Merge pull request #38 from useLiquidOps/fix/unqueue-on-timeout-error

Fix queue errors and infinite errors

Author: martonlederer

src/controller/queue.lua

@@ -1,5 +1,3 @@
-local utils = require ".utils.utils"
-
 local mod = {}
 
 -- Add or remove a user from the queue in the controller
@@ -46,20 +44,33 @@ function mod.setQueued(address, queued)
   }
 end
 
--- Make a handle function use the global queue of the controller
----@param handle HandlerFunction Handle function to wrap
----@param errorHandler fun(msg: Message, env: Message, err: unknown)? Optional error handler
----@return HandlerFunction
-function mod.useQueue(handle, errorHandler)
-  return function (msg, env)
-    -- default sender of the interaction is the message sender
-    local sender = msg.From
-    local isCreditNotice = msg.Tags.Action == "Credit-Notice"
-
-    -- if the message is a credit notice, update the sender
-    if isCreditNotice then
-      sender = msg.Tags.Sender
-    end
+-- Get the user to be queued, depending on the type of the message
+---@param msg Message Message to process
+---@return string
+function mod.getUserToQueue(msg)
+  -- return sender if it is a credit notice
+  if msg.Tags.Action == "Credit-Notice" then
+    return msg.Tags.Sender
+  end
+
+  -- the msg sender should be queued if it is not a credit-notice
+  return msg.From
+end
+
+-- Make a handler use the global queue of the controller. This is
+-- usually needed for handlers that impelement complex behavior by
+-- waiting for several message responses before completion to prevent
+-- double spending
+---@param config table Configuration for the handler
+---@return table
+function mod.useQueue(config)
+  -- original handle function and error handler
+  local handle = config.handle
+  local errorHandler = config.errorHandler
+
+  -- override handle function to queue and unqueue
+  config.handle = function (msg, env)
+    local sender = mod.getUserToQueue(msg)
 
     -- update and set queue
     local res = mod.setQueued(sender, true).receive()
@@ -76,7 +87,10 @@ function mod.useQueue(handle, errorHandler)
         errorHandler(msg, env, err)
       else
         -- no error handler, throw the error
-        error(err)
+        -- do not error() here - that would trigger
+        -- the handler's error handler, which would
+        -- try to unqueue the user
+        Handlers.defaultErrorHandler(msg, env, err)
       end
 
       return
@@ -99,6 +113,26 @@ function mod.useQueue(handle, errorHandler)
       end
     end
   end
+
+  -- override error handler to unqueue the user
+  config.errorHandler = function (msg, env, err)
+    -- call wrapped error handler if provided
+    if errorHandler ~= nil then
+      errorHandler(msg, env, err or "Unknown error")
+    else
+      Handlers.defaultErrorHandler(msg, env, err)
+    end
+
+    -- get user to unqueue
+    local sender = mod.getUserToQueue(msg)
+
+    -- unqueue and notify if it failed
+    mod
+      .setQueued(sender, false)
+      .notifyOnFailedQueue()
+  end
+
+  return config
 end
 
 return mod

src/process.lua

@@ -239,22 +239,21 @@ local function setup_handlers()
       msg.reply({ ["Borrow-Balance"] = tostring(borrowBalance) })
     end
   )
-  Handlers.add(
-    "borrow-loan-borrow",
-    Handlers.utils.hasMatchingTag("Action", "Borrow"),
-    -- needs unqueueing because of coroutines
-    queue.useQueue(oracle.withOracle(borrow))
-  )
-  Handlers.advanced({
+  Handlers.advanced(queue.useQueue({
+    name = "borrow-loan-borrow",
+    pattern = { Action = "Borrow" },
+    handle = oracle.withOracle(borrow)
+  }))
+  Handlers.advanced(queue.useQueue({
     name = "borrow-repay",
     pattern = {
       From = CollateralID,
       Action = "Credit-Notice",
       ["X-Action"] = "Repay"
     },
-    handle = queue.useQueue(repay.handler),
+    handle = repay.handler,
     errorHandler = repay.error
-  })
+  }))
   Handlers.add(
     "borrow-position-collateralization",
     Handlers.utils.hasMatchingTag("Action", "Position"),
@@ -271,16 +270,16 @@ local function setup_handlers()
     position.handlers.allPositions
   )
 
-  Handlers.advanced({
+  Handlers.advanced(queue.useQueue({
     name = "supply-mint",
     pattern = {
       From = CollateralID,
       Action = "Credit-Notice",
       ["X-Action"] = "Mint"
     },
-    handle = queue.useQueue(mint.handler),
+    handle = mint.handler,
     errorHandler = mint.error
-  })
+  }))
   Handlers.add(
     "supply-price",
     Handlers.utils.hasMatchingTag("Action", "Exchange-Rate-Current"),
@@ -302,12 +301,11 @@ local function setup_handlers()
       })
     end
   )
-  -- needs unqueueing because of coroutines
-  Handlers.add(
-    "supply-redeem",
-    Handlers.utils.hasMatchingTag("Action", "Redeem"),
-    queue.useQueue(oracle.withOracle(redeem))
-  )
+  Handlers.advanced(queue.useQueue({
+    name = "supply-redeem",
+    pattern = { Action = "Redeem" },
+    handle = oracle.withOracle(redeem)
+  }))
 
   Handlers.add(
     "token-info",
@@ -329,12 +327,11 @@ local function setup_handlers()
     Handlers.utils.hasMatchingTag("Action", "Balances"),
     balance.balances
   )
-  -- needs unqueueing because of coroutines
-  Handlers.add(
-    "token-transfer",
-    Handlers.utils.hasMatchingTag("Action", "Transfer"),
-    queue.useQueue(oracle.withOracle(transfer))
-  )
+  Handlers.advanced(queue.useQueue({
+    name = "token-transfer",
+    pattern = { Action = "Transfer" },
+    handle = oracle.withOracle(transfer)
+  }))
 
   HandlersAdded = true
 end

src/utils/handlers.lua

@@ -464,6 +464,7 @@ end
 -- @treturn The response from the handler(s). Returns a default message if no handler matches.
 function handlers.evaluate(msg, env)
   local handled = false
+  local toRemove = {} -- handlers to remove after evaluation
   assert(type(msg) == 'table', 'msg is not valid')
   assert(type(env) == 'table', 'env is not valid')
 
@@ -482,8 +483,8 @@ function handlers.evaluate(msg, env)
             o.onRemove("timeout")
             o.onRemove = nil
           end
-          handlers.remove(o.name)
-          match = 0
+          o.handle = function () end
+          table.insert(toRemove, o.name)
         end
       end
 
@@ -550,7 +551,7 @@ function handlers.evaluate(msg, env)
               o.onRemove("expired")
               o.onRemove = nil
             end
-            handlers.remove(o.name)
+            table.insert(toRemove, o.name)
           end
         end
       end
@@ -563,8 +564,16 @@ function handlers.evaluate(msg, env)
   -- reset current error handler
   handlers.currentErrorHandler = handlers.defaultErrorHandler
 
+  -- remove marked handlers
+  for _, name in ipairs(toRemove) do
+    handlers.remove(name)
+  end
+
   -- make sure the request was handled
-  assert(handled or msg.Id == ao.id, "The request could not be handled")
+  assert(
+    handled or msg.Id == ao.id or string.match(msg.Action or "", "Error$"),
+    "The request could not be handled"
+  )
 end
 
 return handlers