[filebeat] httpjson join improvement

x-pack/filebeat/docs/inputs/input-httpjson.asciidoc

@@ -205,7 +205,7 @@ Some built-in helper functions are provided to work with the input state inside
 - `hmac`: calculates the hmac signature of a list of strings concatenated together. Supports sha1 or sha256. Example `[[hmac "sha256" "secret" "string1" "string2" (formatDate (now) "RFC1123")]]`
 - `base64Encode`: Joins and base64 encodes all supplied strings. Example `[[base64Encode "string1" "string2"]]`
 - `base64EncodeNoPad`: Joins and base64 encodes all supplied strings without padding. Example `[[base64EncodeNoPad "string1" "string2"]]`
-- `join`: joins a list of strings using the specified separator. Example: `[[join .body.arr ","]]`
+- `join`: joins a list using the specified separator. Example: `[[join .body.arr ","]]`
 - `sprintf`: formats according to a format specifier and returns the resulting string. Refer to https://pkg.go.dev/fmt#Sprintf[the Go docs] for usage. Example: `[[sprintf "%d:%q" 34 "quote this"]]`
 
 In addition to the provided functions, any of the native functions for https://golang.org/pkg/time/#Time[`time.Time`], https://golang.org/pkg/net/http/#Header[`http.Header`], and https://golang.org/pkg/net/url/#Values[`url.Values`] types can be used on the corresponding objects. Examples: `[[(now).Day]]`, `[[.last_response.header.Get "key"]]`

x-pack/filebeat/input/httpjson/internal/v2/value_tpl.go

@@ -58,7 +58,7 @@ func (t *valueTpl) Unpack(in string) error {
  "hmac": hmacString,
  "base64Encode": base64Encode,
  "base64EncodeNoPad": base64EncodeNoPad,
- "join": strings.Join,
+ "join": join,
  "sprintf": fmt.Sprintf,
  }).
  Delims(leftDelim, rightDelim).
@@ -289,3 +289,30 @@ func hmacString(hmacType string, hmacKey string, values ...string) string {
  // Get result and encode as hexadecimal string
  return hex.EncodeToString(mac.Sum(nil))
 }
+
+// join concatenates the elements of its first argument to create a single string. The separator
+// string sep is placed between elements in the resulting string. If the first argument is not of
+// type string or []string, its elements will be stringified.
+func join(v interface{}, sep string) string {
+ // check for []string or string to avoid using reflect
+ switch t := v.(type) {
+ case []string:
+ return strings.Join(t, sep)
+ case string:
+ return t
+ }
+
+ // if we have a slice of a different type, convert it to []string
+ switch reflect.TypeOf(v).Kind() {
+ case reflect.Slice, reflect.Array:
+ s := reflect.ValueOf(v)
+ vs := make([]string, s.Len())
+ for i := 0; i < s.Len(); i++ {
+ vs[i] = fmt.Sprint(s.Index(i))
+ }
+ return strings.Join(vs, sep)
+ }
+
+ // return the stringified single value
+ return fmt.Sprint(v)
+}

x-pack/filebeat/input/httpjson/internal/v2/value_tpl_test.go

@@ -292,24 +292,36 @@ func TestValueTpl(t *testing.T) {
  expectedError: errEmptyTemplateResult.Error(),
  },
  {
- name: "func join",
- value: `[[join .last_response.body.arr ","]]`,
+ name: "func join",
+ value: `[[join .last_response.body.strarr ","]] [[join .last_response.body.iarr ","]] ` +
+ `[[join .last_response.body.narr ","]] [[join .last_response.body.singlevalstr ","]] ` +
+ `[[join .last_response.body.singlevalint ","]]`,
  paramCtx: &transformContext{
  firstEvent: &common.MapStr{},
  lastEvent: &common.MapStr{},
  lastResponse: newTestResponse(
  common.MapStr{
- "arr": []string{
+ "strarr": []string{
  "foo",
  "bar",
  },
+ "iarr": []interface{}{
+ "foo",
+ 2,
+ },
+ "narr": []int{
+ 1,
+ 2,
+ },
+ "singlevalstr": "foo",
+ "singlevalint": 2,
  },
  http.Header{},
  "",
  ),
  },
  paramTr: transformable{},
- expectedVal: "foo,bar",
+ expectedVal: "foo,bar foo,2 1,2 foo 2",
  },
  {
  name: "func sprintf",