better search/download of rpms

Search only for installed packages, but download only available.
If the package is not available (anymore?) in repos, try to diff
with cached rpm file (can be downloaded manually by end-user).

Author: praiskup

dnf-plugins/diff.py

@@ -46,13 +46,11 @@ def configure(self):
         )
 
     def _resolve_local_package(self, name):
-        self.base.fill_sack()
         subj = dnf.subject.Subject(name)
         q = subj.get_best_query(self.base.sack)
-        q = q.available()
-        q = q.latest()
+        q = q.installed()
         if len(q.run()) == 0:
-            msg = _("No package %s available.") % (name)
+            msg = _("No package %s is installed.") % (name)
             raise dnf.exceptions.PackageNotFoundError(msg)
 
         return list(q)
@@ -77,6 +75,7 @@ def _diff_package(self, package, package_name, files):
                              rpm_file_name,
                              fname])
 
+
     def _list_of_changed_files(self, package):
         proc = subprocess.Popen(
             ['/usr/libexec/dnf-diff-changed-files', package],
@@ -85,9 +84,31 @@ def _list_of_changed_files(self, package):
         lines = [x.decode('ascii').rstrip() for x in proc.stdout.readlines()]
         return lines
 
+
+    def _download_packages(self, to_download):
+        pkg_list = []
+        for pkg in to_download:
+            pkg_spec = '{name}-{evr}.{arch}'.format(
+                    name=pkg.name,
+                    evr=pkg.evr,
+                    arch=pkg.arch,
+            )
+            subj = dnf.subject.Subject(pkg_spec)
+
+            q = subj.get_best_query(self.base.sack).available().latest()
+            if not list(q):
+                logger.warning(_("package {0} not available in repos, trying local cache".format(pkg_spec)))
+            else:
+                pkg_list.extend(list(q))
+
+        self.base.download_packages(pkg_list)
+
+
     def run(self):
+        self.base.fill_sack()
+
         to_download = self._resolve_local_package(self.opts.pkg)
-        self.base.download_packages(to_download)
+        self._download_packages(to_download)
 
         for pkg in to_download:
             check_pkg = '{0}.{1}'.format(pkg.name, pkg.arch)

rpm/dnf-plugin-diff.spec

@@ -2,7 +2,7 @@
 
 Name:           dnf-plugin-diff
 Version:        0.0
-Release:        1%{?dist}
+Release:        2%{?dist}
 Summary:        Diff changes in packages
 BuildArch: noarch