From a379506bc2d25857766d74a7422189e20cbabeec Mon Sep 17 00:00:00 2001
From: Ivan Dyachkov <dev@dyachkov.org>
Date: Wed, 24 Jan 2024 18:58:45 +0100
Subject: [PATCH] feat: support random bytes in payload

---
 src/emqtt_bench.erl | 78 +++++++++++++++++++++++++--------------------
 1 file changed, 44 insertions(+), 34 deletions(-)

diff --git a/src/emqtt_bench.erl b/src/emqtt_bench.erl
index 1746497..7607cdd 100644
--- a/src/emqtt_bench.erl
+++ b/src/emqtt_bench.erl
@@ -78,7 +78,13 @@
          {size, $s, "size", {integer, 256},
           "payload size"},
          {message, $m, "message", string,
-          "set the message content for publish"},
+          "Set the message content for publish. "
+          "Either a literal message content, or path to a file with payload template "
+          "specified via 'template://<file_path>'. "
+          "Available variables: %TIMESTAMP%, %TIMESTAMPMS%, %TIMESTAMPUS%, %TIMESTAMPNS%, %UNIQUE%, %RANDOM%. "
+          "When using 'template://', --size option does not have effect except for when %RANDOM% placeholder "
+          "is used."
+         },
          {qos, $q, "qos", {integer, 0},
           "subscribe qos"},
          {qoe, $Q, "qoe", {boolean, false},
@@ -348,6 +354,7 @@ main(pub, Opts) ->
                 undefined
         end,
     start(pub, [ {payload, Payload}
+               , {payload_size, Size}
                , {limit_fun, MsgLimit}
                , {publish_signal_pid, PublishSignalPid}
                | Opts]);
@@ -819,39 +826,41 @@ publish(Client, Opts) ->
     ok = ensure_publish_begin_time(),
     Flags   = [{qos, proplists:get_value(qos, Opts)},
                {retain, proplists:get_value(retain, Opts)}],
-   Payload0 = proplists:get_value(payload, Opts),
-   Payload = case Payload0 of
-                 {template, Bin} ->
-                     Now = os:system_time(nanosecond),
-                     TsNS = integer_to_binary(Now),
-                     TsUS = integer_to_binary(erlang:convert_time_unit(Now, nanosecond, microsecond)),
-                     TsMS = integer_to_binary(erlang:convert_time_unit(Now, nanosecond, millisecond)),
-                     Unique = integer_to_binary(erlang:unique_integer()),
-                     Substitutions =
-                         #{ <<"%TIMESTAMP%">> => TsMS
-                          , <<"%TIMESTAMPMS%">> => TsMS
-                          , <<"%TIMESTAMPUS%">> => TsUS
-                          , <<"%TIMESTAMPNS%">> => TsNS
-                          , <<"%UNIQUE%">> => Unique
-                          },
-                     maps:fold(
-                       fun(Placeholder, Val, Acc) -> binary:replace(Acc, Placeholder, Val) end,
-                       Bin,
-                       Substitutions);
-                 _ ->
-                     Payload0
-             end,
-   %% prefix dynamic headers.
-   NewPayload = case proplists:get_value(payload_hdrs, Opts, []) of
-                   [] -> Payload;
-                   PayloadHdrs ->
-                      with_payload_headers(PayloadHdrs, Payload)
-                end,
-   case emqtt:publish(Client, topic_opt(Opts), NewPayload, Flags) of
-      ok -> ok;
-      {ok, _} -> ok;
-      {error, Reason} -> {error, Reason}
-   end.
+    Size = proplists:get_value(payload_size, Opts),
+    Payload0 = proplists:get_value(payload, Opts),
+    Payload = case Payload0 of
+                  {template, Bin} ->
+                      Now = os:system_time(nanosecond),
+                      TsNS = integer_to_binary(Now),
+                      TsUS = integer_to_binary(erlang:convert_time_unit(Now, nanosecond, microsecond)),
+                      TsMS = integer_to_binary(erlang:convert_time_unit(Now, nanosecond, millisecond)),
+                      Unique = integer_to_binary(erlang:unique_integer()),
+                      Substitutions =
+                          #{ <<"%TIMESTAMP%">> => TsMS
+                           , <<"%TIMESTAMPMS%">> => TsMS
+                           , <<"%TIMESTAMPUS%">> => TsUS
+                           , <<"%TIMESTAMPNS%">> => TsNS
+                           , <<"%UNIQUE%">> => Unique
+                           , <<"%RANDOM%">> => rand:bytes(Size)
+                           },
+                      maps:fold(
+                        fun(Placeholder, Val, Acc) -> binary:replace(Acc, Placeholder, Val) end,
+                        Bin,
+                        Substitutions);
+                  _ ->
+                      Payload0
+              end,
+    %% prefix dynamic headers.
+    NewPayload = case proplists:get_value(payload_hdrs, Opts, []) of
+                     [] -> Payload;
+                     PayloadHdrs ->
+                         with_payload_headers(PayloadHdrs, Payload)
+                 end,
+    case emqtt:publish(Client, topic_opt(Opts), NewPayload, Flags) of
+        ok -> ok;
+        {ok, _} -> ok;
+        {error, Reason} -> {error, Reason}
+    end.
 
 session_property_opts(Opts) ->
     case session_property_opts(Opts, #{}) of
@@ -1052,6 +1061,7 @@ loop_opts(Opts) ->
     lists:filter(fun({K,__V}) ->
                          lists:member(K, [ interval_of_msg
                                          , payload
+                                         , payload_size
                                          , payload_hdrs
                                          , qos
                                          , retain