ENH: reprotest:lib: add distro abstraction

Many distros may want to use reprotest and the current implementation
depends on the Debian toolchain. Abstract away the debian-specific
toolchain to a separate module, and provide a way to extend this for
cross-distro compatility.

reprotest/lib/adt_testbed.py

@@ -40,6 +40,7 @@
 
 # from debian import debian_support
 
+from reprotest.lib.system_interface.debian import debian_interface
 from reprotest.lib import adtlog
 from reprotest.lib import VirtSubproc
 from reprotest.lib.util import TempPath, Path, killtree
@@ -52,13 +53,14 @@
 class Testbed:
     def __init__(self, vserver_argv, output_dir, user,
                  setup_commands=[], add_apt_pockets=[], copy_files=[]):
+        self.system_interface = debian_interface()
         self.sp = None
         self.lastsend = None
         self.scratch = None
         self.modified = False
         self._need_reset_apt = False
         self.stop_sent = False
-        self.dpkg_arch = None
+        self.system_arch = None
         self.exec_cmd = None
         self.output_dir = output_dir
         self.shared_downtmp = None  # testbed's downtmp on the host, if supported
@@ -212,8 +214,8 @@ def _opened(self, pl):
                     self.user = c.split('=', 1)[1]
 
         # determine testbed architecture
-        self.dpkg_arch = self.check_exec(['dpkg', '--print-architecture'], True).strip()
-        adtlog.info('testbed dpkg architecture: ' + self.dpkg_arch)
+        self.system_arch = self.check_exec(self.system_interface.get_arch_exec(), True).strip()
+        adtlog.info('testbed package architecture: ' + self.system_arch)
 
         # do we have eatmydata?
         (code, out, err) = self.execute(['which', 'eatmydata'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
@@ -222,9 +224,9 @@ def _opened(self, pl):
             self.eatmydata_prefix = [out.strip()]
 
         # record package versions of pristine testbed
-        if self.output_dir and self.execute(['which', 'dpkg-query'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)[0] == 0:
+        if self.output_dir and self.system_interface.can_query_packages():
             pkglist = TempPath(self, 'testbed-packages', autoclean=False)
-            self.check_exec(['sh', '-ec', "dpkg-query --show -f '${Package}\\t${Version}\\n' > %s" % pkglist.tb])
+            self.check_exec(self.system_interface.get_testbed_packages(pkglist))
             pkglist.copyup()
 
         self.post_boot_setup()

reprotest/lib/system_interface/__init__.py

@@ -0,0 +1,26 @@
+# adt_testbed.py is part of autopkgtest
+# autopkgtest is a tool for testing Debian binary packages
+#
+# autopkgtest is Copyright (C) 2006-2015 Canonical Ltd.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# 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.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+#
+# See the file CREDITS for a full list of credits information (often
+# installed as /usr/share/doc/autopkgtest/CREDITS).
+
+class system_interface:
+
+    def __init__ (self):
+        print("lel")

reprotest/lib/system_interface/debian.py

@@ -0,0 +1,56 @@
+# adt_testbed.py is part of autopkgtest
+# autopkgtest is a tool for testing Debian binary packages
+#
+# autopkgtest is Copyright (C) 2006-2015 Canonical Ltd.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# 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.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+#
+# See the file CREDITS for a full list of credits information (often
+# installed as /usr/share/doc/autopkgtest/CREDITS).
+
+import os
+import sys
+import errno
+import time
+import pipes
+import traceback
+import re
+import signal
+import subprocess
+import tempfile
+import shutil
+import urllib.parse
+
+from . import system_interface
+
+# TODO: removing this import disables install_tmp, may want to restore
+# it at some point if I'm improving support for building Debian packages in
+# particular.
+
+class debian_interface(system_interface):
+
+    def get_arch_exec(self):
+        return ['dpkg', '--print-architecture']
+
+    def get_testbed_packages(self, target_file):
+        return ['sh', '-ec', 
+                "dpkg-query --show -f '${Package}\\t${Version}\\n' > %s" % target_file.tb]
+
+    def can_query_packages(self):
+        try:
+            return subprocess.check_call(['which', 'dpkg-query'], stdout=subprocess.DEVNULL) == 0
+        except:
+            return 0
+