base_component.rb

# Encoding: utf-8
# Cloud Foundry Java Buildpack
# Copyright 2013-2016 the original author or authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

require 'fileutils'
require 'java_buildpack/component'
require 'java_buildpack/util/cache/application_cache'
require 'java_buildpack/util/format_duration'
require 'java_buildpack/util/shell'
require 'java_buildpack/util/space_case'
require 'java_buildpack/util/sanitizer'

module JavaBuildpack
 module Component

 # A convenience base class for all components in the buildpack. This base class ensures that the contents of the
 # +context+ are assigned to instance variables matching their keys. It also ensures that all contract methods are
 # implemented.
 class BaseComponent
 include JavaBuildpack::Util::Shell

 # Creates an instance. The contents of +context+ are assigned to the instance variables matching their keys.
 #
 # @param [Hash] context a collection of utilities used by components
 # @option context [JavaBuildpack::Component::Application] :application the application
 # @option context [Hash] :configuration the component's configuration
 # @option context [JavaBuildpack::Component::Droplet] :droplet the droplet
 def initialize(context)
 @application = context[:application]
 @component_name = self.class.to_s.space_case
 @configuration = context[:configuration]
 @droplet = context[:droplet]
 end

 # If the component should be used when staging an application
 #
 # @return [Array<String>, String, nil] If the component should be used when staging the application, a +String+ or
 # an +Array<String>+ that uniquely identifies the component (e.g.
 # +open_jdk=1.7.0_40+). Otherwise, +nil+.
 def detect
 fail "Method 'detect' must be defined"
 end

 # Modifies the application's file system. The component is expected to transform the application's file system in
 # whatever way is necessary (e.g. downloading files or creating symbolic links) to support the function of the
 # component. Status output written to +STDOUT+ is expected as part of this invocation.
 #
 # @return [Void]
 def compile
 fail "Method 'compile' must be defined"
 end

 # Modifies the application's runtime configuration. The component is expected to transform members of the
 # +context+ # (e.g. +@java_home+, +@java_opts+, etc.) in whatever way is necessary to support the function of the
 # component.
 #
 # Container components are also expected to create the command required to run the application. These components
 # are expected to read the +context+ values and take them into account when creating the command.
 #
 # @return [void, String] components other than containers and JREs are not expected to return any value.
 # Container and JRE components are expected to return a command required to run the
 # application.
 def release
 fail "Method 'release' must be defined"
 end

 protected

 # Downloads an item with the given name and version from the given URI, then yields the resultant file to the
 # given # block.
 #
 # @param [JavaBuildpack::Util::TokenizedVersion] version
 # @param [String] uri
 # @param [String] name an optional name for the download. Defaults to +@component_name+.
 # @return [Void]
 def download(version, uri, name = @component_name)
 download_start_time = Time.now
 print "-----> Downloading #{name} #{version} from #{uri.sanitize_uri} "

 JavaBuildpack::Util::Cache::ApplicationCache.new.get(uri) do |file, downloaded|
 puts downloaded ? "(#{(Time.now - download_start_time).duration})" : '(found in cache)'
 yield file
 end
 end

 # Downloads a given JAR file and stores it.
 #
 # @param [String] version the version of the download
 # @param [String] uri the uri of the download
 # @param [String] jar_name the name to save the jar as
 # @param [Pathname] target_directory the directory to store the JAR file in. Defaults to the component's sandbox.
 # @param [String] name an optional name for the download. Defaults to +@component_name+.
 # @return [Void]
 def download_jar(version, uri, jar_name, target_directory = @droplet.sandbox, name = @component_name)
 download(version, uri, name) do |file|
 FileUtils.mkdir_p target_directory
 FileUtils.cp_r(file.path, target_directory + jar_name)
 end
 end

 # Downloads a given TAR file and expands it.
 #
 # @param [String] version the version of the download
 # @param [String] uri the uri of the download
 # @param [Pathname] target_directory the directory to expand the TAR file to. Defaults to the component's
 # sandbox.
 # @param [String] name an optional name for the download and expansion. Defaults to +@component_name+.
 # @return [Void]
 def download_tar(version, uri, target_directory = @droplet.sandbox, name = @component_name)
 download(version, uri, name) do |file|
 with_timing "Expanding #{name} to #{target_directory.relative_path_from(@droplet.root)}" do
 FileUtils.mkdir_p target_directory
 shell "tar x#{compression_flag(file)}f #{file.path} -C #{target_directory} --strip 1 2>&1"
 end
 end
 end

 # Downloads a given ZIP file and expands it.
 #
 # @param [Boolean] strip_top_level whether to strip the top-level directory when expanding. Defaults to +true+.
 # @param [Pathname] target_directory the directory to expand the ZIP file to. Defaults to the component's
 # sandbox.
 # @param [String] name an optional name for the download. Defaults to +@component_name+.
 # @return [Void]
 def download_zip(version, uri, strip_top_level = true, target_directory = @droplet.sandbox,
 name = @component_name)
 download(version, uri, name) do |file|
 with_timing "Expanding #{name} to #{target_directory.relative_path_from(@droplet.root)}" do
 if strip_top_level
 Dir.mktmpdir do |root|
 shell "unzip -qq #{file.path} -d #{root} 2>&1"

 FileUtils.mkdir_p target_directory.parent
 FileUtils.mv Pathname.new(root).children.first, target_directory
 end
 else
 FileUtils.mkdir_p target_directory
 shell "unzip -qq #{file.path} -d #{target_directory} 2>&1"
 end
 end
 end
 end

 # Wrap the execution of a block with timing information
 #
 # @param [String] caption the caption to print when timing starts
 # @return [Void]
 def with_timing(caption)
 start_time = Time.now
 print " #{caption} "

 yield

 puts "(#{(Time.now - start_time).duration})"
 end

 private

 def gzipped?(file)
 file.path.end_with? '.gz'
 end

 def bzipped?(file)
 file.path.end_with? '.bz2'
 end

 def compression_flag(file)
 if gzipped?(file)
 'z'
 elsif bzipped?(file)
 'j'
 else
 ''
 end
 end

 end

 end
end