add constant

Author: Watson1978

lib/fluent/plugin/in_otlp.rb

@@ -95,7 +95,7 @@ def valid_content_encoding?(content_encoding)
       end
 
       def response(code, content_type, body)
-        [code, { "Content-Type" => content_type }, body]
+        [code, { Otlp::CONTENT_TYPE => content_type }, body]
       end
 
       def response_unsupported_media_type

lib/fluent/plugin/otlp/constant.rb

@@ -4,10 +4,12 @@
 require "openssl"
 
 module Fluent::Plugin::Otlp
+  CONTENT_TYPE = "Content-Type"
   CONTENT_TYPE_PAIN = "text/plain"
   CONTENT_TYPE_PROTOBUF = "application/x-protobuf"
   CONTENT_TYPE_JSON = "application/json"
 
+  CONTENT_ENCODING = "Content-Encoding"
   CONTENT_ENCODING_GZIP = "gzip"
 
   RECORD_TYPE_LOGS = "otlp_logs"

lib/fluent/plugin/out_otlp.rb

@@ -107,9 +107,9 @@ def create_connection(chunk)
         raise ::Fluent::UnrecoverableError, e.message
       end
 
-      headers = { "Content-Type" => Otlp::CONTENT_TYPE_PROTOBUF }
+      headers = { Otlp::CONTENT_TYPE => Otlp::CONTENT_TYPE_PROTOBUF }
       if @compress == :gzip
-        headers["Content-Encoding"] = Otlp::CONTENT_ENCODING_GZIP
+        headers[Otlp::CONTENT_ENCODING] = Otlp::CONTENT_ENCODING_GZIP
         gz = Zlib::GzipWriter.new(StringIO.new)
         gz << body
         body = gz.close.string