Write install-files configuration extension

1 files changed, 109 insertions, 0 deletions

diff --git a/install-files.configure b/install-files.configure
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+++ b/install-files.configure
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+#!/usr/bin/python
+# Copyright (C) 2013  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.
+
+
+''' A Morph configuration extension for adding arbitrary files to a system
+
+It will read the manifest files specified in the environment variable
+INSTALL_FILES, then use the contens of those files to determine which files
+to install into the target system.
+
+'''
+
+import cliapp
+import os
+import re
+import sys
+import shlex
+import shutil
+import stat
+
+class InstallFilesConfigureExtension(cliapp.Application):
+
+    '''Install the files specified in the manifests listed in INSTALL_FILES
+
+    The manifest is formatted as:
+
+        <octal mode> <uid decimal> <gid decimal> <filename>
+
+    Where the filename is how the file is found inside whatever directory
+    the manifest is stored in, and also the path within the system to
+    install to.
+
+    Directories on the target must be created if they do not exist.
+    
+    This extension supports files, symlinks and directories.
+
+    '''
+
+    def process_args(self, args):
+        target_root = args[0]
+        manifests = shlex.split(os.environ['INSTALL_FILES'])
+        for manifest in manifests:
+            self.install_manifest(manifest, target_root)
+
+    def install_manifest(self, manifest, target_root):
+        manifest_dir = os.path.dirname(manifest)
+        with open(manifest) as f:
+            entries = f.readlines()
+            for entry in entries:
+                self.install_entry(entry, manifest_dir, target_root)
+
+    def install_entry(self, entry, manifest_root, target_root):
+        entry_data = re.split('\W+', entry.strip(), maxsplit=3)
+        mode = int(entry_data[0], 8)
+        uid = int(entry_data[1])
+        gid = int(entry_data[2])
+        path = entry_data[3]
+        dest_path = os.path.join(target_root, './' + path)
+        if stat.S_ISDIR(mode):
+            if os.path.exists(dest_path):
+                dest_stat = os.stat(dest_path)
+                if (mode != dest_stat.st_mode
+                    or uid != dest_stat.st_uid
+                    or gid != dest_stat.st_gid):
+                        raise cliapp.AppException('"%s" exists and is not '
+                                                  'identical to directory '
+                                                  '"%s"' % (dest_path, entry))
+            else:
+                os.mkdir(dest_path, mode)
+                os.chown(dest_path, uid, gid)
+
+        elif stat.S_ISLNK(mode):
+            if os.path.lexists(dest_path):
+                raise cliapp.AppException('Symlink already exists at %s'
+                                          % dest_path)
+            else:
+                linkdest = os.readlink(os.path.join(manifest_root,
+                                                    './' + path))
+                os.symlink(linkdest, dest_path)
+                os.lchown(dest_path, uid, gid)
+
+        elif stat.S_ISREG(mode):
+            if os.path.exists(dest_path):
+                raise cliapp.AppException('File already exists at %s'
+                                           % dest_path)
+            else:
+                shutil.copyfile(os.path.join(manifest_root, './' + path),
+                                dest_path)
+                os.chmod(dest_path, mode)
+                os.chown(dest_path, uid, gid)
+
+        else:
+            raise cliapp.AppException('Mode given in "%s" is not a file,'
+                                      ' symlink or directory' % entry)
+
+InstallFilesConfigureExtension().run()