notice: attach hostname information by default

The hostname information has to be present in many of our integrations
from the Airbrake gem. This information is just too useful and it
should be retreived by default.

lib/airbrake-ruby.rb

@@ -4,6 +4,7 @@
 require 'thread'
 require 'set'
 require 'English'
+require 'socket'
 
 require 'airbrake-ruby/version'
 require 'airbrake-ruby/config'

lib/airbrake-ruby/notice.rb

@@ -48,6 +48,10 @@ class Notice
       :params
     ].freeze
 
+    ##
+    # @return [String] the name of the host machine
+    HOSTNAME = Socket.gethostname.freeze
+
     def initialize(config, exception, params = {})
       @config = config
 
@@ -145,7 +149,10 @@ def context(params)
 
         # Legacy Airbrake v4 behaviour.
         component: params.delete(:component),
-        action: params.delete(:action)
+        action: params.delete(:action),
+
+        # Make sure we always send hostname.
+        hostname: HOSTNAME
       }.merge(CONTEXT).delete_if { |_key, val| val.nil? || val.empty? }
     end
 

spec/notice_spec.rb

@@ -105,6 +105,11 @@
       expect(notice.to_json).
         to match(/"notifier":{"name":"airbrake-ruby","version":".+","url":".+"}/)
     end
+
+    it "always contains context/hostname" do
+      expect(notice.to_json).
+        to match(/"context":{.*"hostname":".+".*}/)
+    end
   end
 
   describe "#[]" do