feat: Adds automatic thread scaling at runtime and php_ini configuration in Caddyfile (#1266)

Adds option to scale threads at runtime

Adds php_ini configuration in Caddyfile

threadregular.go

@@ -0,0 +1,139 @@
+package frankenphp
+
+import (
+	"net/http"
+	"sync"
+)
+
+// representation of a non-worker PHP thread
+// executes PHP scripts in a web context
+// implements the threadHandler interface
+type regularThread struct {
+	state         *threadState
+	thread        *phpThread
+	activeRequest *http.Request
+}
+
+var (
+	regularThreads     []*phpThread
+	regularThreadMu    = &sync.RWMutex{}
+	regularRequestChan chan *http.Request
+)
+
+func convertToRegularThread(thread *phpThread) {
+	thread.setHandler(&regularThread{
+		thread: thread,
+		state:  thread.state,
+	})
+	attachRegularThread(thread)
+}
+
+// beforeScriptExecution returns the name of the script or an empty string on shutdown
+func (handler *regularThread) beforeScriptExecution() string {
+	switch handler.state.get() {
+	case stateTransitionRequested:
+		detachRegularThread(handler.thread)
+		return handler.thread.transitionToNewHandler()
+	case stateTransitionComplete:
+		handler.state.set(stateReady)
+		return handler.waitForRequest()
+	case stateReady:
+		return handler.waitForRequest()
+	case stateShuttingDown:
+		detachRegularThread(handler.thread)
+		// signal to stop
+		return ""
+	}
+	panic("unexpected state: " + handler.state.name())
+}
+
+// return true if the worker should continue to run
+func (handler *regularThread) afterScriptExecution(exitStatus int) {
+	handler.afterRequest(exitStatus)
+}
+
+func (handler *regularThread) getActiveRequest() *http.Request {
+	return handler.activeRequest
+}
+
+func (handler *regularThread) name() string {
+	return "Regular PHP Thread"
+}
+
+func (handler *regularThread) waitForRequest() string {
+	handler.state.markAsWaiting(true)
+
+	var r *http.Request
+	select {
+	case <-handler.thread.drainChan:
+		// go back to beforeScriptExecution
+		return handler.beforeScriptExecution()
+	case r = <-regularRequestChan:
+	}
+
+	handler.activeRequest = r
+	handler.state.markAsWaiting(false)
+	fc := r.Context().Value(contextKey).(*FrankenPHPContext)
+
+	if err := updateServerContext(handler.thread, r, true, false); err != nil {
+		rejectRequest(fc.responseWriter, err.Error())
+		handler.afterRequest(0)
+		handler.thread.Unpin()
+		// go back to beforeScriptExecution
+		return handler.beforeScriptExecution()
+	}
+
+	// set the scriptFilename that should be executed
+	return fc.scriptFilename
+}
+
+func (handler *regularThread) afterRequest(exitStatus int) {
+	fc := handler.activeRequest.Context().Value(contextKey).(*FrankenPHPContext)
+	fc.exitStatus = exitStatus
+	maybeCloseContext(fc)
+	handler.activeRequest = nil
+}
+
+func handleRequestWithRegularPHPThreads(r *http.Request, fc *FrankenPHPContext) {
+	metrics.StartRequest()
+	select {
+	case regularRequestChan <- r:
+		// a thread was available to handle the request immediately
+		<-fc.done
+		metrics.StopRequest()
+		return
+	default:
+		// no thread was available
+	}
+
+	// if no thread was available, mark the request as queued and fan it out to all threads
+	metrics.QueuedRequest()
+	for {
+		select {
+		case regularRequestChan <- r:
+			metrics.DequeuedRequest()
+			<-fc.done
+			metrics.StopRequest()
+			return
+		case scaleChan <- fc:
+			// the request has triggered scaling, continue to wait for a thread
+		}
+	}
+}
+
+func attachRegularThread(thread *phpThread) {
+	regularThreadMu.Lock()
+	regularThreads = append(regularThreads, thread)
+	regularThreadMu.Unlock()
+}
+
+func detachRegularThread(thread *phpThread) {
+	regularThreadMu.Lock()
+	for i, t := range regularThreads {
+		if t == thread {
+			regularThreads = append(regularThreads[:i], regularThreads[i+1:]...)
+			break
+		}
+	}
+	regularThreadMu.Unlock()
+}