first part of uwsgi_legion_scrolls() function api

core/legion.c

@@ -81,6 +81,37 @@ void uwsgi_parse_legion(char *key, uint16_t keylen, char *value, uint16_t vallen
 	}
 }
 
+// this function is called when a node is added or removed (heavy locking is needed)
+static void legion_rebuild_scrolls(struct uwsgi_legion *ul) {
+	uint64_t max_size = ul->scrolls_max_size;
+
+	// first, try to add myself
+	if (ul->scroll_len + (uint64_t) 2 > max_size) {
+		uwsgi_log("[DANGER] you have configured a too much tiny buffer for the scrolls list !!! tune it with --legion-scroll-list-max-size\n");
+		ul->scroll_len = 0;
+		return;
+	}
+
+	char *ptr = ul->scrolls;
+	*ptr ++= (uint8_t) (ul->scroll_len & 0xff);
+	*ptr ++= (uint8_t) ((ul->scroll_len >> 8) &0xff);
+	memcpy(ptr, ul->scroll, ul->scroll_len); ptr += ul->scroll_len;
+	ul->scrolls_len = 2 + ul->scroll_len;
+	// ok start adding nodes;
+	struct uwsgi_legion_node *uln = ul->nodes_head;
+	while(uln) {
+		if (ul->scrolls_len + 2 + uln->scroll_len > max_size) {
+			uwsgi_log("[DANGER] you have configured a too much tiny buffer for the scrolls list !!! tune it with --legion-scroll-list-max-size\n");
+			return;
+		}
+		*ptr ++= (uint8_t) (uln->scroll_len & 0xff);
+        	*ptr ++= (uint8_t) ((uln->scroll_len >> 8) &0xff);
+        	memcpy(ptr, uln->scroll, uln->scroll_len); ptr += uln->scroll_len;
+        	ul->scrolls_len += 2 + uln->scroll_len;
+		uln = uln->next;
+	}
+}
+
 // critical section (remember to lock when you use it)
 struct uwsgi_legion_node *uwsgi_legion_add_node(struct uwsgi_legion *ul, uint16_t valor, char *name, uint16_t name_len, char *uuid) {
 
@@ -104,6 +135,8 @@ struct uwsgi_legion_node *uwsgi_legion_add_node(struct uwsgi_legion *ul, uint16_
 		ul->nodes_head = node;
 	}
 
+	legion_rebuild_scrolls(ul);
+
 	return node;
 
 
@@ -141,6 +174,8 @@ void uwsgi_legion_remove_node(struct uwsgi_legion *ul, struct uwsgi_legion_node
 	}
 
 	free(node);
+
+	legion_rebuild_scrolls(ul);
 }
 
 struct uwsgi_legion_node *uwsgi_legion_get_node(struct uwsgi_legion *ul, uint64_t valor, char *name, uint16_t name_len, char *uuid) {
@@ -937,8 +972,14 @@ void uwsgi_opt_legion(char *opt, char *value, void *foobar) {
 		uwsgi.legion_scroll_max_size = 4096;
 	}
 
+	if (!uwsgi.legion_scroll_list_max_size) {
+		uwsgi.legion_scroll_list_max_size = 32768;
+	}
+
 	ul->lord_scroll_size = uwsgi.legion_scroll_max_size;
 	ul->lord_scroll = uwsgi_calloc_shared(ul->lord_scroll_size);
+	ul->scrolls_max_size = uwsgi.legion_scroll_list_max_size;
+	ul->scrolls = uwsgi_calloc_shared(ul->scrolls_max_size);
 
 	uwsgi_legion_add(ul);
 }
@@ -1020,3 +1061,15 @@ char *uwsgi_legion_lord_scroll(char *name, uint16_t *rlen) {
 	uwsgi_rwunlock(legion->lock);
 	return buf;
 }
+
+char *uwsgi_legion_scrolls(char *name, uint64_t *rlen) {
+	char *buf = NULL;
+        struct uwsgi_legion *legion = uwsgi_legion_get_by_name(name);
+        if (!legion) return NULL;
+	uwsgi_rlock(legion->lock);
+	buf = uwsgi_malloc(legion->scrolls_len);
+	memcpy(buf, legion->scrolls, legion->scrolls_len);
+	*rlen = legion->scrolls_len;
+	uwsgi_rwunlock(legion->lock);
+	return buf;
+}

plugins/python/uwsgi_pymodule.c

@@ -474,6 +474,37 @@ PyObject *py_uwsgi_lord_scroll(PyObject * self, PyObject * args) {
         return ret;
 }
 
+static void scrolls_items(uint16_t pos, char *key, uint16_t keylen, void *data) {
+	PyObject *list = (PyObject *) data;
+	PyObject *zero = PyString_FromStringAndSize(key, keylen);
+	PyList_Append(list, zero);
+	Py_DECREF(zero);
+}
+
+PyObject *py_uwsgi_scrolls(PyObject * self, PyObject * args) {
+        char *legion_name = NULL;
+
+        if (!PyArg_ParseTuple(args, "s:scrolls", &legion_name)) {
+                return NULL;
+        }
+
+	uint64_t rlen = 0;
+        char *buf = uwsgi_legion_scrolls(legion_name, &rlen);
+	if (!buf) goto end;
+	PyObject *list = PyList_New(0);
+	if (uwsgi_hooked_parse_array(buf, rlen, scrolls_items, list)) {
+		goto error;
+	}
+	free(buf);
+	return list;
+error:
+	free(buf);
+end:
+	Py_INCREF(Py_None);
+	return Py_None;
+}
+
+
 #endif
 
 PyObject *py_uwsgi_register_signal(PyObject * self, PyObject * args) {
@@ -2434,6 +2465,7 @@ static PyMethodDef uwsgi_advanced_methods[] = {
 #ifdef UWSGI_SSL
 	{"i_am_the_lord", py_uwsgi_i_am_the_lord, METH_VARARGS, ""},
 	{"lord_scroll", py_uwsgi_lord_scroll, METH_VARARGS, ""},
+	{"scrolls", py_uwsgi_scrolls, METH_VARARGS, ""},
 #endif
 	{"async_sleep", py_uwsgi_async_sleep, METH_VARARGS, ""},
 	{"async_connect", py_uwsgi_async_connect, METH_VARARGS, ""},

uwsgi.h

@@ -624,6 +624,10 @@ union uwsgi_sockaddr_ptr {
 		EVP_CIPHER_CTX *encrypt_ctx;
 		EVP_CIPHER_CTX *decrypt_ctx;
 
+		char *scrolls;
+		uint64_t scrolls_len;
+		uint64_t scrolls_max_size;
+
 		// found nodes dynamic lists
 		struct uwsgi_legion_node *nodes_head;
 		struct uwsgi_legion_node *nodes_tail;
@@ -2239,6 +2243,7 @@ struct uwsgi_server {
 		int legion_tolerance;
 		int legion_skew_tolerance;
 		uint16_t legion_scroll_max_size;
+		uint64_t legion_scroll_list_max_size;
 #endif
 
 #ifdef __linux__
@@ -3921,6 +3926,8 @@ int uwsgi_cache_magic_exists(char *, uint16_t, char *);
 int uwsgi_cache_magic_clear(char *);
 void uwsgi_cache_magic_context_hook(char *, uint16_t, char *, uint16_t, void *);
 
+char *uwsgi_legion_scrolls(char *, uint64_t *);
+
 #ifdef UWSGI_ZLIB
 #include <zlib.h>
 int uwsgi_deflate_init(z_stream *, char *, size_t);