refactor http-log plugin to reuse main http code for different serial…

…ization formats

kong/plugins/http-log/handler.lua

@@ -13,13 +13,11 @@ local HTTPS = "https"
 -- @param `method` http method to be used to send data
 -- @param `parsed_url` contains the host details
 -- @param `message`  Message to be logged
--- @return `payload` http payload
-local function generate_post_payload(method, parsed_url, message)
-  local body = cjson.encode(message)
-  local payload = string.format(
+-- @return `body` http payload
+local function generate_post_payload(method, parsed_url, body)
+  return string.format(
     "%s %s HTTP/1.1\r\nHost: %s\r\nConnection: Keep-Alive\r\nContent-Type: application/json\r\nContent-Length: %s\r\n\r\n%s",
     method:upper(), parsed_url.path, parsed_url.host, string.len(body), body)
-  return payload
 end
 
 -- Parse host url
@@ -44,8 +42,9 @@ end
 -- @param `premature`
 -- @param `conf`     Configuration table, holds http endpoint details
 -- @param `message`  Message to be logged
-local function log(premature, conf, message)
+local function log(premature, conf, body, name)
   if premature then return end
+  name = "["..name.."] "
 
   local ok, err
   local parsed_url = parse_url(conf.http_endpoint)
@@ -57,40 +56,47 @@ local function log(premature, conf, message)
 
   ok, err = sock:connect(host, port)
   if not ok then
-    ngx.log(ngx.ERR, "[http-log] failed to connect to "..host..":"..tostring(port)..": ", err)
+    ngx.log(ngx.ERR, name.."failed to connect to "..host..":"..tostring(port)..": ", err)
     return
   end
 
   if parsed_url.scheme == HTTPS then
     local _, err = sock:sslhandshake(true, host, false)
     if err then
-      ngx.log(ngx.ERR, "[http-log] failed to do SSL handshake with "..host..":"..tostring(port)..": ", err)
+      ngx.log(ngx.ERR, name.."failed to do SSL handshake with "..host..":"..tostring(port)..": ", err)
     end
   end
 
-  ok, err = sock:send(generate_post_payload(conf.method, parsed_url, message))
+  ok, err = sock:send(generate_post_payload(conf.method, parsed_url, body))
   if not ok then
-    ngx.log(ngx.ERR, "[http-log] failed to send data to "..host..":"..tostring(port)..": ", err)
+    ngx.log(ngx.ERR, name.."failed to send data to "..host..":"..tostring(port)..": ", err)
   end
 
   ok, err = sock:setkeepalive(conf.keepalive)
   if not ok then
-    ngx.log(ngx.ERR, "[http-log] failed to keepalive to "..host..":"..tostring(port)..": ", err)
+    ngx.log(ngx.ERR, name.."failed to keepalive to "..host..":"..tostring(port)..": ", err)
     return
   end
 end
 
-function HttpLogHandler:new()
-  HttpLogHandler.super.new(self, "http-log")
+-- Only provide `name` when deriving from this class. Not when initializing an instance.
+function HttpLogHandler:new(name)
+  HttpLogHandler.super.new(self, name or "http-log")
+end
+
+-- serializes context data into an html message body
+-- @param `ngx` The context table for the request being logged
+-- @return html body as string
+function HttpLogHandler:serialize(ngx)
+  return cjson.encode(basic_serializer.serialize(ngx))
 end
 
 function HttpLogHandler:log(conf)
   HttpLogHandler.super.log(self)
 
-  local message = basic_serializer.serialize(ngx)
-  local ok, err = ngx.timer.at(0, log, conf, message)
+  local ok, err = ngx.timer.at(0, log, conf, self:serialize(ngx), self._name)
   if not ok then
-    ngx.log(ngx.ERR, "[http-log] failed to create timer: ", err)
+    ngx.log(ngx.ERR, "["..self._name.."] failed to create timer: ", err)
   end
 end