add scripting js/lua

internal/sarin/request.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/joho/godotenv"
 	"github.com/valyala/fasthttp"
+	"go.aykhans.me/sarin/internal/script"
 	"go.aykhans.me/sarin/internal/types"
 	utilsSlice "go.aykhans.me/utils/slice"
 )
@@ -26,6 +27,9 @@ type valuesData struct {
 // NewRequestGenerator creates a new RequestGenerator function that generates HTTP requests
 // with the specified configuration. The returned RequestGenerator is NOT safe for concurrent
 // use by multiple goroutines.
+//
+// Note: Scripts must be validated before calling this function (e.g., in NewSarin).
+// The caller is responsible for managing the scriptTransformer lifecycle.
 func NewRequestGenerator(
 	methods []string,
 	requestURL *url.URL,
@@ -35,6 +39,7 @@ func NewRequestGenerator(
 	bodies []string,
 	values []string,
 	fileCache *FileCache,
+	scriptTransformer *script.Transformer,
 ) (RequestGenerator, bool) {
 	randSource := NewDefaultRandSource()
 	//nolint:gosec // G404: Using non-cryptographic rand for load testing, not security
@@ -53,6 +58,8 @@ func NewRequestGenerator(
 
 	valuesGenerator := NewValuesGeneratorFunc(values, templateFuncMap)
 
+	hasScripts := scriptTransformer != nil && !scriptTransformer.IsEmpty()
+
 	var (
 		data valuesData
 		path string
@@ -98,13 +105,24 @@ func NewRequestGenerator(
 			if requestURL.Scheme == "https" {
 				req.URI().SetScheme("https")
 			}
+
+			// Apply script transformations if any
+			if hasScripts {
+				reqData := script.RequestDataFromFastHTTP(req)
+				if err = scriptTransformer.Transform(reqData); err != nil {
+					return err
+				}
+				script.ApplyToFastHTTP(reqData, req)
+			}
+
 			return nil
 		}, isPathGeneratorDynamic ||
 			isMethodGeneratorDynamic ||
 			isParamsGeneratorDynamic ||
 			isHeadersGeneratorDynamic ||
 			isCookiesGeneratorDynamic ||
-			isBodyGeneratorDynamic
+			isBodyGeneratorDynamic ||
+			hasScripts
 }
 
 func NewMethodGeneratorFunc(localRand *rand.Rand, methods []string, templateFunctions template.FuncMap) (RequestGeneratorWithData, bool) {

internal/sarin/sarin.go

@@ -14,6 +14,7 @@ import (
 	tea "github.com/charmbracelet/bubbletea"
 	"github.com/charmbracelet/lipgloss"
 	"github.com/valyala/fasthttp"
+	"go.aykhans.me/sarin/internal/script"
 	"go.aykhans.me/sarin/internal/types"
 )
 
@@ -52,11 +53,13 @@ type sarin struct {
 	hostClients []*fasthttp.HostClient
 	responses   *SarinResponseData
 	fileCache   *FileCache
+	scriptChain *script.Chain
 }
 
 // NewSarin creates a new sarin instance for load testing.
 // It can return the following errors:
 // - types.ProxyDialError
+// - script loading errors
 func NewSarin(
 	ctx context.Context,
 	methods []string,
@@ -75,6 +78,8 @@ func NewSarin(
 	values []string,
 	collectStats bool,
 	dryRun bool,
+	luaScripts []string,
+	jsScripts []string,
 ) (*sarin, error) {
 	if workers == 0 {
 		workers = 1
@@ -85,6 +90,19 @@ func NewSarin(
 		return nil, err
 	}
 
+	// Load script sources
+	luaSources, err := script.LoadSources(ctx, luaScripts, script.EngineTypeLua)
+	if err != nil {
+		return nil, err
+	}
+
+	jsSources, err := script.LoadSources(ctx, jsScripts, script.EngineTypeJavaScript)
+	if err != nil {
+		return nil, err
+	}
+
+	scriptChain := script.NewChain(luaSources, jsSources)
+
 	srn := &sarin{
 		workers:        workers,
 		requestURL:     requestURL,
@@ -103,6 +121,7 @@ func NewSarin(
 		dryRun:         dryRun,
 		hostClients:    hostClients,
 		fileCache:      NewFileCache(time.Second * 10),
+		scriptChain:    scriptChain,
 	}
 
 	if collectStats {
@@ -193,7 +212,20 @@ func (q sarin) Worker(
 	defer fasthttp.ReleaseRequest(req)
 	defer fasthttp.ReleaseResponse(resp)
 
-	requestGenerator, isDynamic := NewRequestGenerator(q.methods, q.requestURL, q.params, q.headers, q.cookies, q.bodies, q.values, q.fileCache)
+	// Create script transformer for this worker (engines are not thread-safe)
+	// Scripts are pre-validated in NewSarin, so this should not fail
+	var scriptTransformer *script.Transformer
+	if !q.scriptChain.IsEmpty() {
+		scriptTransformer, err := q.scriptChain.NewTransformer()
+		if err != nil {
+			panic(err)
+		}
+		defer scriptTransformer.Close()
+	}
+
+	requestGenerator, isDynamic := NewRequestGenerator(
+		q.methods, q.requestURL, q.params, q.headers, q.cookies, q.bodies, q.values, q.fileCache, scriptTransformer,
+	)
 
 	if q.dryRun {
 		switch {