Support dnf when specified or yum is missing

* handle install/upgrade, version checks, and downgrades

* Allow users to specify packages to be installed with dnf

* Use dnf if yum isn't available, letting older cloud-configs work on
  future Fedoras

Change-Id: Ib3ff49cfdd3e545aa199c944c110852700625496

heat_cfntools/cfntools/cfn_helper.py

@@ -290,6 +290,20 @@ class RpmHelper(object):
         command = CommandRunner(cmd_str).run()
         return command.status == 0
 
+    @classmethod
+    def dnf_package_available(cls, pkg):
+        """Indicates whether pkg is available via dnf.
+
+        Arguments:
+            pkg -- A package name (with optional version and release spec).
+                   e.g., httpd
+                   e.g., httpd-2.2.22
+                   e.g., httpd-2.2.22-1.fc21
+        """
+        cmd_str = "dnf -y --showduplicates list available %s" % pkg
+        command = CommandRunner(cmd_str).run()
+        return command.status == 0
+
     @classmethod
     def zypper_package_available(cls, pkg):
         """Indicates whether pkg is available via zypper.
@@ -305,8 +319,8 @@ class RpmHelper(object):
         return command.status == 0
 
     @classmethod
-    def install(cls, packages, rpms=True, zypper=False):
-        """Installs (or upgrades) a set of packages via RPM or via Yum.
+    def install(cls, packages, rpms=True, zypper=False, dnf=False):
+        """Installs (or upgrades) packages via RPM, yum, dnf, or zypper.
 
         Arguments:
             packages -- a list of packages to install
@@ -320,6 +334,11 @@ class RpmHelper(object):
                           - pkg name with version spec (httpd-2.2.22), or
                           - pkg name with version-release spec
                             (httpd-2.2.22-1.fc16)
+            zypper   -- if True:
+                        * overrides use of yum, use zypper instead
+            dnf      -- if True:
+                        * overrides use of yum, use dnf instead
+                        * packages must be in same format as yum pkg list
         """
         if rpms:
             cmd = "rpm -U --force --nosignature "
@@ -329,6 +348,11 @@ class RpmHelper(object):
             cmd = "zypper -n install "
             cmd += " ".join(packages)
             LOG.info("Installing packages: %s" % cmd)
+        elif dnf:
+            # use dnf --best to upgrade outdated-but-installed packages
+            cmd = "dnf -y --best install "
+            cmd += " ".join(packages)
+            LOG.info("Installing packages: %s" % cmd)
         else:
             cmd = "yum -y install "
             cmd += " ".join(packages)
@@ -338,8 +362,8 @@ class RpmHelper(object):
             LOG.warn("Failed to install packages: %s" % cmd)
 
     @classmethod
-    def downgrade(cls, packages, rpms=True, zypper=False):
-        """Downgrades a set of packages via RPM or via Yum.
+    def downgrade(cls, packages, rpms=True, zypper=False, dnf=False):
+        """Downgrades a set of packages via RPM, yum, dnf, or zypper.
 
         Arguments:
             packages -- a list of packages to downgrade
@@ -352,6 +376,8 @@ class RpmHelper(object):
                           - pkg name with version spec (httpd-2.2.22), or
                           - pkg name with version-release spec
                             (httpd-2.2.22-1.fc16)
+            dnf     -- if True:
+                       * Use dnf instead of RPM/yum
         """
         if rpms:
             cls.install(packages)
@@ -362,6 +388,13 @@ class RpmHelper(object):
             command = CommandRunner(cmd).run()
             if command.status:
                 LOG.warn("Failed to downgrade packages: %s" % cmd)
+        elif dnf:
+            cmd = "dnf -y downgrade "
+            cmd += " ".join(packages)
+            LOG.info("Downgrading packages: %s", cmd)
+            command = CommandRunner(cmd).run()
+            if command.status:
+                LOG.warn("Failed to downgrade packages: %s" % cmd)
         else:
             cmd = "yum -y downgrade "
             cmd += " ".join(packages)
@@ -374,7 +407,7 @@ class RpmHelper(object):
 class PackagesHandler(object):
     _packages = {}
 
-    _package_order = ["dpkg", "rpm", "apt", "yum"]
+    _package_order = ["dpkg", "rpm", "apt", "yum", "dnf"]
 
     @staticmethod
     def _pkgsort(pkg1, pkg2):
@@ -460,6 +493,51 @@ class PackagesHandler(object):
         if downgrades:
             RpmHelper.downgrade(downgrades, zypper=True)
 
+    def _handle_dnf_packages(self, packages):
+        """Handle installation, upgrade, or downgrade of packages via dnf.
+
+        Arguments:
+        packages -- a package entries map of the form:
+                      "pkg_name" : "version",
+                      "pkg_name" : ["v1", "v2"],
+                      "pkg_name" : []
+
+        For each package entry:
+          * if no version is supplied and the package is already installed, do
+            nothing
+          * if no version is supplied and the package is _not_ already
+            installed, install it
+          * if a version string is supplied, and the package is already
+            installed, determine whether to downgrade or upgrade (or do nothing
+            if version matches installed package)
+          * if a version array is supplied, choose the highest version from the
+            array and follow same logic for version string above
+        """
+        # collect pkgs for batch processing at end
+        installs = []
+        downgrades = []
+        for pkg_name, versions in packages.iteritems():
+            ver = RpmHelper.newest_rpm_version(versions)
+            pkg = "%s-%s" % (pkg_name, ver) if ver else pkg_name
+            if RpmHelper.rpm_package_installed(pkg):
+                # FIXME:print non-error, but skipping pkg
+                pass
+            elif not RpmHelper.dnf_package_available(pkg):
+                LOG.warn("Skipping package '%s'. Not available via yum" % pkg)
+            elif not ver:
+                installs.append(pkg)
+            else:
+                current_ver = RpmHelper.rpm_package_version(pkg)
+                rc = RpmHelper.compare_rpm_versions(current_ver, ver)
+                if rc < 0:
+                    installs.append(pkg)
+                elif rc > 0:
+                    downgrades.append(pkg)
+        if installs:
+            RpmHelper.install(installs, rpms=False, dnf=True)
+        if downgrades:
+            RpmHelper.downgrade(downgrades, rpms=False, dnf=True)
+
     def _handle_yum_packages(self, packages):
         """Handle installation, upgrade, or downgrade of packages via yum.
 
@@ -480,6 +558,17 @@ class PackagesHandler(object):
           * if a version array is supplied, choose the highest version from the
             array and follow same logic for version string above
         """
+
+        cmd = CommandRunner("which yum").run()
+        if cmd.status == 1:
+            # yum not available, use DNF if available
+            self._handle_dnf_packages(packages)
+            return
+        elif cmd.status == 127:
+            # `which` command not found
+            LOG.info("`which` not found. Using yum without checking if dnf "
+                     "is available")
+
         # collect pkgs for batch processing at end
         installs = []
         downgrades = []
@@ -531,6 +620,7 @@ class PackagesHandler(object):
 
     # map of function pointers to handle different package managers
     _package_handlers = {"yum": _handle_yum_packages,
+                         "dnf": _handle_dnf_packages,
                          "zypper": _handle_zypper_packages,
                          "rpm": _handle_rpm_packages,
                          "apt": _handle_apt_packages,
@@ -552,6 +642,7 @@ class PackagesHandler(object):
           * rpm
           * apt
           * yum
+          * dnf
         """
         if not self._packages:
             return

heat_cfntools/tests/test_cfn_helper.py

@@ -82,6 +82,9 @@ class TestPackages(MockPopenTestCase):
 
     def test_yum_install(self):
         install_list = []
+        self.mock_unorder_cmd_run(
+            ['su', 'root', '-c', 'which yum']) \
+            .AndReturn(FakePOpen(returncode=0))
         for pack in ('httpd', 'wordpress', 'mysql-server'):
             self.mock_unorder_cmd_run(
                 ['su', 'root', '-c', 'rpm -q %s' % pack]) \
@@ -110,6 +113,71 @@ class TestPackages(MockPopenTestCase):
         cfn_helper.PackagesHandler(packages).apply_packages()
         self.m.VerifyAll()
 
+    def test_dnf_install_yum_unavailable(self):
+        install_list = []
+        self.mock_unorder_cmd_run(
+            ['su', 'root', '-c', 'which yum']) \
+            .AndReturn(FakePOpen(returncode=1))
+        pkgs = ('httpd', 'mysql-server', 'wordpress')
+        for pack in pkgs:
+            self.mock_unorder_cmd_run(
+                ['su', 'root', '-c', 'rpm -q %s' % pack]) \
+                .AndReturn(FakePOpen(returncode=1))
+            self.mock_unorder_cmd_run(
+                ['su', 'root', '-c',
+                 'dnf -y --showduplicates list available %s' % pack]) \
+                .AndReturn(FakePOpen(returncode=0))
+            install_list.append(pack)
+
+        # This mock call corresponding to 'su root -c dnf -y list upgrades .*'
+        # and 'su root -c dnf -y install .*'
+        # But there is no way to ignore the order of the parameters, so only
+        # check the return value.
+        self.mock_cmd_run(mox.IgnoreArg()).AndReturn(FakePOpen(
+            returncode=0))
+
+        self.m.ReplayAll()
+        packages = {
+            "yum": {
+                "mysql-server": [],
+                "httpd": [],
+                "wordpress": []
+            }
+        }
+
+        cfn_helper.PackagesHandler(packages).apply_packages()
+        self.m.VerifyAll()
+
+    def test_dnf_install(self):
+        install_list = []
+        for pack in ('httpd', 'wordpress', 'mysql-server'):
+            self.mock_unorder_cmd_run(
+                ['su', 'root', '-c', 'rpm -q %s' % pack]) \
+                .AndReturn(FakePOpen(returncode=1))
+            self.mock_unorder_cmd_run(
+                ['su', 'root', '-c',
+                 'dnf -y --showduplicates list available %s' % pack]) \
+                .AndReturn(FakePOpen(returncode=0))
+            install_list.append(pack)
+
+        # This mock call corresponding to 'su root -c dnf -y --best install .*'
+        # But there is no way to ignore the order of the parameters, so only
+        # check the return value.
+        self.mock_cmd_run(mox.IgnoreArg()).AndReturn(FakePOpen(
+            returncode=0))
+
+        self.m.ReplayAll()
+        packages = {
+            "dnf": {
+                "mysql-server": [],
+                "httpd": [],
+                "wordpress": []
+            }
+        }
+
+        cfn_helper.PackagesHandler(packages).apply_packages()
+        self.m.VerifyAll()
+
     def test_zypper_install(self):
         install_list = []
         for pack in ('httpd', 'wordpress', 'mysql-server'):