Add play module defaults support

executor_extra_test.go

@@ -1403,6 +1403,49 @@ func TestExecutorExtra_RunIncludeRole_Good_PublicVarsPersist(t *testing.T) {
 	assert.Equal(t, "hello from public role", e.results["localhost"]["after_public_role"].Msg)
 }
 
+func TestExecutorExtra_RunPlay_Good_ModuleDefaultsApplyToTasks(t *testing.T) {
+	dir := t.TempDir()
+	e := NewExecutor(dir)
+	e.SetInventoryDirect(&Inventory{
+		All: &InventoryGroup{
+			Hosts: map[string]*Host{
+				"localhost": {},
+			},
+		},
+	})
+
+	mock := newTrackingMockClient()
+	e.clients["localhost"] = mock
+	mock.expectCommand(`cd "/tmp/module-defaults" && pwd`, "/tmp/module-defaults\n", "", 0)
+
+	gatherFacts := false
+	play := &Play{
+		Name:        "Module defaults",
+		Hosts:       "localhost",
+		Connection:  "local",
+		GatherFacts: &gatherFacts,
+		ModuleDefaults: map[string]map[string]any{
+			"command": {
+				"chdir": "/tmp/module-defaults",
+			},
+		},
+		Tasks: []Task{
+			{
+				Name:     "Run command with defaults",
+				Module:   "command",
+				Args:     map[string]any{"cmd": "pwd"},
+				Register: "command_result",
+			},
+		},
+	}
+
+	require.NoError(t, e.runPlay(context.Background(), play))
+
+	require.NotNil(t, e.results["localhost"]["command_result"])
+	assert.Equal(t, "/tmp/module-defaults\n", e.results["localhost"]["command_result"].Stdout)
+	assert.True(t, mock.hasExecuted(`cd "/tmp/module-defaults" && pwd`))
+}
+
 func TestExecutorExtra_GetHostsIter_Good(t *testing.T) {
 	inv := &Inventory{
 		All: &InventoryGroup{

modules.go

@@ -67,8 +67,10 @@ func (e *Executor) executeModule(ctx context.Context, host string, client sshExe
 		}
 	}
 
-	// Template the args
-	args := e.templateArgs(task.Args, host, task)
+	// Merge play-level module defaults before templating so defaults and task
+	// arguments can both resolve host-scoped variables.
+	args := mergeModuleDefaults(task.Args, e.resolveModuleDefaults(play, module))
+	args = e.templateArgs(args, host, task)
 
 	switch module {
 	// Command execution
@@ -199,6 +201,56 @@ func (e *Executor) executeModule(ctx context.Context, host string, client sshExe
 	}
 }
 
+func (e *Executor) resolveModuleDefaults(play *Play, module string) map[string]any {
+	if play == nil || len(play.ModuleDefaults) == 0 || module == "" {
+		return nil
+	}
+
+	canonical := NormalizeModule(module)
+
+	merged := make(map[string]any)
+	seen := false
+	keys := make([]string, 0, len(play.ModuleDefaults))
+	for key := range play.ModuleDefaults {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+
+	for _, key := range keys {
+		if NormalizeModule(key) != canonical {
+			continue
+		}
+		defaults := play.ModuleDefaults[key]
+		if len(defaults) == 0 {
+			continue
+		}
+		for k, v := range defaults {
+			merged[k] = v
+		}
+		seen = true
+	}
+
+	if !seen {
+		return nil
+	}
+	return merged
+}
+
+func mergeModuleDefaults(args, defaults map[string]any) map[string]any {
+	if len(args) == 0 && len(defaults) == 0 {
+		return nil
+	}
+
+	merged := make(map[string]any, len(args)+len(defaults))
+	for k, v := range defaults {
+		merged[k] = v
+	}
+	for k, v := range args {
+		merged[k] = v
+	}
+	return merged
+}
+
 func (e *Executor) resolveBecomePassword(host string) string {
 	if e == nil {
 		return ""

parser.go

@@ -450,7 +450,8 @@ func (t *Task) UnmarshalYAML(node *yaml.Node) error {
 		"no_log": true, "become": true, "become_user": true,
 		"delegate_to": true, "delegate_facts": true, "run_once": true, "tags": true,
 		"block": true, "rescue": true, "always": true, "notify": true, "listen": true,
-		"retries": true, "delay": true, "until": true,
+		"module_defaults": true,
+		"retries":         true, "delay": true, "until": true,
 		"action": true, "local_action": true,
 		"ansible.builtin.action": true, "ansible.legacy.action": true,
 		"ansible.builtin.local_action": true, "ansible.legacy.local_action": true,

types.go

@@ -22,26 +22,27 @@ type Playbook struct {
 //
 //	play := Play{Name: "Configure web", Hosts: "webservers", Become: true}
 type Play struct {
-	Name           string            `yaml:"name"`
-	Hosts          string            `yaml:"hosts"`
-	ImportPlaybook string            `yaml:"import_playbook,omitempty"`
-	Connection     string            `yaml:"connection,omitempty"`
-	Become         bool              `yaml:"become,omitempty"`
-	BecomeUser     string            `yaml:"become_user,omitempty"`
-	GatherFacts    *bool             `yaml:"gather_facts,omitempty"`
-	ForceHandlers  bool              `yaml:"force_handlers,omitempty"`
-	AnyErrorsFatal bool              `yaml:"any_errors_fatal,omitempty"`
-	Vars           map[string]any    `yaml:"vars,omitempty"`
-	VarsFiles      any               `yaml:"vars_files,omitempty"` // string or []string
-	PreTasks       []Task            `yaml:"pre_tasks,omitempty"`
-	Tasks          []Task            `yaml:"tasks,omitempty"`
-	PostTasks      []Task            `yaml:"post_tasks,omitempty"`
-	Roles          []RoleRef         `yaml:"roles,omitempty"`
-	Handlers       []Task            `yaml:"handlers,omitempty"`
-	Tags           []string          `yaml:"tags,omitempty"`
-	Environment    map[string]string `yaml:"environment,omitempty"`
-	Serial         any               `yaml:"serial,omitempty"` // int or string
-	MaxFailPercent int               `yaml:"max_fail_percentage,omitempty"`
+	Name           string                    `yaml:"name"`
+	Hosts          string                    `yaml:"hosts"`
+	ImportPlaybook string                    `yaml:"import_playbook,omitempty"`
+	Connection     string                    `yaml:"connection,omitempty"`
+	Become         bool                      `yaml:"become,omitempty"`
+	BecomeUser     string                    `yaml:"become_user,omitempty"`
+	GatherFacts    *bool                     `yaml:"gather_facts,omitempty"`
+	ForceHandlers  bool                      `yaml:"force_handlers,omitempty"`
+	AnyErrorsFatal bool                      `yaml:"any_errors_fatal,omitempty"`
+	Vars           map[string]any            `yaml:"vars,omitempty"`
+	VarsFiles      any                       `yaml:"vars_files,omitempty"` // string or []string
+	ModuleDefaults map[string]map[string]any `yaml:"module_defaults,omitempty"`
+	PreTasks       []Task                    `yaml:"pre_tasks,omitempty"`
+	Tasks          []Task                    `yaml:"tasks,omitempty"`
+	PostTasks      []Task                    `yaml:"post_tasks,omitempty"`
+	Roles          []RoleRef                 `yaml:"roles,omitempty"`
+	Handlers       []Task                    `yaml:"handlers,omitempty"`
+	Tags           []string                  `yaml:"tags,omitempty"`
+	Environment    map[string]string         `yaml:"environment,omitempty"`
+	Serial         any                       `yaml:"serial,omitempty"` // int or string
+	MaxFailPercent int                       `yaml:"max_fail_percentage,omitempty"`
 }
 
 // UnmarshalYAML handles play-level aliases such as ansible.builtin.import_playbook.