Make relabel "split" separator configurable (#151)

README.adoc

@@ -491,6 +491,7 @@ namespace "app1" {
   relabel "request_uri" {
     from = "request"
     split = 2
+    separator = " " // <1>
 
     match "^/users/[0-9]+" {
       replacement = "/users/:id"
@@ -502,6 +503,7 @@ namespace "app1" {
   }
 }
 ----
+<1> The `separator` property is optional; if omitted, the space character (`" "`) will be assumed as separator.
 
 If a match is found, the `replacement` replaces each occurrence of the corresponding match in the original value. Otherwise the processing continues to check the following match statements.
 
@@ -515,6 +517,7 @@ namespaces:
   - target_label: request_uri
     from: request
     split: 2
+    separator: ' '
     matches:
     - regexp: "^/users/[0-9]+"
       replacement: "/users/:id"

config/struct_relabel.go

@@ -13,6 +13,7 @@ type RelabelConfig struct {
 	Whitelist   []string            `hcl:"whitelist"`
 	Matches     []RelabelValueMatch `hcl:"match"`
 	Split       int                 `hcl:"split"`
+	Separator   string              `hcl:"separator"`
 
 	WhitelistExists bool
 	WhitelistMap    map[string]interface{}

relabeling/mapping.go

@@ -8,7 +8,12 @@ import (
 // config (matching against whitelists, regular expressions etc.)
 func (r *Relabeling) Map(sourceValue string) (string, error) {
 	if r.Split > 0 {
-		values := strings.Split(sourceValue, " ")
+		separator := r.Separator
+		if separator == "" {
+			separator = " "
+		}
+
+		values := strings.Split(sourceValue, separator)
 
 		if len(values) >= r.Split {
 			sourceValue = values[r.Split-1]