Fixes to summation1 and summation2

* summation1 only sends during run()
* summation2 tracks the sum via metrics instead of an export

internal/runtime/import_test.go

@@ -16,6 +16,9 @@ import (
 	"github.com/grafana/alloy/internal/runtime/logging"
 	"github.com/grafana/alloy/internal/service"
 	"github.com/grafana/alloy/internal/util"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/testutil"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"golang.org/x/tools/txtar"
 
@@ -93,9 +96,10 @@ func buildTestImportFile(t *testing.T, filename string) testImportFile {
 func TestForeach(t *testing.T) {
 	directory := "./testdata/foreach"
 	for _, file := range getTestFiles(directory, t) {
+		reg := prometheus.NewRegistry()
 		tc := buildTestImportFile(t, filepath.Join(directory, file.Name()))
 		t.Run(tc.description, func(t *testing.T) {
-			testConfig2(t, tc.main, tc.reloadConfig, nil)
+			testConfig2(t, reg, tc.main, tc.reloadConfig, nil)
 		})
 	}
 }
@@ -320,7 +324,7 @@ func TestImportError(t *testing.T) {
 
 func testConfig(t *testing.T, config string, reloadConfig string, update func()) {
 	defer verifyNoGoroutineLeaks(t)
-	ctrl, f := setup(t, config)
+	ctrl, f := setup(t, config, nil)
 
 	err := ctrl.LoadSource(f, nil, "")
 	require.NoError(t, err)
@@ -372,9 +376,9 @@ func testConfig(t *testing.T, config string, reloadConfig string, update func())
 }
 
 // This function is a copy of testConfig above.
-func testConfig2(t *testing.T, config string, reloadConfig string, update func()) {
+func testConfig2(t *testing.T, reg *prometheus.Registry, config string, reloadConfig string, update func()) {
 	defer verifyNoGoroutineLeaks(t)
-	ctrl, f := setup(t, config)
+	ctrl, f := setup(t, config, reg)
 
 	err := ctrl.LoadSource(f, nil, "")
 	require.NoError(t, err)
@@ -393,12 +397,15 @@ func testConfig2(t *testing.T, config string, reloadConfig string, update func()
 	}()
 
 	// Check for initial condition
-	require.Eventually(t, func() bool {
-		export := getExport[testcomponents.SummationExports_2](t, ctrl, "", "testcomponents.summation2.final")
-		// If each iteration of the for loop adds a 1,
-		// and there are 4 iterations, we expect 4 to be the end result.
-		//TODO: Make the expected "sum" value configurable?
-		return export.Sum == 4
+	require.EventuallyWithT(t, func(c *assert.CollectT) {
+		expectedMetrics := `
+# HELP testcomponents_summation2 Summation of all integers received
+# TYPE testcomponents_summation2 counter
+testcomponents_summation2{component_id="testcomponents.summation2.final",component_path="/"} 1
+`
+		if err := testutil.GatherAndCompare(reg, strings.NewReader(expectedMetrics), "testcomponents_summation2"); err != nil {
+			c.Errorf("mismatch metrics: %v", err)
+		}
 	}, 3*time.Second, 10*time.Millisecond)
 
 	// if update != nil {
@@ -430,7 +437,7 @@ func testConfig2(t *testing.T, config string, reloadConfig string, update func()
 
 func testConfigError(t *testing.T, config string, expectedError string) {
 	defer verifyNoGoroutineLeaks(t)
-	ctrl, f := setup(t, config)
+	ctrl, f := setup(t, config, nil)
 	err := ctrl.LoadSource(f, nil, "")
 	require.ErrorContains(t, err, expectedError)
 	ctx, cancel := context.WithCancel(context.Background())
@@ -447,14 +454,14 @@ func testConfigError(t *testing.T, config string, expectedError string) {
 	}()
 }
 
-func setup(t *testing.T, config string) (*alloy_runtime.Runtime, *alloy_runtime.Source) {
+func setup(t *testing.T, config string, reg prometheus.Registerer) (*alloy_runtime.Runtime, *alloy_runtime.Source) {
 	s, err := logging.New(os.Stderr, logging.DefaultOptions)
 	require.NoError(t, err)
 	ctrl := alloy_runtime.New(alloy_runtime.Options{
 		Logger:       s,
 		DataPath:     t.TempDir(),
 		MinStability: featuregate.StabilityPublicPreview,
-		Reg:          nil,
+		Reg:          reg,
 		Services:     []service.Service{},
 	})
 	f, err := alloy_runtime.ParseSource(t.Name(), []byte(config))

internal/runtime/internal/testcomponents/sumation1.go

@@ -23,8 +23,7 @@ func init() {
 
 // Accepts a single integer input and forwards it to all the components listed in forward_to.
 type SummationConfig_Entry struct {
-	Input int `alloy:"input,attr"`
-	//TODO: What should the type be?
+	Input     int           `alloy:"input,attr"`
 	ForwardTo []IntReceiver `alloy:"forward_to,attr"`
 }
 
@@ -34,15 +33,16 @@ type SummationExports_Entry struct {
 type Summation_Entry struct {
 	opts component.Options
 	log  log.Logger
+	cfg  SummationConfig_Entry
 }
 
 // NewSummation creates a new summation component.
 func NewSummation_Entry(o component.Options, cfg SummationConfig_Entry) (*Summation_Entry, error) {
-	t := &Summation_Entry{opts: o, log: o.Logger}
-	if err := t.Update(cfg); err != nil {
-		return nil, err
-	}
-	return t, nil
+	return &Summation_Entry{
+		opts: o,
+		log:  o.Logger,
+		cfg:  cfg,
+	}, nil
 }
 
 var (
@@ -51,17 +51,16 @@ var (
 
 // Run implements Component.
 func (t *Summation_Entry) Run(ctx context.Context) error {
+	for _, r := range t.cfg.ForwardTo {
+		r.ReceiveInt(t.cfg.Input)
+	}
+
 	<-ctx.Done()
 	return nil
 }
 
 // Update implements Component.
 func (t *Summation_Entry) Update(args component.Arguments) error {
-	c := args.(SummationConfig_Entry)
-
-	for _, r := range c.ForwardTo {
-		r.ReceiveInt(c.Input)
-	}
-
+	// TODO: Implement this?
 	return nil
 }

internal/runtime/internal/testcomponents/sumation2.go

@@ -6,7 +6,7 @@ import (
 	"github.com/go-kit/log"
 	"github.com/grafana/alloy/internal/component"
 	"github.com/grafana/alloy/internal/featuregate"
-	"go.uber.org/atomic"
+	"github.com/prometheus/client_golang/prometheus"
 )
 
 func init() {
@@ -17,7 +17,7 @@ func init() {
 		Exports:   SummationExports_2{},
 
 		Build: func(opts component.Options, args component.Arguments) (component.Component, error) {
-			return NewSummation_2(opts, args.(SummationConfig_2))
+			return NewSummation_2(opts)
 		},
 	})
 }
@@ -27,52 +27,54 @@ type IntReceiver interface {
 }
 
 type IntReceiverImpl struct {
-	sum             atomic.Int32
-	updateSumExport func(int)
+	incrementSum func(int)
 }
 
 func (r IntReceiverImpl) ReceiveInt(i int) {
-	new := r.sum.Add(int32(i))
-	r.updateSumExport(int(new))
+	r.incrementSum(i)
 }
 
 type SummationConfig_2 struct {
 }
 
 type SummationExports_2 struct {
-	Receiver  IntReceiver `alloy:"receiver,attr"`
-	Sum       int         `alloy:"sum,attr"`
-	LastAdded int         `alloy:"last_added,attr"`
+	Receiver IntReceiver `alloy:"receiver,attr"`
 }
 
 type Summation_2 struct {
-	opts     component.Options
-	log      log.Logger
+	opts component.Options
+	log  log.Logger
+
+	reg      prometheus.Registerer
+	counter  prometheus.Counter
 	receiver IntReceiver
 }
 
 // NewSummation creates a new summation component.
-func NewSummation_2(o component.Options, cfg SummationConfig_2) (*Summation_2, error) {
-	recv := IntReceiverImpl{}
-
-	recv.updateSumExport = func(newSum int) {
-		o.Logger.Log("msg", "Summation_2: new sum", "sum", newSum)
-		o.OnStateChange(SummationExports_2{
-			Receiver: recv,
-			Sum:      newSum,
-		})
-	}
-
-	o.OnStateChange(SummationExports_2{
-		Receiver: recv,
+func NewSummation_2(o component.Options) (*Summation_2, error) {
+	counter := prometheus.NewCounter(prometheus.CounterOpts{
+		Name: "testcomponents_summation2",
+		Help: "Summation of all integers received",
 	})
 
+	recv := IntReceiverImpl{
+		incrementSum: func(i int) {
+			counter.Add(float64(i))
+		},
+	}
+
 	t := &Summation_2{
 		opts:     o,
 		log:      o.Logger,
 		receiver: recv,
+		reg:      o.Registerer,
+		counter:  counter,
 	}
 
+	o.OnStateChange(SummationExports_2{
+		Receiver: t.receiver,
+	})
+
 	return t, nil
 }
 
@@ -82,12 +84,16 @@ var (
 
 // Run implements Component.
 func (t *Summation_2) Run(ctx context.Context) error {
+	if err := t.reg.Register(t.counter); err != nil {
+		return err
+	}
+	defer t.reg.Unregister(t.counter)
+
 	<-ctx.Done()
 	return nil
 }
 
 // Update implements Component.
 func (t *Summation_2) Update(args component.Arguments) error {
-
 	return nil
 }

internal/runtime/testdata/foreach/foreach_1.txtar

@@ -1,6 +1,6 @@
 -- main.alloy --
 foreach "testForeach" {
-  collection = [1, 2, 3, 4]
+  collection = [1]
 
   template {
     // Similar to testcomponents.summation, but with a "forward_to"