remove appsignal, print errors for Papertrail

Appsignal continues to spam the log with Thread warnings, and we have no
one to maintain the integration. This change means at least errors will
be sent into papertrail, where they can be surfaced by Slack.

Gemfile

@@ -8,7 +8,6 @@ git_source(:github) do |repo|
   "https://github.com/#{repo}.git"
 end
 
-gem 'appsignal', '0.11.6.beta.0'
 gem 'librato-metrics'
 gem 'metriks-librato_metrics', github: 'indirect/metriks-librato_metrics'
 gem 'metriks-middleware'

Gemfile.lock

@@ -15,9 +15,6 @@ GEM
   remote: https://rubygems.org/
   specs:
     aggregate (0.2.2)
-    appsignal (0.11.6.beta.0)
-      rack
-      thread_safe
     artifice (0.6)
       rack-test
     ast (2.2.0)
@@ -100,15 +97,13 @@ GEM
       tilt (>= 1.3, < 3)
     slop (3.6.0)
     thor (0.19.1)
-    thread_safe (0.3.5)
     tilt (2.0.2)
     unicode-display_width (0.3.1)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  appsignal (= 0.11.6.beta.0)
   artifice
   compact_index
   dalli

lib/bundler_api/agent_reporting.rb

@@ -56,11 +56,7 @@ def known_id?(id)
     BundlerApi.redis.setex(id, 120, true)
     false
   rescue => ex
-    # Sometimes we get these, and there's no point throwing out a perfectly
-    # good metric. We still, however, want to report it in Appsignal so that
-    # we know what's up.
-    Appsignal.add_exception(ex) if defined?(Appsignal)
-
+    STDERR.puts "[Error][AgentReporting] `known_id?` raised #{e.class}: #{e.message}"
     false
   end
 end

lib/bundler_api/metriks.rb

@@ -35,7 +35,7 @@ def source_name(worker = nil)
 
     def error_handler
       -> (e) do
-        STDOUT.puts("[Metriks][Librato] #{e.class} raised during metric submission: #{e.message}")
+        STDOUT.puts("[Error][Librato] #{e.class} raised during metric submission: #{e.message}")
 
         if e.is_a?(::Metriks::LibratoMetricsReporter::RequestFailedError)
           STDOUT.puts("  Response body: #{e.res.body}")

lib/bundler_api/web.rb

@@ -6,7 +6,6 @@
 require 'bundler_api/agent_reporting'
 require 'bundler_api/checksum'
 require 'bundler_api/gem_info'
-require 'bundler_api/appsignal'
 require 'bundler_api/cache'
 require 'bundler_api/metriks'
 require 'bundler_api/runtime_instrumentation'
@@ -22,8 +21,6 @@ class BundlerApi::Web < Sinatra::Base
   NEW_INDEX_ENABLED    = ENV['NEW_INDEX_DISABLED'].nil?
 
   unless ENV['RACK_ENV'] == 'test'
-    use Appsignal::Rack::Listener, name: 'bundler-api'
-    use Appsignal::Rack::SinatraInstrumentation
     use Metriks::Middleware
     use BundlerApi::AgentReporting
   end
@@ -277,7 +274,8 @@ def in_background
       begin
         yield
       rescue => e
-        Appsignal.send_exception(e)
+        STDOUT.puts "[Error][Web] #{e.class} raised during background task: #{e.message}")
+        STDERR.puts e.backtrace.join("\n  ")
       end
     end
   end