Active Storage Preview Warnings

hatchet.json

@@ -76,6 +76,10 @@
   "rails51": [
     "schneems/rails51_webpacker"
   ],
+  "rails52": [
+    "sharpstone/active_storage_non_local",
+    "sharpstone/active_storage_local"
+  ],
   "multibuildpack": [
     "sharpstone/node_multi"
   ],

hatchet.lock

@@ -79,6 +79,10 @@
   - fc537b7091260d8cc6fdf2bc0fac7032d910a261
 - - "./repos/rails51/rails51_webpacker"
   - d8460fc9eeb93108b6037a3ea755ec7a111ad03c
+- - "./repos/rails52/active_storage_local"
+  - a1b6b18e081001b407898532fb9cb061a29ceee1
+- - "./repos/rails52/active_storage_non_local"
+  - cba59b7559f1f806684b65654228d44fcda91a82
 - - "./repos/rake/asset_precompile_fail"
   - 16f7834331d6bb3fc5c284130b14eb1ff74d99d5
 - - "./repos/rake/asset_precompile_not_found"

lib/language_pack/base.rb

@@ -21,7 +21,7 @@ class LanguagePack::Base
   DEFAULT_LEGACY_STACK = "cedar"
   ROOT_DIR             = File.expand_path("../../..", __FILE__)
 
-  attr_reader :build_path, :cache
+  attr_reader :build_path, :cache, :stack
 
   # changes directory to the build_path
   # @param [String] the path of the build dir

lib/language_pack/rails5.rb

@@ -30,4 +30,57 @@ def default_config_vars
   def install_plugins
     # do not install plugins, do not call super, do not warn
   end
+
+  def best_practice_warnings
+    return unless bundler.has_gem?("activestorage")
+    return unless File.exist?("config/storage.yml")
+
+    warn_local_storage if local_storage?
+    warn_no_ffmpeg     if needs_ffmpeg?
+  end
+
+  private
+    def has_ffmpeg?
+      run("which ffmpeg")
+      return $?.success?
+    end
+
+    def needs_ffmpeg?
+      !has_ffmpeg?
+    end
+
+    def local_storage?
+      out = run!('bin/rails runner "puts %Q{heroku_detecting_active_storage_config=#{Rails.application.config.active_storage.service}}"')
+      out =~ /heroku_detecting_active_storage_config=local/
+    end
+
+    def warn_local_storage
+      mcount("warn.activestorage.local_storage")
+      warn(<<-WARNING)
+You set your `config.active_storage.service` to :local in production.
+If you are uploading files to this app, they will not persist after the app
+is restarted, on one-off dynos, or if the app has multiple dynos.
+Heroku applications have an ephemeral files system. To
+persist uploaded files, please use a service such as S3 and update your Rails
+configuration.
+
+For more information can be found in this article:
+  https://devcenter.heroku.com/articles/active-storage-on-heroku
+
+WARNING
+    end
+
+    def warn_no_ffmpeg
+      mcount("warn.activestorage.no_binaries.stack-#{stack}")
+      mcount("warn.activestorage.no_binaries.all")
+      warn(<<-WARNING)
+We detected that some binary dependencies required to
+use all the preview features of Active Storage are not
+present on this system.
+
+For more information please see:
+  https://devcenter.heroku.com/articles/active-storage-on-heroku
+
+WARNING
+    end
 end

spec/hatchet/rails5_spec.rb

@@ -1,10 +1,31 @@
 require_relative '../spec_helper'
 
-describe "Rails 5.x" do
-
+describe "Rails 5" do
   it "works" do
     Hatchet::Runner.new("rails5").deploy do |app, heroku|
       expect(app.run("rails -v")).to match("")
     end
   end
+
+  describe "active storage" do
+    it "non-local storage warnings" do
+      Hatchet::Runner.new("active_storage_non_local").deploy do |app, heroku|
+        expect(app.output).to     match('binary dependencies required')
+        expect(app.output).to_not match('config.active_storage.service')
+      end
+    end
+
+    it "local storage warnings" do
+      Hatchet::Runner.new(
+        "active_storage_local",
+        buildpacks: [
+          # "https://github.com/heroku/heroku-buildpack-activestorage-preview",
+          Hatchet::App.default_buildpack
+        ]
+      ).deploy do |app, heroku|
+        expect(app.output).to match('binary dependencies required')
+        expect(app.output).to match('config.active_storage.service')
+      end
+    end
+  end
 end