With a hard-coded payload size, for some use cases like uploading a big

OpenAPI spec in DevPortal or updating a big config entry for plugins,
they can not work as expected. With the new parameter, the user can
decide the payload size to meet their needs.

In this PR, a new parameter, `worker_events_max_payload` is added, which
allows to specify the payload size the `worker_events` lib can accept.
The default size is 64k, and the max allowed to set is 16M Bytes.

The corresponding PR for `worker_events` lib is [#37](Kong/lua-resty-events#37)

FTI-4963

kong.conf.default

@@ -269,6 +269,11 @@
                                  # Similarly to `error_template_html`, the template
                                  # is required to contain one single `%s` placeholder for
                                  # the error message.
+
+#worker_events_max_payload =     # Specifies the max payload size the `worker_events` can
+                                 # accept.
+                                 # Default is 64k - 1024 * 64. The max allowed is 16M Bytes.
+
 #------------------------------------------------------------------------------
 # HYBRID MODE
 #------------------------------------------------------------------------------

kong/global.lua

@@ -182,17 +182,21 @@ function _GLOBAL.init_worker_events()
                  and configuration.prefix
                  or require("pl.path").abspath(ngx.config.prefix())
 
+  local max_payload_len = configuration
+                           and configuration.worker_events_max_payload
+
   local sock = ngx.config.subsystem == "stream"
                and "stream_worker_events.sock"
                or "worker_events.sock"
 
   local listening = "unix:" .. prefix .. "/" .. sock
 
   opts = {
-    unique_timeout = 5,     -- life time of unique event data in lrucache
-    broker_id = 0,          -- broker server runs in nginx worker #0
-    listening = listening,  -- unix socket for broker listening
-    max_queue_len = 1024 * 50,  -- max queue len for events buffering
+    unique_timeout = 5,                   -- life time of unique event data in lrucache
+    broker_id = 0,                        -- broker server runs in nginx worker #0
+    listening = listening,                -- unix socket for broker listening
+    max_payload_len = max_payload_len,    -- max payload size in bytes
+    max_queue_len = 1024 * 50,            -- max queue len for events buffering
   }
 
   worker_events = require "resty.events.compat"

kong/templates/kong_defaults.lua

@@ -42,6 +42,7 @@ cluster_dp_labels = NONE
 lmdb_environment_path = dbless.lmdb
 lmdb_map_size = 2048m
 mem_cache_size = 128m
+worker_events_max_payload = 64k
 ssl_cert = NONE
 ssl_cert_key = NONE
 client_ssl = off