X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/5964efeaa53eb62b51b814b67ff413f0593a03a0..9ba558e8b4fa1b132e834c1fbab074a3ac848169:/examples/lua/chord/chord.lua

diff --git a/examples/lua/chord/chord.lua b/examples/lua/chord/chord.lua
index 687d485d80..523b15017c 100644
--- a/examples/lua/chord/chord.lua
+++ b/examples/lua/chord/chord.lua
@@ -13,12 +13,12 @@ fix_fingers_delay = 120
 check_predecessor_delay = 120
 lookup_delay = 10
 
--- current node (don't worry, globals are duplicated in each process)
+-- current node (don't worry, globals are duplicated in each simulated process)
 my_node = {
   id = my_id,
   next_finger_to_fix = 1,
   fingers = {},
-  predecessor = nil
+  predecessor = nil,
   comm_recv = nil
 }
 
@@ -26,18 +26,30 @@ my_node = {
 -- Arguments:
 -- - my id
 -- - the id of a guy I know in the system (except for the first node)
-function node(my_id, known_id)
+function node(...)
+
+  -- TODO simplify the deployment file
+  local known_id
+  local args = {...}
+  my_node.id = tonumber(args[1])
+  if #args == 4 then
+    known_id = tonumber(args[2])
+  end
 
-  simgrid.info("Hello, I'm a node")
+  -- initialize the node
+  for i = 1, nb_bits do
+    my_node.fingers[i] = my_node.id
+  end
+  my_node.comm_recv = simgrid.task.irecv(my_node.id)
 
   -- join the ring
-  local success = false
+  local join_success = false
   if known_id == nil then
     -- first node
     create()
-    success = true
+    join_success = true
   else
-    success = join(known_id)
+    join_success = join(known_id)
   end
 
   -- main loop
@@ -49,17 +61,19 @@ function node(my_id, known_id)
     local next_check_predecessor_date = now + check_predecessor_delay
     local next_lookup_date = now + lookup_delay
 
-    local task
-    my_node.comm_recv = simgrid.task.irecv(my_node.id)
+    local task, err
 
     while now < max_simulation_time do
 
-      task = simgrid.comm.test(node.comm_recv)
+      task, err = my_node.comm_recv:test()
 
       if task then
 	-- I received a task: answer it
         my_node.comm_recv = simgrid.task.irecv(my_node.id)
 	handle_task(task)
+      elseif err then
+        -- the communication has failed: nevermind
+        my_node.comm_recv = simgrid.task.irecv(my_node.id)
       else
         -- no task was received: do periodic calls
 	if now >= next_stabilize_date then
@@ -73,6 +87,7 @@ function node(my_id, known_id)
 	elseif now >= next_check_predecessor_date then
 	  check_predecessor()
 	  next_check_predecessor_date = simgrid.get_clock() + check_predecessor_delay
+
 	elseif now >= next_lookup_date then
 	  random_lookup()
 	  next_lookup_date = simgrid.get_clock() + lookup_delay
@@ -90,31 +105,49 @@ function node(my_id, known_id)
   end
 end
 
+-- Makes the current node leave the ring
+function leave()
+
+  simgrid.info("Leaving the ring")
+  -- TODO: notify others
+end
+
 -- This function is called when the current node receives a task.
 -- - task: the task received
 function handle_task(task)
 
-  local type = task[type]
+  local type = task.type
 
   if type == "find successor" then
 
+    simgrid.info("Received a 'find successor' request from " .. task.answer_to ..
+        " for id " .. task.request_id)
+
     -- is my successor the successor?
-    if is_in_interval(task[request_id], my_node.id + 1, my_node.fingers[1]) then
-      task[type] = "find successor answer"
-      task[answer] = my_node.fingers[1]
-      task:dsend(task[answer_to])
+    if is_in_interval(task.request_id, my_node.id + 1, my_node.fingers[1]) then
+
+      simgrid.info("Sending back a 'find successor answer' to " ..
+          task.answer_to .. ": the successor of " .. task.request_id ..
+	  " is " .. my_node.fingers[1])
+
+      task.type = "find successor answer"
+      task.answer = my_node.fingers[1]
+      task:dsend(task.answer_to)
     else
       -- forward the request to the closest preceding finger in my table
-      task:dsend(closest_preceding_node(task[request_id]))
+
+      simgrid.info("Forwarding the 'find successor' request to my closest preceding finger")
+      task:dsend(closest_preceding_node(task.request_id))
     end
 
   elseif type == "get predecessor" then
-    task[answer] = my_node.predecessor
-    task:dsend(task[answer_to])
+    task.type = "get predecessor answer"
+    task.answer = my_node.predecessor
+    task:dsend(task.answer_to)
 
   elseif type == "notify" then
     -- someone is telling me that he may be my new predecessor
-    notify(task[request_id])
+    notify(task.request_id)
 
   elseif type == "predecessor leaving" then
     -- TODO
@@ -129,7 +162,7 @@ function handle_task(task)
     -- ignoring
 
   else
-    error("Unknown type of task received: " .. task[type])
+    error("Unknown type of task received: " .. task.type)
   end
 end
 
@@ -160,6 +193,36 @@ function is_in_interval(id, a, b)
   return id <= b
 end
 
+-- Returns whether the current node is in the ring.
+function has_joined()
+
+  return my_node.fingers[1] ~= nil
+end
+
+-- Creates a new Chord ring.
+function create()
+  my_node.predecessor = nil
+  my_node.fingers[1] = my_node.id
+end
+
+-- Attemps to join the Chord ring.
+-- - known_id: id of a node already in the ring
+-- - return value: true if the join was successful
+function join(known_id)
+
+  simgrid.info("Joining the ring with id " .. my_node.id .. ", knowing node " .. known_id)
+
+  local successor = remote_find_successor(known_id, my_node.id)
+  if successor == nil then
+    simgrid.info("Cannot join the ring.")
+    return false
+  end
+
+  my_node.predecessor = nil
+  my_node.fingers[1] = successor
+  return true
+end
+
 -- Returns the closest preceding finger of an id with respect to the finger
 -- table of the current node.
 -- - id: the id to find
@@ -167,16 +230,16 @@ end
 function closest_preceding_node(id)
 
   for i = nb_bits, 1, -1 do
-    if is_in_interval(my_node.fingers[i].id, my_node.id + 1, id - 1) then
+    if is_in_interval(my_node.fingers[i], my_node.id + 1, id - 1) then
       -- finger i is the first one before id
-      return my_node.fingers[i].id
+      return my_node.fingers[i]
     end
   end
 end
 
 -- Finds the successor of an id
 -- id: the id to find
--- return value: the id of the successor, or -1 if the request failed
+-- return value: the id of the successor, or nil if the request failed
 function find_successor(id)
 
   if is_in_interval(id, my_node.id + 1, my_node.fingers[1]) then
@@ -195,31 +258,43 @@ end
 -- return value: the id of the successor, or nil if the request failed
 function remote_find_successor(ask_to, id)
 
-  local task = simgrid.task.new(comp_size, comm_size)
-  task[type] = "find successor"
-  task[request_id] = id
-  task[answer_to] = my_node.id
+  local task = simgrid.task.new("", comp_size, comm_size)
+  task.type = "find successor"
+  task.request_id = id
+  task.answer_to = my_node.id
 
+  simgrid.info("Sending a 'find successor' request to " .. ask_to .. " for id " .. id)
   if task:send(ask_to, timeout) then
     -- request successfully sent: wait for an answer
+
+    simgrid.info("Sent the 'find successor' request to " .. ask_to ..
+        " for id " .. id .. ", waiting for the answer")
+
     while true do
-      task = simgrid.comm.wait(my_node.comm_recv, timeout)
+      task = my_node.comm_recv:wait(timeout)
       my_node.comm_recv = simgrid.task.irecv(my_node.id)
     
       if not task then
 	-- failed to receive the answer
+	simgrid.info("Failed to receive the answer to my 'find successor' request")
 	return nil
       else
 	-- a task was received: is it the expected answer?
-	if task[type] ~= "find successor answer" or task[request_id] ~= id then
+	if task.type ~= "find successor answer" or task.request_id ~= id then
           -- this is not our answer
+	  simgrid.info("Received another request of type " .. task.type)
 	  handle_task(task)
 	else
 	  -- this is our answer
-	  return task[answer]
+	  simgrid.info("Received the answer to my 'find successor' request for id " ..
+	      id .. ": the successor is " .. task.answer)
+	  return task.answer
 	end
       end
     end
+  else
+    simgrid.info("Failed to send the 'find successor' request to " .. ask_to ..
+        " for id " .. id)
   end
 
   return successor
@@ -230,14 +305,14 @@ end
 -- return value: the id of its predecessor, or nil if the request failed
 function remote_get_predecessor(ask_to)
 
-  local task = simgrid.task.new(comp_size, comm_size)
-  task[type] = "get predecessor"
-  task[answer_to] = my_node.id
+  local task = simgrid.task.new("", comp_size, comm_size)
+  task.type = "get predecessor"
+  task.answer_to = my_node.id
 
   if task:send(ask_to, timeout) then
     -- request successfully sent: wait for an answer
     while true do
-      task = simgrid.comm.wait(my_node.comm_recv, timeout)
+      task = my_node.comm_recv:wait(timeout)
       my_node.comm_recv = simgrid.task.irecv(my_node.id)
     
       if not task then
@@ -245,13 +320,13 @@ function remote_get_predecessor(ask_to)
 	return nil
       else
 	-- a task was received: is it the expected answer?
-	if task[type] ~= "get predecessor answer" then
+	if task.type ~= "get predecessor answer" then
           -- this is not our answer
 	  handle_task(task)
 	else
 	  -- this is our answer
 	  -- FIXME make sure the message answers to this particular request
-	  return task[answer]
+	  return task.answer
 	end
       end
     end
@@ -272,7 +347,7 @@ function stabilize()
   end
 
   -- this node is a candidate to become my new successor
-  if candidate ~= nil and is_in_interval(candidate, my_node.id + 1, successor -1) then
+  if candidate ~= nil and is_in_interval(candidate, my_node.id + 1, successor - 1) then
     my_node.fingers[1] = candidate
   end
 
@@ -296,9 +371,9 @@ end
 -- - candidate the possible new predecessor
 function remote_notify(notify_to, candidate_predecessor)
 
-  local task = simgrid.task.new(comp_size, comm_size)
-  task[type] = "notify"
-  task[request_id] = candidate_predecessor
+  local task = simgrid.task.new("", comp_size, comm_size)
+  task.type = "notify"
+  task.request_id = candidate_predecessor
   task:dsend(notify_to)
 end
 
@@ -309,7 +384,7 @@ function fix_fingers()
   local id = find_successor(my_node.id + 2^i)
   if id ~= nil then
     if id ~= my_node.fingers[i] then
-      fingers[i] = id
+      my_node.fingers[i] = id
     end
     my_node.next_finger_to_fix = (i % nb_bits) + 1
   end