From 000a832751563cfe571363a27e293fd3d9db31a4 Mon Sep 17 00:00:00 2001
From: Alexander Sulfrian <asulfrian@zedat.fu-berlin.de>
Date: Sun, 16 Jan 2022 07:43:05 +0100
Subject: Packages: Support different compression methods

The new Reader classes implement different compression methods for the files
parsed by the Packages backends. Each source can specify a default compression
format. The user can configure a compression format per Source and the filename
and extension for the metadata files are generated automatically.
---
 src/lib/Bcfg2/Server/Plugins/Packages/Source.py | 39 +++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

(limited to 'src/lib/Bcfg2/Server/Plugins/Packages/Source.py')

diff --git a/src/lib/Bcfg2/Server/Plugins/Packages/Source.py b/src/lib/Bcfg2/Server/Plugins/Packages/Source.py
index 86f7698f7..c80604d01 100644
--- a/src/lib/Bcfg2/Server/Plugins/Packages/Source.py
+++ b/src/lib/Bcfg2/Server/Plugins/Packages/Source.py
@@ -49,6 +49,7 @@ in your ``Source`` subclass.  For an example of this kind of
 import os
 import re
 import sys
+import Bcfg2.Options
 from Bcfg2.Logger import Debuggable
 from Bcfg2.Compat import HTTPError, HTTPBasicAuthHandler, \
     HTTPPasswordMgrWithDefaultRealm, install_opener, build_opener, urlopen, \
@@ -111,6 +112,12 @@ class Source(Debuggable):  # pylint: disable=R0902
     #: when they are handled by :mod:`Bcfg2.Server.Plugins.Packages`.
     ptype = None
 
+    #: The default compression format used by this Source class. This
+    #: is the file the package metadata files should be loaded. It is
+    #: used if a source has no custom compression format specified
+    #: in the :attr:`server_options`.
+    default_compression = 'None'
+
     def __init__(self, basepath, xsource):  # pylint: disable=R0912
         """
         :param basepath: The base filesystem path under which cache
@@ -328,6 +335,38 @@ class Source(Debuggable):  # pylint: disable=R0902
                     self.conditions.append(lambda m, el=el:
                                            el.get("name") == m.hostname)
 
+    def _get_reader(self):
+        ctype = self.default_compression
+        if 'compression' in self.server_options:
+            ctype = self.server_options['compression']
+
+        for mod in Bcfg2.Options.setup.packages_readers:
+            if mod.__name__.endswith(".%s" % ctype.title()):
+                return getattr(mod, "%sReader" % ctype.title())
+
+        raise ValueError("Packages: Unknown compression type %s" % ctype)
+
+    def _get_extension(self):
+        cls = self._get_reader()
+        if cls.extension is None:
+            raise ValueError("%s does not define an extension" %
+                             cls.__name__)
+        return cls.extension
+
+    def build_filename(self, basename):
+        extension = self._get_extension()
+        if extension == '':
+            return basename
+        return "%s.%s" % (basename, extension)
+
+    def open_file(self, fname):
+        try:
+            cls = self._get_reader()
+            return cls(fname)
+        except IOError:
+            self.logger.error("Packages: Failed to read file %s" % fname)
+            raise
+
     @property
     def cachekey(self):
         """ A unique key for this source that will be used to generate
-- 
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