support using modules inside of foreach

internal/runtime/internal/controller/loader.go

@@ -512,7 +512,7 @@ func (l *Loader) populateConfigBlockNodes(args map[string]any, g *dag.Graph, con
 			node = exist.(BlockNode)
 			node.UpdateBlock(block)
 		} else {
-			node, newConfigNodeDiags = NewConfigNode(block, l.globals)
+			node, newConfigNodeDiags = NewConfigNode(block, l.globals, l.componentNodeManager.customComponentReg)
 			diags = append(diags, newConfigNodeDiags...)
 			if diags.HasErrors() {
 				continue
@@ -625,6 +625,8 @@ func (l *Loader) wireGraphEdges(g *dag.Graph) diag.Diagnostics {
 			continue
 		case *CustomComponentNode:
 			l.wireCustomComponentNode(g, n)
+		case *ForeachConfigNode:
+			l.wireForEachNode(g, n)
 		}
 
 		// Finally, wire component references.
@@ -656,6 +658,14 @@ func (l *Loader) wireCustomComponentNode(g *dag.Graph, cc *CustomComponentNode)
 	}
 }
 
+func (l *Loader) wireForEachNode(g *dag.Graph, fn *ForeachConfigNode) {
+	refs := l.findCustomComponentReferences(fn.Block())
+	for ref := range refs {
+		// add edges between the foreach node and declare/import nodes.
+		g.AddEdge(dag.Edge{From: fn, To: ref})
+	}
+}
+
 // Variables returns the Variables the Loader exposes for other components to
 // reference.
 func (l *Loader) Variables() map[string]interface{} {
@@ -915,10 +925,10 @@ func (l *Loader) isRootController() bool {
 	return l.globals.ControllerID == ""
 }
 
-// findCustomComponentReferences returns references to import/declare nodes in a declare block.
-func (l *Loader) findCustomComponentReferences(declare *ast.BlockStmt) map[BlockNode]struct{} {
+// findCustomComponentReferences returns references to import/declare nodes in a block.
+func (l *Loader) findCustomComponentReferences(block *ast.BlockStmt) map[BlockNode]struct{} {
 	uniqueReferences := make(map[BlockNode]struct{})
-	l.collectCustomComponentReferences(declare.Body, uniqueReferences)
+	l.collectCustomComponentReferences(block.Body, uniqueReferences)
 	return uniqueReferences
 }
 
@@ -938,7 +948,7 @@ func (l *Loader) collectCustomComponentReferences(stmts ast.Body, uniqueReferenc
 		)
 
 		switch {
-		case componentName == declareType:
+		case componentName == declareType || componentName == templateType:
 			l.collectCustomComponentReferences(blockStmt.Body, uniqueReferences)
 		case foundDeclare:
 			uniqueReferences[declareNode] = struct{}{}

internal/runtime/internal/controller/node_config.go

@@ -18,7 +18,7 @@ const (
 
 // NewConfigNode creates a new ConfigNode from an initial ast.BlockStmt.
 // The underlying config isn't applied until Evaluate is called.
-func NewConfigNode(block *ast.BlockStmt, globals ComponentGlobals) (BlockNode, diag.Diagnostics) {
+func NewConfigNode(block *ast.BlockStmt, globals ComponentGlobals, customReg *CustomComponentRegistry) (BlockNode, diag.Diagnostics) {
 	switch block.GetBlockName() {
 	case argumentBlockID:
 		return NewArgumentConfigNode(block, globals), nil
@@ -31,7 +31,7 @@ func NewConfigNode(block *ast.BlockStmt, globals ComponentGlobals) (BlockNode, d
 	case importsource.BlockImportFile, importsource.BlockImportString, importsource.BlockImportHTTP, importsource.BlockImportGit:
 		return NewImportConfigNode(block, globals, importsource.GetSourceType(block.GetBlockName())), nil
 	case foreachID:
-		return NewForeachConfigNode(block, globals), nil
+		return NewForeachConfigNode(block, globals, customReg), nil
 	default:
 		var diags diag.Diagnostics
 		diags.Add(diag.Diagnostic{

internal/runtime/internal/controller/node_config_foreach.go

@@ -14,11 +14,17 @@ import (
 	"github.com/grafana/alloy/syntax/vm"
 )
 
+const templateType = "template"
+
 type ForeachConfigNode struct {
 	nodeID           string
 	label            string
 	moduleController ModuleController
 
+	// customReg is the customComponentRegistry of the current loader.
+	// We pass it so that the foreach children have access to modules.
+	customReg *CustomComponentRegistry
+
 	customComponents          map[string]CustomComponent
 	customComponentHashCounts map[string]int
 
@@ -39,7 +45,7 @@ type ForeachArguments struct {
 	Collection []string `alloy:"collection,attr"`
 }
 
-func NewForeachConfigNode(block *ast.BlockStmt, globals ComponentGlobals) *ForeachConfigNode {
+func NewForeachConfigNode(block *ast.BlockStmt, globals ComponentGlobals, customReg *CustomComponentRegistry) *ForeachConfigNode {
 	nodeID := BlockComponentID(block).String()
 	globalID := nodeID
 	if globals.ControllerID != "" {
@@ -51,6 +57,7 @@ func NewForeachConfigNode(block *ast.BlockStmt, globals ComponentGlobals) *Forea
 		label:                     block.Label,
 		block:                     block,
 		moduleController:          globals.NewModuleController(globalID),
+		customReg:                 customReg,
 		forEachChildrenUpdateChan: make(chan struct{}, 1),
 		customComponents:          make(map[string]CustomComponent, 0),
 		customComponentHashCounts: make(map[string]int, 0),
@@ -61,7 +68,11 @@ func (fn *ForeachConfigNode) Label() string { return fn.label }
 
 func (fn *ForeachConfigNode) NodeID() string { return fn.nodeID }
 
-func (fn *ForeachConfigNode) Block() *ast.BlockStmt { return fn.block }
+func (fn *ForeachConfigNode) Block() *ast.BlockStmt {
+	fn.mut.RLock()
+	defer fn.mut.RUnlock()
+	return fn.block
+}
 
 type Arguments struct {
 	Collection []any  `alloy:"collection,attr"`
@@ -75,7 +86,7 @@ func (fn *ForeachConfigNode) Evaluate(scope *vm.Scope) error {
 	var argsBody ast.Body
 	var template *ast.BlockStmt
 	for _, stmt := range fn.block.Body {
-		if blockStmt, ok := stmt.(*ast.BlockStmt); ok && blockStmt.GetBlockName() == "template" {
+		if blockStmt, ok := stmt.(*ast.BlockStmt); ok && blockStmt.GetBlockName() == templateType {
 			template = blockStmt
 			continue // we don't add the template to the argsBody
 		}
@@ -115,8 +126,7 @@ func (fn *ForeachConfigNode) Evaluate(scope *vm.Scope) error {
 		vars := deepCopyMap(scope.Variables)
 		vars[args.Var] = args.Collection[i]
 
-		// TODO: use the registry from the loader to access the modules
-		customComponentRegistry := NewCustomComponentRegistry(nil, vm.NewScope(vars))
+		customComponentRegistry := NewCustomComponentRegistry(fn.customReg, vm.NewScope(vars))
 		if err := cc.LoadBody(template.Body, map[string]any{}, customComponentRegistry); err != nil {
 			return fmt.Errorf("updating custom component in foreach: %w", err)
 		}

internal/runtime/internal/controller/node_config_foreach_test.go

@@ -26,7 +26,7 @@ func TestCreateCustomComponents(t *testing.T) {
 		template {
 		}
 	}`
-	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t))
+	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t), nil)
 	require.NoError(t, foreachConfigNode.Evaluate(vm.NewScope(make(map[string]interface{}))))
 	customComponentIds := foreachConfigNode.moduleController.(*ModuleControllerMock).CustomComponents
 	require.ElementsMatch(t, customComponentIds, []string{"foreach_1_1", "foreach_2_1", "foreach_3_1"})
@@ -44,7 +44,7 @@ func TestCreateCustomComponentsDuplicatedIds(t *testing.T) {
 		template {
 		}
 	}`
-	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t))
+	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t), nil)
 	require.NoError(t, foreachConfigNode.Evaluate(vm.NewScope(make(map[string]interface{}))))
 	customComponentIds := foreachConfigNode.moduleController.(*ModuleControllerMock).CustomComponents
 	require.ElementsMatch(t, customComponentIds, []string{"foreach_1_1", "foreach_2_1", "foreach_1_2"})
@@ -62,7 +62,7 @@ func TestCreateCustomComponentsWithUpdate(t *testing.T) {
 		template {
 		}
 	}`
-	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t))
+	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t), nil)
 	require.NoError(t, foreachConfigNode.Evaluate(vm.NewScope(make(map[string]interface{}))))
 	customComponentIds := foreachConfigNode.moduleController.(*ModuleControllerMock).CustomComponents
 	require.ElementsMatch(t, customComponentIds, []string{"foreach_1_1", "foreach_2_1", "foreach_3_1"})
@@ -101,7 +101,7 @@ func TestRunCustomComponents(t *testing.T) {
 		template {
 		}
 	}`
-	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t))
+	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t), nil)
 	require.NoError(t, foreachConfigNode.Evaluate(vm.NewScope(make(map[string]interface{}))))
 	ctx, cancel := context.WithCancel(context.Background())
 	go foreachConfigNode.Run(ctx)
@@ -129,7 +129,7 @@ func TestRunCustomComponentsAfterUpdate(t *testing.T) {
 		template {
 		}
 	}`
-	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t))
+	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t), nil)
 	require.NoError(t, foreachConfigNode.Evaluate(vm.NewScope(make(map[string]interface{}))))
 	ctx, cancel := context.WithCancel(context.Background())
 	go foreachConfigNode.Run(ctx)
@@ -176,7 +176,7 @@ func TestCreateCustomComponentsCollectionObjectsWithUpdate(t *testing.T) {
 		template {
 		}
 	}`
-	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t))
+	foreachConfigNode := NewForeachConfigNode(getBlockFromConfig(t, config), getComponentGlobals(t), nil)
 	vars := map[string]interface{}{
 		"obj1": map[string]string{
 			"label1": "a",

internal/runtime/testdata/foreach/foreach_7.txtar

@@ -0,0 +1,32 @@
+Module used inside of a foreach.
+
+-- main.alloy --
+import.file "testImport" {
+  filename = "module.alloy"
+}
+
+foreach "testForeach" {
+  collection = [5, 5]
+  var = "num"
+
+  template {
+    testImport.a "cc" {
+      max = num
+      receiver = testcomponents.summation_receiver.sum.receiver
+    }
+  }
+}
+
+testcomponents.summation_receiver "sum" {
+}
+
+-- module.alloy --
+declare "a" {
+  argument "max" {}
+  argument "receiver" {}
+  testcomponents.pulse "pt" {
+    max = argument.max.value
+    frequency = "10ms"
+    forward_to = [argument.receiver.value]
+  }
+}