Fix: parametrize the k6 runner

The k6 runner was left hard-coded because I forgot about it.

This is a really noisy change that is adding a parameter to specifying
the runner that should be used. The goal is to be able to write tests
that don't actually run k6 scripts, but instead use pre-defined
responses to make it predictable. This also helps with the accounting
package that needs to actually run the prober to figure out the number
of metrics it produces.

Signed-off-by: Marcelo E. Magallon <marcelo.magallon@grafana.com>

cmd/synthetic-monitoring-agent/main.go

@@ -17,6 +17,7 @@ import (
 	"github.com/grafana/synthetic-monitoring-agent/internal/checks"
 	"github.com/grafana/synthetic-monitoring-agent/internal/feature"
 	"github.com/grafana/synthetic-monitoring-agent/internal/http"
+	"github.com/grafana/synthetic-monitoring-agent/internal/k6runner"
 	"github.com/grafana/synthetic-monitoring-agent/internal/pusher"
 	"github.com/grafana/synthetic-monitoring-agent/internal/version"
 	"github.com/grafana/synthetic-monitoring-agent/pkg/pb/synthetic_monitoring"
@@ -164,6 +165,8 @@ func run(args []string, stdout io.Writer) error {
 	}
 	defer conn.Close()
 
+	k6Runner := k6runner.New("k6") // FIXME(mem): get this from options
+
 	checksUpdater, err := checks.NewUpdater(checks.UpdaterOptions{
 		Conn:           conn,
 		Logger:         zl.With().Str("subsystem", "updater").Logger(),
@@ -173,6 +176,7 @@ func run(args []string, stdout io.Writer) error {
 		IsConnected:    readynessHandler.Set,
 		PromRegisterer: promRegisterer,
 		Features:       features,
+		K6Runner:       k6Runner,
 	})
 	if err != nil {
 		return fmt.Errorf("Cannot create checks updater: %w", err)
@@ -191,6 +195,7 @@ func run(args []string, stdout io.Writer) error {
 			TenantCh:       tenantCh,
 			PromRegisterer: promRegisterer,
 			Features:       features,
+			K6Runner:       k6Runner,
 		})
 		if err != nil {
 			return fmt.Errorf("Cannot create ad-hoc checks handler: %w", err)

go.mod

@@ -34,6 +34,7 @@ require (
 	github.com/jpillora/backoff v1.0.0
 	github.com/mccutchen/go-httpbin/v2 v2.8.0
 	github.com/quasilyte/go-ruleguard/dsl v0.3.22
+	github.com/spf13/afero v1.9.5
 	kernel.org/pub/linux/libs/security/libcap/cap v1.2.69
 )
 

internal/adhoc/adhoc.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/grafana/synthetic-monitoring-agent/internal/feature"
+	"github.com/grafana/synthetic-monitoring-agent/internal/k6runner"
 	"github.com/grafana/synthetic-monitoring-agent/internal/pkg/logproto"
 	"github.com/grafana/synthetic-monitoring-agent/internal/prober"
 	"github.com/grafana/synthetic-monitoring-agent/internal/pusher"
@@ -37,6 +38,7 @@ type Handler struct {
 	tenantCh                     chan<- sm.Tenant
 	runnerFactory                func(context.Context, *sm.AdHocRequest) (*runner, error)
 	grpcAdhocChecksClientFactory func(conn ClientConn) (sm.AdHocChecksClient, error)
+	proberFactory                prober.ProberFactory
 }
 
 // Error represents errors returned from this package.
@@ -102,6 +104,7 @@ type HandlerOpts struct {
 	TenantCh       chan<- sm.Tenant
 	PromRegisterer prometheus.Registerer
 	Features       feature.Collection
+	K6Runner       k6runner.Runner
 
 	// these two fields exists so that tests can pass alternate
 	// implementations, they are unexported so that clients of this
@@ -139,6 +142,7 @@ func NewHandler(opts HandlerOpts) (*Handler, error) {
 		tenantCh:                     opts.TenantCh,
 		runnerFactory:                opts.runnerFactory,
 		grpcAdhocChecksClientFactory: opts.grpcAdhocChecksClientFactory,
+		proberFactory:                prober.NewProberFactory(opts.K6Runner),
 		api: apiInfo{
 			conn: opts.Conn,
 		},
@@ -384,7 +388,7 @@ func (h *Handler) defaultRunnerFactory(ctx context.Context, req *sm.AdHocRequest
 		Settings: req.AdHocCheck.Settings,
 	}
 
-	p, target, err := prober.NewFromCheck(ctx, h.logger, check)
+	p, target, err := h.proberFactory.New(ctx, h.logger, check)
 	if err != nil {
 		return nil, err
 	}

internal/checks/checks.go

@@ -14,6 +14,7 @@ import (
 	"time"
 
 	"github.com/grafana/synthetic-monitoring-agent/internal/feature"
+	"github.com/grafana/synthetic-monitoring-agent/internal/k6runner"
 	"github.com/grafana/synthetic-monitoring-agent/internal/pkg/logproto"
 	"github.com/grafana/synthetic-monitoring-agent/internal/pusher"
 	"github.com/grafana/synthetic-monitoring-agent/internal/scraper"
@@ -71,7 +72,8 @@ type Updater struct {
 	scrapersMutex  sync.Mutex
 	scrapers       map[int64]*scraper.Scraper
 	metrics        metrics
-	scraperFactory func(context.Context, sm.Check, chan<- pusher.Payload, sm.Probe, zerolog.Logger, prometheus.Counter, *prometheus.CounterVec) (*scraper.Scraper, error)
+	k6Runner       k6runner.Runner
+	scraperFactory func(context.Context, sm.Check, chan<- pusher.Payload, sm.Probe, zerolog.Logger, prometheus.Counter, *prometheus.CounterVec, k6runner.Runner) (*scraper.Scraper, error)
 }
 
 type apiInfo struct {
@@ -100,7 +102,8 @@ type UpdaterOptions struct {
 	IsConnected    func(bool)
 	PromRegisterer prometheus.Registerer
 	Features       feature.Collection
-	ScraperFactory func(context.Context, sm.Check, chan<- pusher.Payload, sm.Probe, zerolog.Logger, prometheus.Counter, *prometheus.CounterVec) (*scraper.Scraper, error)
+	K6Runner       k6runner.Runner
+	ScraperFactory func(context.Context, sm.Check, chan<- pusher.Payload, sm.Probe, zerolog.Logger, prometheus.Counter, *prometheus.CounterVec, k6runner.Runner) (*scraper.Scraper, error)
 }
 
 func NewUpdater(opts UpdaterOptions) (*Updater, error) {
@@ -215,6 +218,7 @@ func NewUpdater(opts UpdaterOptions) (*Updater, error) {
 		tenantCh:       opts.TenantCh,
 		IsConnected:    opts.IsConnected,
 		scrapers:       make(map[int64]*scraper.Scraper),
+		k6Runner:       opts.K6Runner,
 		scraperFactory: scraperFactory,
 		metrics: metrics{
 			changeErrorsCounter: changeErrorsCounter,
@@ -816,7 +820,7 @@ func (c *Updater) addAndStartScraperWithLock(ctx context.Context, check sm.Check
 		return err
 	}
 
-	scraper, err := c.scraperFactory(ctx, check, c.publishCh, *c.probe, c.logger, scrapeCounter, scrapeErrorCounter)
+	scraper, err := c.scraperFactory(ctx, check, c.publishCh, *c.probe, c.logger, scrapeCounter, scrapeErrorCounter, c.k6Runner)
 	if err != nil {
 		return fmt.Errorf("cannot create new scraper: %w", err)
 	}

internal/checks/checks_test.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/grafana/synthetic-monitoring-agent/internal/feature"
+	"github.com/grafana/synthetic-monitoring-agent/internal/k6runner"
 	"github.com/grafana/synthetic-monitoring-agent/internal/prober"
 	"github.com/grafana/synthetic-monitoring-agent/internal/prober/logger"
 	"github.com/grafana/synthetic-monitoring-agent/internal/pusher"
@@ -271,18 +272,21 @@ func (testProber) Probe(ctx context.Context, target string, registry *prometheus
 	return false
 }
 
-func testProbeFactory(ctx context.Context, logger zerolog.Logger, check sm.Check) (prober.Prober, string, error) {
+type testProbeFactory struct {
+}
+
+func (f testProbeFactory) New(ctx context.Context, logger zerolog.Logger, check sm.Check) (prober.Prober, string, error) {
 	return testProber{}, check.Target, nil
 }
 
-func testScraperFactory(ctx context.Context, check sm.Check, payloadCh chan<- pusher.Payload, _ sm.Probe, logger zerolog.Logger, scrapeCounter prometheus.Counter, scrapeErrorCounter *prometheus.CounterVec) (*scraper.Scraper, error) {
+func testScraperFactory(ctx context.Context, check sm.Check, payloadCh chan<- pusher.Payload, _ sm.Probe, logger zerolog.Logger, scrapeCounter prometheus.Counter, scrapeErrorCounter *prometheus.CounterVec, k6Runner k6runner.Runner) (*scraper.Scraper, error) {
 	return scraper.NewWithOpts(
 		ctx,
 		check,
 		scraper.ScraperOpts{
 			ErrorCounter:  scrapeErrorCounter,
 			Logger:        logger,
-			ProbeFactory:  testProbeFactory,
+			ProbeFactory:  testProbeFactory{},
 			PublishCh:     payloadCh,
 			ScrapeCounter: scrapeCounter,
 		},