[hotfix/analytics] more robust buffer

kong/plugins/log_serializers/alf.lua

@@ -65,6 +65,7 @@ function _M.serialize_entry(ngx)
 
   local alf_req_body = analytics_data.req_body or ""
   local alf_res_body = analytics_data.res_body or ""
+  local alf_req_post_args = analytics_data.req_post_args or {}
 
   -- timers
   local proxy_started_at, proxy_ended_at = ngx.ctx.proxy_started_at, ngx.ctx.proxy_ended_at
@@ -128,7 +129,7 @@ function _M.serialize_entry(ngx)
       bodySize = string.len(alf_req_body),
       postData = {
         mimeType = alf_req_mimeType,
-        params = dic_to_array(ngx.req.get_post_args()),
+        params = dic_to_array(alf_req_post_args),
         text = alf_req_body
       }
     },
@@ -182,7 +183,7 @@ function _M.new_alf(ngx, token, environment)
         version = "1.2",
         creator = {
           name = "mashape-analytics-agent-kong",
-          version = "1.0.1"
+          version = "1.0.2"
         },
         entries = {_M.serialize_entry(ngx)}
       }

kong/plugins/mashape-analytics/buffer.lua

@@ -1,7 +1,7 @@
 -- ALF buffer module
 --
 -- This module contains a buffered array of ALF objects. When the buffer is full (max number of entries
--- or max payload size), it is converted to a JSON payload and moved to another buffer of payloads to be
+-- or max payload size), it is converted to a JSON payload and moved a queue of payloads to be
 -- sent to the server.
 --
 -- 1 buffer of ALFs (gets flushed once it reached the mmax size)
@@ -30,6 +30,7 @@ local ANALYTICS_SOCKET = {
 
 local buffer_mt = {}
 buffer_mt.__index = buffer_mt
+buffer_mt.MAX_BUFFER_SIZE = MAX_BUFFER_SIZE
 
 -- A handler for delayed batch sending. When no call has been made for X seconds
 -- (X being conf.delay), we send the batch to keep analytics as close to real-time
@@ -85,8 +86,15 @@ function buffer_mt:add_alf(alf)
   local next_n_entries = #self.entries + 1
   local alf_size = string.len(str)
 
+  -- If the alf_size exceeds the payload limit by itself, we have a big problem
+  if alf_size > self.MAX_SIZE then
+    ngx.log(ngx.ERR, string.format("[mashape-analytics] ALF size exceeded the maximum size (%sMB) accepted by the socket server. Dropping it.",
+                                   self.MAX_SIZE / MB))
+    return
+  end
+
   -- If size or entries exceed the max limits
-  local full = next_n_entries > self.MAX_ENTRIES or self:get_size() > self.MAX_SIZE
+  local full = next_n_entries > self.MAX_ENTRIES or (self:get_size() + alf_size) > self.MAX_SIZE
   if full then
     self:flush()
     -- Batch size reached, let's send the data
@@ -129,7 +137,11 @@ end
 -- 3. Empty the buffer and reset the current buffer size
 function buffer_mt:flush()
   local payload = self:payload_string()
-  table.insert(self.sending_queue, payload)
+  table.insert(self.sending_queue, {
+    payload = payload,
+    n_entries = #self.entries,
+    size = self:get_size()
+  })
   self.entries = {}
   self.entries_size = 0
 end
@@ -145,23 +157,29 @@ function buffer_mt.send_batch(premature, self)
     return
   end
 
-  -- Let's send the oldest payload in our buffer
-  local message = self.sending_queue[1]
+  -- Let's send the oldest batch in our queue
+  local batch_to_send = table.remove(self.sending_queue, 1)
 
-  local batch_saved = false
+  local drop_batch = false
   local client = http:new()
   client:set_timeout(50000) -- 5 sec
 
   local ok, err = client:connect(ANALYTICS_SOCKET.host, ANALYTICS_SOCKET.port)
   if ok then
-    local res, err = client:request({path = ANALYTICS_SOCKET.path, body = message})
+    local res, err = client:request({path = ANALYTICS_SOCKET.path, body = batch_to_send.payload})
     if not res then
-      ngx.log(ngx.ERR, "[mashape-analytics] failed to send batch: "..err)
+      ngx.log(ngx.ERR, string.format("[mashape-analytics] failed to send batch (%s ALFs %s bytes): %s",
+                                     batch_to_send.n_entries, batch_to_send.size, err))
     elseif res.status == 200 then
-      batch_saved = true
+      drop_batch = true
       ngx.log(ngx.DEBUG, string.format("[mashape-analytics] successfully saved the batch. (%s)", res.body))
+    elseif res.status == 400 then
+      ngx.log(ngx.ERR, string.format("[mashape-analytics] socket server refused the batch (%s ALFs %s bytes). Dropping batch. Status: (%s) Error: (%s)",
+                                     batch_to_send.n_entries, batch_to_send.size, res.status, res.body))
+      drop_batch = true
     else
-      ngx.log(ngx.ERR, string.format("[mashape-analytics] socket server refused the batch. Status: (%s) Error: (%s)", res.status, res.body))
+      ngx.log(ngx.ERR, string.format("[mashape-analytics] socket server could not save the batch (%s ALFs %s bytes). Status: (%s) Error: (%s)",
+                                     batch_to_send.n_entries, batch_to_send.size, res.status, res.body))
     end
 
     -- close connection, or put it into the connection pool
@@ -177,16 +195,16 @@ function buffer_mt.send_batch(premature, self)
     ngx.log(ngx.ERR, "[mashape-analytics] failed to connect to the socket server: "..err)
   end
 
-  if batch_saved then
-    -- Remove the payload that was sent
-    table.remove(self.sending_queue, 1)
+  if not drop_batch then
+    -- If the batch is not dropped, then add it back to the end of the queue and it will be tried again later
+    table.insert(self.sending_queue, batch_to_send)
   end
 
   self.lock_sending = false
 
-  -- Keep sendind data if the buffer is not yet emptied
+  -- Keep sendind data if the queue is not yet emptied
   if #self.sending_queue > 0 then
-    local ok, err = ngx.timer.at(0, self.send_batch, self)
+    local ok, err = ngx.timer.at(2, self.send_batch, self)
     if not ok then
       ngx.log(ngx.ERR, "[mashape-analytics] failed to create batch retry timer: ", err)
     end

kong/plugins/mashape-analytics/handler.lua

@@ -32,11 +32,24 @@ function AnalyticsHandler:access(conf)
   -- Retrieve and keep in memory the bodies for this request
   ngx.ctx.analytics = {
     req_body = "",
-    res_body = ""
+    res_body = "",
+    req_post_args = {}
   }
 
+  ngx.req.read_body()
+
+  local status, res = pcall(ngx.req.get_post_args)
+  if not status then
+    if res == "requesty body in temp file not supported" then
+      ngx.log(ngx.ERR, "[mashape-analytics] cannot read request body from temporary file. Try increasing the client_body_buffer_size directive.")
+    else
+      ngx.log(ngx.ERR, res)
+    end
+  else
+    ngx.ctx.analytics.req_post_args = res
+  end
+
   if conf.log_body then
-    ngx.req.read_body()
     ngx.ctx.analytics.req_body = ngx.req.get_body_data()
   end
 end

spec/plugins/mashape-analytics/alf_serializer_spec.lua

@@ -90,7 +90,7 @@ describe("ALF serializer", function()
       assert.equal("1.2", alf.har.log.version)
       assert.truthy(alf.har.log.creator)
       assert.equal("mashape-analytics-agent-kong", alf.har.log.creator.name)
-      assert.equal("1.0.1", alf.har.log.creator.version)
+      assert.equal("1.0.2", alf.har.log.creator.version)
       assert.truthy(alf.har.log.entries)
       assert.equal(1, #(alf.har.log.entries))
     end)

spec/plugins/mashape-analytics/buffer_spec.lua

@@ -64,11 +64,56 @@ describe("ALFBuffer", function()
         alf_buffer.flush:revert()
       end)
     end)
+    it("should call :flush() when reaching its max size", function()
+      -- How many stubs to reach the limit?
+      local COMMA_LEN = string.len(",")
+      local JSON_ARR_LEN = string.len("[]")
+      local max_n_stubs = math.ceil(ALFBuffer.MAX_BUFFER_SIZE / (STUB_LEN + COMMA_LEN)) -- + the comma after each ALF in the JSON payload
+
+      -- Create a new buffer
+      local buffer = ALFBuffer.new({batch_size = max_n_stubs + 100, delay = 2})
+
+      local s = spy.on(buffer, "flush")
+
+      -- Add max_n_stubs - 1 entries
+      for i = 1, max_n_stubs - 1 do
+        buffer:add_alf(ALF_STUB)
+      end
+
+      assert.spy(s).was_not_called()
+
+      -- We should have `(max_n_stubs - 1) * (STUB_LEN + COMMA_LEN) + JSON_ARR_LEN - COMMA_LEN` because no comma for latest object`
+      -- as our current buffer size.
+      assert.equal((max_n_stubs - 1) * (STUB_LEN + COMMA_LEN) + JSON_ARR_LEN - COMMA_LEN, buffer:get_size())
+
+      -- adding one more entry
+      buffer:add_alf(ALF_STUB)
+      assert.spy(s).was.called()
+    end)
+    it("should drop an ALF if it is too big by itself", function()
+      local str = string.rep(".", ALFBuffer.MAX_BUFFER_SIZE)
+      local huge_alf = {foo = str}
+
+      local buffer = ALFBuffer.new(CONF_STUB)
+
+      local s = spy.on(_G.ngx, "log")
+
+      buffer:add_alf(huge_alf)
+
+      assert.spy(s).was.called()
+      assert.equal(0, buffer.entries_size)
+      assert.equal(0, #buffer.entries)
+
+      finally(function()
+        _G.ngx.log:revert()
+      end)
+    end)
     describe(":flush()", function()
       it("should have emptied the current buffer and added a payload to be sent", function()
         assert.equal(1, #alf_buffer.entries)
         assert.equal(1, #alf_buffer.sending_queue)
-        assert.equal("string", type(alf_buffer.sending_queue[1]))
+        assert.equal("table", type(alf_buffer.sending_queue[1]))
+        assert.equal("string", type(alf_buffer.sending_queue[1].payload))
         assert.equal(STUB_LEN, alf_buffer.entries_size)
       end)
     end)

spec/plugins/mashape-analytics/fixtures/requests.lua

@@ -8,8 +8,7 @@ return {
         get_method = function() return "GET" end,
         http_version = function() return 1.1 end,
         get_headers = function() return {["Accept"] = "/*/", ["Host"] = "mockbin.com"} end,
-        get_uri_args = function() return {["hello"] = "world", ["foo"] = "bar", ["number"] = 2} end,
-        get_post_args = function() return {["hello"] = {"world", "earth"}} end
+        get_uri_args = function() return {["hello"] = "world", ["foo"] = "bar", ["number"] = 2} end
       },
       resp = {
         get_headers = function() return {["Connection"] = "close", ["Content-Type"] = "application/json", ["Content-Length"] = "934"} end
@@ -30,6 +29,7 @@ return {
         analytics = {
           req_body = "hello=world&hello=earth",
           res_body = "{\"message\":\"response body\"}",
+          req_post_args = {["hello"] = {"world", "earth"}},
           response_received = 143284457211
         }
       }
@@ -100,8 +100,7 @@ return {
         get_method = function() return "GET" end,
         http_version = function() return 1.1 end,
         get_headers = function() return {["Accept"] = "/*/", ["Host"] = "mockbin.com"} end,
-        get_uri_args = function() return {["hello"] = "world", ["foo"] = "bar"} end,
-        get_post_args = function() return {["hello"] = {"world", "earth"}} end
+        get_uri_args = function() return {["hello"] = "world", ["foo"] = "bar"} end
       },
       resp = {
         get_headers = function() return {["Connection"] = "close", ["Content-Type"] = "application/json", ["Content-Length"] = "934"} end
@@ -122,6 +121,7 @@ return {
         analytics = {
           req_body = "hello=world&hello=earth",
           res_body = "{\"message\":\"response body\"}",
+          req_post_args = {["hello"] = {"world", "earth"}},
           response_received = 143284457211
         }
       }