fix(zypp): Reuse the repositories, use libzypp in "chroot" (#1329)

## Problem

- When changing the product from openSUSE Tumleweed to openSUSE MicroOS
the Tumbleweed repository is refreshed again
- The code initializes the libzypp in the Live ISO system, there are
some workarounds to avoid reusing the Live ISO repositories

Related cards:
-
https://trello.com/c/liPX29Cu/3695-5-research-improve-software-management-performance
 

## Solution

- When the changed product uses the same repositories then just reuse
them, do not create the repositories again
- Run libzypp in `/run/agama/zypp` repository to not mess with the
package management from the Live ISO, removed the related workarounds

## Notes

- The reusing is simple all-or-nothing, i.e. the products must use the
very same repositories. In the future we could improve it to allow
reusing just a subset of the repositories.
- Maybe it will need some adoption when the system is registered, but as
there is no real product to register I'm leaving this for the future.
- I put the zypp lock to `/run/agama/zypp` as well, that means now you
can run `zypper` in the Live system while Agama is running, yay!
:star_struck:
- That workaround with switching `Yast::Stage` is not needed anymore, it
was needed when we run the proposal using the YaST code, it is not
needed with the new refactored code.

## Testing

- Tested manually (mvidner: in container, switched products 3 times,
without hitting Install)

service/lib/agama/software/manager.rb

@@ -39,7 +39,6 @@
 Yast.import "Packages"
 Yast.import "PackageCallbacks"
 Yast.import "Pkg"
-Yast.import "Stage"
 
 module Agama
   module Software
@@ -72,6 +71,11 @@ class Manager # rubocop:disable Metrics/ClassLength
       PROPOSAL_ID = "agama-user-software-selection"
       private_constant :PROPOSAL_ID
 
+      # create the libzypp lock and the zypp caches in a special directory to
+      # not be affected by the Live system package management
+      TARGET_DIR = "/run/agama/zypp"
+      private_constant :TARGET_DIR
+
       attr_accessor :languages
 
       # Available products for installation.
@@ -97,6 +101,7 @@ def initialize(config, logger)
         @user_patterns = []
         @selected_patterns_change_callbacks = []
         on_progress_change { logger.info(progress.to_s) }
+        initialize_target
       end
 
       # Selects a product with the given id.
@@ -112,8 +117,10 @@ def select_product(id)
 
         raise ArgumentError unless new_product
 
+        update_repositories(new_product)
+
         @product = new_product
-        repositories.delete_all
+
         update_issues
         true
       end
@@ -124,14 +131,9 @@ def probe
 
         logger.info "Probing software"
 
-        # as we use liveDVD with normal like ENV, lets temporary switch to normal to use its repos
-        Yast::Stage.Set("normal")
-
         if repositories.empty?
-          start_progress(4)
-          store_original_repos
+          start_progress(3)
           Yast::PackageCallbacks.InitPackageCallbacks(logger)
-          progress.step(_("Initializing target repositories")) { initialize_target_repos }
           progress.step(_("Initializing sources")) { add_base_repos }
         else
           start_progress(2)
@@ -140,12 +142,16 @@ def probe
         progress.step(_("Refreshing repositories metadata")) { repositories.load }
         progress.step(_("Calculating the software proposal")) { propose }
 
-        Yast::Stage.Set("initial")
         update_issues
       end
 
-      def initialize_target_repos
-        Yast::Pkg.TargetInitialize("/")
+      def initialize_target
+        # create the zypp lock also in the target directory
+        ENV["ZYPP_LOCKFILE_ROOT"] = TARGET_DIR
+        # cleanup the previous content (after service restart or crash)
+        FileUtils.rm_rf(TARGET_DIR)
+        FileUtils.mkdir_p(TARGET_DIR)
+        Yast::Pkg.TargetInitialize(TARGET_DIR)
         import_gpg_keys
       end
 
@@ -186,14 +192,13 @@ def install
 
       # Writes the repositories information to the installed system
       def finish
-        start_progress(2)
+        start_progress(1)
         progress.step(_("Writing repositories to the target system")) do
           Yast::Pkg.SourceSaveAll
           Yast::Pkg.TargetFinish
           Yast::Pkg.SourceCacheCopyTo(Yast::Installation.destdir)
           registration.finish
         end
-        progress.step(_("Restoring original repositories")) { restore_original_repos }
       end
 
       # Determine whether the given tag is provided by the selected packages
@@ -415,31 +420,6 @@ def add_base_repos
         product.repositories.each { |url| repositories.add(url) }
       end
 
-      REPOS_BACKUP = "/etc/zypp/repos.d.agama.backup"
-      private_constant :REPOS_BACKUP
-
-      REPOS_DIR = "/etc/zypp/repos.d"
-      private_constant :REPOS_DIR
-
-      # ensure that repos backup is there and repos.d is empty
-      def store_original_repos
-        # Backup was already created, so just remove all repos
-        if File.directory?(REPOS_BACKUP)
-          logger.info "removing #{REPOS_DIR}"
-          FileUtils.rm_rf(REPOS_DIR)
-        else # move repos to backup
-          logger.info "moving #{REPOS_DIR} to #{REPOS_BACKUP}"
-          FileUtils.mv(REPOS_DIR, REPOS_BACKUP)
-        end
-      end
-
-      def restore_original_repos
-        logger.info "removing #{REPOS_DIR}"
-        FileUtils.rm_rf(REPOS_DIR)
-        logger.info "moving #{REPOS_BACKUP} to #{REPOS_DIR}"
-        FileUtils.mv(REPOS_BACKUP, REPOS_DIR)
-      end
-
       # Adds resolvables for selected product
       def select_resolvables
         proposal.set_resolvables("agama", :pattern, product.mandatory_patterns)
@@ -514,6 +494,24 @@ def missing_registration?
       def pattern_exist?(pattern_name)
         !Y2Packager::Resolvable.find(kind: :pattern, name: pattern_name).empty?
       end
+
+      # update the zypp repositories for the new product, either delete them
+      # or keep them untouched
+      # @param new_product [Agama::Software::Product] the new selected product
+      def update_repositories(new_product)
+        # reuse the repositories when they are the same as for the previously
+        # selected product
+        # TODO: what about registered products?
+        # TODO: allow a partial match? i.e. keep the same repositories, delete
+        # additional repositories and add missing ones
+        if product&.repositories&.sort == new_product.repositories.sort
+          # the same repositories, we just needed to reset the package selection
+          Yast::Pkg.PkgReset()
+        else
+          # delete all, the #probe call will add the new repos
+          repositories.delete_all
+        end
+      end
     end
   end
 end

service/test/agama/software/manager_test.rb

@@ -50,6 +50,7 @@
       disabled:   disabled_repos
     )
   end
+  let(:products) { [] }
 
   let(:proposal) do
     instance_double(
@@ -126,6 +127,20 @@
         expect(manager.product.id).to eq("test1")
       end
     end
+
+    context "when GPG keys are available at /" do
+      let(:gpg_keys) { ["/usr/lib/gnupg/keys/gpg-key.asc"] }
+
+      it "imports the GPG keys" do
+        expect(Yast::Pkg).to receive(:ImportGPGKey).with(gpg_keys.first, true)
+        described_class.new(config, logger)
+      end
+    end
+
+    it "initializes the package system" do
+      expect(Yast::Pkg).to receive(:TargetInitialize)
+      described_class.new(config, logger)
+    end
   end
 
   shared_examples "software issues" do |tested_method|
@@ -184,35 +199,10 @@
   end
 
   describe "#probe" do
-    let(:rootdir) { Dir.mktmpdir }
-    let(:repos_dir) { File.join(rootdir, "etc", "zypp", "repos.d") }
-    let(:backup_repos_dir) { File.join(rootdir, "etc", "zypp", "repos.d.backup") }
-
     before do
-      stub_const("Agama::Software::Manager::REPOS_DIR", repos_dir)
-      stub_const("Agama::Software::Manager::REPOS_BACKUP", backup_repos_dir)
-      FileUtils.mkdir_p(repos_dir)
       subject.select_product("Tumbleweed")
     end
 
-    after do
-      FileUtils.remove_entry(rootdir)
-    end
-
-    it "initializes the package system" do
-      expect(Yast::Pkg).to receive(:TargetInitialize).with("/")
-      subject.probe
-    end
-
-    context "when GPG keys are available at /" do
-      let(:gpg_keys) { ["/usr/lib/gnupg/keys/gpg-key.asc"] }
-
-      it "imports the GPG keys" do
-        expect(Yast::Pkg).to receive(:ImportGPGKey).with(gpg_keys.first, true)
-        subject.probe
-      end
-    end
-
     it "creates a packages proposal" do
       expect(proposal).to receive(:calculate)
       subject.probe
@@ -351,31 +341,13 @@
   end
 
   describe "#finish" do
-    let(:rootdir) { Dir.mktmpdir }
-    let(:repos_dir) { File.join(rootdir, "etc", "zypp", "repos.d") }
-    let(:backup_repos_dir) { File.join(rootdir, "etc", "zypp", "repos.d.backup") }
-
-    before do
-      stub_const("Agama::Software::Manager::REPOS_DIR", repos_dir)
-      stub_const("Agama::Software::Manager::REPOS_BACKUP", backup_repos_dir)
-      FileUtils.mkdir_p(repos_dir)
-      FileUtils.mkdir_p(backup_repos_dir)
-      FileUtils.touch(File.join(backup_repos_dir, "example.repo"))
-      puts Dir[File.join(repos_dir, "**", "*")]
-    end
-
-    after do
-      FileUtils.remove_entry(rootdir)
-    end
-
-    it "releases the packaging system and restores the backup" do
+    it "releases the packaging system" do
       expect(Yast::Pkg).to receive(:SourceSaveAll)
       expect(Yast::Pkg).to receive(:TargetFinish)
       expect(Yast::Pkg).to receive(:SourceCacheCopyTo)
         .with(Yast::Installation.destdir)
 
       subject.finish
-      expect(File).to exist(File.join(repos_dir, "example.repo"))
     end
   end