Fluent-bit only supports Lua 5.1

confgenerator/logging_modify_fields.go

@@ -155,9 +155,12 @@ function process(tag, timestamp, record)
 		var conv string
 		switch field.Type {
 		case "integer":
-			conv = "math.tointeger"
+			// Fluent-bit currently targets Lua 5.1, which uses the same type for numbers and integers.
+			// When converting back to msgpack, if a number can be represented as an integer, fluent-bit does so, otherwise it uses a float.
+			// If fluent-bit ever supports Lua 5.3, we can switch this to math.tointeger and use proper integers.
+			conv = "math.floor(tonumber(v))"
 		case "float":
-			conv = "tonumber"
+			conv = "tonumber(v)"
 		}
 		if conv != "" {
 			// Leave existing string value if not convertible

confgenerator/testdata/valid/linux/logging-processor_modify_fields/golden_3a94b231d99baac9194545a8222cd9c8.lua → confgenerator/testdata/valid/linux/logging-processor_modify_fields/golden_11707260be42e8aa17deb8c0f15d2568.lua

@@ -35,7 +35,7 @@ record["default"] = value
 end)(v)
 local v = __field_2;
 
-local v2 = tonumber(v)
+local v2 = tonumber(v)(v)
 if v2 ~= fail then v = v2
 end
 (function(value)
@@ -47,7 +47,7 @@ record["hello"] = value
 end)(v)
 local v = __field_3;
 
-local v2 = math.tointeger(v)
+local v2 = math.floor(tonumber(v))(v)
 if v2 ~= fail then v = v2
 end
 (function(value)

confgenerator/testdata/valid/linux/logging-processor_modify_fields/golden_fluent_bit_main.conf

@@ -69,7 +69,7 @@
     Match  p1.sample_logs
     Name   lua
     call   process
-    script 3a94b231d99baac9194545a8222cd9c8.lua
+    script 11707260be42e8aa17deb8c0f15d2568.lua
 
 [FILTER]
     Match  p1.sample_logs