From 7b38c66538ebf7aa5867de34324243ab0c361a3e Mon Sep 17 00:00:00 2001
From: EMQ-YangM <yangm@emqx.io>
Date: Thu, 19 May 2022 13:47:56 +0800
Subject: [PATCH] feat: add rule engine function float2str/2

---
 CHANGES-4.3.md                                       |  1 +
 apps/emqx_rule_engine/src/emqx_rule_engine.appup.src | 12 ++++++++----
 apps/emqx_rule_engine/src/emqx_rule_funcs.erl        |  4 ++++
 apps/emqx_rule_engine/src/emqx_rule_utils.erl        |  4 ++++
 apps/emqx_rule_engine/test/emqx_rule_funcs_SUITE.erl |  7 +++++++
 5 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/CHANGES-4.3.md b/CHANGES-4.3.md
index 18ac43deb..acc6c550e 100644
--- a/CHANGES-4.3.md
+++ b/CHANGES-4.3.md
@@ -28,6 +28,7 @@ File format:
 * SSL closed error bug fixed for redis client.
 * Fix mqtt-sn client disconnected due to re-send a duplicated qos2 message
 * rule-engine function hexstr2bin/1 support half byte
+* add rule-engine function float2str/2, user can specify the float output precision.
 
 * Improved resilience against autocluster partitioning during cluster
   startup. [#7876]
diff --git a/apps/emqx_rule_engine/src/emqx_rule_engine.appup.src b/apps/emqx_rule_engine/src/emqx_rule_engine.appup.src
index 24a4a5358..4c2f653d9 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine.appup.src
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine.appup.src
@@ -2,7 +2,8 @@
 %% Unless you know what you are doing, DO NOT edit manually!!
 {VSN,
   [{"4.3.9",
-    [{load_module,emqx_rule_events,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_events,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_funcs,brutal_purge,soft_purge,[]},
      {add_module,emqx_rule_date},
      {load_module,emqx_rule_maps,brutal_purge,soft_purge,[]},
@@ -10,7 +11,8 @@
      {load_module,emqx_rule_engine,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]}]},
    {"4.3.8",
-    [{add_module,emqx_rule_date},
+    [{load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
+     {add_module,emqx_rule_date},
      {load_module,emqx_rule_maps,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_cli,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
@@ -134,7 +136,8 @@
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]}]},
    {<<".*">>,[]}],
   [{"4.3.9",
-    [{load_module,emqx_rule_events,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_events,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_funcs,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_maps,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_registry,brutal_purge,soft_purge,[]},
@@ -142,7 +145,8 @@
      {load_module,emqx_rule_engine_api,brutal_purge,soft_purge,[]},
      {delete_module,emqx_rule_date}]},
    {"4.3.8",
-    [{load_module,emqx_rule_maps,brutal_purge,soft_purge,[]},
+    [{load_module,emqx_rule_utils,brutal_purge,soft_purge,[]},
+     {load_module,emqx_rule_maps,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_engine_cli,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_sqltester,brutal_purge,soft_purge,[]},
      {load_module,emqx_rule_runtime,brutal_purge,soft_purge,[]},
diff --git a/apps/emqx_rule_engine/src/emqx_rule_funcs.erl b/apps/emqx_rule_engine/src/emqx_rule_funcs.erl
index 5800c19d0..282c8929d 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_funcs.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_funcs.erl
@@ -93,6 +93,7 @@
         , bool/1
         , int/1
         , float/1
+        , float2str/2
         , map/1
         , bin2hexstr/1
         , hexstr2bin/1
@@ -537,6 +538,9 @@ int(Data) ->
 float(Data) ->
     emqx_rule_utils:float(Data).
 
+float2str(Float, Precision) ->
+    emqx_rule_utils:float2str(Float, Precision).
+
 map(Data) ->
     emqx_rule_utils:map(Data).
 
diff --git a/apps/emqx_rule_engine/src/emqx_rule_utils.erl b/apps/emqx_rule_engine/src/emqx_rule_utils.erl
index dc08ad0c3..d287f1ad0 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_utils.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_utils.erl
@@ -32,6 +32,7 @@
 
 %% type converting
 -export([ str/1
+        , float2str/2
         , bin/1
         , bool/1
         , int/1
@@ -265,6 +266,9 @@ str(List) when is_list(List) ->
     end;
 str(Data) -> error({invalid_str, Data}).
 
+float2str(Float, Precision) when is_float(Float) and is_integer(Precision)->
+    float_to_binary(Float, [{decimals, Precision}, compact]).
+
 utf8_bin(Str) when is_binary(Str); is_list(Str) ->
     unicode:characters_to_binary(Str);
 utf8_bin(Str) ->
diff --git a/apps/emqx_rule_engine/test/emqx_rule_funcs_SUITE.erl b/apps/emqx_rule_engine/test/emqx_rule_funcs_SUITE.erl
index 116c99f29..98f6ad0b7 100644
--- a/apps/emqx_rule_engine/test/emqx_rule_funcs_SUITE.erl
+++ b/apps/emqx_rule_engine/test/emqx_rule_funcs_SUITE.erl
@@ -125,6 +125,13 @@ t_float(_) ->
     ?assertError({invalid_number, {a, v}}, emqx_rule_funcs:float({a, v})),
     ?assertError(_, emqx_rule_funcs:float("a")).
 
+
+t_float2str(_) ->
+    ?assertEqual(<<"20.2">>, emqx_rule_funcs:float2str(20.2, 1)),
+    ?assertEqual(<<"20.2">>, emqx_rule_funcs:float2str(20.2, 10)),
+    ?assertEqual(<<"20.199999999999999">>, emqx_rule_funcs:float2str(20.2, 15)),
+    ?assertEqual(<<"20.1999999999999993">>, emqx_rule_funcs:float2str(20.2, 16)).
+
 t_map(_) ->
     ?assertEqual(#{ver => <<"1.0">>, name => "emqx"}, emqx_rule_funcs:map([{ver, <<"1.0">>}, {name, "emqx"}])),
     ?assertEqual(#{<<"a">> => 1}, emqx_rule_funcs:map(<<"{\"a\":1}">>)),