Add traffic_server command line option for debugging in Au test.

Author: Walter Karas

src/traffic_server/traffic_server.cc

@@ -174,6 +174,16 @@ static int poll_timeout         = -1; // No value set.
 static int cmd_disable_freelist = 0;
 static bool signal_received[NSIG];
 
+/*
+To be able to attach with a debugger to traffic_server running in an Au test case, temporarily add the
+parameter block_for_debug=True to the call to Test.MakeATSProcess().  This means Au test will wait
+effectively indefinitely (10 hours) for traffic_server to initialize itself.  Run the modified Au test,
+attach the debugger to the traffic_server process, set one or more breakpoints, set the variable
+cmd_block to 0, then continue.  On linux, the command 'ps -ef | fgrep -e --block' will help identify the
+PID of the traffic_server process (second column of output).
+*/
+static int cmd_block = 0;
+
 // 1: the main thread delayed accepting, start accepting.
 // 0: delay accept, wait for cache initialization.
 // -1: cache is already initialized, don't delay.
@@ -217,6 +227,7 @@ static ArgumentDescription argument_descriptions[] = {
   {"bind_stderr", '-', "Regular file to bind stderr to", "S512", &bind_stderr, "PROXY_BIND_STDERR", nullptr},
   {"accept_mss", '-', "MSS for client connections", "I", &accept_mss, nullptr, nullptr},
   {"poll_timeout", 't', "poll timeout in milliseconds", "I", &poll_timeout, nullptr, nullptr},
+  {"block", '-', "block for debug attach", "T", &cmd_block, nullptr, nullptr},
   HELP_ARGUMENT_DESCRIPTION(),
   VERSION_ARGUMENT_DESCRIPTION(),
   RUNROOT_ARGUMENT_DESCRIPTION(),
@@ -1753,6 +1764,12 @@ main(int /* argc ATS_UNUSED */, const char **argv)
   command_index = find_cmd_index(command_string);
   command_valid = command_flag && command_index >= 0;
 
+  // Attach point when TS is blocked for debugging is in this loop.
+  //
+  while (cmd_block) {
+    sleep(1);
+  }
+
   ink_freelist_init_ops(cmd_disable_freelist, cmd_disable_pfreelist);
 
 #if TS_HAS_TESTS

tests/gold_tests/autest-site/trafficserver.test.ext

@@ -27,9 +27,11 @@ def make_id(s):
 
 # this forms is for the global process define
 
-
+# 'block_for_debug', if True, causes traffic_server to run with the --block option enabled, and effectively
+# disables timeouts that could be triggered by running traffic_server under a debugger.
 def MakeATSProcess(obj, name, command='traffic_server', select_ports=True,
-                   enable_tls=False, enable_cache=True, enable_quic=False):
+                   enable_tls=False, enable_cache=True, enable_quic=False,
+                   block_for_debug=False):
     #####################################
     # common locations
 
@@ -60,6 +62,14 @@ def MakeATSProcess(obj, name, command='traffic_server', select_ports=True,
     storage_dir = os.path.join(ts_dir, 'storage')
     cache_dir = os.path.join(ts_dir, 'cache')
 
+    if block_for_debug:
+       if command.startswith('traffic_server'):
+          command += ' --block'
+       elif command.startswith('traffic_manager'):
+          if '--tsArgs' not in command:
+              command += ' --tsArgs'
+          command += ' --block'
+
     # create process
     p = obj.Processes.Process(name, command)
     #p_debug = obj.Processes.Process("port-debug", "ss --listen --tcp --process")
@@ -341,6 +351,15 @@ def MakeATSProcess(obj, name, command='traffic_server', select_ports=True,
     else:
         p.ReturnCode = 0
 
+    if block_for_debug:
+        p.Env['PROXY_BLOCK'] = '1'
+        # Cause traffic_server to wait effectviely indefinitely (10 hours) for the debugger to attach.
+        p.StartupTimeout = 10 * 60 * 60
+        # Hitting breakpoints may cause long delays in traffic_server transaction processing, so make
+        # the timeout for test processes (that may interact with traffic_server) effectively forever
+        # (10 hours).
+        obj.Variables.Autest.Process.TimeOut = 10 * 60 * 60
+
     return p