From da7220b7c4e40fd4a8363e7839e8820d31557e44 Mon Sep 17 00:00:00 2001
From: Sam Coward <scoward@pivotal.io>
Date: Tue, 2 Jan 2018 14:53:56 -0500
Subject: [PATCH] Add stack association to buildpack model [#153256959]

- Add "stack" to buildpack model
- At migration time, stacks.yml will be read (location from STACKS_YML env var)
  to determine what stack should be assigned to existing buildpacks
- Buildpacks are now unique over name AND stack
- Sets buildpack stack from manifest.yml in buildpack zip on creation
- Validate buildpack model stack against stack in buildpack zip manifest.yml
- Validate stack exists upon buildpack bits upload
- Include stack name in serialized buildpack filename
- Only provide buildpacks for the relevant stack to the staging container
- Handle buildpack stacks appropriately in the buildpack installer

NOTE: The API checkshum has changed due to adding stack as an input

Signed-off-by: Dave Goddard <dave@goddard.id.au>
Signed-off-by: Victoria Henry <vhenry@pivotal.io>
Signed-off-by: Jackson Feeny <jacksonfeeny@gmail.com>
Signed-off-by: Sam Coward <scoward@pivotal.io>
Signed-off-by: Dave Goddard <dave@goddard.id.au>
Signed-off-by: Sam Coward <scoward@pivotal.io>
---
 .../runtime/buildpacks_controller.rb          |   7 +-
 app/fetchers/buildpack_lifecycle_fetcher.rb   |  11 +-
 app/jobs/runtime/buildpack_installer.rb       |  22 +++-
 app/models/runtime/buildpack.rb               |  13 +-
 app/presenters/v2/buildpack_presenter.rb      |  17 +++
 app/presenters/v2/presenter_provider.rb       |   1 +
 ...0102183100_add_stack_to_buildpack_table.rb |  30 +++++
 .../buildpack/buildpack_entry_generator.rb    |   8 +-
 .../diego/buildpack/lifecycle_protocol.rb     |  13 +-
 .../diego/lifecycles/buildpack_lifecycle.rb   |   9 +-
 lib/cloud_controller/upload_buildpack.rb      |  26 ++++
 spec/api/api_version_spec.rb                  |   2 +-
 spec/api/documentation/buildpacks_api_spec.rb |   3 +-
 spec/request/apps_spec.rb                     |   7 +-
 spec/support/fakes/blueprints.rb              |   2 +
 spec/support/test_zip.rb                      |  21 +--
 .../runtime/buildpack_bits_controller_spec.rb | 117 +++++++++++++----
 .../runtime/buildpacks_controller_spec.rb     |  40 ++++--
 .../controllers/v3/builds_controller_spec.rb  |  11 +-
 .../jobs/runtime/buildpack_delete_spec.rb     |   2 +-
 .../jobs/runtime/buildpack_installer_spec.rb  | 124 +++++++++++++++---
 .../buildpack_entry_generator_spec.rb         |  33 +++--
 .../buildpack/lifecycle_protocol_spec.rb      |   2 +-
 .../cloud_controller/upload_buildpack_spec.rb |  76 ++++++++++-
 spec/unit/models/runtime/buildpack_spec.rb    |  20 +--
 .../presenters/v2/buildpack_presenter_spec.rb |  42 ++++++
 vendor/errors/v2.yml                          |  16 ++-
 27 files changed, 545 insertions(+), 130 deletions(-)
 create mode 100644 app/presenters/v2/buildpack_presenter.rb
 create mode 100644 db/migrations/20180102183100_add_stack_to_buildpack_table.rb
 create mode 100644 spec/unit/presenters/v2/buildpack_presenter_spec.rb

diff --git a/app/controllers/runtime/buildpacks_controller.rb b/app/controllers/runtime/buildpacks_controller.rb
index 88f56f4d457..ee134f33254 100644
--- a/app/controllers/runtime/buildpacks_controller.rb
+++ b/app/controllers/runtime/buildpacks_controller.rb
@@ -6,17 +6,18 @@ def self.dependencies
 
     define_attributes do
       attribute :name, String
+      attribute :stack, String, default: 'unknown'
       attribute :position, Integer, default: 0
       attribute :enabled, Message::Boolean, default: true
       attribute :locked, Message::Boolean, default: false
     end
 
-    query_parameters :name
+    query_parameters :name, :stack
 
     def self.translate_validation_exception(e, attributes)
-      buildpack_errors = e.errors.on(:name)
+      buildpack_errors = e.errors.on([:name, :stack])
       if buildpack_errors && buildpack_errors.include?(:unique)
-        CloudController::Errors::ApiError.new_from_details('BuildpackNameTaken', attributes['name'])
+        CloudController::Errors::ApiError.new_from_details('BuildpackNameStackTaken', attributes['name'], attributes['stack'])
       else
         CloudController::Errors::ApiError.new_from_details('BuildpackInvalid', e.errors.full_messages)
       end
diff --git a/app/fetchers/buildpack_lifecycle_fetcher.rb b/app/fetchers/buildpack_lifecycle_fetcher.rb
index a8ef6224a4c..ab0a83ee4b3 100644
--- a/app/fetchers/buildpack_lifecycle_fetcher.rb
+++ b/app/fetchers/buildpack_lifecycle_fetcher.rb
@@ -4,14 +4,19 @@ class << self
       def fetch(buildpack_names, stack_name)
         {
           stack: Stack.find(name: stack_name),
-          buildpack_infos: ordered_buildpacks(buildpack_names),
+          buildpack_infos: ordered_buildpacks(buildpack_names, stack_name),
         }
       end
 
       private
 
-      def ordered_buildpacks(buildpack_names)
-        buildpacks = Buildpack.where(name: buildpack_names).all
+      ## NOTE: if a requested system buildpack is not on the requested stack,
+      ##       the BuildpackInfo object will have a name and not a record (even
+      ##       though the buildpack exists). At this point the error returned
+      ##       to the user will probably be VERY confusing
+
+      def ordered_buildpacks(buildpack_names, stack_name)
+        buildpacks = Buildpack.where(name: buildpack_names, stack: stack_name).all
 
         buildpack_names.map do |buildpack_name|
           buildpack_record = buildpacks.find { |b| b.name == buildpack_name }
diff --git a/app/jobs/runtime/buildpack_installer.rb b/app/jobs/runtime/buildpack_installer.rb
index cfac8f1c698..2f50d662ab8 100644
--- a/app/jobs/runtime/buildpack_installer.rb
+++ b/app/jobs/runtime/buildpack_installer.rb
@@ -14,9 +14,9 @@ def perform
           logger = Steno.logger('cc.background')
           logger.info "Installing buildpack #{name}"
 
-          buildpack = Buildpack.find(name: name)
+          buildpack = find_existing_buildpack
           if buildpack.nil?
-            buildpack = Buildpack.create(name: name)
+            buildpack = Buildpack.create(name: name, stack: 'unknown')
             created = true
           elsif buildpack.locked
             logger.info "Buildpack #{name} locked, not updated"
@@ -34,6 +34,8 @@ def perform
 
           buildpack.update(opts)
           logger.info "Buildpack #{name} installed or updated"
+        rescue AmbiguousBuildpackException => abe
+          logger.error abe.message
         rescue => e
           logger.error("Buildpack #{name} failed to install or update. Error: #{e.inspect}")
           raise e
@@ -51,6 +53,22 @@ def buildpack_uploader
           buildpack_blobstore = CloudController::DependencyLocator.instance.buildpack_blobstore
           UploadBuildpack.new(buildpack_blobstore)
         end
+
+        private
+
+        def find_existing_buildpack
+          stack = buildpack_uploader.extract_stack_from_buildpack(file)
+          return Buildpack.find(name: name, stack: stack) if stack.to_s != ''
+
+          buildpacks = Buildpack.where(name: name)
+          if buildpacks.count > 1
+            raise AmbiguousBuildpackException.new("Buildpack #{name} has #{buildpacks.count} stacks, not updated")
+          end
+          buildpacks.first
+        end
+
+        class AmbiguousBuildpackException < RuntimeError
+        end
       end
     end
   end
diff --git a/app/models/runtime/buildpack.rb b/app/models/runtime/buildpack.rb
index 6ab63186a41..ee800ca1579 100644
--- a/app/models/runtime/buildpack.rb
+++ b/app/models/runtime/buildpack.rb
@@ -2,11 +2,13 @@ module VCAP::CloudController
   class Buildpack < Sequel::Model
     plugin :list
 
-    export_attributes :name, :position, :enabled, :locked, :filename
-    import_attributes :name, :position, :enabled, :locked, :filename, :key
+    export_attributes :name, :stack, :position, :enabled, :locked, :filename
+    import_attributes :name, :stack, :position, :enabled, :locked, :filename, :key
 
-    def self.list_admin_buildpacks
-      exclude(key: nil).exclude(key: '').order(:position).all
+    def self.list_admin_buildpacks(stack_name=nil)
+      scoped = exclude(key: nil).exclude(key: '')
+      scoped = scoped.where(stack: stack_name) if stack_name
+      scoped.order(:position).all
     end
 
     def self.at_last_position
@@ -18,8 +20,9 @@ def self.user_visibility_filter(user)
     end
 
     def validate
-      validates_unique :name
+      validates_unique [:name, :stack]
       validates_format(/\A(\w|\-)+\z/, :name, message: 'name can only contain alphanumeric characters')
+      validates_presence :stack
     end
 
     def locked?
diff --git a/app/presenters/v2/buildpack_presenter.rb b/app/presenters/v2/buildpack_presenter.rb
new file mode 100644
index 00000000000..01a347c4eaf
--- /dev/null
+++ b/app/presenters/v2/buildpack_presenter.rb
@@ -0,0 +1,17 @@
+module CloudController
+  module Presenters
+    module V2
+      class BuildpackPresenter < DefaultPresenter
+        extend PresenterProvider
+
+        present_for_class 'VCAP::CloudController::Buildpack'
+
+        def entity_hash(controller, buildpack, opts, depth, parents, orphans=nil)
+          entity = super
+          entity['filename'] = "#{buildpack.filename} (#{buildpack.stack})".strip
+          entity
+        end
+      end
+    end
+  end
+end
diff --git a/app/presenters/v2/presenter_provider.rb b/app/presenters/v2/presenter_provider.rb
index f0476df89e4..7d569085245 100644
--- a/app/presenters/v2/presenter_provider.rb
+++ b/app/presenters/v2/presenter_provider.rb
@@ -33,3 +33,4 @@ def self.presenters
 require_relative 'space_presenter'
 require_relative 'organization_presenter'
 require_relative 'service_plan_presenter'
+require_relative 'buildpack_presenter'
diff --git a/db/migrations/20180102183100_add_stack_to_buildpack_table.rb b/db/migrations/20180102183100_add_stack_to_buildpack_table.rb
new file mode 100644
index 00000000000..82b918df636
--- /dev/null
+++ b/db/migrations/20180102183100_add_stack_to_buildpack_table.rb
@@ -0,0 +1,30 @@
+require 'yaml'
+
+def default_stack
+  stacks_yml_path = ENV.fetch('STACKS_YML', nil)
+  YAML.safe_load(File.read(stacks_yml_path))['default'] if stacks_yml_path && File.exist?(stacks_yml_path)
+end
+
+Sequel.migration do
+  up do
+    alter_table(:buildpacks) do
+      add_column :stack, String, size: 255, null: true
+      drop_index :name, unique: true
+      add_index [:name, :stack], unique: true, name: :unique_name_and_stack
+    end
+
+    self['UPDATE buildpacks SET stack = ?', default_stack || 'unknown'].update
+
+    alter_table(:buildpacks) do
+      set_column_not_null :stack
+    end
+  end
+
+  down do
+    alter_table(:buildpacks) do
+      drop_index [:name, :stack], unique: true
+      drop_column :stack
+      add_index :name, unique: true, name: :unique_name
+    end
+  end
+end
diff --git a/lib/cloud_controller/diego/buildpack/buildpack_entry_generator.rb b/lib/cloud_controller/diego/buildpack/buildpack_entry_generator.rb
index 792ddcbb80c..f8aa9517b28 100644
--- a/lib/cloud_controller/diego/buildpack/buildpack_entry_generator.rb
+++ b/lib/cloud_controller/diego/buildpack/buildpack_entry_generator.rb
@@ -6,8 +6,8 @@ def initialize(blobstore_url_generator)
           @blobstore_url_generator = blobstore_url_generator
         end
 
-        def buildpack_entries(buildpack_infos)
-          return default_admin_buildpacks if buildpack_infos.empty?
+        def buildpack_entries(buildpack_infos, stack_name)
+          return default_admin_buildpacks(stack_name) if buildpack_infos.empty?
 
           buildpack_infos.map do |buildpack_info|
             if buildpack_info.buildpack_exists_in_db? && buildpack_info.buildpack_enabled?
@@ -26,8 +26,8 @@ def custom_buildpack_entry(buildpack)
           { name: 'custom', key: buildpack.url, url: buildpack.url }
         end
 
-        def default_admin_buildpacks
-          VCAP::CloudController::Buildpack.list_admin_buildpacks.
+        def default_admin_buildpacks(stack_name)
+          VCAP::CloudController::Buildpack.list_admin_buildpacks(stack_name).
             select(&:enabled).
             collect { |buildpack| admin_buildpack_entry(buildpack) }
         end
diff --git a/lib/cloud_controller/diego/buildpack/lifecycle_protocol.rb b/lib/cloud_controller/diego/buildpack/lifecycle_protocol.rb
index 5e921c9ffa5..8b76c29cb5a 100644
--- a/lib/cloud_controller/diego/buildpack/lifecycle_protocol.rb
+++ b/lib/cloud_controller/diego/buildpack/lifecycle_protocol.rb
@@ -18,20 +18,15 @@ def initialize(blobstore_url_generator=::CloudController::DependencyLocator.inst
           end
 
           def lifecycle_data(staging_details)
+            stack                                             = staging_details.lifecycle.staging_stack
             lifecycle_data                                    = Diego::Buildpack::LifecycleData.new
             lifecycle_data.app_bits_download_uri              = @blobstore_url_generator.package_download_url(staging_details.package)
             lifecycle_data.app_bits_checksum                  = staging_details.package.checksum_info
             lifecycle_data.buildpack_cache_checksum           = staging_details.package.app.buildpack_cache_sha256_checksum
-            lifecycle_data.build_artifacts_cache_download_uri = @blobstore_url_generator.buildpack_cache_download_url(
-              staging_details.package.app_guid,
-              staging_details.lifecycle.staging_stack
-            )
-            lifecycle_data.build_artifacts_cache_upload_uri = @blobstore_url_generator.buildpack_cache_upload_url(
-              staging_details.package.app_guid,
-              staging_details.lifecycle.staging_stack
-            )
+            lifecycle_data.build_artifacts_cache_download_uri = @blobstore_url_generator.buildpack_cache_download_url(staging_details.package.app_guid, stack)
+            lifecycle_data.build_artifacts_cache_upload_uri = @blobstore_url_generator.buildpack_cache_upload_url(staging_details.package.app_guid, stack)
             lifecycle_data.droplet_upload_uri                 = @blobstore_url_generator.droplet_upload_url(staging_details.staging_guid)
-            lifecycle_data.buildpacks                         = @buildpack_entry_generator.buildpack_entries(staging_details.lifecycle.buildpack_infos)
+            lifecycle_data.buildpacks                         = @buildpack_entry_generator.buildpack_entries(staging_details.lifecycle.buildpack_infos, stack)
             lifecycle_data.stack                              = staging_details.lifecycle.staging_stack
 
             lifecycle_data.message
diff --git a/lib/cloud_controller/diego/lifecycles/buildpack_lifecycle.rb b/lib/cloud_controller/diego/lifecycles/buildpack_lifecycle.rb
index 33e543a38eb..576d9174fc2 100644
--- a/lib/cloud_controller/diego/lifecycles/buildpack_lifecycle.rb
+++ b/lib/cloud_controller/diego/lifecycles/buildpack_lifecycle.rb
@@ -36,7 +36,7 @@ def staging_environment_variables
     end
 
     def staging_stack
-      requested_stack || app_stack || VCAP::CloudController::Stack.default.name
+      requested_stack || app_stack || buildpack_stack || VCAP::CloudController::Stack.default.name
     end
 
     private
@@ -57,6 +57,13 @@ def app_stack
       @package.app.buildpack_lifecycle_data.try(:stack)
     end
 
+    def buildpack_stack
+      stacks = Buildpack.where(name: buildpacks_to_use).select(:stack).uniq
+      if stacks.length == 1
+        stacks.first
+      end
+    end
+
     attr_reader :validator
   end
 end
diff --git a/lib/cloud_controller/upload_buildpack.rb b/lib/cloud_controller/upload_buildpack.rb
index 3b5865cefb2..ab3d5669497 100644
--- a/lib/cloud_controller/upload_buildpack.rb
+++ b/lib/cloud_controller/upload_buildpack.rb
@@ -24,6 +24,8 @@ def upload_buildpack(buildpack, bits_file_path, new_filename)
 
       old_buildpack_key = nil
 
+      new_stack = determine_new_stack(buildpack, bits_file_path)
+
       begin
         Buildpack.db.transaction do
           buildpack.lock!
@@ -32,6 +34,7 @@ def upload_buildpack(buildpack, bits_file_path, new_filename)
             key: new_key,
             filename: new_filename,
             sha256_checksum: sha256,
+            stack: new_stack,
           )
         end
       rescue Sequel::Error
@@ -47,8 +50,31 @@ def upload_buildpack(buildpack, bits_file_path, new_filename)
       true
     end
 
+    def extract_stack_from_buildpack(bits_file_path)
+      bits_file_path = bits_file_path.path if bits_file_path.respond_to?(:path)
+      output, _, status = Open3.capture3('unzip', '-p', bits_file_path, 'manifest.yml')
+      YAML.safe_load(output).dig('stack') if status.success?
+    end
+
     private
 
+    def determine_new_stack(buildpack, bits_file_path)
+      extracted_stack = extract_stack_from_buildpack(bits_file_path)
+      if extracted_stack.to_s != '' && !Stack.where(name: extracted_stack).first
+        raise CloudController::Errors::ApiError.new_from_details('BuildpackStackDoesNotExist', extracted_stack)
+      end
+      new_stack = [extracted_stack, buildpack.stack, Stack.default.name].find { |s| s.to_s != '' && s.to_s != 'unknown' }
+      if buildpack.stack != 'unknown' && buildpack.stack != new_stack
+        raise CloudController::Errors::ApiError.new_from_details('BuildpackStacksDontMatch', new_stack, buildpack.stack)
+      end
+
+      if buildpack.stack != new_stack && Buildpack.find(name: buildpack.name, stack: new_stack)
+        raise CloudController::Errors::ApiError.new_from_details('BuildpackNameStackTaken', buildpack.name, new_stack)
+      end
+
+      new_stack
+    end
+
     def new_bits?(buildpack, key)
       buildpack.key != key
     end
diff --git a/spec/api/api_version_spec.rb b/spec/api/api_version_spec.rb
index a7dc004fd79..9c6128464be 100644
--- a/spec/api/api_version_spec.rb
+++ b/spec/api/api_version_spec.rb
@@ -2,7 +2,7 @@
 require 'vcap/digester'
 
 RSpec.describe 'Stable API warning system', api_version_check: true do
-  API_FOLDER_CHECKSUM = '8d08df242e77b29ef0374b7557031985fcdfba43'.freeze
+  API_FOLDER_CHECKSUM = '5e3e3c64074e05882c6748b578a9a62f80694c94'.freeze
 
   it 'tells the developer if the API specs change' do
     api_folder = File.expand_path('..', __FILE__)
diff --git a/spec/api/documentation/buildpacks_api_spec.rb b/spec/api/documentation/buildpacks_api_spec.rb
index 5e88b80e225..3ee54d27e9b 100644
--- a/spec/api/documentation/buildpacks_api_spec.rb
+++ b/spec/api/documentation/buildpacks_api_spec.rb
@@ -19,6 +19,7 @@
         required: opts[:required],
         example_values: ['Golang_buildpack']
 
+      field :stack, 'The name of the stack to associate this buildpack with', example_values: ['cflinuxfs2']
       field :position, 'The order in which the buildpacks are checked during buildpack auto-detection.'
       field :enabled, 'Whether or not the buildpack will be used for staging', default: true
       field :locked, 'Whether or not the buildpack is locked to prevent updates', default: false
@@ -33,7 +34,7 @@
       include_context 'updatable_fields', required: true
 
       example 'Creates an admin Buildpack' do
-        client.post '/v2/buildpacks', fields_json, headers
+        client.post '/v2/buildpacks', fields_json(stack: 'cflinuxfs2'), headers
         expect(status).to eq 201
         standard_entity_response parsed_response, :buildpack, expected_values: { name: 'Golang_buildpack' }
       end
diff --git a/spec/request/apps_spec.rb b/spec/request/apps_spec.rb
index 62d6b5e1696..35ca3f62f5d 100644
--- a/spec/request/apps_spec.rb
+++ b/spec/request/apps_spec.rb
@@ -4,6 +4,7 @@
   let(:user) { VCAP::CloudController::User.make }
   let(:user_header) { headers_for(user, email: user_email, user_name: user_name) }
   let(:space) { VCAP::CloudController::Space.make }
+  let(:stack) { VCAP::CloudController::Stack.make }
   let(:user_email) { Sham.email }
   let(:user_name) { 'some-username' }
 
@@ -14,14 +15,14 @@
 
   describe 'POST /v3/apps' do
     it 'creates an app' do
-      buildpack      = VCAP::CloudController::Buildpack.make
+      buildpack      = VCAP::CloudController::Buildpack.make(stack: stack.name)
       create_request = {
         name: 'my_app',
         environment_variables: { open: 'source' },
         lifecycle: {
           type: 'buildpack',
           data: {
-            stack: nil,
+            stack: buildpack.stack,
             buildpacks: [buildpack.name]
           }
         },
@@ -50,7 +51,7 @@
             'type' => 'buildpack',
             'data' => {
               'buildpacks' => [buildpack.name],
-              'stack'      => VCAP::CloudController::Stack.default.name,
+              'stack'      => stack.name,
             }
           },
           'relationships' => {
diff --git a/spec/support/fakes/blueprints.rb b/spec/support/fakes/blueprints.rb
index 78d2c49052d..29a32088783 100644
--- a/spec/support/fakes/blueprints.rb
+++ b/spec/support/fakes/blueprints.rb
@@ -26,6 +26,7 @@
   status              { |_| %w(active suspended cancelled).sample(1).first }
   error_message       { |index| "error-message-#{index}" }
   sequence_id         { |index| index }
+  stack               { |index| "cflinuxfs-#{index}" }
 end
 
 module VCAP::CloudController
@@ -395,6 +396,7 @@ module VCAP::CloudController
 
   Buildpack.blueprint do
     name { Sham.name }
+    stack { Sham.stack }
     key { Sham.guid }
     position { 0 }
     enabled { true }
diff --git a/spec/support/test_zip.rb b/spec/support/test_zip.rb
index 199249c44fe..cbca72070eb 100644
--- a/spec/support/test_zip.rb
+++ b/spec/support/test_zip.rb
@@ -1,14 +1,15 @@
+require 'zip'
+
 module TestZip
-  def self.create(zip_name, file_count, file_size=1024)
-    files = []
-    file_count.times do |i|
-      tf = Tempfile.new("ziptest_#{i}")
-      files << tf
-      tf.write('A' * file_size)
-      tf.close
-    end
+  def self.create(zip_name, file_count, file_size=1024, &blk)
+    Zip::File.open(zip_name, Zip::File::CREATE) do |zipfile|
+      file_count.times do |i|
+        zipfile.get_output_stream("ziptest_#{i}") do |f|
+          f.write('A' * file_size)
+        end
+      end
 
-    child = POSIX::Spawn::Child.new('zip', zip_name, *files.map(&:path))
-    child.status.exitstatus == 0 || raise("Failed zipping:\n#{child.err}\n#{child.out}")
+      blk.call(zipfile) if blk
+    end
   end
 end
diff --git a/spec/unit/controllers/runtime/buildpack_bits_controller_spec.rb b/spec/unit/controllers/runtime/buildpack_bits_controller_spec.rb
index 348769818ba..446ca52094c 100644
--- a/spec/unit/controllers/runtime/buildpack_bits_controller_spec.rb
+++ b/spec/unit/controllers/runtime/buildpack_bits_controller_spec.rb
@@ -8,6 +8,26 @@ module VCAP::CloudController
     let(:sha_valid_zip) { Digester.new(algorithm: Digest::SHA256).digest_file(valid_zip) }
     let(:sha_valid_zip2) { Digester.new(algorithm: Digest::SHA256).digest_file(valid_zip2) }
     let(:sha_valid_tar_gz) { Digester.new(algorithm: Digest::SHA256).digest_file(valid_tar_gz) }
+    let(:valid_zip_manifest) do
+      zip_name = File.join(tmpdir, filename)
+      TestZip.create(zip_name, 1, 1024) do |zipfile|
+        zipfile.get_output_stream('manifest.yml') do |f|
+          f.write("---\nstack: stack-from-manifest\n")
+        end
+      end
+      zip_file = File.new(zip_name)
+      Rack::Test::UploadedFile.new(zip_file)
+    end
+    let(:valid_zip_unknown_stack) do
+      zip_name = File.join(tmpdir, filename)
+      TestZip.create(zip_name, 1, 1024) do |zipfile|
+        zipfile.get_output_stream('manifest.yml') do |f|
+          f.write("---\nstack: unknown-stack\n")
+        end
+      end
+      zip_file = File.new(zip_name)
+      Rack::Test::UploadedFile.new(zip_file)
+    end
     let(:valid_zip) do
       zip_name = File.join(tmpdir, filename)
       TestZip.create(zip_name, 1, 1024)
@@ -29,10 +49,7 @@ module VCAP::CloudController
     let(:expected_sha_valid_zip) { "#{@buildpack.guid}_#{sha_valid_zip}" }
 
     before do
-      @file = double(:file, {
-        public_url: 'https://some-bucket.example.com/ab/cd/abcdefg',
-        key: '123-456',
-      })
+      @file = double(:file, { public_url: 'https://some-bucket.example.com/ab/cd/abcdefg', key: '123-456' })
       buildpack_blobstore = CloudController::DependencyLocator.instance.buildpack_blobstore
       allow(buildpack_blobstore).to receive(:files).and_return(double(:files, head: @file, create: {}))
 
@@ -42,7 +59,7 @@ module VCAP::CloudController
     after { FileUtils.rm_rf(tmpdir) }
 
     context 'Buildpack binaries' do
-      let(:test_buildpack) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'upload_binary_buildpack', position: 0 }) }
+      let(:test_buildpack) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'upload_binary_buildpack', stack: 'stack', position: 0 }) }
 
       before { CloudController::DependencyLocator.instance.register(:upload_handler, UploadHandler.new(TestConfig.config_instance)) }
 
@@ -51,6 +68,9 @@ module VCAP::CloudController
           TestConfig.override(directories: { tmpdir: File.dirname(valid_zip.path) })
           @cache = Delayed::Worker.delay_jobs
           Delayed::Worker.delay_jobs = false
+
+          Stack.create(name: 'stack')
+          Stack.create(name: 'stack-from-manifest')
         end
 
         after { Delayed::Worker.delay_jobs = @cache }
@@ -75,20 +95,65 @@ module VCAP::CloudController
           expected_key = "#{test_buildpack.guid}_#{sha_valid_zip}"
 
           put "/v2/buildpacks/#{test_buildpack.guid}/bits", upload_body
+          expect(last_response.status).to eq(201)
+
           buildpack = Buildpack.find(name: 'upload_binary_buildpack')
           expect(buildpack.key).to eq(expected_key)
           expect(buildpack.filename).to eq(filename)
+          expect(buildpack.stack).to eq('stack')
           expect(buildpack_blobstore.exists?(expected_key)).to be true
         end
 
         it 'gets the uploaded file from the upload handler' do
           upload_handler = CloudController::DependencyLocator.instance.upload_handler
-          expect(upload_handler).to receive(:uploaded_file).
-            with(hash_including('buildpack_name' => filename), 'buildpack').
-            and_return(valid_zip)
+          expect(upload_handler).to receive(:uploaded_file).with(hash_including('buildpack_name' => filename), 'buildpack').and_return(valid_zip)
           put "/v2/buildpacks/#{test_buildpack.guid}/bits", upload_body
         end
 
+        it 'sets the buildpack stack if it is unset and in buildpack manifest' do
+          test_buildpack.update(stack: 'unknown')
+
+          put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip_manifest, buildpack_name: valid_zip_manifest.path }
+          expect(last_response.status).to eql 201
+
+          buildpack = Buildpack.find(name: 'upload_binary_buildpack')
+          expect(buildpack.stack).to eq('stack-from-manifest')
+        end
+
+        it 'returns ERROR (422) if provided stack does not exist' do
+          test_buildpack.update(stack: 'unknown')
+
+          put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip_unknown_stack, buildpack_name: valid_zip_unknown_stack.path }
+          expect(last_response.status).to eql 422
+
+          buildpack = Buildpack.find(name: 'upload_binary_buildpack')
+          expect(buildpack.stack).to eq('unknown')
+        end
+
+        it 'sets the buildpack stack to default if it is unset and NOT in buildpack manifest' do
+          test_buildpack.update(stack: 'unknown')
+
+          put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip, buildpack_name: valid_zip.path }
+          expect(last_response.status).to eql 201
+
+          buildpack = Buildpack.find(name: 'upload_binary_buildpack')
+          expect(buildpack.stack).to eq('default-stack-name')
+        end
+
+        it 'requires an existing stack to be the same as one in the manifest if it exists' do
+          test_buildpack.update(stack: 'not-from-manifest')
+
+          put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip_manifest, buildpack_name: valid_zip_manifest.path }
+          expect(last_response.status).to eql 422
+
+          json = MultiJson.load(last_response.body)
+          expect(json['code']).to eq(390011)
+          expect(json['description']).to eql 'Uploaded buildpack stack (stack-from-manifest) does not match not-from-manifest'
+
+          buildpack = Buildpack.find(name: 'upload_binary_buildpack')
+          expect(buildpack.stack).to eq('not-from-manifest')
+        end
+
         it 'requires a filename as part of the upload' do
           put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: 'abc' }
           expect(last_response.status).to eql 400
@@ -126,19 +191,29 @@ module VCAP::CloudController
 
           put "/v2/buildpacks/#{test_buildpack.guid}/bits", upload_body
           response = MultiJson.load(last_response.body)
-          entity = response['entity']
-          expect(entity['name']).to eq('upload_binary_buildpack')
-          expect(entity['filename']).to eq(filename)
+          expect(response['entity']['name']).to eq('upload_binary_buildpack')
+          expect(response['entity']['filename']).to eq("#{filename} (stack)")
           expect(buildpack_blobstore.exists?(expected_sha)).to be false
         end
 
         it 'reports a no content if the same buildpack is uploaded again' do
-          put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip }
-          put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip }
+          2.times { put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip } }
 
           expect(last_response.status).to eq(204)
         end
 
+        it 'does not allow uploading a buildpack which will update the stack that already has a buildpack with the same name' do
+          first_buildpack = VCAP::CloudController::Buildpack.create_from_hash({ name: 'nice_buildpack', stack: 'unknown', position: 0 })
+          put "/v2/buildpacks/#{first_buildpack.guid}/bits", { buildpack: valid_zip_manifest }
+
+          expect(Buildpack.find(name: 'nice_buildpack').stack).to eq('stack-from-manifest')
+
+          new_buildpack = VCAP::CloudController::Buildpack.create_from_hash({ name: first_buildpack.name, stack: 'unknown', position: 0 })
+          put "/v2/buildpacks/#{new_buildpack.guid}/bits", { buildpack: valid_zip_manifest }
+
+          expect(last_response.status).to eq(409)
+        end
+
         it 'allowed when same bits but different filename are uploaded again' do
           put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip }
           new_name = File.join(File.dirname(valid_zip.path), 'newfilename.zip')
@@ -155,13 +230,13 @@ module VCAP::CloudController
         end
 
         it 'does not allow upload if the buildpack is locked' do
-          locked_buildpack = VCAP::CloudController::Buildpack.create_from_hash({ name: 'locked_buildpack', locked: true, position: 0 })
+          locked_buildpack = VCAP::CloudController::Buildpack.create_from_hash({ name: 'locked_buildpack', stack: 'stack', locked: true, position: 0 })
           put "/v2/buildpacks/#{locked_buildpack.guid}/bits", { buildpack: valid_zip2 }
           expect(last_response.status).to eq(409)
         end
 
         it 'does allow upload if the buildpack has been unlocked' do
-          locked_buildpack = VCAP::CloudController::Buildpack.create_from_hash({ name: 'locked_buildpack', locked: true, position: 0 })
+          locked_buildpack = VCAP::CloudController::Buildpack.create_from_hash({ name: 'locked_buildpack', stack: 'stack', locked: true, position: 0 })
           put "/v2/buildpacks/#{locked_buildpack.guid}", '{"locked": false}'
 
           put "/v2/buildpacks/#{locked_buildpack.guid}/bits", { buildpack: valid_zip2 }
@@ -177,7 +252,7 @@ module VCAP::CloudController
         end
 
         context 'when the same bits are uploaded twice' do
-          let(:test_buildpack2) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'buildpack2', position: 0 }) }
+          let(:test_buildpack2) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'buildpack2', stack: 'stack', position: 0 }) }
           before do
             put "/v2/buildpacks/#{test_buildpack.guid}/bits", { buildpack: valid_zip2 }
             put "/v2/buildpacks/#{test_buildpack2.guid}/bits", { buildpack: valid_zip2 }
@@ -196,20 +271,14 @@ module VCAP::CloudController
         let(:staging_password) { 'password' }
         let(:staging_config) do
           {
-            staging: {
-              timeout_in_seconds: 240,
-              auth: {
-                user: staging_user,
-                password: staging_password,
-              },
-            },
+            staging: { timeout_in_seconds: 240, auth: { user: staging_user, password: staging_password } },
             directories: { tmpdir: File.dirname(valid_zip.path) },
           }
         end
 
         before do
           TestConfig.override(staging_config)
-          VCAP::CloudController::Buildpack.create_from_hash({ name: 'get_binary_buildpack', key: 'xyz', position: 0 })
+          VCAP::CloudController::Buildpack.create_from_hash({ name: 'get_binary_buildpack', stack: 'stack', key: 'xyz', position: 0 })
         end
 
         it 'returns NOT AUTHENTICATED (401) users without correct basic auth' do
diff --git a/spec/unit/controllers/runtime/buildpacks_controller_spec.rb b/spec/unit/controllers/runtime/buildpacks_controller_spec.rb
index 0cba02f8df5..6f0b46dcd1a 100644
--- a/spec/unit/controllers/runtime/buildpacks_controller_spec.rb
+++ b/spec/unit/controllers/runtime/buildpacks_controller_spec.rb
@@ -7,7 +7,7 @@ def ordered_buildpacks
     end
 
     let(:user) { make_user }
-    let(:req_body) { MultiJson.dump({ name: 'dynamic_test_buildpack', position: 1 }) }
+    let(:req_body) { MultiJson.dump({ name: 'dynamic_test_buildpack', stack: 'stack', position: 1 }) }
 
     before { set_current_user_as_admin }
 
@@ -19,6 +19,7 @@ def ordered_buildpacks
       it do
         expect(VCAP::CloudController::BuildpacksController).to have_creatable_attributes({
           name:     { type: 'string', required: true },
+          stack:    { type: 'string', default: 'unknown' },
           position: { type: 'integer', default: 0 },
           enabled:  { type: 'bool', default: true },
           locked:   { type: 'bool', default: false }
@@ -28,6 +29,7 @@ def ordered_buildpacks
       it do
         expect(VCAP::CloudController::BuildpacksController).to have_updatable_attributes({
           name:     { type: 'string' },
+          stack:    { type: 'string' },
           position: { type: 'integer' },
           enabled:  { type: 'bool' },
           locked:   { type: 'bool' }
@@ -59,12 +61,30 @@ def ordered_buildpacks
         expect(buildpack.position).to eq(1)
       end
 
+      it 'defaults stack to unknown when nil' do
+        expect do
+          post '/v2/buildpacks', MultiJson.dump({ name: 'a_buildpack', position: 1 })
+          expect(last_response.status).to eq(201)
+        end.to change { Buildpack.count }.from(0).to(1)
+        buildpack = Buildpack.first
+        expect(buildpack.stack).to eq('unknown')
+      end
+
+      it 'uses specified stack' do
+        expect do
+          post '/v2/buildpacks', MultiJson.dump({ name: 'a_buildpack', stack: 'cflinuxfs99', position: 1 })
+          expect(last_response.status).to eq(201)
+        end.to change { Buildpack.count }.from(0).to(1)
+        buildpack = Buildpack.first
+        expect(buildpack.stack).to eq('cflinuxfs99')
+      end
+
       it 'respects position param' do
-        Buildpack.create(name: 'pre-existing-buildpack', position: 1)
-        Buildpack.create(name: 'pre-existing-buildpack-2', position: 2)
+        Buildpack.create(name: 'pre-existing-buildpack', stack: 'stack', position: 1)
+        Buildpack.create(name: 'pre-existing-buildpack-2', stack: 'stack', position: 2)
 
         expect {
-          post '/v2/buildpacks', MultiJson.dump({ name: 'new-buildpack', position: 2 })
+          post '/v2/buildpacks', MultiJson.dump({ name: 'new-buildpack', stack: 'stack', position: 2 })
         }.to change { ordered_buildpacks }.from(
           [['pre-existing-buildpack', 1], ['pre-existing-buildpack-2', 2]]
         ).to(
@@ -73,15 +93,15 @@ def ordered_buildpacks
       end
 
       it 'returns duplicate name message correctly' do
-        Buildpack.make(name: 'dynamic_test_buildpack')
+        Buildpack.make(name: 'dynamic_test_buildpack', stack: 'stack')
         post '/v2/buildpacks', req_body
-        expect(last_response.status).to eq(400)
+        expect(last_response.status).to eq(409)
         expect(decoded_response['code']).to eq(290001)
         expect(Buildpack.count).to eq(1)
       end
 
       it 'returns buildpack invalid message correctly' do
-        post '/v2/buildpacks', MultiJson.dump({ name: 'invalid_name!' })
+        post '/v2/buildpacks', MultiJson.dump({ name: 'invalid_name!', stack: 'stack' })
         expect(last_response.status).to eq(400)
         expect(decoded_response['code']).to eq(290003)
         expect(Buildpack.count).to eq(0)
@@ -97,8 +117,8 @@ def ordered_buildpacks
     end
 
     describe '#update' do
-      let!(:buildpack1) { VCAP::CloudController::Buildpack.create({ name: 'first_buildpack', key: 'xyz', filename: 'a', position: 1 }) }
-      let!(:buildpack2) { VCAP::CloudController::Buildpack.create({ name: 'second_buildpack', key: 'xyz', filename: 'b', position: 2 }) }
+      let!(:buildpack1) { VCAP::CloudController::Buildpack.create({ name: 'first_buildpack', stack: 'stack', key: 'xyz', filename: 'a', position: 1 }) }
+      let!(:buildpack2) { VCAP::CloudController::Buildpack.create({ name: 'second_buildpack', stack: 'stack', key: 'xyz', filename: 'b', position: 2 }) }
 
       it 'can update the buildpack name' do
         set_current_user_as_admin
@@ -127,7 +147,7 @@ def ordered_buildpacks
     end
 
     describe '#delete' do
-      let!(:buildpack1) { VCAP::CloudController::Buildpack.create({ name: 'first_buildpack', key: 'xyz', position: 1 }) }
+      let!(:buildpack1) { VCAP::CloudController::Buildpack.create({ name: 'first_buildpack', stack: 'stack', key: 'xyz', position: 1 }) }
 
       it 'returns NOT AUTHORIZED (403) for non admins' do
         set_current_user(user)
diff --git a/spec/unit/controllers/v3/builds_controller_spec.rb b/spec/unit/controllers/v3/builds_controller_spec.rb
index d56e6951d07..5f7afda498b 100644
--- a/spec/unit/controllers/v3/builds_controller_spec.rb
+++ b/spec/unit/controllers/v3/builds_controller_spec.rb
@@ -4,6 +4,7 @@
   describe '#create' do
     let(:org) { VCAP::CloudController::Organization.make }
     let(:space) { VCAP::CloudController::Space.make(organization: org) }
+    let(:stack) { VCAP::CloudController::Stack.default.name }
     let(:app_model) { VCAP::CloudController::AppModel.make(space: space) }
     let(:package) do
       VCAP::CloudController::PackageModel.make(
@@ -25,7 +26,7 @@
     before do
       allow(CloudController::DependencyLocator.instance).to receive(:stagers).and_return(stagers)
       allow(stagers).to receive(:stager_for_app).and_return(stager)
-      app_model.lifecycle_data.update(buildpacks: nil, stack: VCAP::CloudController::Stack.default.name)
+      app_model.lifecycle_data.update(buildpacks: nil, stack: stack)
       set_current_user_as_admin
     end
 
@@ -98,14 +99,14 @@
     end
 
     describe 'buildpack lifecycle' do
-      let(:buildpack) { VCAP::CloudController::Buildpack.make }
+      let(:buildpack) { VCAP::CloudController::Buildpack.make(stack: stack) }
       let(:buildpack_request) { 'http://dan-and-zach-awesome-pack.com' }
       let(:buildpack_lifecycle) do
         {
           type: 'buildpack',
           data: {
             buildpacks: [buildpack_request],
-            stack: 'cflinuxfs2'
+            stack: stack
           },
         }
       end
@@ -166,7 +167,7 @@
               type: 'buildpack',
               data: {
                 buildpacks: [],
-                stack: 'cflinuxfs2'
+                stack: stack
               },
             }
           end
@@ -185,7 +186,7 @@
               type: 'buildpack',
               data: {
                 buildpacks: nil,
-                stack: 'cflinuxfs2'
+                stack: stack
               },
             }
           end
diff --git a/spec/unit/jobs/runtime/buildpack_delete_spec.rb b/spec/unit/jobs/runtime/buildpack_delete_spec.rb
index 3d89f71baca..75c319541e4 100644
--- a/spec/unit/jobs/runtime/buildpack_delete_spec.rb
+++ b/spec/unit/jobs/runtime/buildpack_delete_spec.rb
@@ -7,7 +7,7 @@ module Jobs::Runtime
       let(:buildpack_guid) { buildpack.guid }
       let(:timeout) { 90000 }
 
-      let(:buildpack) { VCAP::CloudController::Buildpack.create({ name: 'first_buildpack', key: 'xyz', position: 1 }) }
+      let(:buildpack) { VCAP::CloudController::Buildpack.make }
 
       before do
         allow(BuildpackBitsDelete).to receive(:delete_when_safe)
diff --git a/spec/unit/jobs/runtime/buildpack_installer_spec.rb b/spec/unit/jobs/runtime/buildpack_installer_spec.rb
index 6fbef48f115..5b31085352b 100644
--- a/spec/unit/jobs/runtime/buildpack_installer_spec.rb
+++ b/spec/unit/jobs/runtime/buildpack_installer_spec.rb
@@ -20,30 +20,114 @@ module Jobs::Runtime
         context 'when the buildpack is enabled and unlocked' do
           let(:options) { { locked: true } }
 
-          it 'creates a new buildpack' do
-            expect {
-              job.perform
-            }.to change { Buildpack.count }.from(0).to(1)
-
-            buildpack = Buildpack.find(name: buildpack_name)
-            expect(buildpack).to_not be_nil
-            expect(buildpack.name).to eq(buildpack_name)
-            expect(buildpack.key).to start_with(buildpack.guid)
-            expect(buildpack.filename).to end_with(File.basename(zipfile))
-            expect(buildpack).to be_locked
+          context 'buildpack zip does not specify stack' do
+            it 'creates a new buildpack with default stack' do
+              expect {
+                job.perform
+              }.to change { Buildpack.count }.from(0).to(1)
+
+              buildpack = Buildpack.first
+              expect(buildpack).to_not be_nil
+              expect(buildpack.name).to eq(buildpack_name)
+              expect(buildpack.stack).to eq(Stack.default.name)
+              expect(buildpack.key).to start_with(buildpack.guid)
+              expect(buildpack.filename).to end_with(File.basename(zipfile))
+              expect(buildpack).to be_locked
+            end
+
+            it 'updates an existing buildpack' do
+              buildpack1 = Buildpack.make(name: buildpack_name, key: 'new_key')
+
+              update_job = BuildpackInstaller.new(buildpack_name, zipfile2, { enabled: false })
+              update_job.perform
+
+              buildpack2 = Buildpack.find(name: buildpack_name)
+              expect(buildpack2).to_not be_nil
+              expect(buildpack2.enabled).to be false
+              expect(buildpack2.filename).to end_with(File.basename(zipfile2))
+              expect(buildpack2.key).to_not eql(buildpack1.key)
+            end
+
+            it 'does nothing if multiple buildpacks with same name' do
+              Buildpack.make(name: buildpack_name, stack: 'stack-1', filename: nil)
+              Buildpack.make(name: buildpack_name, stack: 'stack-2', filename: nil)
+
+              update_job = BuildpackInstaller.new(buildpack_name, zipfile2, { enabled: false })
+              expect {
+                update_job.perform
+              }.to_not change { Buildpack.count }
+
+              buildpack1 = Buildpack.find(name: buildpack_name, stack: 'stack-1')
+              expect(buildpack1).to_not be_nil
+              expect(buildpack1.filename).to be_nil
+
+              buildpack2 = Buildpack.find(name: buildpack_name, stack: 'stack-2')
+              expect(buildpack2).to_not be_nil
+              expect(buildpack2.filename).to be_nil
+            end
           end
 
-          it 'updates an existing buildpack' do
-            buildpack1 = Buildpack.make(name: buildpack_name, key: 'new_key')
+          context 'buildpack zip specifies stack' do
+            before { Stack.make(name: 'manifest-stack') }
+            let(:zipfile) do
+              path = Tempfile.new('bp-zip-with-stack').path
+              TestZip.create(path, 1, 1024) do |zipfile|
+                zipfile.get_output_stream('manifest.yml') do |f|
+                  f.write("---\nstack: manifest-stack\n")
+                end
+              end
+              path
+            end
+            after { FileUtils.rm(zipfile) }
+
+            it 'creates a new buildpack with that stack' do
+              expect {
+                job.perform
+              }.to change { Buildpack.count }.from(0).to(1)
+
+              buildpack = Buildpack.first
+              expect(buildpack).to_not be_nil
+              expect(buildpack.name).to eq(buildpack_name)
+              expect(buildpack.stack).to eq('manifest-stack')
+              expect(buildpack.key).to start_with(buildpack.guid)
+              expect(buildpack.filename).to end_with(File.basename(zipfile))
+              expect(buildpack).to be_locked
+            end
+
+            it 'updates an existing buildpack' do
+              buildpack1 = Buildpack.make(name: buildpack_name, stack: 'manifest-stack', key: 'new_key')
 
-            update_job = BuildpackInstaller.new(buildpack_name, zipfile2, { enabled: false })
-            update_job.perform
+              update_job = BuildpackInstaller.new(buildpack_name, zipfile, { enabled: false })
+              update_job.perform
 
-            buildpack2 = Buildpack.find(name: buildpack_name)
-            expect(buildpack2).to_not be_nil
-            expect(buildpack2.enabled).to be false
-            expect(buildpack2.filename).to end_with(File.basename(zipfile2))
-            expect(buildpack2.key).to_not eql(buildpack1.key)
+              buildpack2 = Buildpack.find(name: buildpack_name)
+              expect(buildpack2).to_not be_nil
+              expect(buildpack2.enabled).to be false
+              expect(buildpack2.filename).to end_with(File.basename(zipfile))
+              expect(buildpack2.key).to_not eql(buildpack1.key)
+            end
+
+            it 'creates a new buildpack if existing buildpacks have different stacks' do
+              Buildpack.make(name: buildpack_name, stack: 'stack-1', filename: nil)
+              Buildpack.make(name: buildpack_name, stack: 'stack-2', filename: nil)
+
+              update_job = BuildpackInstaller.new(buildpack_name, zipfile, { enabled: false })
+              expect {
+                update_job.perform
+              }.to change { Buildpack.count }.by(1)
+
+              buildpack1 = Buildpack.find(name: buildpack_name, stack: 'stack-1')
+              expect(buildpack1).to_not be_nil
+              expect(buildpack1.filename).to be_nil
+
+              buildpack2 = Buildpack.find(name: buildpack_name, stack: 'stack-2')
+              expect(buildpack2).to_not be_nil
+              expect(buildpack2.filename).to be_nil
+
+              buildpack3 = Buildpack.find(name: buildpack_name, stack: 'manifest-stack')
+              expect(buildpack3).to_not be_nil
+              expect(buildpack3.filename).to_not be_nil
+            end
           end
         end
 
diff --git a/spec/unit/lib/cloud_controller/diego/buildpack/buildpack_entry_generator_spec.rb b/spec/unit/lib/cloud_controller/diego/buildpack/buildpack_entry_generator_spec.rb
index 97d78d45582..c925a50ffad 100644
--- a/spec/unit/lib/cloud_controller/diego/buildpack/buildpack_entry_generator_spec.rb
+++ b/spec/unit/lib/cloud_controller/diego/buildpack/buildpack_entry_generator_spec.rb
@@ -14,10 +14,13 @@ module Buildpack
         let(:blobstore_url_generator) { double('fake url generator') }
 
         let!(:java_buildpack) do
-          VCAP::CloudController::Buildpack.create(name: 'java', key: 'java-buildpack-key', position: 1, sha256_checksum: 'checksum')
+          VCAP::CloudController::Buildpack.create(name: 'java', stack: 'stack', key: 'java-buildpack-key', position: 1, sha256_checksum: 'checksum')
         end
         let!(:ruby_buildpack) do
-          VCAP::CloudController::Buildpack.create(name: 'ruby', key: 'ruby-buildpack-key', position: 2, sha256_checksum: 'checksum')
+          VCAP::CloudController::Buildpack.create(name: 'ruby', stack: 'stack', key: 'ruby-buildpack-key', position: 2, sha256_checksum: 'checksum')
+        end
+        let!(:ruby_buildpack_other_stack) do
+          VCAP::CloudController::Buildpack.create(name: 'ruby', stack: 'stack2', key: 'ruby-buildpack-stack2-key', position: 3, sha256_checksum: 'checksum')
         end
 
         before do
@@ -40,8 +43,8 @@ module Buildpack
             let(:admin_buildpack_info) { BuildpackInfo.new('java', VCAP::CloudController::Buildpack.find(name: 'java')) }
             let(:buildpack_infos) { [custom_buildpack_info, admin_buildpack_info] }
 
-            it 'returns both buildpacks' do
-              expect(buildpack_entry_generator.buildpack_entries(buildpack_infos)).to eq([
+            it 'returns both buildpacks for the stack' do
+              expect(buildpack_entry_generator.buildpack_entries(buildpack_infos, 'stack')).to eq([
                 { name: 'custom', key: 'http://example.com/my_buildpack_url.zip', url: 'http://example.com/my_buildpack_url.zip', skip_detect: true },
                 { name: 'java', key: 'java-buildpack-key', url: admin_buildpack_download_url, skip_detect: true, sha256: 'checksum' },
               ])
@@ -53,7 +56,7 @@ module Buildpack
               let(:buildpack) { 'http://example.com/my_buildpack_url.zip' }
 
               it "should use the buildpack_uri and name it 'custom', and use the url as the key" do
-                expect(buildpack_entry_generator.buildpack_entries(buildpack_infos)).to eq([
+                expect(buildpack_entry_generator.buildpack_entries(buildpack_infos, 'stack')).to eq([
                   { name: 'custom', key: 'http://example.com/my_buildpack_url.zip', url: 'http://example.com/my_buildpack_url.zip', skip_detect: true }
                 ])
               end
@@ -63,7 +66,7 @@ module Buildpack
               let(:buildpack) { 'http://example.com/my_buildpack_url' }
 
               it "should use the buildpack_uri and name it 'custom', and use the url as the key" do
-                expect(buildpack_entry_generator.buildpack_entries(buildpack_infos)).to eq([
+                expect(buildpack_entry_generator.buildpack_entries(buildpack_infos, 'stack')).to eq([
                   { name: 'custom', key: 'http://example.com/my_buildpack_url', url: 'http://example.com/my_buildpack_url', skip_detect: true }
                 ])
               end
@@ -74,7 +77,7 @@ module Buildpack
             let(:buildpack) { 'java' }
 
             it 'should use that buildpack' do
-              expect(buildpack_entry_generator.buildpack_entries(buildpack_infos)).to eq([
+              expect(buildpack_entry_generator.buildpack_entries(buildpack_infos, 'stack')).to eq([
                 { name: 'java', key: 'java-buildpack-key', url: admin_buildpack_download_url, skip_detect: true, sha256: 'checksum' }
               ])
             end
@@ -85,7 +88,7 @@ module Buildpack
               end
 
               it 'fails fast with a clear error' do
-                expect { buildpack_entry_generator.buildpack_entries(buildpack_infos) }.to raise_error /Unsupported buildpack type/
+                expect { buildpack_entry_generator.buildpack_entries(buildpack_infos, 'stack') }.to raise_error /Unsupported buildpack type/
               end
             end
           end
@@ -93,10 +96,18 @@ module Buildpack
           context 'when the user has not requested a buildpack' do
             let(:buildpack_infos) { [] }
 
-            it 'should use the list of admin buildpacks' do
-              expect(buildpack_entry_generator.buildpack_entries(buildpack_infos)).to eq([
+            it 'should use the list of admin buildpacks for the specified stack' do
+              expect(buildpack_entry_generator.buildpack_entries(buildpack_infos, 'stack')).to eq([
+                { name: 'java', key: 'java-buildpack-key', url: admin_buildpack_download_url, sha256: 'checksum', skip_detect: false },
+                { name: 'ruby', key: 'ruby-buildpack-key', url: admin_buildpack_download_url, sha256: 'checksum', skip_detect: false },
+              ])
+            end
+
+            it 'should use the list of all admin buildpacks if no stack  is specified' do
+              expect(buildpack_entry_generator.buildpack_entries(buildpack_infos, nil)).to eq([
                 { name: 'java', key: 'java-buildpack-key', url: admin_buildpack_download_url, sha256: 'checksum', skip_detect: false },
                 { name: 'ruby', key: 'ruby-buildpack-key', url: admin_buildpack_download_url, sha256: 'checksum', skip_detect: false },
+                { name: 'ruby', key: 'ruby-buildpack-stack2-key', url: admin_buildpack_download_url, sha256: 'checksum', skip_detect: false },
               ])
             end
           end
@@ -105,7 +116,7 @@ module Buildpack
             let(:buildpack) { '???' }
 
             it 'fails fast with a clear error' do
-              expect { buildpack_entry_generator.buildpack_entries(buildpack_infos) }.to raise_error /Unsupported buildpack type/
+              expect { buildpack_entry_generator.buildpack_entries(buildpack_infos, 'stack') }.to raise_error /Unsupported buildpack type/
             end
           end
         end
diff --git a/spec/unit/lib/cloud_controller/diego/buildpack/lifecycle_protocol_spec.rb b/spec/unit/lib/cloud_controller/diego/buildpack/lifecycle_protocol_spec.rb
index 23d919b92cb..a5ddffed0a2 100644
--- a/spec/unit/lib/cloud_controller/diego/buildpack/lifecycle_protocol_spec.rb
+++ b/spec/unit/lib/cloud_controller/diego/buildpack/lifecycle_protocol_spec.rb
@@ -41,7 +41,7 @@ module Buildpack
           end
 
           before do
-            VCAP::CloudController::Buildpack.create(name: 'ruby', key: 'ruby-buildpack-key', position: 2)
+            VCAP::CloudController::Buildpack.create(name: 'ruby', stack: 'potato-stack', key: 'ruby-buildpack-key', position: 2)
             allow(blobstore_url_generator).to receive(:admin_buildpack_download_url).and_return('bp-download-url')
           end
 
diff --git a/spec/unit/lib/cloud_controller/upload_buildpack_spec.rb b/spec/unit/lib/cloud_controller/upload_buildpack_spec.rb
index f8334202d4b..dbbbcaa02eb 100644
--- a/spec/unit/lib/cloud_controller/upload_buildpack_spec.rb
+++ b/spec/unit/lib/cloud_controller/upload_buildpack_spec.rb
@@ -3,7 +3,7 @@
 module VCAP::CloudController
   RSpec.describe UploadBuildpack do
     let(:buildpack_blobstore) { double(:buildpack_blobstore).as_null_object }
-    let!(:buildpack) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'upload_binary_buildpack', position: 0 }) }
+    let!(:buildpack) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'upload_binary_buildpack', stack: 'cflinuxfs2', position: 0 }) }
 
     let(:upload_buildpack) { UploadBuildpack.new(buildpack_blobstore) }
 
@@ -13,9 +13,16 @@ module VCAP::CloudController
     let(:sha_valid_zip) { Digester.new(algorithm: Digest::SHA256).digest_file(valid_zip) }
     let(:sha_valid_zip2) { Digester.new(algorithm: Digest::SHA256).digest_file(valid_zip2) }
 
+    let(:valid_zip_manifest_stack) { nil }
     let(:valid_zip) do
       zip_name = File.join(tmpdir, filename)
-      TestZip.create(zip_name, 1, 1024)
+      TestZip.create(zip_name, 1, 1024) do |zipfile|
+        if valid_zip_manifest_stack
+          zipfile.get_output_stream('manifest.yml') do |f|
+            f.write("---\nstack: #{valid_zip_manifest_stack}\n")
+          end
+        end
+      end
       zip_file = File.new(zip_name)
       Rack::Test::UploadedFile.new(zip_file)
     end
@@ -37,6 +44,69 @@ module VCAP::CloudController
       end
 
       context 'and the upload to the blobstore succeeds' do
+        context 'stack from manifest' do
+          context 'same as buildpack' do
+            let(:valid_zip_manifest_stack) { 'cflinuxfs2' }
+
+            it 'copies new bits to the blobstore' do
+              expect(buildpack_blobstore).to receive(:cp_to_blobstore).with(valid_zip, expected_sha_valid_zip)
+
+              upload_buildpack.upload_buildpack(buildpack, valid_zip, filename)
+            end
+          end
+
+          context 'different from buildpack' do
+            let(:valid_zip_manifest_stack) { 'cflinuxfs3' }
+            before do
+              VCAP::CloudController::Stack.create(name: 'cflinuxfs3')
+            end
+
+            it 'raises an error and does not update stack' do
+              expect { upload_buildpack.upload_buildpack(buildpack, valid_zip, filename) }.to raise_error(CloudController::Errors::ApiError)
+              bp = Buildpack.find(name: buildpack.name)
+              expect(bp).to_not be_nil
+              expect(bp.stack).to eq('cflinuxfs2')
+            end
+          end
+
+          context 'stack previously unknown' do
+            let!(:buildpack) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'upload_binary_buildpack', stack: 'unknown', position: 0 }) }
+            context 'known' do
+              let(:valid_zip_manifest_stack) { 'cflinuxfs3' }
+              before do
+                VCAP::CloudController::Stack.create(name: 'cflinuxfs3')
+              end
+
+              it 'copies new bits to the blobstore and updates the stack' do
+                expect(buildpack_blobstore).to receive(:cp_to_blobstore).with(valid_zip, expected_sha_valid_zip)
+
+                expect do
+                  upload_buildpack.upload_buildpack(buildpack, valid_zip, filename)
+                end.to change { buildpack.stack }.from('unknown').to('cflinuxfs3')
+              end
+
+              context 'buildpack with same name and stack exists' do
+                let(:valid_zip_manifest_stack) { 'cflinuxfs3' }
+
+                it 'raises an error' do
+                  VCAP::CloudController::Buildpack.create(name: buildpack.name, stack: 'cflinuxfs3')
+                  expect { upload_buildpack.upload_buildpack(buildpack, valid_zip, filename) }.to raise_error(CloudController::Errors::ApiError)
+                end
+              end
+            end
+
+            context 'unknown' do
+              let(:valid_zip_manifest_stack) { 'new-and-unknown' }
+              it 'raises an error' do
+                expect { upload_buildpack.upload_buildpack(buildpack, valid_zip, filename) }.to raise_error(CloudController::Errors::ApiError)
+                bp = Buildpack.find(name: buildpack.name)
+                expect(bp).to_not be_nil
+                expect(bp.filename).to be_nil
+              end
+            end
+          end
+        end
+
         it 'updates the buildpack filename' do
           expect {
             upload_buildpack.upload_buildpack(buildpack, valid_zip, filename)
@@ -116,7 +186,7 @@ module VCAP::CloudController
         end
 
         context 'when the same bits are uploaded twice' do
-          let(:buildpack2) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'buildpack2', position: 0 }) }
+          let(:buildpack2) { VCAP::CloudController::Buildpack.create_from_hash({ name: 'buildpack2', stack: 'cflinuxfs2', position: 0 }) }
 
           it 'should have different keys' do
             upload_buildpack.upload_buildpack(buildpack, valid_zip2, filename)
diff --git a/spec/unit/models/runtime/buildpack_spec.rb b/spec/unit/models/runtime/buildpack_spec.rb
index f0f5bce0948..f1352f3617c 100644
--- a/spec/unit/models/runtime/buildpack_spec.rb
+++ b/spec/unit/models/runtime/buildpack_spec.rb
@@ -9,12 +9,12 @@ def ordered_buildpacks
     it { is_expected.to have_timestamp_columns }
 
     describe 'Validations' do
-      it { is_expected.to validate_uniqueness :name }
+      it { is_expected.to validate_uniqueness [:name, :stack] }
 
       describe 'name' do
         it 'does not allow non-word non-dash characters' do
           ['git://github.com', '$abc', 'foobar!'].each do |name|
-            buildpack = Buildpack.new(name: name)
+            buildpack = Buildpack.new(name: name, stack: 'unknown')
             expect(buildpack).not_to be_valid
             expect(buildpack.errors.on(:name)).to be_present
           end
@@ -22,7 +22,7 @@ def ordered_buildpacks
 
         it 'allows word and dash characters' do
           ['name', 'name-with-dash', '-name-'].each do |name|
-            buildpack = Buildpack.new(name: name)
+            buildpack = Buildpack.new(name: name, stack: 'unknown')
             expect(buildpack).to be_valid
           end
         end
@@ -30,8 +30,8 @@ def ordered_buildpacks
     end
 
     describe 'Serialization' do
-      it { is_expected.to export_attributes :name, :position, :enabled, :locked, :filename }
-      it { is_expected.to import_attributes :name, :position, :enabled, :locked, :filename, :key }
+      it { is_expected.to export_attributes :name, :stack, :position, :enabled, :locked, :filename }
+      it { is_expected.to import_attributes :name, :stack, :position, :enabled, :locked, :filename, :key }
 
       it 'does not string mung(e)?' do
         expect(Buildpack.new(name: "my_custom_buildpack\r\n").to_json).to eq '"my_custom_buildpack\r\n"'
@@ -92,7 +92,7 @@ def ordered_buildpacks
         end
 
         context 'and there are buildpacks with null keys' do
-          let!(:null_buildpack) { Buildpack.create(name: 'nil_key_custom_buildpack', position: 0) }
+          let!(:null_buildpack) { Buildpack.create(name: 'nil_key_custom_buildpack', stack: 'stack', position: 0) }
 
           it 'only returns buildpacks with non-null keys' do
             expect(Buildpack.all).to include(null_buildpack)
@@ -102,7 +102,7 @@ def ordered_buildpacks
         end
 
         context 'and there are buildpacks with empty keys' do
-          let!(:empty_buildpack) { Buildpack.create(name: 'nil_key_custom_buildpack', key: '', position: 0) }
+          let!(:empty_buildpack) { Buildpack.create(name: 'nil_key_custom_buildpack', stack: 'stack', key: '', position: 0) }
 
           it 'only returns buildpacks with non-null keys' do
             expect(Buildpack.all).to include(empty_buildpack)
@@ -137,7 +137,7 @@ def ordered_buildpacks
 
     describe '#update' do
       let!(:buildpacks) do
-        Array.new(4) { |i| Buildpack.create(name: "name_#{100 - i}", position: i + 1) }
+        Array.new(4) { |i| Buildpack.create(name: "name_#{100 - i}", stack: 'stack', position: i + 1) }
       end
 
       it 'does not modify the frozen hash provided by Sequel' do
@@ -148,8 +148,8 @@ def ordered_buildpacks
     end
 
     describe '#destroy' do
-      let!(:buildpack1) { VCAP::CloudController::Buildpack.create({ name: 'first_buildpack', key: 'xyz', position: 1 }) }
-      let!(:buildpack2) { VCAP::CloudController::Buildpack.create({ name: 'second_buildpack', key: 'xyz', position: 2 }) }
+      let!(:buildpack1) { VCAP::CloudController::Buildpack.create({ name: 'first_buildpack', stack: 'stack', key: 'xyz', position: 1 }) }
+      let!(:buildpack2) { VCAP::CloudController::Buildpack.create({ name: 'second_buildpack', stack: 'stack', key: 'xyz', position: 2 }) }
 
       it 'removes the specified buildpack' do
         expect {
diff --git a/spec/unit/presenters/v2/buildpack_presenter_spec.rb b/spec/unit/presenters/v2/buildpack_presenter_spec.rb
new file mode 100644
index 00000000000..13013d5cc37
--- /dev/null
+++ b/spec/unit/presenters/v2/buildpack_presenter_spec.rb
@@ -0,0 +1,42 @@
+require 'spec_helper'
+
+module CloudController::Presenters::V2
+  RSpec.describe BuildpackPresenter do
+    let(:buildpack_presenter) { BuildpackPresenter.new }
+    let(:controller) { 'controller' }
+    let(:opts) { {} }
+    let(:depth) { 0 }
+    let(:parents) { 'parents' }
+    let(:orphans) { 'orphans' }
+    let(:relations_presenter) { instance_double(RelationsPresenter, to_hash: relations_hash) }
+    let(:relations_hash) { {} }
+    before do
+      allow(RelationsPresenter).to receive(:new).and_return(relations_presenter)
+    end
+
+    describe '#entity_hash' do
+      let(:buildpack) { VCAP::CloudController::Buildpack.make }
+
+      it 'returns the space entity and associated urls' do
+        expected_entity_hash = {
+          'name' => buildpack.name,
+          'stack' => buildpack.stack,
+          'enabled' => buildpack.enabled,
+          'locked' => buildpack.locked,
+          'position' => buildpack.position,
+          'filename' => "#{buildpack.filename} (#{buildpack.stack})",
+        }
+
+        actual_entity_hash = buildpack_presenter.entity_hash(controller, buildpack, opts, depth, parents, orphans)
+
+        expect(actual_entity_hash).to be_a_response_like(expected_entity_hash)
+      end
+
+      it 'formats correctly when no filename is present' do
+        buildpack.filename = ''
+        actual_entity_hash = buildpack_presenter.entity_hash(controller, buildpack, opts, depth, parents, orphans)
+        expect(actual_entity_hash['filename']).to eq("(#{buildpack.stack})")
+      end
+    end
+  end
+end
diff --git a/vendor/errors/v2.yml b/vendor/errors/v2.yml
index df6a87cc311..6f3fbe7bb26 100644
--- a/vendor/errors/v2.yml
+++ b/vendor/errors/v2.yml
@@ -839,9 +839,9 @@
   message: "Service broker returned dashboard client configuration without a dashboard URL"
 
 290001:
-  name: BuildpackNameTaken
-  http_code: 400
-  message: "The buildpack name is already in use: %s"
+  name: BuildpackNameStackTaken
+  http_code: 409
+  message: "The buildpack name %s is already in use for the stack %s"
 
 290002:
   name: BuildpackBitsUploadInvalid
@@ -1153,3 +1153,13 @@
   name: SharedServiceInstanceNotDeleteableInTargetSpace
   http_code: 403
   message: 'You cannot delete service instances that have been shared with you'
+
+390011:
+  name: BuildpackStacksDontMatch
+  http_code: 422
+  message: 'Uploaded buildpack stack (%s) does not match %s'
+
+390012:
+  name: BuildpackStackDoesNotExist
+  http_code: 422
+  message: 'Uploaded buildpack stack (%s) does not exist'