feat(protocol): send worker id to broker

### Summary

This is a feature that sends worker id to broker. This feature is needed for
future PRs to implement worker id based broker queues (to replace worker
connection based queues).

lualib/resty/events/protocol.lua

@@ -4,6 +4,7 @@ local _recv_frame = frame.recv
 local _send_frame = frame.send
 
 local ngx = ngx
+local worker_id = ngx.worker.id
 local tcp = ngx.socket.tcp
 local re_match = ngx.re.match
 local req_sock = ngx.req.socket
@@ -13,6 +14,8 @@ local flush = ngx.flush
 local subsystem = ngx.config.subsystem
 
 local type = type
+local tonumber = tonumber
+local tostring = tostring
 local str_sub = string.sub
 local setmetatable = setmetatable
 
@@ -82,12 +85,22 @@ function _Server.new(self)
 
     sock:settimeout(DEFAULT_TIMEOUT)
 
+    local data, err = _recv_frame(sock)
+    if err then
+        return nil, "failed to read worker id from worker: " .. err
+    end
+
+    local worker_id = tonumber(data, 10)
+    if not worker_id then
+        return nil, "invalid worker id: " .. data
+    end
+
     return setmetatable({
+        worker_id = worker_id,
         sock = sock,
     }, _SERVER_MT)
 end
 
-
 local _Client = {
     _VERSION = "0.1.0",
     is_timeout = is_timeout,
@@ -154,6 +167,11 @@ function _Client.connect(self, addr)
         end
     end -- subsystem == "http"
 
+    local _, err = send_frame(self, tostring(worker_id() or -1))
+    if err then
+        return nil, "failed to worker id: " .. err
+    end
+
     return true
 end
 

t/protocol.t

@@ -7,7 +7,7 @@ use Test::Nginx::Socket::Lua;
 
 repeat_each(2);
 
-plan tests => repeat_each() * (blocks() * 9) - 6;
+plan tests => repeat_each() * (blocks() * 9) - 4;
 
 $ENV{TEST_NGINX_HTML_DIR} ||= html_dir();
 
@@ -33,6 +33,7 @@ __DATA__
                 end
 
                 ngx.log(ngx.DEBUG, "Upgrade: ", ngx.var.http_upgrade)
+                ngx.log(ngx.DEBUG, "Worker ID: ", conn.worker_id)
 
                 local data, err = conn:recv_frame()
                 if not data or err then
@@ -84,6 +85,7 @@ GET /test
 world
 --- error_log
 Upgrade: Kong-Worker-Events/1
+Worker ID: 0
 srv recv data: hello
 srv send data: world
 cli recv len: 5
@@ -122,5 +124,3 @@ addr is nginx.sock
 [error]
 [crit]
 [alert]
-
-