GCVCALLP-127: Fail fast instead of blocking call when async slots are full

Author: Bence Szigeti

modules/rest_client/rest_client.c

@@ -69,6 +69,7 @@ int ssl_verifyhost = 1;
 int curl_http_version = CURL_HTTP_VERSION_NONE;
 
 int enable_expect_100;
+int no_async_fallback;
 
 struct tls_mgm_binds tls_api;
 
@@ -206,6 +207,7 @@ static const param_export_t params[] = {
 	{ "enable_expect_100",	INT_PARAM, &enable_expect_100	},
 	{ "no_concurrent_connects",	INT_PARAM, &no_concurrent_connects	},
 	{ "curl_conn_lifetime",	INT_PARAM, &curl_conn_lifetime	},
+	{ "no_async_fallback",	INT_PARAM, &no_async_fallback	},
 	{ 0, 0, 0 }
 };
 

modules/rest_client/rest_methods.c

@@ -879,6 +879,13 @@ int start_async_http_req(struct sip_msg *msg, enum rest_client_method method,
 
 	multi_list = get_multi();
 	if (!multi_list) {
+		if (no_async_fallback) {
+			LM_ERR("failed to get a multi handle, max_async_transfers (%d) "
+			       "reached\n", max_async_transfers);
+			curl_easy_cleanup(handle);
+			ret = RCL_NO_MULTI_HANDLE;
+			goto cleanup;
+		}
 		LM_WARN("failed to get a multi handle, doing a blocking transfer\n");
 		rc = rest_easy_perform(handle, url, NULL);
 		clean_header_list;

modules/rest_client/rest_methods.h

@@ -48,6 +48,7 @@ extern int ssl_verifyhost;
 extern int curl_http_version;
 extern int no_concurrent_connects;
 extern unsigned int curl_conn_lifetime;
+extern int no_async_fallback;
 
 /* handle for use with synchronous reqs */
 extern CURL *sync_handle;
@@ -69,6 +70,7 @@ enum rest_client_method {
 #define RCL_CONNECT_TIMEOUT     -2
 #define RCL_TRANSFER_TIMEOUT    -3
 #define RCL_ALREADY_CONNECTING  -4
+#define RCL_NO_MULTI_HANDLE     -5
 #define RCL_INTERNAL_ERR       -10
 
 typedef struct _rest_trace_param {