Added PackageDownloader and PackageExtractor classes (fate#320772)

for sharing package downloading and extracting functionality

.gitignore

@@ -45,7 +45,6 @@ library/packages/src/packages
 
 # Package
 package/yast2-*.tar.bz2
-package/yast2.spec
 
 # other
 home:*:*

library/packages/src/lib/packages/package_downloader.rb

@@ -0,0 +1,77 @@
+# encoding: utf-8
+# ------------------------------------------------------------------------------
+# Copyright (c) 2017 SUSE LLC
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of version 2 of the GNU General Public License as published by the
+# Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# ------------------------------------------------------------------------------
+
+require "yast"
+
+require "tempfile"
+require "shellwords"
+
+require "yast2/execute"
+
+Yast.import "Pkg"
+
+module Yast2
+  # Represents a update repository to be used during self-update
+  #
+  # @example Downloading a package
+  #   begin
+  #     downloader = PackageDownloader.new(3, "yast2")
+  #     tmp = Tempfile.new("downloaded-package-")
+  #     downloader.download(tmp.path)
+  #     # do something with the package...
+  #   ensure
+  #     tmp.close
+  #     tmp.unlink
+  #   end
+  #
+  class PackageDownloader
+    include Yast::Logger
+    include Yast::I18n
+
+    # @return [Integer] Repository ID
+    attr_reader :repo_id
+    # @return [String] Name of the package
+    attr_reader :package_name
+
+    # Error while downloading the package.
+    class FetchError < StandardError; end
+
+    # Constructor
+    #
+    # @param [Integer] repo_id Repository ID
+    # @param [String] package_name Name of the package to download
+    def initialize(repo_id, package_name)
+      textdomain "base"
+
+      @repo_id = repo_id
+      @package_name = package_name
+    end
+
+    # Download the package locally to the given path.
+    #
+    # It is responsibility of the caller to remove the downloaded package
+    # when it is not needed anymore.
+    #
+    # @param [#to_s] path path where the downloaded package will be stored
+    #
+    # @raise PackageNotFound
+    def download(path)
+      log.info("Downloading package #{package_name} from repo #{repo_id} to #{path}")
+      if !Yast::Pkg.ProvidePackage(repo_id, package_name, path.to_s)
+        log.error("Package #{package_name} could not be retrieved.")
+        raise FetchError
+      end
+    end
+  end
+end

library/packages/src/lib/packages/package_extractor.rb

@@ -0,0 +1,72 @@
+# encoding: utf-8
+# ------------------------------------------------------------------------------
+# Copyright (c) 2017 SUSE LLC
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of version 2 of the GNU General Public License as published by the
+# Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+#
+# ------------------------------------------------------------------------------
+
+require "shellwords"
+
+require "yast"
+require "yast2/execute"
+
+module Yast2
+  # Extracts the RPM package contents to a directory.
+  #
+  # @example Extracting a package into a temporary directory
+  #  extractor = PackageExtractor("./my_package-0.1-0.noarch.rpm")
+  #  Dir.mktmpdir do |tmpdir|
+  #    extractor.extract(tmpdir)
+  #    # do something with the content in tmpdir...
+  #  end
+  class PackageExtractor
+    include Yast::Logger
+
+    # Path to the package to extract.
+    # @return [String] package path
+    attr_reader :package_path
+
+    # The package could not be extracted
+    class ExtractionFailed < StandardError; end
+
+    # Constructor
+    #
+    # @param [String] package_path the path to the package to extract
+    def initialize(package_path)
+      @package_path = package_path
+    end
+
+    # Command to extract an RPM, the contents is extracted into the current
+    # working directory.
+    EXTRACT_CMD = "rpm2cpio %<source>s | cpio --quiet --sparse -dimu --no-absolute-filenames".freeze
+
+    # Extracts the RPM contents to the given directory.
+    #
+    # It is responsibility of the caller to remove the downloaded package
+    # when it is not needed anymore.
+    #
+    # @param dir [String] Directory where the RPM contents will be extracted to
+    #
+    # @raise ExtractionFailed
+    def extract(dir)
+      Dir.chdir(dir) do
+        cmd = format(EXTRACT_CMD, source: Shellwords.escape(package_path))
+        log.info("Extracting package #{package_path} to #{dir}...")
+
+        # we need a shell to process the pipe,
+        # the "allowed_exitstatus" option forces Cheetah to return the exit code
+        ret = Yast::Execute.locally("sh", "-c", cmd, allowed_exitstatus: 0..255)
+        log.info("Extraction result: #{ret}")
+
+        raise ExtractionFailed unless ret.zero?
+      end
+    end
+  end
+end

library/packages/test/data/rpm/dummy_package.spec

@@ -0,0 +1,44 @@
+#
+# spec file for package dummy_package
+#
+# Copyright (c) 2017 SUSE LINUX GmbH, Nuernberg, Germany.
+#
+# All modifications and additions to the file contributed by third parties
+# remain the property of their copyright owners, unless otherwise agreed
+# upon. The license for this file, and modifications and additions to the
+# file, is the same license as for the pristine package itself (unless the
+# license for the pristine package is not an Open Source License, in which
+# case the license is the MIT License). An "Open Source License" is a
+# license that conforms to the Open Source Definition (Version 1.9)
+# published by the Open Source Initiative.
+
+# This is just a testing dummy package for verifying the package
+# extraction functionality, it only contains a single testing text file.
+#
+# Run "rpmbuild -bb dummy_package.spec" to build the package.
+
+Name:           dummy_package
+
+Version:        0.1
+Release:        0
+Summary:        A dummy package
+License:        MIT
+Group:          Metapackages
+BuildRoot:      %{_tmppath}/%{name}-%{version}-build
+BuildArch:      noarch
+
+%description
+This is just a dummy package for testing.
+
+%prep
+
+%install
+# install a dummy test file
+mkdir -p $RPM_BUILD_ROOT/%{_prefix}/share/doc/packages/%{name}
+echo "just a testing dummy package" > $RPM_BUILD_ROOT/%{_prefix}/share/doc/packages/%{name}/test
+
+%files
+%defattr(644,root,root,755)
+%doc %dir %{_prefix}/share/doc/packages/%{name}
+%doc %{_prefix}/share/doc/packages/%{name}/
+

library/packages/test/package_downloader_test.rb

@@ -0,0 +1,27 @@
+ #!/usr/bin/env rspec
+
+require_relative "test_helper"
+
+require "packages/package_downloader"
+
+describe Yast2::PackageDownloader do
+  Yast.import "Pkg"
+
+  let(:repo_id) { 1 }
+  let(:package) { "package_to_download" }
+  let(:path) { "dummy" }
+
+  subject { Yast2::PackageDownloader.new(repo_id, package) }
+
+  describe "#download" do
+    it "downloads the requested package" do
+      expect(Yast::Pkg).to receive(:ProvidePackage).with(repo_id, package, path).and_return(true)
+      subject.download(path)
+    end
+
+    it "raises FetchError when download fails" do
+      expect(Yast::Pkg).to receive(:ProvidePackage).with(repo_id, package, path).and_return(nil)
+      expect { subject.download(path) }.to raise_error(Yast2::PackageDownloader::FetchError)
+    end
+  end
+end

library/packages/test/package_extractor_test.rb

@@ -0,0 +1,35 @@
+#!/usr/bin/env rspec
+
+require "tempfile"
+require_relative "test_helper"
+require "packages/package_extractor"
+
+describe Yast2::PackageExtractor do
+  # a testing RPM package
+  let(:dummy_package_path) { File.expand_path("../data/rpm/dummy_package-0.1-0.noarch.rpm", __FILE__)}
+  # the testing file in the package
+  let(:dummy_file) { "usr/share/doc/packages/dummy_package/test" }
+  # the contents of the testing file
+  let(:dummy_file_contents) { "just a testing dummy package\n" }
+
+  describe "#extract" do
+    it "extracts the package" do
+      Dir.mktmpdir do |tmpdir|
+        extractor = Yast2::PackageExtractor.new(dummy_package_path)
+        extractor.extract(tmpdir)
+
+        # check the extracted content
+        extracted = File.join(tmpdir, dummy_file)
+        expect(File.file?(extracted)).to be(true)
+        expect(File.read(extracted)).to eq(dummy_file_contents)
+      end
+    end
+
+    it "raises ExtractionFailed when the extraction fails" do
+      Dir.mktmpdir do |tmpdir|
+        extractor = Yast2::PackageExtractor.new("non-existing-package")
+        expect {extractor.extract(tmpdir)}.to raise_error(Yast2::PackageExtractor::ExtractionFailed)
+      end
+    end
+  end
+end

package/yast2.spec

@@ -47,6 +47,11 @@ BuildRequires:  yast2-pkg-bindings >= 2.20.3
 BuildRequires:  yast2-ruby-bindings >= 3.1.36
 BuildRequires:  yast2-testsuite
 BuildRequires:  yast2-ycp-ui-bindings >= 3.1.8
+# for the PackageExtractor tests, just make sure they are present,
+# these should be installed in the default build anyway
+BuildRequires:  rpm
+BuildRequires:  cpio
+
 # for ag_tty (/bin/stty)
 # for /usr/bin/md5sum
 Requires:       coreutils
@@ -97,6 +102,10 @@ Requires:       idnkit
 Requires:       bind-utils
 %endif
 Obsoletes:      yast2-devel-doc
+# for the PackageExtractor class, just make sure they are present,
+# these should be present even in a very minimal installation
+Requires:  rpm
+Requires:  cpio
 
 %description
 This package contains scripts and data needed for SUSE Linux