refactor: decouple worker threads from non-worker threads

exponential_backoff.go

@@ -0,0 +1,60 @@
+package frankenphp
+
+import (
+	"sync"
+	"time"
+)
+
+const maxBackoff = 1 * time.Second
+const minBackoff = 100 * time.Millisecond
+const maxConsecutiveFailures = 6
+
+type exponentialBackoff struct {
+	backoff      time.Duration
+	failureCount int
+	mu           sync.RWMutex
+	upFunc       sync.Once
+}
+
+func newExponentialBackoff() *exponentialBackoff {
+	return &exponentialBackoff{backoff: minBackoff}
+}
+
+func (e *exponentialBackoff) reset() {
+	e.mu.Lock()
+	e.upFunc = sync.Once{}
+	wait := e.backoff * 2
+	e.mu.Unlock()
+	go func() {
+		time.Sleep(wait)
+		e.mu.Lock()
+		defer e.mu.Unlock()
+		e.upFunc.Do(func() {
+			// if we come back to a stable state, reset the failure count
+			if e.backoff == minBackoff {
+				e.failureCount = 0
+			}
+
+			// earn back the backoff over time
+			if e.failureCount > 0 {
+				e.backoff = max(e.backoff/2, minBackoff)
+			}
+		})
+	}()
+}
+
+func (e *exponentialBackoff) trigger(onMaxFailures func(failureCount int)) {
+	e.mu.RLock()
+	e.upFunc.Do(func() {
+		if e.failureCount >= maxConsecutiveFailures {
+			onMaxFailures(e.failureCount)
+		}
+		e.failureCount += 1
+	})
+	wait := e.backoff
+	e.mu.RUnlock()
+	time.Sleep(wait)
+	e.mu.Lock()
+	e.backoff = min(e.backoff*2, maxBackoff)
+	e.mu.Unlock()
+}

frankenphp.c

@@ -243,7 +243,7 @@ PHP_FUNCTION(frankenphp_finish_request) { /* {{{ */
   php_header();
 
   if (ctx->has_active_request) {
-    go_frankenphp_finish_request(thread_index, false);
+    go_frankenphp_finish_request_manually(thread_index);
   }
 
   ctx->finished = true;
@@ -443,7 +443,7 @@ PHP_FUNCTION(frankenphp_handle_request) {
 
   frankenphp_worker_request_shutdown();
   ctx->has_active_request = false;
-  go_frankenphp_finish_request(thread_index, true);
+  go_frankenphp_finish_worker_request(thread_index);
 
   RETURN_TRUE;
 }
@@ -802,9 +802,9 @@ static void set_thread_name(char *thread_name) {
 }
 
 static void *php_thread(void *arg) {
-  char thread_name[16] = {0};
-  snprintf(thread_name, 16, "php-%" PRIxPTR, (uintptr_t)arg);
   thread_index = (uintptr_t)arg;
+  char thread_name[16] = {0};
+  snprintf(thread_name, 16, "php-%" PRIxPTR, thread_index);
   set_thread_name(thread_name);
 
 #ifdef ZTS
@@ -814,7 +814,6 @@ static void *php_thread(void *arg) {
   ZEND_TSRMLS_CACHE_UPDATE();
 #endif
 #endif
-
   local_ctx = malloc(sizeof(frankenphp_server_context));
 
   /* check if a default filter is set in php.ini and only filter if
@@ -823,7 +822,10 @@ static void *php_thread(void *arg) {
   cfg_get_string("filter.default", &default_filter);
   should_filter_var = default_filter != NULL;
 
-  while (go_handle_request(thread_index)) {
+  go_frankenphp_on_thread_startup(thread_index);
+
+  // perform work until go signals to stop
+  while (go_frankenphp_on_thread_work(thread_index)) {
   }
 
   go_frankenphp_release_known_variable_keys(thread_index);
@@ -832,6 +834,8 @@ static void *php_thread(void *arg) {
   ts_free_thread();
 #endif
 
+  go_frankenphp_on_thread_shutdown(thread_index);
+
   return NULL;
 }
 
@@ -883,28 +887,7 @@ static void *php_main(void *arg) {
 
   frankenphp_sapi_module.startup(&frankenphp_sapi_module);
 
-  pthread_t *threads = malloc(num_threads * sizeof(pthread_t));
-  if (threads == NULL) {
-    perror("malloc failed");
-    exit(EXIT_FAILURE);
-  }
-
-  for (uintptr_t i = 0; i < num_threads; i++) {
-    if (pthread_create(&(*(threads + i)), NULL, &php_thread, (void *)i) != 0) {
-      perror("failed to create PHP thread");
-      free(threads);
-      exit(EXIT_FAILURE);
-    }
-  }
-
-  for (int i = 0; i < num_threads; i++) {
-    if (pthread_join((*(threads + i)), NULL) != 0) {
-      perror("failed to join PHP thread");
-      free(threads);
-      exit(EXIT_FAILURE);
-    }
-  }
-  free(threads);
+  go_frankenphp_main_thread_is_ready();
 
   /* channel closed, shutdown gracefully */
   frankenphp_sapi_module.shutdown(&frankenphp_sapi_module);
@@ -920,25 +903,29 @@ static void *php_main(void *arg) {
     frankenphp_sapi_module.ini_entries = NULL;
   }
 #endif
-
-  go_shutdown();
-
+  go_frankenphp_shutdown_main_thread();
   return NULL;
 }
 
-int frankenphp_init(int num_threads) {
+int frankenphp_new_main_thread(int num_threads) {
   pthread_t thread;
 
   if (pthread_create(&thread, NULL, &php_main, (void *)(intptr_t)num_threads) !=
       0) {
-    go_shutdown();
-
     return -1;
   }
-
   return pthread_detach(thread);
 }
 
+int frankenphp_new_php_thread(uintptr_t thread_index) {
+  pthread_t thread;
+  if (pthread_create(&thread, NULL, &php_thread, (void *)thread_index) != 0) {
+    return 1;
+  }
+  pthread_detach(thread);
+  return 0;
+}
+
 int frankenphp_request_startup() {
   if (php_request_startup() == SUCCESS) {
     return SUCCESS;