT_FILE="$UNIT_DIR/$SERVICE_NAME.service"
 
+# FIXME: the must run as root (because of CI). It's also broken...
+
 function setup() {
     skip_if_not_systemd
     skip_if_remote