Add user-defined dependencies to podman generate systemd

cmd/podman/generate/systemd.go

@@ -25,6 +25,9 @@ const (
 	restartPolicyFlagName     = "restart-policy"
 	restartSecFlagName        = "restart-sec"
 	newFlagName               = "new"
+	wantsFlagName             = "wants"
+	afterFlagName             = "after"
+	requiresFlagName          = "requires"
 )
 
 var (
@@ -97,6 +100,15 @@ func init() {
 	flags.StringVar(&format, formatFlagName, "", "Print the created units in specified format (json)")
 	_ = systemdCmd.RegisterFlagCompletionFunc(formatFlagName, common.AutocompleteFormat(nil))
 
+	flags.StringArrayVar(&systemdOptions.Wants, wantsFlagName, nil, "Add (weak) requirement dependencies to the generated unit file")
+	_ = systemdCmd.RegisterFlagCompletionFunc(wantsFlagName, completion.AutocompleteNone)
+
+	flags.StringArrayVar(&systemdOptions.After, afterFlagName, nil, "Add dependencies order to the generated unit file")
+	_ = systemdCmd.RegisterFlagCompletionFunc(afterFlagName, completion.AutocompleteNone)
+
+	flags.StringArrayVar(&systemdOptions.Requires, requiresFlagName, nil, "Similar to wants, but declares stronger requirement dependencies")
+	_ = systemdCmd.RegisterFlagCompletionFunc(requiresFlagName, completion.AutocompleteNone)
+
 	flags.SetNormalizeFunc(utils.TimeoutAliasFlags)
 }
 

docs/source/markdown/podman-generate-systemd.1.md

@@ -68,6 +68,22 @@ Set the systemd unit name prefix for pods. The default is *pod*.
 
 Set the systemd unit name separator between the name/id of a container/pod and the prefix. The default is *-*.
 
+#### **--wants**=*dependency_name*
+
+Add the systemd unit wants (`Wants=`) option, that this service is (weak) dependent on. This option may be specified more than once. This option does not influence the order in which services are started or stopped.
+
+User-defined dependencies will be appended to the generated unit file, but any existing options such as needed or defined by default (e.g. `online.target`) will **not** be removed or overridden.
+
+#### **--after**=*dependency_name*
+
+Add the systemd unit after (`After=`) option, that ordering dependencies between the list of dependencies and this service. This option may be specified more than once.
+
+User-defined dependencies will be appended to the generated unit file, but any existing options such as needed or defined by default (e.g. `online.target`) will **not** be removed or overridden.
+
+#### **--requires**=*dependency_name*
+
+Set the systemd unit requires (`Requires=`) option. Similar to wants, but declares a stronger requirement dependency.
+
 #### **--template**
 
 Add template specifiers to run multiple services from the systemd unit file.

pkg/api/handlers/libpod/generate.go

@@ -17,17 +17,20 @@ func GenerateSystemd(w http.ResponseWriter, r *http.Request) {
 	runtime := r.Context().Value(api.RuntimeKey).(*libpod.Runtime)
 	decoder := r.Context().Value(api.DecoderKey).(*schema.Decoder)
 	query := struct {
-		Name             bool    `schema:"useName"`
-		New              bool    `schema:"new"`
-		NoHeader         bool    `schema:"noHeader"`
-		TemplateUnitFile bool    `schema:"templateUnitFile"`
-		RestartPolicy    *string `schema:"restartPolicy"`
-		RestartSec       uint    `schema:"restartSec"`
-		StopTimeout      uint    `schema:"stopTimeout"`
-		StartTimeout     uint    `schema:"startTimeout"`
-		ContainerPrefix  string  `schema:"containerPrefix"`
-		PodPrefix        string  `schema:"podPrefix"`
-		Separator        string  `schema:"separator"`
+		Name             bool     `schema:"useName"`
+		New              bool     `schema:"new"`
+		NoHeader         bool     `schema:"noHeader"`
+		TemplateUnitFile bool     `schema:"templateUnitFile"`
+		RestartPolicy    *string  `schema:"restartPolicy"`
+		RestartSec       uint     `schema:"restartSec"`
+		StopTimeout      uint     `schema:"stopTimeout"`
+		StartTimeout     uint     `schema:"startTimeout"`
+		ContainerPrefix  string   `schema:"containerPrefix"`
+		PodPrefix        string   `schema:"podPrefix"`
+		Separator        string   `schema:"separator"`
+		Wants            []string `schema:"wants"`
+		After            []string `schema:"after"`
+		Requires         []string `schema:"requires"`
 	}{
 		StartTimeout:    0,
 		StopTimeout:     util.DefaultContainerConfig().Engine.StopTimeout,
@@ -55,6 +58,9 @@ func GenerateSystemd(w http.ResponseWriter, r *http.Request) {
 		PodPrefix:        query.PodPrefix,
 		Separator:        query.Separator,
 		RestartSec:       &query.RestartSec,
+		Wants:            query.Wants,
+		After:            query.After,
+		Requires:         query.Requires,
 	}
 
 	report, err := containerEngine.GenerateSystemd(r.Context(), utils.GetName(r), options)

pkg/api/server/register_generate.go

@@ -72,6 +72,27 @@ func (s *APIServer) registerGenerateHandlers(r *mux.Router) error {
 	//    type: integer
 	//    default: 0
 	//    description: Configures the time to sleep before restarting a service.
+	//  - in: query
+	//    name: wants
+	//    type: array
+	//    items:
+	//        type: string
+	//    default: []
+	//    description: Systemd Wants list for the container or pods.
+	//  - in: query
+	//    name: after
+	//    type: array
+	//    items:
+	//        type: string
+	//    default: []
+	//    description: Systemd After list for the container or pods.
+	//  - in: query
+	//    name: requires
+	//    type: array
+	//    items:
+	//        type: string
+	//    default: []
+	//    description: Systemd Requires list for the container or pods.
 	// produces:
 	// - application/json
 	// responses:

pkg/bindings/generate/types.go

@@ -32,4 +32,10 @@ type SystemdOptions struct {
 	PodPrefix *string
 	// Separator - systemd unit name separator between name/id and prefix
 	Separator *string
+	// Wants - systemd wants list for the container or pods
+	Wants *[]string
+	// After - systemd after list for the container or pods
+	After *[]string
+	// Requires - systemd requires list for the container or pods
+	Requires *[]string
 }

pkg/domain/entities/generate.go

@@ -26,6 +26,12 @@ type GenerateSystemdOptions struct {
 	NoHeader bool
 	// TemplateUnitFile - make use of %i and %I to differentiate between the different instances of the unit
 	TemplateUnitFile bool
+	// Wants - systemd wants list for the container or pods
+	Wants []string
+	// After - systemd after list for the container or pods
+	After []string
+	// Requires - systemd requires list for the container or pods
+	Requires []string
 }
 
 // GenerateSystemdReport

pkg/domain/infra/tunnel/generate.go

@@ -8,7 +8,17 @@ import (
 )
 
 func (ic *ContainerEngine) GenerateSystemd(ctx context.Context, nameOrID string, opts entities.GenerateSystemdOptions) (*entities.GenerateSystemdReport, error) {
-	options := new(generate.SystemdOptions).WithUseName(opts.Name).WithContainerPrefix(opts.ContainerPrefix).WithNew(opts.New).WithNoHeader(opts.NoHeader).WithTemplateUnitFile(opts.TemplateUnitFile).WithPodPrefix(opts.PodPrefix).WithSeparator(opts.Separator)
+	options := new(
+		generate.SystemdOptions).
+		WithUseName(opts.Name).
+		WithContainerPrefix(opts.ContainerPrefix).
+		WithNew(opts.New).WithNoHeader(opts.NoHeader).
+		WithTemplateUnitFile(opts.TemplateUnitFile).
+		WithPodPrefix(opts.PodPrefix).
+		WithSeparator(opts.Separator).
+		WithWants(opts.Wants).
+		WithAfter(opts.After).
+		WithRequires(opts.Requires)
 
 	if opts.StartTimeout != nil {
 		options.WithStartTimeout(*opts.StartTimeout)

pkg/systemd/generate/containers.go

@@ -94,13 +94,33 @@ type containerInfo struct {
 	RunRoot string
 	// Add %i and %I to description and execute parts
 	IdentifySpecifier bool
+	// Wants are the list of services that this service is (weak) dependent on. This
+	// option does not influence the order in which services are started or stopped.
+	Wants []string
+	// After ordering dependencies between the list of services and this service.
+	After []string
+	// Similar to Wants, but declares a stronger requirement dependency.
+	Requires []string
 }
 
 const containerTemplate = headerTemplate + `
 {{{{- if .BoundToServices}}}}
 BindsTo={{{{- range $index, $value := .BoundToServices -}}}}{{{{if $index}}}} {{{{end}}}}{{{{ $value }}}}.service{{{{end}}}}
 After={{{{- range $index, $value := .BoundToServices -}}}}{{{{if $index}}}} {{{{end}}}}{{{{ $value }}}}.service{{{{end}}}}
 {{{{- end}}}}
+{{{{- if or .Wants .After .Requires }}}}
+
+# User-defined dependencies
+{{{{- end}}}}
+{{{{- if .Wants}}}}
+Wants={{{{- range $index, $value := .Wants }}}}{{{{ if $index}}}} {{{{end}}}}{{{{ $value }}}}{{{{end}}}}
+{{{{- end}}}}
+{{{{- if .After}}}}
+After={{{{- range $index, $value := .After }}}}{{{{ if $index}}}} {{{{end}}}}{{{{ $value }}}}{{{{end}}}}
+{{{{- end}}}}
+{{{{- if .Requires}}}}
+Requires={{{{- range $index, $value := .Requires }}}}{{{{ if $index}}}} {{{{end}}}}{{{{ $value }}}}{{{{end}}}}
+{{{{- end}}}}
 
 [Service]
 Environment={{{{.EnvVariable}}}}=%n{{{{- if (eq .IdentifySpecifier true) }}}}-%i{{{{- end}}}}
@@ -201,6 +221,9 @@ func generateContainerInfo(ctr *libpod.Container, options entities.GenerateSyste
 		CreateCommand:     createCommand,
 		RunRoot:           runRoot,
 		containerEnv:      envs,
+		Wants:             options.Wants,
+		After:             options.After,
+		Requires:          options.Requires,
 	}
 
 	return &info, nil