Ditch all use of pyanaconda's simpleconfig

lorax uses pyanaconda's SimpleConfigParser in three different
places (twice with a copy that's been dumped into pylorax, once
by importing it), just to do a fairly simple job: read some
values out of /etc/os-release. The only value SimpleConfigParser
is adding over Python's own ConfigParser here is to read a file
with no section headers, and to unquote the values. The cost is
either a dependency on pyanaconda, or needing to copy the whole
of simpleparser plus some other utility bits from pyanaconda
into lorax. This seems like a bad trade-off.

This changes the approach: we copy one very simple utility
function from pyanaconda (`unquote`), and do some very simple
wrapping of ConfigParser to handle reading a file without any
section headers, and returning unquoted values. This way we can
read what we need out of os-release without needing a dep on
pyanaconda or to copy lots of things from it into pylorax.

Resolves: #449
Resolves: #450

Signed-off-by: Adam Williamson <awilliam@redhat.com>

src/pylorax/api/compose.py

@@ -40,8 +40,6 @@ import pytoml as toml
 import shutil
 from uuid import uuid4
 
-from pyanaconda.simpleconfig import SimpleConfigFile
-
 # Use pykickstart to calculate disk image size
 from pykickstart.parser import KickstartParser
 from pykickstart.version import makeVersion
@@ -51,7 +49,7 @@ from pylorax.api.projects import ProjectsError
 from pylorax.api.recipes import read_recipe_and_id
 from pylorax.api.timestamp import TS_CREATED, write_timestamp
 from pylorax.imgutils import default_image_name
-from pylorax.sysutils import joinpaths
+from pylorax.sysutils import joinpaths, flatconfig
 
 
 def test_templates(dbo, share_dir):
@@ -356,14 +354,13 @@ def start_build(cfg, dnflock, gitlock, branch, recipe_name, compose_type, test_m
     # Get the title, project, and release version from the host
     if not os.path.exists("/etc/os-release"):
         log.error("/etc/os-release is missing, cannot determine product or release version")
-    os_release = SimpleConfigFile("/etc/os-release")
+    os_release = flatconfig("/etc/os-release")
-    os_release.read()
 
-    log.debug("os_release = %s", os_release)
+    log.debug("os_release = %s", dict(os_release.items()))
 
-    cfg_args["title"] = os_release.get("PRETTY_NAME")
+    cfg_args["title"] = os_release.get("PRETTY_NAME", "")
-    cfg_args["project"] = os_release.get("NAME")
+    cfg_args["project"] = os_release.get("NAME", "")
-    cfg_args["releasever"] = os_release.get("VERSION_ID")
+    cfg_args["releasever"] = os_release.get("VERSION_ID", "")
     cfg_args["volid"] = ""
 
     cfg_args.update({

src/pylorax/api/dnfbase.py

@@ -26,7 +26,7 @@ import os
 import shutil
 
 from pylorax import DEFAULT_PLATFORM_ID
-from pylorax.simpleconfig import SimpleConfigFile
+from pylorax.sysutils import flatconfig
 
 def get_base_object(conf):
     """Get the DNF object with settings from the config file
@@ -76,9 +76,8 @@ def get_base_object(conf):
         log.warning("/etc/os-release is missing, cannot determine platform id, falling back to %s", DEFAULT_PLATFORM_ID)
         platform_id = DEFAULT_PLATFORM_ID
     else:
-        os_release = SimpleConfigFile("/etc/os-release")
+        os_release = flatconfig("/etc/os-release")
-        os_release.read()
+        platform_id = os_release.get("PLATFORM_ID", DEFAULT_PLATFORM_ID)
-        platform_id = os_release.get("PLATFORM_ID") or DEFAULT_PLATFORM_ID
     log.info("Using %s for module_platform_id", platform_id)
     dbc.module_platform_id = platform_id
 

src/pylorax/simpleconfig.py

@@ -1,203 +0,0 @@
-#
-# simpleconifg.py - representation of a simple configuration file (sh-like)
-#
-# Copyright (C) 1999-2015 Red Hat, Inc.
-#
-# This copyrighted material is made available to anyone wishing to use,
-# modify, copy, or redistribute it subject to the terms and conditions of
-# the GNU General Public License v.2, or (at your option) any later version.
-# This program is distributed in the hope that it will be useful, but WITHOUT
-# ANY WARRANTY expressed or implied, including the implied warranties 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.  Any Red Hat trademarks that are incorporated in the
-# source code or documentation are not subject to the GNU General Public
-# License and may only be used or replicated with the express permission of
-# Red Hat, Inc.
-#
-import os
-import shlex
-import string  # pylint: disable=deprecated-module
-import tempfile
-from pyanaconda.core.util import upperASCII
-
-_SAFECHARS = frozenset(string.ascii_letters + string.digits + '@%_-+=:,./')
-
-def unquote(s):
-    return ' '.join(shlex.split(s))
-
-def quote(s, always=False):
-    """ If always is set it returns a quoted value
-    """
-    if not always:
-        for c in s:
-            if c not in _SAFECHARS:
-                break
-        else:
-            return s
-    return '"' + s.replace('"', '\\"') + '"'
-
-def find_comment(s):
-    """ Look for a # comment outside of a quoted string.
-        If there are no quotes, find the last # in the string.
-
-        :param str s: string to check for comment and quotes
-        :returns: index of comment or None
-        :rtype: int or None
-
-        Handles comments inside quotes and quotes inside quotes.
-    """
-    q = None
-    for i in range(len(s)):
-        if not q and s[i] == '#':
-            return i
-
-        # Ignore quotes inside other quotes
-        if s[i] in "'\"":
-            if s[i] == q:
-                q = None
-            elif q is None:
-                q = s[i]
-    return None
-
-
-def write_tmpfile(filename, data):
-    # Create a temporary in the same directory as the target file to ensure
-    # the new file is on the same filesystem
-    tmpf = tempfile.NamedTemporaryFile(mode="w", delete=False,
-                                       dir=os.path.dirname(filename) or '.',
-                                       prefix="." + os.path.basename(filename))
-    tmpf.write(data)
-    tmpf.close()
-
-    # Change the permissions (currently 0600) to match the original file
-    if os.path.exists(filename):
-        m = os.stat(filename).st_mode
-    else:
-        m = 0o0644
-    os.chmod(tmpf.name, m)
-
-    # Move the temporary file over the top of the original
-    os.rename(tmpf.name, filename)
-
-class SimpleConfigFile(object):
-    """ Edit values in a configuration file without changing comments.
-        Supports KEY=VALUE lines and ignores everything else.
-        Supports adding new keys.
-        Supports deleting keys.
-        Preserves comment, blank lines and comments on KEY lines
-        Does not support duplicate key entries.
-    """
-    def __init__(self, filename=None, read_unquote=True, write_quote=True,
-                 always_quote=False):
-        self.filename = filename
-        self.read_unquote = read_unquote
-        self.write_quote = write_quote
-        self.always_quote = always_quote
-        self.reset()
-
-    def reset(self):
-        self._lines = []
-        self.info = {}
-
-    def read(self, filename=None):
-        """ passing filename will override the filename passed to init.
-
-            save the lines into self._lines and the key/value pairs into
-            self.info
-        """
-        filename = filename or self.filename
-        with open(filename) as f:
-            for line in f:
-                self._lines.append(line)
-                key, value, _comment = self._parseline(line)
-                if key:
-                    self.info[key] = value
-
-    def write(self, filename=None, use_tmp=True):
-        """ passing filename will override the filename passed to init.
-        """
-        filename = filename or self.filename
-        if not filename:
-            return None
-
-        if use_tmp:
-            write_tmpfile(filename, str(self))
-        else:
-            # write directly to the file
-            with open(filename, "w") as fobj:
-                fobj.write(str(self))
-
-    def set(self, *args):
-        for key, value in args:
-            self.info[upperASCII(key)] = value
-
-    def unset(self, *keys):
-        for key in (upperASCII(k) for k in keys):
-            if key in self.info:
-                del self.info[key]
-
-    def get(self, key):
-        return self.info.get(upperASCII(key), "")
-
-    def _parseline(self, line):
-        """ parse a line into a key, value and comment
-
-            :param str line: Line to be parsed
-            :returns: Tuple of key, value, comment
-            :rtype: tuple
-
-            Handle comments and optionally unquote quoted strings
-            Returns (key, value, comment) or (None, None, comment)
-            key is always UPPERCASE and comment may by "" if none was found.
-        """
-        s = line.strip()
-        # Look for a # outside any quotes
-        comment = ""
-        comment_index = find_comment(s)
-        if comment_index is not None:
-            comment = s[comment_index:]
-            s = s[:comment_index]   # remove from comment to EOL
-
-        key, eq, val = s.partition('=')
-        key = key.strip()
-        val = val.strip()
-        if self.read_unquote:
-            val = unquote(val)
-        if key != '' and eq == '=':
-            return (upperASCII(key), val, comment)
-        else:
-            return (None, None, comment)
-
-    def _kvpair(self, key, comment=""):
-        value = self.info[key]
-        if self.write_quote or self.always_quote:
-            value = quote(value, self.always_quote)
-        if comment:
-            comment = " " + comment
-        return key + '=' + value + comment + "\n"
-
-    def __str__(self):
-        """ Return the file that was read, replacing existing keys with new values
-            removing keys that have been deleted and adding new keys.
-        """
-        oldkeys = []
-        s = ""
-        for line in self._lines:
-            key, _value, comment = self._parseline(line)
-            if key is None:
-                s += line
-            else:
-                if key not in self.info:
-                    continue
-                oldkeys.append(key)
-                s += self._kvpair(key, comment)
-
-        # Add new keys
-        for key in self.info:
-            if key not in oldkeys:
-                s += self._kvpair(key)
-
-        return s

src/pylorax/sysutils.py

@@ -30,6 +30,8 @@ import pwd
 import grp
 import glob
 import shutil
+import shlex
+from configparser import ConfigParser
 
 from pylorax.executils import runcmd
 
@@ -106,3 +108,24 @@ def remove(target):
 
 def linktree(src, dst):
     runcmd(["/bin/cp", "-alx", src, dst])
+
+def unquote(s):
+    return ' '.join(shlex.split(s))
+
+class UnquotingConfigParser(ConfigParser):
+    """A ConfigParser, only with unquoting of the values."""
+    def get(self, *args, **kwargs):
+        ret = super().get(*args, **kwargs)
+        if ret:
+            ret = unquote(ret)
+        return ret
+
+def flatconfig(filename):
+    """Use UnquotingConfigParser to read a flat config file (without
+    section headers) by adding a section header.
+    """
+    with open (filename, 'r') as conffh:
+        conftext = "[main]\n" + conffh.read()
+    config = UnquotingConfigParser()
+    config.read_string(conftext)
+    return config['main']

src/sbin/lorax

@@ -35,7 +35,7 @@ import librepo
 import pylorax
 from pylorax import DRACUT_DEFAULT, DEFAULT_PLATFORM_ID
 from pylorax.cmdline import lorax_parser
-from pylorax.simpleconfig import SimpleConfigFile
+from pylorax.sysutils import flatconfig
 import selinux
 
 def setup_logging(opts):
@@ -225,9 +225,8 @@ def get_dnf_base_object(installroot, sources, mirrorlists=None, repos=None,
         log.warning("/etc/os-release is missing, cannot determine platform id, falling back to %s", DEFAULT_PLATFORM_ID)
         platform_id = DEFAULT_PLATFORM_ID
     else:
-        os_release = SimpleConfigFile("/etc/os-release")
+        os_release = flatconfig("/etc/os-release")
-        os_release.read()
+        platform_id = os_release.get("PLATFORM_ID", DEFAULT_PLATFORM_ID)
-        platform_id = os_release.get("PLATFORM_ID") or DEFAULT_PLATFORM_ID
     log.info("Using %s for module_platform_id", platform_id)
     conf.module_platform_id = platform_id