add ascii macro post processor

docs/configuration/index.md

@@ -186,6 +186,7 @@ Support operators are:
 | `:utc`                | 1700834034 -> 2023-11-24 13:53:54 UTC | convert unix timestamp into human readable date (utc timezone) |
 | `:fmt=<fmt>`          | 123.45 -> 123.4                       | apply format, ex.: $(total \| fmt=%.1f) (using GOs fmt.Sprintf) |
 | `:s/regexp/replace/`  | C:\ % -> C                            | apply regexp replacement, ex.: $(name \| 's/\\W//' ) (using GOs regexp.Compile) |
+| `:ascii`              | C:\ % -> C                            | remove any none-ascii characters |
 
 for example, define a dummy command which prints the hostname in lower case letters:
 

pkg/snclient/macro_test.go

@@ -40,6 +40,7 @@ func TestMacros(t *testing.T) {
 		{In: "${characters | 's/^(.*)ß.*?([a-z]+)/$2$1/g' }", Expect: "utföäü"},
 		{In: "${characters | 's/.*(u{1}).*/U/g' }", Expect: "U"},
 		{In: "${characters | 's/\\W//' }", Expect: "utf"},
+		{In: "${characters | ascii }", Expect: "utf"},
 		{In: "$(seconds)$(seconds)", Expect: "130130"},
 		{In: "...'$(seconds)'...", Expect: "...'130'..."},
 	}

pkg/snclient/macros.go

@@ -26,6 +26,8 @@ var (
 	reRuntimeMacro = regexp.MustCompile(`%[` + runtimeMacroChars + `]+%|\$[` + runtimeMacroChars + `]+\$`)
 
 	reFloatFormat = regexp.MustCompile(`^%[.\d]*f$`)
+
+	reAsciiOnly = regexp.MustCompile(`\W`)
 )
 
 /* replaceMacros replaces variables in given string (config ini file style macros).
@@ -182,6 +184,8 @@ func replaceMacroOperators(value string, flags []string) string {
 			value = utils.DurationString(time.Duration(convert.Float64(value) * float64(time.Second)))
 		case "age":
 			value = fmt.Sprintf("%d", time.Now().Unix()-convert.Int64(value))
+		case "ascii":
+			value = reAsciiOnly.ReplaceAllString(value, "")
 		default:
 			value = replaceMacroOpString(value, flag)
 		}