morphlib: add buildenvironment and tests

BuildEnvironment should contain all the information about whatever
settings affect the build. A subset of these will affect the cache
key, but CacheKeyComputer filters them itself.

BuildEnvironment has consumed the purpose of Morph.clean_env() because
the build environment is a good place to store this information.

The environment variables are decided based on the current settings.
The current environment can be accessed by the env attribute.

The tests are a little invasive because it reads environment variables
and most of the work is done in the constructor, but they should test
everything useful.

1 files changed, 97 insertions, 0 deletions

diff --git a/morphlib/buildenvironment.py b/morphlib/buildenvironment.py
new file mode 100644
index 00000000..a9395ec4
--- /dev/null
+++ b/morphlib/buildenvironment.py
@@ -0,0 +1,97 @@
+# Copyright (C) 2012  Codethink Limited
+# 
+# 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; version 2 of the License.
+# 
+# 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.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+import os
+
+import morphlib
+
+class BuildEnvironment():
+
+    def __init__(self, settings, arch=None):
+        self.arch = morphlib.util.arch() if arch == None else arch
+        self.env = self._clean_env(settings)
+
+    _osenv = os.environ
+    _default_path = '/sbin:/usr/sbin:/bin:/usr/bin'
+    _override_term = 'dumb'
+    _override_shell = '/bin/sh'
+    _override_username = 'tomjon'
+    _override_locale = 'C'
+    _override_home = '/tmp'
+    _ccache_path = '/usr/lib/ccache'
+
+    def _clean_env(self, settings):
+        '''Create a fresh set of environment variables for a clean build.
+        
+        Return a dict with the new environment.
+        
+        '''
+        
+        path = self._osenv['PATH']
+
+        # copy a set of white-listed variables from the original env
+        copied_vars = dict.fromkeys([
+            'DISTCC_HOSTS',
+            'TMPDIR',
+            'LD_PRELOAD',
+            'LD_LIBRARY_PATH',
+            'FAKEROOTKEY',
+            'FAKED_MODE',
+            'FAKEROOT_FD_BASE',
+        ])
+        for name in copied_vars:
+            copied_vars[name] = self._osenv.get(name, None)
+
+        env = {}
+        
+        # apply the copied variables to the clean env
+        for name in copied_vars:
+            if copied_vars[name] is not None:
+                env[name] = copied_vars[name]
+
+        env['TERM'] = self._override_term
+        env['SHELL'] = self._override_shell
+        env['USER'] = \
+            env['USERNAME'] = \
+            env['LOGNAME'] = self._override_username
+        env['LC_ALL'] = self._override_locale
+        env['HOME'] = self._override_home
+
+        if settings['keep-path'] or settings['bootstrap']:
+            env['PATH'] = path
+        else:
+            env['PATH'] = self._default_path
+
+        env['TOOLCHAIN_TARGET'] = settings['toolchain-target']
+        env['CFLAGS'] = settings['target-cflags']
+        env['PREFIX'] = settings['prefix']
+        env['BOOTSTRAP'] = 'true' if settings['bootstrap'] else 'false'
+        if not settings['no-ccache']:
+            env['PATH'] = ('%s:%s' % (self._ccache_path, env['PATH']))
+# FIXME: we should set CCACHE_BASEDIR so any objects that refer to their
+#        current directory get corrected. This improve the cache hit rate
+#            env['CCACHE_BASEDIR'] = self.tempdir.dirname
+            env['CCACHE_EXTRAFILES'] = ':'.join(
+                f for f in ('/baserock/binutils.meta',
+                            '/baserock/eglibc.meta',
+                            '/baserock/gcc.meta') if os.path.exists(f)
+            )
+            if settings['ccache-remotedir'] != '':
+                env['CCACHE_REMOTEDIR'] = settings['ccache-remotedir']
+            env['CCACHE_REMOTENLEVELS'] = str(settings['ccache-remotenlevels'])
+            if not settings['no-distcc']:
+                env['CCACHE_PREFIX'] = 'distcc'
+            
+        return env