MINOR: lua: register and execute sample-fetches in LUA
This patch permits to write LUA samples fetches. Note that
all the fethes declared trough LUA are automatically prefixed
by "lua.".
diff --git a/include/types/hlua.h b/include/types/hlua.h
index 1241778..a4d1444 100644
--- a/include/types/hlua.h
+++ b/include/types/hlua.h
@@ -52,6 +52,15 @@
int function_ref;
};
+/* This struct contains the lua data used to bind
+ * Lua function on HAProxy hook like sample-fetches
+ * or actions.
+ */
+struct hlua_function {
+ char *name;
+ int function_ref;
+};
+
/* This struct contains the pointer provided on the most
* of internal HAProxy calls during the processing of
* rules, converters and sample-fetches. This struct is
diff --git a/src/hlua.c b/src/hlua.c
index 22b6eb3..633e7a4 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -1080,6 +1080,162 @@
return 0;
}
+/* Wrapper called by HAProxy to execute a sample-fetch. this wrapper
+ * doesn't allow "yield" functions because the HAProxy engine cannot
+ * resume sample-fetches.
+ */
+static int hlua_sample_fetch_wrapper(struct proxy *px, struct session *s, void *l7,
+ unsigned int opt, const struct arg *arg_p,
+ struct sample *smp, const char *kw, void *private)
+{
+ struct hlua_function *fcn = (struct hlua_function *)private;
+
+ /* If it is the first run, initialize the data for the call. */
+ if (s->hlua.state == HLUA_STOP) {
+ /* Check stack available size. */
+ if (!lua_checkstack(s->hlua.T, 2)) {
+ send_log(px, LOG_ERR, "Lua sample-fetch '%s': full stack.", fcn->name);
+ if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE))
+ Alert("Lua sample-fetch '%s': full stack.\n", fcn->name);
+ return 0;
+ }
+
+ /* Restore the function in the stack. */
+ lua_rawgeti(s->hlua.T, LUA_REGISTRYINDEX, fcn->function_ref);
+
+ /* push arguments in the stack. */
+ if (!hlua_txn_new(s->hlua.T, s, px, l7)) {
+ send_log(px, LOG_ERR, "Lua sample-fetch '%s': full stack.", fcn->name);
+ if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE))
+ Alert("Lua sample-fetch '%s': full stack.\n", fcn->name);
+ return 0;
+ }
+ s->hlua.nargs = 1;
+
+ /* push keywords in the stack. */
+ for (; arg_p && arg_p->type != ARGT_STOP; arg_p++) {
+ /* Check stack available size. */
+ if (!lua_checkstack(s->hlua.T, 1)) {
+ send_log(px, LOG_ERR, "Lua sample-fetch '%s': full stack.", fcn->name);
+ if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE))
+ Alert("Lua sample-fetch '%s': full stack.\n", fcn->name);
+ return 0;
+ }
+ if (!lua_checkstack(s->hlua.T, 1)) {
+ send_log(px, LOG_ERR, "Lua sample-fetch '%s': full stack.", fcn->name);
+ if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE))
+ Alert("Lua sample-fetch '%s': full stack.\n", fcn->name);
+ return 0;
+ }
+ hlua_arg2lua(s->hlua.T, arg_p);
+ s->hlua.nargs++;
+ }
+
+ /* Set the currently running flag. */
+ s->hlua.state = HLUA_RUN;
+ }
+
+ /* Execute the function. */
+ switch (hlua_ctx_resume(&s->hlua, 0)) {
+ /* finished. */
+ case HLUA_E_OK:
+ /* Convert the returned value in sample. */
+ hlua_lua2smp(s->hlua.T, -1, smp);
+ lua_pop(s->hlua.T, 1);
+
+ /* Set the end of execution flag. */
+ smp->flags &= ~SMP_F_MAY_CHANGE;
+ return 1;
+
+ /* yield. */
+ case HLUA_E_AGAIN:
+ send_log(px, LOG_ERR, "Lua sample-fetch '%s': cannot use yielded functions.", fcn->name);
+ if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE))
+ Alert("Lua sample-fetch '%s': cannot use yielded functions.\n", fcn->name);
+ return 0;
+
+ /* finished with error. */
+ case HLUA_E_ERRMSG:
+ /* Display log. */
+ send_log(px, LOG_ERR, "Lua sample-fetch '%s': %s.", fcn->name, lua_tostring(s->hlua.T, -1));
+ if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE))
+ Alert("Lua sample-fetch '%s': %s.\n", fcn->name, lua_tostring(s->hlua.T, -1));
+ lua_pop(s->hlua.T, 1);
+ return 0;
+
+ case HLUA_E_ERR:
+ /* Display log. */
+ send_log(px, LOG_ERR, "Lua sample-fetch '%s' returns an unknown error.", fcn->name);
+ if (!(global.mode & MODE_QUIET) || (global.mode & MODE_VERBOSE))
+ Alert("Lua sample-fetch '%s': returns an unknown error.\n", fcn->name);
+
+ default:
+ return 0;
+ }
+}
+
+/* This fucntion is an LUA binding used for registering
+ * "sample-fetch" functions. It expects a converter name used
+ * in the haproxy configuration file, and an LUA function.
+ */
+__LJMP static int hlua_register_fetches(lua_State *L)
+{
+ const char *name;
+ int ref;
+ int len;
+ struct sample_fetch_kw_list *sfk;
+ struct hlua_function *fcn;
+
+ MAY_LJMP(check_args(L, 2, "register_fetches"));
+
+ /* First argument : sample-fetch name. */
+ name = MAY_LJMP(luaL_checkstring(L, 1));
+
+ /* Second argument : lua function. */
+ ref = MAY_LJMP(hlua_checkfunction(L, 2));
+
+ /* Allocate and fill the sample fetch keyword struct. */
+ sfk = malloc(sizeof(struct sample_fetch_kw_list) +
+ sizeof(struct sample_fetch) * 2);
+ if (!sfk)
+ WILL_LJMP(luaL_error(L, "lua out of memory error."));
+ fcn = malloc(sizeof(*fcn));
+ if (!fcn)
+ WILL_LJMP(luaL_error(L, "lua out of memory error."));
+
+ /* Fill fcn. */
+ fcn->name = strdup(name);
+ if (!fcn->name)
+ WILL_LJMP(luaL_error(L, "lua out of memory error."));
+ fcn->function_ref = ref;
+
+ /* List head */
+ sfk->list.n = sfk->list.p = NULL;
+
+ /* sample-fetch keyword. */
+ len = strlen("lua.") + strlen(name) + 1;
+ sfk->kw[0].kw = malloc(len);
+ if (!sfk->kw[0].kw)
+ return luaL_error(L, "lua out of memory error.");
+
+ snprintf((char *)sfk->kw[0].kw, len, "lua.%s", name);
+ sfk->kw[0].process = hlua_sample_fetch_wrapper;
+ sfk->kw[0].arg_mask = ARG5(0,STR,STR,STR,STR,STR);
+ sfk->kw[0].val_args = NULL;
+ sfk->kw[0].out_type = SMP_T_STR;
+ sfk->kw[0].use = SMP_USE_HTTP_ANY;
+ sfk->kw[0].val = 0;
+ sfk->kw[0].private = fcn;
+
+ /* End of array. */
+ memset(&sfk->kw[1], 0, sizeof(struct sample_fetch));
+
+ /* Register this new fetch. */
+ sample_register_fetches(sfk);
+
+ return 0;
+}
+
/* This function is called by the main configuration key "lua-load". It loads and
* execute an lua file during the parsing of the HAProxy configuration file. It is
* the main lua entry point.
@@ -1217,6 +1373,7 @@
/* Register special functions. */
hlua_class_function(gL.T, "register_init", hlua_register_init);
hlua_class_function(gL.T, "register_task", hlua_register_task);
+ hlua_class_function(gL.T, "register_fetches", hlua_register_fetches);
/* Store the table __index in the metable. */
lua_settable(gL.T, -3);