Allow any unicode characters in the TagValue

Prometheus permits any characters: https://prometheus.io/docs/concepts/data_model/#metric-names-and-labels In gRPC propagation, the tags are binary encoded as UTF-8 strings, so there should be no problem there. For HTTP, we can use mime encoding.
census-instrumentation · Mar 19, 2018 · 2935694 · 2935694
1 parent d218d58
commit 2935694
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/tags/TagContext.md b/tags/TagContext.md
@@ -20,8 +20,8 @@ A string or string wrapper, with some restrictions:
 
 ## TagValue
 
-A string or string wrapper with the same restrictions as `TagKey`, except that it
-is allowed to be empty.
+A TagValue can be any unicode string. It's size when encoded in UTF-8
+should be less than 256 bytes. An empty value is allowed.
 
 ## Serialization