Packages: Add Essential packages to specification (#1084)

Signed-off-by: Sol Jerome <sol.jerome@gmail.com>

5 files changed, 30 insertions, 12 deletions

diff --git a/doc/server/plugins/generators/packages.txt b/doc/server/plugins/generators/packages.txt
index e4035053a..2bc3dab31 100644
--- a/doc/server/plugins/generators/packages.txt
+++ b/doc/server/plugins/generators/packages.txt
@@ -205,14 +205,13 @@ something like this::
 
     .. versionadded:: 1.1.0
 
-    The default behavior of the Packages plugin is to not make
-    any assumptions about which packages you want to have added
-    automatically. For that reason, neither **Recommended** nor
-    **Suggested** packages are added as dependencies by default. You
-    will notice that the default behavior for apt is to add Recommended
-    packages as dependencies. You can configure the Packages plugin to
-    add recommended packages by adding the ``recommended`` attribute,
-    e.g.:
+    The default behavior of the Packages plugin is to not make any
+    assumptions about which packages you want to have added automatically
+    [#f1]_. For that reason, neither **Recommended** nor **Suggested**
+    packages are added as dependencies by default. You will notice
+    that the default behavior for apt is to add Recommended packages as
+    dependencies. You can configure the Packages plugin to add recommended
+    packages by adding the ``recommended`` attribute, e.g.:
 
     .. code-block:: xml
 
@@ -221,6 +220,14 @@ something like this::
     .. warning:: You must regenerate the Packages cache when adding or
                  removing the recommended attribute.
 
+    .. [#f1] Bcfg2 will by default add **Essential** packages to the
+             client specification. You can disable this behavior by
+             setting the ``essential`` attribute to *false*:
+
+    .. code-block:: xml
+
+        <Source type="apt" essential="false" ...>
+
 Yum sources can be similarly specified::
 
     <Sources>
diff --git a/src/lib/Bcfg2/Server/Plugins/Packages/Apt.py b/src/lib/Bcfg2/Server/Plugins/Packages/Apt.py
index f76bf7fa1..cbe2b4f2c 100644
--- a/src/lib/Bcfg2/Server/Plugins/Packages/Apt.py
+++ b/src/lib/Bcfg2/Server/Plugins/Packages/Apt.py
@@ -12,6 +12,7 @@ class AptCollection(Collection):
 class AptSource(Source):
     basegroups = ['apt', 'debian', 'ubuntu', 'nexenta']
     ptype = 'deb'
+    essentialpkgs = set()
 
     def __init__(self, basepath, xsource, config):
         Source.__init__(self, basepath, xsource, config)
@@ -50,10 +51,9 @@ class AptSource(Source):
     def read_files(self):
         bdeps = dict()
         bprov = dict()
+        depfnames = ['Depends', 'Pre-Depends']
         if self.recommended:
-            depfnames = ['Depends', 'Pre-Depends', 'Recommends']
-        else:
-            depfnames = ['Depends', 'Pre-Depends']
+            depfnames.append('Recommends')
         for fname in self.files:
             if not self.rawurl:
                 barch = [x
@@ -77,6 +77,8 @@ class AptSource(Source):
                     pkgname = words[1].strip().rstrip()
                     self.pkgnames.add(pkgname)
                     bdeps[barch][pkgname] = []
+                elif words[0] == 'Essential' and self.essential:
+                    self.essentialpkgs.add(pkgname)
                 elif words[0] in depfnames:
                     vindex = 0
                     for dep in words[1].split(','):
diff --git a/src/lib/Bcfg2/Server/Plugins/Packages/Collection.py b/src/lib/Bcfg2/Server/Plugins/Packages/Collection.py
index 59c50fe8b..959dac03b 100644
--- a/src/lib/Bcfg2/Server/Plugins/Packages/Collection.py
+++ b/src/lib/Bcfg2/Server/Plugins/Packages/Collection.py
@@ -97,6 +97,12 @@ class Collection(Bcfg2.Server.Plugin.Debuggable):
                 return source.get_deps(self.metadata, package)
         return []
 
+    def get_essential(self):
+        essential = set()
+        for source in self.sources:
+            essential |= source.essentialpkgs
+        return essential
+
     def get_provides(self, package):
         for source in self.sources:
             providers = source.get_provides(self.metadata, package)
diff --git a/src/lib/Bcfg2/Server/Plugins/Packages/Source.py b/src/lib/Bcfg2/Server/Plugins/Packages/Source.py
index b33fde60a..5394a4bbd 100644
--- a/src/lib/Bcfg2/Server/Plugins/Packages/Source.py
+++ b/src/lib/Bcfg2/Server/Plugins/Packages/Source.py
@@ -54,6 +54,7 @@ class Source(Bcfg2.Server.Plugin.Debuggable):
 
         self.gpgkeys = [el.text for el in xsource.findall("GPGKey")]
 
+        self.essential = xsource.get('essential', 'true').lower() == 'true'
         self.recommended = xsource.get('recommended', 'false').lower() == 'true'
 
         self.rawurl = xsource.get('rawurl', '')
diff --git a/src/lib/Bcfg2/Server/Plugins/Packages/__init__.py b/src/lib/Bcfg2/Server/Plugins/Packages/__init__.py
index 0d5e7d50f..e4793a28d 100644
--- a/src/lib/Bcfg2/Server/Plugins/Packages/__init__.py
+++ b/src/lib/Bcfg2/Server/Plugins/Packages/__init__.py
@@ -146,6 +146,8 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
         initial = set()
         # base is the set of initial packages with groups expanded
         base = set()
+        # essential pkgs are those marked as such by the distribution
+        essential = collection.get_essential()
         to_remove = []
         for struct in structures:
             for pkg in struct.xpath('//Package | //BoundPackage'):
@@ -167,7 +169,7 @@ class Packages(Bcfg2.Server.Plugin.Plugin,
                 else:
                     self.logger.error("Packages: Malformed Package: %s" %
                                       lxml.etree.tostring(pkg))
-        base.update(initial)
+        base.update(initial | essential)
         for el in to_remove:
             el.getparent().remove(el)