Don't leak info when not in development. Fixes #256

lib/puma/cli.rb

@@ -302,6 +302,10 @@ module Puma
       ENV['RACK_ENV'] = env
     end
 
+    def development?
+      @options[:environment] == "development"
+    end
+
     def delete_pidfile
       if path = @options[:pidfile]
         File.unlink path
@@ -512,6 +516,10 @@ module Puma
       server.min_threads = @options[:min_threads]
       server.max_threads = @options[:max_threads]
 
+      unless development?
+        server.leak_stack_on_error = false
+      end
+
       @server = server
 
       if str = @options[:control_url]
@@ -597,6 +605,10 @@ module Puma
       server.max_threads = max_t
       server.inherit_binder @binder
 
+      unless development?
+        server.leak_stack_on_error = false
+      end
+
       Signal.trap "SIGTERM" do
         server.stop
       end

lib/puma/server.rb

@@ -68,10 +68,12 @@ module Puma
 
       @first_data_timeout = FIRST_DATA_TIMEOUT
 
+      @leak_stack_on_error = true
+
       ENV['RACK_ENV'] ||= "development"
     end
 
-    attr_accessor :binder
+    attr_accessor :binder, :leak_stack_on_error
 
     forward :add_tcp_listener,  :@binder
     forward :add_ssl_listener,  :@binder
@@ -379,7 +381,7 @@ module Puma
 
             return :async
           end
-        rescue => e
+        rescue StandardError => e
           @events.unknown_error self, e, "Rack app"
 
           status, headers, res_body = lowlevel_error(e)
@@ -571,7 +573,11 @@ module Puma
     # A fallback rack response if +@app+ raises as exception.
     #
     def lowlevel_error(e)
-      [500, {}, ["Puma caught this error: #{e}\n#{e.backtrace.join("\n")}"]]
+      if @leak_stack_on_error
+        [500, {}, ["Puma caught this error: #{e.message} (#{e.class})\n#{e.backtrace.join("\n")}"]]
+      else
+        [500, {}, ["A really lowlevel plumbing error occured. Please contact your local Maytag(tm) repair man.\n"]]
+      end
     end
 
     # Wait for all outstanding requests to finish.

test/test_puma_server.rb

@@ -204,4 +204,21 @@ class TestPumaServer < Test::Unit::TestCase
 
     assert_equal "HTTP/1.0 200 OK\r\n\r\n", data
   end
+
+  def test_doesnt_print_backtrace_in_production
+    @events = Puma::Events.strings
+    @server = Puma::Server.new @app, @events
+
+    @server.app = proc { |e| raise "don't leak me bro" }
+    @server.leak_stack_on_error = false
+    @server.add_tcp_listener @host, @port
+    @server.run
+
+    sock = TCPSocket.new @host, @port
+    sock << "GET / HTTP/1.0\r\n\r\n"
+
+    data = sock.read
+
+    assert_not_match(/don't leak me bro/, data)
+  end
 end