add SandboxRequests to fastlyMeta (#215)

Author: joeshaw

_examples/reusable-sandbox/main.go

@@ -11,15 +11,13 @@ import (
 )
 
 func main() {
-	var requestCount int
 	fsthttp.ServeMany(func(ctx context.Context, w fsthttp.ResponseWriter, r *fsthttp.Request) {
-		requestCount++
 		meta, err := r.FastlyMeta()
 		if err != nil {
 			fsthttp.Error(w, err.Error(), fsthttp.StatusInternalServerError)
 			return
 		}
-		fmt.Fprintf(w, "Request %v, Hello, %s (sandbox: %q, request: %q)!\n", requestCount, r.RemoteAddr, meta.SandboxID, meta.RequestID)
+		fmt.Fprintf(w, "Request %v, Hello, %s (sandbox: %q, request: %q)!\n", meta.SandboxRequests, r.RemoteAddr, meta.SandboxID, meta.RequestID)
 	}, &fsthttp.ServeManyOptions{
 		NextTimeout: 1 * time.Second,
 		MaxRequests: 100,

end_to_end_tests/serve-many/main.go

@@ -35,6 +35,7 @@ func main() {
 		w.Header().Set("Content-Type", "text/plain")
 		w.Header().Set("Sandbox-ID", sandboxID)
 		w.Header().Set("Request-ID", requestID)
+		w.Header().Set("Sandbox-Requests", fmt.Sprintf("%d", meta.SandboxRequests))
 		w.Write([]byte("OK"))
 	}
 

end_to_end_tests/serve-many/main_test.go

@@ -22,13 +22,17 @@ func TestSandboxReuse(t *testing.T) {
 	defer resp.Body.Close()
 
 	sandboxID, requestID := resp.Header.Get("Sandbox-ID"), resp.Header.Get("Request-ID")
+	sandboxRequests := resp.Header.Get("Sandbox-Requests")
 
 	if sandboxID == "" || requestID == "" {
 		t.Fatalf("Sandbox-ID and/or Request-ID are empty: %s, %s", sandboxID, requestID)
 	}
 	if sandboxID != requestID {
 		t.Errorf("sandboxID = %s, requestID = %s; expected them to match", sandboxID, requestID)
 	}
+	if sandboxRequests != "1" {
+		t.Errorf("sandboxRequests = %s; expected 1", sandboxRequests)
+	}
 	prevSandboxID := sandboxID
 
 	// Second request.  This should reuse the sandbox, so the sandbox ID
@@ -49,13 +53,17 @@ func TestSandboxReuse(t *testing.T) {
 	defer resp.Body.Close()
 
 	sandboxID, requestID = resp.Header.Get("Sandbox-ID"), resp.Header.Get("Request-ID")
+	sandboxRequests = resp.Header.Get("Sandbox-Requests")
 
 	if sandboxID != prevSandboxID {
 		t.Errorf("sandboxID = %s, previous sandboxID = %s; expected them to match", sandboxID, sandboxID)
 	}
 	if sandboxID == requestID {
 		t.Errorf("sandboxID = %s, requestID = %s; expected them to differ", sandboxID, requestID)
 	}
+	if sandboxRequests != "2" {
+		t.Errorf("sandboxRequests = %s; expected 2", sandboxRequests)
+	}
 	prevSandboxID = sandboxID
 
 	// Third request, we should have a new sandbox ID and it should match the request ID
@@ -70,11 +78,15 @@ func TestSandboxReuse(t *testing.T) {
 	defer resp.Body.Close()
 
 	sandboxID, requestID = resp.Header.Get("Sandbox-ID"), resp.Header.Get("Request-ID")
+	sandboxRequests = resp.Header.Get("Sandbox-Requests")
 
 	if sandboxID == prevSandboxID {
 		t.Errorf("sandboxID = %s, previous sandboxID = %s; expected them to differ", sandboxID, sandboxID)
 	}
 	if sandboxID != requestID {
 		t.Errorf("sandboxID = %s, requestID = %s; expected them to match", sandboxID, requestID)
 	}
+	if sandboxRequests != "1" {
+		t.Errorf("sandboxRequests = %s; expected 1", sandboxRequests)
+	}
 }

fsthttp/handle.go

@@ -21,20 +21,22 @@ func Serve(h Handler) {
 		panic(fmt.Errorf("get client handles: %w", err))
 	}
 
-	serve(h, abireq, abibody)
+	serve(h, abireq, abibody, 1)
 
 	// wait for any stale-while-revalidate goroutines to complete.
 	guestCacheSWRPending.Wait()
 }
 
-func serve(h Handler, abireq *fastly.HTTPRequest, abibody *fastly.HTTPBody) {
+func serve(h Handler, abireq *fastly.HTTPRequest, abibody *fastly.HTTPBody, sandboxRequests int) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
 	clientRequest, err := newClientRequest(abireq, abibody)
 	if err != nil {
 		panic(fmt.Errorf("create client Request: %w", err))
 	}
+	clientRequest.sandboxRequests = sandboxRequests
+
 	clientResponseWriter, err := newResponseWriter()
 	if err != nil {
 		panic(fmt.Errorf("create client ResponseWriter: %w", err))
@@ -65,18 +67,18 @@ type ServeManyOptions struct {
 // ServeMany allows a single Compute instance to handle multiple requests.
 func ServeMany(h HandlerFunc, serveOpts *ServeManyOptions) {
 	start := time.Now()
+	requestCount := 1
 
 	abireq, abibody, err := fastly.BodyDownstreamGet()
 	if err != nil {
 		panic(fmt.Errorf("get client handles: %w", err))
 	}
-	serve(h, abireq, abibody)
+	serve(h, abireq, abibody, requestCount)
 
 	// Serve the rest
-	var requests int
 	for {
-		requests++
-		if serveOpts.MaxRequests != 0 && requests >= serveOpts.MaxRequests {
+		requestCount++
+		if serveOpts.MaxRequests != 0 && requestCount > serveOpts.MaxRequests {
 			break
 		}
 
@@ -106,7 +108,7 @@ func ServeMany(h HandlerFunc, serveOpts *ServeManyOptions) {
 			panic(fmt.Errorf("get client handles: %w", err))
 		}
 
-		serve(h, abireq, abibody)
+		serve(h, abireq, abibody, requestCount)
 	}
 
 	// wait for any stale-while-revalidate goroutines to complete.

fsthttp/request.go

@@ -121,6 +121,8 @@ type Request struct {
 
 	abi        reqAbi
 	downstream reqAbi
+
+	sandboxRequests int
 }
 
 type reqAbi struct {
@@ -363,9 +365,11 @@ func (req *Request) FastlyMeta() (*FastlyMeta, error) {
 	}
 
 	var err error
-	var fastlyMeta FastlyMeta
 
-	fastlyMeta.SandboxID = os.Getenv("FASTLY_TRACE_ID")
+	fastlyMeta := &FastlyMeta{
+		SandboxID:       os.Getenv("FASTLY_TRACE_ID"),
+		SandboxRequests: req.sandboxRequests,
+	}
 
 	fastlyMeta.RequestID, err = req.downstream.req.DownstreamRequestID()
 	if err != nil {
@@ -392,7 +396,7 @@ func (req *Request) FastlyMeta() (*FastlyMeta, error) {
 		return nil, fmt.Errorf("get fastly key is valid: %w", err)
 	}
 
-	req.fastlyMeta = &fastlyMeta
+	req.fastlyMeta = fastlyMeta
 
 	return req.fastlyMeta, nil
 }
@@ -1093,6 +1097,11 @@ type FastlyMeta struct {
 	// FastlyKeyIsValid is true if the request contains a valid Fastly API token.
 	// This is for services to restrict authenticating PURGE requests for the readthrough cache.
 	FastlyKeyIsValid bool
+
+	// SandboxRequests is the number of requests handled by the sandbox so far.
+	// For example, if this is were 3, it means that this is the 3rd request handled by the sandbox.
+	// This will be zero if this is not a client request.
+	SandboxRequests int
 }
 
 // DecompressResponseOptions control the auto decompress response behaviour.