package generate import ( "bytes" "fmt" "io/ioutil" "os" "path/filepath" "sort" "strings" "text/template" "time" "github.com/containers/libpod/libpod" "github.com/containers/libpod/pkg/domain/entities" "github.com/containers/libpod/version" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) // podInfo contains data required for generating a pod's systemd // unit file. type podInfo struct { // ServiceName of the systemd service. ServiceName string // Name or ID of the infra container. InfraNameOrID string // StopTimeout sets the timeout Podman waits before killing the container // during service stop. StopTimeout uint // RestartPolicy of the systemd unit (e.g., no, on-failure, always). RestartPolicy string // PIDFile of the service. Required for forking services. Must point to the // PID of the associated conmon process. PIDFile string // PodIDFile of the unit. PodIDFile string // GenerateTimestamp, if set the generated unit file has a time stamp. GenerateTimestamp bool // RequiredServices are services this service requires. Note that this // service runs before them. RequiredServices []string // PodmanVersion for the header. Will be set internally. Will be auto-filled // if left empty. PodmanVersion string // Executable is the path to the podman executable. Will be auto-filled if // left empty. Executable string // TimeStamp at the time of creating the unit file. Will be set internally. TimeStamp string // CreateCommand is the full command plus arguments of the process the // container has been created with. CreateCommand []string // PodCreateCommand - a post-processed variant of CreateCommand to use // when creating the pod. PodCreateCommand string // EnvVariable is generate.EnvVariable and must not be set. EnvVariable string // ExecStartPre1 of the unit. ExecStartPre1 string // ExecStartPre2 of the unit. ExecStartPre2 string // ExecStart of the unit. ExecStart string // ExecStop of the unit. ExecStop string // ExecStopPost of the unit. ExecStopPost string } const podTemplate = headerTemplate + `Requires={{- range $index, $value := .RequiredServices -}}{{if $index}} {{end}}{{ $value }}.service{{end}} Before={{- range $index, $value := .RequiredServices -}}{{if $index}} {{end}}{{ $value }}.service{{end}} [Service] Environment={{.EnvVariable}}=%n Restart={{.RestartPolicy}} {{- if .ExecStartPre1}} ExecStartPre={{.ExecStartPre1}} {{- end}} {{- if .ExecStartPre2}} ExecStartPre={{.ExecStartPre2}} {{- end}} ExecStart={{.ExecStart}} ExecStop={{.ExecStop}} {{- if .ExecStopPost}} ExecStopPost={{.ExecStopPost}} {{- end}} PIDFile={{.PIDFile}} KillMode=none Type=forking [Install] WantedBy=multi-user.target default.target` // PodUnits generates systemd units for the specified pod and its containers. // Based on the options, the return value might be the content of all units or // the files they been written to. func PodUnits(pod *libpod.Pod, options entities.GenerateSystemdOptions) (string, error) { // Error out if the pod has no infra container, which we require to be the // main service. if !pod.HasInfraContainer() { return "", fmt.Errorf("error generating systemd unit files: Pod %q has no infra container", pod.Name()) } podInfo, err := generatePodInfo(pod, options) if err != nil { return "", err } infraID, err := pod.InfraContainerID() if err != nil { return "", err } // Compute the container-dependency graph for the Pod. containers, err := pod.AllContainers() if err != nil { return "", err } if len(containers) == 0 { return "", fmt.Errorf("error generating systemd unit files: Pod %q has no containers", pod.Name()) } graph, err := libpod.BuildContainerGraph(containers) if err != nil { return "", err } // Traverse the dependency graph and create systemdgen.containerInfo's for // each container. containerInfos := []*containerInfo{} for ctr, dependencies := range graph.DependencyMap() { // Skip the infra container as we already generated it. if ctr.ID() == infraID { continue } ctrInfo, err := generateContainerInfo(ctr, options) if err != nil { return "", 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 := containerServiceName(dep, 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{} out, err := executePodTemplate(podInfo, options) if err != nil { return "", err } builder.WriteString(out) for _, info := range containerInfos { info.pod = podInfo builder.WriteByte('\n') out, err := executeContainerTemplate(info, options) if err != nil { return "", err } builder.WriteString(out) } return builder.String(), nil } func generatePodInfo(pod *libpod.Pod, options entities.GenerateSystemdOptions) (*podInfo, error) { // Generate a systemdgen.containerInfo for the infra container. This // containerInfo acts as the main service of the pod. infraCtr, err := pod.InfraContainer() if err != nil { return nil, errors.Wrap(err, "could not find infra container") } timeout := infraCtr.StopTimeout() if options.StopTimeout != nil { timeout = *options.StopTimeout } config := infraCtr.Config() conmonPidFile := config.ConmonPidFile if conmonPidFile == "" { return nil, errors.Errorf("conmon PID file path is empty, try to recreate the container with --conmon-pidfile flag") } createCommand := pod.CreateCommand() if options.New && len(createCommand) == 0 { return nil, errors.Errorf("cannot use --new on pod %q: no create command found", pod.ID()) } nameOrID := pod.ID() ctrNameOrID := infraCtr.ID() if options.Name { nameOrID = pod.Name() ctrNameOrID = infraCtr.Name() } serviceName := fmt.Sprintf("%s%s%s", options.PodPrefix, options.Separator, nameOrID) info := podInfo{ ServiceName: serviceName, InfraNameOrID: ctrNameOrID, RestartPolicy: options.RestartPolicy, PIDFile: conmonPidFile, StopTimeout: timeout, GenerateTimestamp: true, CreateCommand: createCommand, } return &info, nil } // executePodTemplate executes the pod template on the specified podInfo. Note // that the podInfo is also post processed and completed, which allows for an // easier unit testing. func executePodTemplate(info *podInfo, options entities.GenerateSystemdOptions) (string, error) { if err := validateRestartPolicy(info.RestartPolicy); err != nil { return "", err } // Make sure the executable is set. if info.Executable == "" { executable, err := os.Executable() if err != nil { executable = "/usr/bin/podman" logrus.Warnf("Could not obtain podman executable location, using default %s", executable) } info.Executable = executable } info.EnvVariable = EnvVariable info.ExecStart = "{{.Executable}} start {{.InfraNameOrID}}" info.ExecStop = "{{.Executable}} stop {{if (ge .StopTimeout 0)}}-t {{.StopTimeout}}{{end}} {{.InfraNameOrID}}" // Assemble the ExecStart command when creating a new pod. // // Note that we cannot catch all corner cases here such that users // *must* manually check the generated files. A pod might have been // created via a Python script, which would certainly yield an invalid // `info.CreateCommand`. Hence, we're doing a best effort unit // generation and don't try aiming at completeness. if options.New { info.PIDFile = "%t/" + info.ServiceName + ".pid" info.PodIDFile = "%t/" + info.ServiceName + ".pod-id" podCreateIndex := 0 var podRootArgs, podCreateArgs []string switch len(info.CreateCommand) { case 0, 1, 2: return "", errors.Errorf("pod does not appear to be created via `podman pod create`: %v", info.CreateCommand) default: // Make sure that pod was created with `pod create` and // not something else, such as `run --pod new`. for i := 1; i < len(info.CreateCommand); i++ { if info.CreateCommand[i-1] == "pod" && info.CreateCommand[i] == "create" { podCreateIndex = i break } } if podCreateIndex == 0 { return "", errors.Errorf("pod does not appear to be created via `podman pod create`: %v", info.CreateCommand) } podRootArgs = info.CreateCommand[1 : podCreateIndex-2] podCreateArgs = filterPodFlags(info.CreateCommand[podCreateIndex+1:]) } // We're hard-coding the first five arguments and append the // CreateCommand with a stripped command and subcomand. startCommand := []string{info.Executable} startCommand = append(startCommand, podRootArgs...) startCommand = append(startCommand, []string{"pod", "create", "--infra-conmon-pidfile", "{{.PIDFile}}", "--pod-id-file", "{{.PodIDFile}}"}...) startCommand = append(startCommand, podCreateArgs...) info.ExecStartPre1 = "/usr/bin/rm -f {{.PIDFile}} {{.PodIDFile}}" info.ExecStartPre2 = strings.Join(startCommand, " ") info.ExecStart = "{{.Executable}} pod start --pod-id-file {{.PodIDFile}}" info.ExecStop = "{{.Executable}} pod stop --ignore --pod-id-file {{.PodIDFile}} {{if (ge .StopTimeout 0)}}-t {{.StopTimeout}}{{end}}" info.ExecStopPost = "{{.Executable}} pod rm --ignore -f --pod-id-file {{.PodIDFile}}" } if info.PodmanVersion == "" { info.PodmanVersion = version.Version } if info.GenerateTimestamp { info.TimeStamp = fmt.Sprintf("%v", time.Now().Format(time.UnixDate)) } // Sort the slices to assure a deterministic output. sort.Strings(info.RequiredServices) // Generate the template and compile it. // // Note that we need a two-step generation process to allow for fields // embedding other fields. This way we can replace `A -> B -> C` and // make the code easier to maintain at the cost of a slightly slower // generation. That's especially needed for embedding the PID and ID // files in other fields which will eventually get replaced in the 2nd // template execution. templ, err := template.New("pod_template").Parse(podTemplate) if err != nil { return "", errors.Wrap(err, "error parsing systemd service template") } var buf bytes.Buffer if err := templ.Execute(&buf, info); err != nil { return "", err } // Now parse the generated template (i.e., buf) and execute it. templ, err = template.New("pod_template").Parse(buf.String()) if err != nil { return "", errors.Wrap(err, "error parsing systemd service template") } buf = bytes.Buffer{} if err := templ.Execute(&buf, info); err != nil { return "", err } if !options.Files { return buf.String(), nil } buf.WriteByte('\n') cwd, err := os.Getwd() if err != nil { return "", errors.Wrap(err, "error getting current working directory") } path := filepath.Join(cwd, fmt.Sprintf("%s.service", info.ServiceName)) if err := ioutil.WriteFile(path, buf.Bytes(), 0644); err != nil { return "", errors.Wrap(err, "error generating systemd unit") } return path, nil }