Preload info hashes in wrk benchmark

tests/wrk_benchmark_announce.lua

@@ -1,34 +1,67 @@
+-- else the randomness would be the same every run
+math.randomseed(os.time())
+
+local charset = "0123456789ABCDEF"
+
+function hex_to_char(hex)
+    local n = tonumber(hex, 16)
+    local f = string.char(n)
+  return f
+end
+
+function hex_string_to_char_string(hex)
+    local ret = {}
+    local r
+    for i = 0, 19 do
+        local x = i * 2
+		r = hex:sub(x+1, x+2)
+		local f = hex_to_char(r)
+		table.insert(ret, f)
+    end
+    return table.concat(ret)
+end
+
+function url_encode(str)
+    str = string.gsub (str, "([^0-9a-zA-Z !'()*._~-])", -- locale independent
+            function (c) return string.format ("%%%02X", string.byte(c)) end)
+    str = string.gsub (str, " ", "+")
+    return str
+end
+
+function gen_hex_string(length)
+    local ret = {}
+    local r
+    for i = 1, length do
+        r = math.random(1, #charset)
+        table.insert(ret, charset:sub(r, r))
+    end
+    return table.concat(ret)
+end
+
+function random_info_hash()
+    local hexString = gen_hex_string(40)
+    local str = hex_string_to_char_string(hexString)
+    return url_encode(str)
+end
+
 function generate_unique_info_hashes(size)
     local result = {}
-    local seen = {}
-
-    for i = 0, size - 1 do
-        local bytes = {}
-        bytes[1] = i & 0xFF
-        bytes[2] = (i >> 8) & 0xFF
-        bytes[3] = (i >> 16) & 0xFF
-        bytes[4] = (i >> 24) & 0xFF
-
-        local info_hash = bytes
-        local key = table.concat(info_hash, ",")
-
-        if not seen[key] then
-            table.insert(result, info_hash)
-            seen[key] = true
-        end
+
+    for i = 1, size do
+        result[i] = random_info_hash()
     end
 
     return result
 end
 
-info_hashes = generate_unique_info_hashes(10000000)
+info_hashes = generate_unique_info_hashes(5000000)
 
-index = 0
+index = 1
 
 -- the request function that will run at each request
 request = function()
     path = "/announce?info_hash=" .. info_hashes[index] .. "&peer_id=-lt0D80-a%D4%10%19%99%A6yh%9A%E1%CD%96&port=54434&uploaded=885&downloaded=0&left=0&corrupt=0&key=A78381BD&numwant=200&compact=1&no_peer_id=1&supportcrypto=1&redundant=0"
-    index += 1
+    index = index + 1
     headers = {}
     headers["X-Forwarded-For"] = "1.1.1.1"
     return wrk.format("GET", path, headers)