Remove state tracking, use KAS_WORK_DIR env variable

Config.has_changed didn't work reliably so far, so the state cache was
only allowing to associate a work directory with configuration file.
However this was rather unintuitive, specifically when moving the work
dir to a different home - nothing told the user about the persistent
association.

We therefore agreed to remove the state cache for now. It can be
reintroduced at any time once a consistent usage model exists.

To establish a relationship to a work directory inside a shell session,
kas now evaluates the KAS_WORK_DIR environment variable.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

README.md

@@ -29,7 +29,6 @@ Dependencies & installation
 This projects depends on
 
 - Python 3
-- configparser
 - PyYAML
 
 If you need Python 2 support consider sending patches. The most
@@ -67,6 +66,10 @@ manually, e.g.
 $ kas shell /path/to/kas-project.yml -c 'bitbake dosfsutils-native'
 ```
 
+kas will place downloads and build artifacts under the current directory when
+being invoked. You can specify a different location via the environment variable
+`KAS_WORK_DIR`.
+
 
 Use Cases
 ---------

kas/build.py

@@ -67,7 +67,6 @@ class Build:
         macro.add(ReposCheckout())
         macro.add(SetupEnviron())
 
-        # TODO if cfg.has_changed() was not working properly
         macro.add(WriteConfig())
 
         # Build

kas/config.py

@@ -26,10 +26,8 @@ import logging
 import errno
 import json
 import platform
-import hashlib
 import yaml
 from .repos import Repo
-from .kasstate import KasState
 from .libkas import run_cmd
 
 __license__ = 'MIT'
@@ -38,41 +36,15 @@ __copyright__ = 'Copyright (c) Siemens AG, 2017'
 
 class Config:
     def __init__(self):
-        self.state = KasState()
+        self.__kas_work_dir = os.environ.get('KAS_WORK_DIR', os.getcwd())
-
-    def _get_prop(self, item, default):
-        return self.state.get_option(self.section, item, default)
-
-    def _set_prop(self, item, value):
-        self.state.set_option(self.section, item, value)
-
-    @property
-    def section(self):
-        return os.path.realpath(self.filename)
 
     @property
     def build_dir(self):
-        return self._get_prop('build_dir', os.getcwd() + '/build')
+        return os.path.join(self.__kas_work_dir, 'build')
-
-    @build_dir.setter
-    def build_dir(self, value):
-        self._set_prop('build_dir', value)
 
     @property
     def kas_work_dir(self):
-        return self._get_prop('kas_work_dir', os.getcwd())
+        return self.__kas_work_dir
-
-    @kas_work_dir.setter
-    def kas_work_dir(self, value):
-        self._set_prop('kas_work_dir', value)
-
-    @property
-    def hash(self):
-        return self._get_prop('config_hash', 0)
-
-    @hash.setter
-    def hash(self, value):
-        self._set_prop('config_hash', value)
 
     def setup_environ(self):
         (distro, version, id) = platform.dist()
@@ -91,9 +63,6 @@ class Config:
     def get_repo_ref_dir(self):
         return os.environ.get('KAS_REPO_REF_DIR', None)
 
-    def has_changed(self):
-        return self.config_hash != self.hash
-
 
 class ConfigPython(Config):
     def __init__(self, filename, target):
@@ -103,7 +72,6 @@ class ConfigPython(Config):
             with open(self.filename) as file:
                 env = {}
                 data = file.read()
-                self.hash = hashlib.sha512(str(data).encode('utf-8')).hexdigest()
                 exec(data, env)
                 self._config = env
         except IOError:
@@ -291,8 +259,6 @@ class ConfigJson(ConfigStatic):
         self.filename = os.path.abspath(filename)
         try:
             with open(self.filename, 'r') as f:
-                self.hash = hashlib.sha512(f.read().encode('utf-8')).hexdigest()
-                f.seek(0)
                 self._config = json.load(f)
         except json.decoder.JSONDecodeError  as msg:
             logging.error('Could not load JSON config: {}'.format(msg))
@@ -320,8 +286,6 @@ class ConfigYaml(ConfigStatic):
         self.filename = os.path.abspath(filename)
         try:
             with open(self.filename, 'r') as f:
-                self.hash = hashlib.sha512(f.read().encode('utf-8')).hexdigest()
-                f.seek(0)
                 self._config = yaml.load(f)
         except yaml.loader.ParserError as msg:
             logging.error('Could not load YAML config: {}'.format(msg))

kas/kasstate.py

@@ -1,57 +0,0 @@
-# kas - setup tool for bitbake based projects
-#
-# Copyright (c) Siemens AG, 2017
-#
-# Permission is hereby granted, free of charge, to any person obtaining a copy
-# of this software and associated documentation files (the "Software"), to deal
-# in the Software without restriction, including without limitation the rights
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-# copies of the Software, and to permit persons to whom the Software is
-# furnished to do so, subject to the following conditions:
-#
-# The above copyright notice and this permission notice shall be
-# included in all copies or substantial portions of the Software.
-#
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-# SOFTWARE.
-
-import codecs
-import os
-from configparser import SafeConfigParser
-
-__license__ = 'MIT'
-__copyright__ = 'Copyright (c) Siemens AG, 2017'
-
-
-class KasState:
-    def __init__(self):
-        self.filename = os.path.join(os.environ.get('XDG_CONFIG_HOME',
-                                                    os.path.expandvars('$HOME/.config')),
-                                     os.path.join('kas', 'kasstate.ini'))
-        self.parser = SafeConfigParser()
-        try:
-            with codecs.open(self.filename, 'r', encoding='utf-8') as f:
-                self.parser.readfp(f)
-        except:
-            pass
-
-    def __del__(self):
-        if not os.path.exists(os.path.dirname(self.filename)):
-            os.makedirs(os.path.dirname(self.filename))
-        with codecs.open(self.filename, 'w', encoding='utf-8') as f:
-            self.parser.write(f)
-
-    def get_option(self, section, option, default):
-        if not self.parser.has_option(section, option):
-            self.set_option(section, option, default)
-        return self.parser.get(section, option)
-
-    def set_option(self, section, option, value):
-        if not self.parser.has_section(section):
-            self.parser.add_section(section)
-        self.parser.set(section, option, value)