updated documentation and replaced function with strings.Replace call

docs/source/config/encoders/esjson.rst

@@ -64,6 +64,8 @@ Config:
     the JSON output. Defaults to including all of the messages dynamic
     fields. If ``dynamic_fields`` is non-empty, then the ``fields`` list *must*
     contain "DynamicFields" or an error will be raised.
+- replace_dots_with (string):
+    This specifies a string to use as a replacement in JSON output field names. 
 
 Example
 
@@ -73,6 +75,8 @@ Example
     index = "%{Type}-%{%Y.%m.%d}"
     es_index_from_timestamp = true
     type_name = "%{Type}"
+    replace_dots_with = "_"
+
         [ESJsonEncoder.field_mappings]
         Timestamp = "@timestamp"
         Severity = "level"

docs/source/config/encoders/eslogstashv0.rst

@@ -70,6 +70,8 @@ Config:
     the JSON output. Defaults to including all of the messages dynamic
     fields. If ``dynamic_fields`` is non-empty, then the ``fields`` list *must*
     contain "DynamicFields" or an error will be raised.
+- replace_dots_with (string):
+    This specifies a string to use as a replacement in JSON output field names.
 
 Example
 
@@ -78,6 +80,7 @@ Example
     [ESLogstashV0Encoder]
     es_index_from_timestamp = true
     type_name = "%{Type}"
+    replace_dots_with = "_"
 
     [ElasticSearchOutput]
     message_matcher = "Type == 'nginx.access'"

plugins/elasticsearch/encoders.go

@@ -42,20 +42,6 @@ func writeUTF16Escape(b *bytes.Buffer, c rune) {
 	b.WriteByte(lowerhex[c&0xF])
 }
 
-// replaceDots substitutes a string for all instances of '.' characters
-// in another string.
-func replaceDots(str string, sub string) (cname string) {
-    buf := bytes.Buffer{}
-    for _, r := range str {
-        if r == '.' {
-            buf.WriteString(sub)
-        } else {
-            buf.WriteRune(r)
-        }
-    }
-    return buf.String()
-}
-
 // Go json encoder will blow up on invalid utf8 so we use this custom json
 // encoder. Also, go json encoder generates these funny \U escapes which I
 // don't think are valid json.
@@ -109,7 +95,7 @@ func writeField(first bool, b *bytes.Buffer, f *message.Field, raw bool, replace
 	}
 
         if replaceDotsWith != "." {
-	    writeQuotedString(b, replaceDots(f.GetName(), replaceDotsWith))
+	    writeQuotedString(b, strings.Replace(f.GetName(), ".", replaceDotsWith, -1))
         } else {
 	    writeQuotedString(b, f.GetName())
         }