refactor: Change blocked RPC to non-blocked RPC

In the case of all remote workers which are not workable, blocked PRCs
not get RPC results until remote workers are workable. Therefore,
remote interface needs to change blocked RPC to non-blocked RPC with
10s. When time-out occurs, remote interface goes to run local dcurl.

Pass test with a broker and remote interface without remote worker.

Close DLTcollab#161

src/remote_common.c

@@ -7,6 +7,7 @@
 #include "remote_common.h"
 #include <stdio.h>
 #include <string.h>
+#include <sys/time.h>
 #include "common.h"
 
 bool die_on_amqp_error(amqp_rpc_reply_t x, char const *context)
@@ -186,7 +187,12 @@ bool wait_response_message(amqp_connection_state_t *conn,
      * AMQP_FRAME_BODY*/
     for (;;) {
         amqp_maybe_release_buffers(*conn);
-        amqp_simple_wait_frame(*conn, &frame);
+
+        struct timeval t = {10, 0}; /* RPC timeout: 10s*/
+        if (!die_on_error(amqp_simple_wait_frame_noblock(*conn, &frame, &t),
+                          "RPC timeout"))
+            return false;
+
         if (!die_on_amqp_error(amqp_get_rpc_reply(*conn), "Wait method frame"))
             return false;
 
@@ -209,7 +215,11 @@ bool wait_response_message(amqp_connection_state_t *conn,
 #endif
 
         amqp_maybe_release_buffers(*conn);
-        amqp_simple_wait_frame(*conn, &frame);
+
+        if (!die_on_error(amqp_simple_wait_frame_noblock(*conn, &frame, &t),
+                          "RPC timeout"))
+            return false;
+
         if (!die_on_amqp_error(amqp_get_rpc_reply(*conn), "Wait header frame"))
             return false;
 
@@ -230,7 +240,10 @@ bool wait_response_message(amqp_connection_state_t *conn,
         body_target = (size_t) frame.payload.properties.body_size;
         body_received = 0;
         while (body_received < body_target) {
-            amqp_simple_wait_frame(*conn, &frame);
+            if (!die_on_error(amqp_simple_wait_frame_noblock(*conn, &frame, &t),
+                          "RPC timeout"))
+                return false;
+
             if (!die_on_amqp_error(amqp_get_rpc_reply(*conn),
                                    "Wait body frame"))
                 return false;