add wrk Lua code for client requests.

wrk/request.lua

@@ -0,0 +1,34 @@
+local math_random = math.random
+local wrk_format = wrk.format
+local open = io.open
+
+do
+    local frandom, err = open("/dev/urandom", "rb")
+    if not frandom then
+        return nil, 'failed to open /dev/urandom: ' .. err
+    end
+
+    local str = frandom:read(4)
+    frandom:close()
+    if not str then
+        return nil, 'failed to read data from /dev/urandom'
+    end
+
+    local seed = 0
+    for i = 1, 4 do
+        seed = 256 * seed + str:byte(i)
+    end
+    math.randomseed(seed)
+end --do
+
+function request()
+    local n = 100
+
+    local service_id = math_random(n)
+    local uri_id = math_random(n)
+    local url = "/service_" .. service_id .. "/uri_" .. uri_id
+    local header = {}
+    local body = nil
+
+    return wrk_format("GET", url, header, body)
+end