Merge pull request #33 from avatao-content/message-types

Message types

.drone.yml

@@ -10,4 +10,4 @@ pipeline:
       - docker push eu.gcr.io/avatao-challengestore/tutorial-framework:${DRONE_TAG}
     when:
       event: 'tag'
-      branch: refs/tags/egyptianmau-20*
+      branch: refs/tags/bombay-20*

.pylintrc

@@ -1,5 +1,5 @@
 [TYPECHECK]
 
 ignored-modules = zmq
-max-line-length = 150
+max-line-length = 120
 disable = missing-docstring, too-few-public-methods, invalid-name

README.md

@@ -80,4 +80,6 @@ The TFW message format:
 
 Most of the components you need have docstrings included (hang on tight, this is work in progress) – refer to them for usage info.
 
+In the `docs` folder you can find our Sphinx-based API documentation, which you can build using the included `Makefile` (you need to have Sphinx installed, please reach out to us if you have trouble building the docs).
+
 To get started you should take a look at the [test-tutorial-framework](https://github.com/avatao-content/test-tutorial-framework) repository, which serves as an example project as well.

VERSION

@@ -1 +1 @@
-egyptianmau
+bombay

docs/Makefile

@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line.
+SPHINXOPTS    =
+SPHINXBUILD   = sphinx-build
+SPHINXPROJ    = baseimage-tutorial-framework
+SOURCEDIR     = source
+BUILDDIR      = build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)

docs/make.bat

@@ -0,0 +1,36 @@
+@ECHO OFF
+
+pushd %~dp0
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set SOURCEDIR=source
+set BUILDDIR=build
+set SPHINXPROJ=baseimage-tutorial-framework
+
+if "%1" == "" goto help
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
+	echo.installed, then set the SPHINXBUILD environment variable to point
+	echo.to the full path of the 'sphinx-build' executable. Alternatively you
+	echo.may add the Sphinx directory to PATH.
+	echo.
+	echo.If you don't have Sphinx installed, grab it from
+	echo.http://sphinx-doc.org/
+	exit /b 1
+)
+
+%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS%
+goto end
+
+:help
+%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS%
+
+:end
+popd

docs/source/components/components.rst

@@ -0,0 +1,25 @@
+Components
+----------
+
+.. automodule:: tfw.components
+
+.. autoclass:: IdeEventHandler
+    :members:
+
+.. autoclass:: TerminalEventHandler
+    :members:
+
+.. autoclass:: ProcessManagingEventHandler
+    :members:
+
+.. autoclass:: LogMonitoringEventHandler
+    :members:
+
+.. autoclass:: TerminalCommands
+    :members:
+
+.. autoclass:: HistoryMonitor
+    :members:
+
+.. autoclass:: BashMonitor
+    :members:

docs/source/conf.py

@@ -0,0 +1,166 @@
+# -*- coding: utf-8 -*-
+#
+# Configuration file for the Sphinx documentation builder.
+#
+# This file does only contain a selection of the most common options. For a
+# full list see the documentation:
+# http://www.sphinx-doc.org/en/master/config
+
+# -- Path setup --------------------------------------------------------------
+
+# If extensions (or modules to document with autodoc) are in another directory,
+# add these directories to sys.path here. If the directory is relative to the
+# documentation root, use os.path.abspath to make it absolute, like shown here.
+#
+import os
+import sys
+sys.path.insert(0, os.path.abspath('../../lib'))
+
+
+# -- Project information -----------------------------------------------------
+
+project = 'baseimage-tutorial-framework'
+copyright = '2018, Avatao Innovative Learning Kft'
+author = 'Kristóf Tóth'
+
+# The short X.Y version
+version = ''
+# The full version, including alpha/beta/rc tags
+release = 'bombay'
+
+
+# -- General configuration ---------------------------------------------------
+
+# If your documentation needs a minimal Sphinx version, state it here.
+#
+# needs_sphinx = '1.0'
+
+# Add any Sphinx extension module names here, as strings. They can be
+# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
+# ones.
+extensions = [
+    'sphinx.ext.autodoc',
+]
+
+# Add any paths that contain templates here, relative to this directory.
+templates_path = ['_templates']
+
+# The suffix(es) of source filenames.
+# You can specify multiple suffix as a list of string:
+#
+# source_suffix = ['.rst', '.md']
+source_suffix = '.rst'
+
+# The master toctree document.
+master_doc = 'index'
+
+# The language for content autogenerated by Sphinx. Refer to documentation
+# for a list of supported languages.
+#
+# This is also used if you do content translation via gettext catalogs.
+# Usually you set "language" from the command line for these cases.
+language = None
+
+# List of patterns, relative to source directory, that match files and
+# directories to ignore when looking for source files.
+# This pattern also affects html_static_path and html_extra_path .
+exclude_patterns = []
+
+# The name of the Pygments (syntax highlighting) style to use.
+pygments_style = 'sphinx'
+
+
+# -- Options for HTML output -------------------------------------------------
+
+# The theme to use for HTML and HTML Help pages.  See the documentation for
+# a list of builtin themes.
+#
+html_theme = 'alabaster'
+
+# Theme options are theme-specific and customize the look and feel of a theme
+# further.  For a list of options available for each theme, see the
+# documentation.
+#
+# html_theme_options = {}
+
+# Add any paths that contain custom static files (such as style sheets) here,
+# relative to this directory. They are copied after the builtin static files,
+# so a file named "default.css" will overwrite the builtin "default.css".
+html_static_path = ['_static']
+
+# Custom sidebar templates, must be a dictionary that maps document names
+# to template names.
+#
+# The default sidebars (for documents that don't match any pattern) are
+# defined by theme itself.  Builtin themes are using these templates by
+# default: ``['localtoc.html', 'relations.html', 'sourcelink.html',
+# 'searchbox.html']``.
+#
+# html_sidebars = {}
+
+
+# -- Options for HTMLHelp output ---------------------------------------------
+
+# Output file base name for HTML help builder.
+htmlhelp_basename = 'baseimage-tutorial-frameworkdoc'
+
+
+# -- Options for LaTeX output ------------------------------------------------
+
+latex_elements = {
+    # The paper size ('letterpaper' or 'a4paper').
+    #
+    # 'papersize': 'letterpaper',
+
+    # The font size ('10pt', '11pt' or '12pt').
+    #
+    # 'pointsize': '10pt',
+
+    # Additional stuff for the LaTeX preamble.
+    #
+    # 'preamble': '',
+
+    # Latex figure (float) alignment
+    #
+    # 'figure_align': 'htbp',
+}
+
+# Grouping the document tree into LaTeX files. List of tuples
+# (source start file, target name, title,
+#  author, documentclass [howto, manual, or own class]).
+latex_documents = [
+    (master_doc, 'baseimage-tutorial-framework.tex', 'baseimage-tutorial-framework Documentation',
+     'Kristóf Tóth', 'manual'),
+]
+
+
+# -- Options for manual page output ------------------------------------------
+
+# One entry per manual page. List of tuples
+# (source start file, name, description, authors, manual section).
+man_pages = [
+    (master_doc, 'baseimage-tutorial-framework', 'baseimage-tutorial-framework Documentation',
+     [author], 1)
+]
+
+
+# -- Options for Texinfo output ----------------------------------------------
+
+# Grouping the document tree into Texinfo files. List of tuples
+# (source start file, target name, title, author,
+#  dir menu entry, description, category)
+texinfo_documents = [
+    (master_doc, 'baseimage-tutorial-framework', 'baseimage-tutorial-framework Documentation',
+     author, 'baseimage-tutorial-framework', 'One line description of project.',
+     'Miscellaneous'),
+]
+
+
+# -- Extension configuration -------------------------------------------------
+def skip(app, what, name, obj, skip, options):
+    if name == "__init__":
+        return False
+    return skip
+
+def setup(app):
+    app.connect("autodoc-skip-member", skip)

docs/source/foundations/eventhandlers.rst

@@ -0,0 +1,12 @@
+Event handler base classes
+--------------------------
+
+Subclass these to create your cusom event handlers.
+
+.. automodule:: tfw
+
+.. autoclass:: EventHandlerBase
+    :members:
+
+.. autoclass:: TriggeredEventHandler
+    :members:

docs/source/foundations/fsms.rst

@@ -0,0 +1,12 @@
+FSM base classes
+----------------
+
+Subclass these to create an FSM that fits your tutorial/challenge.
+
+.. automodule:: tfw
+
+.. autoclass:: FSMBase
+    :members:
+
+.. autoclass:: LinearFSM
+    :members:

docs/source/foundations/tfwserver.rst

@@ -0,0 +1,7 @@
+TFWServer
+---------
+
+.. automodule:: tfw.networking
+
+.. autoclass:: TFWServer
+    :members:

docs/source/index.rst

@@ -0,0 +1,45 @@
+.. baseimage-tutorial-framework documentation master file, created by
+   sphinx-quickstart on Fri Jun  1 14:29:07 2018.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
+Welcome to baseimage-tutorial-framework's documentation!
+========================================================
+
+Foundations
+-----------
+
+This part covers the soil which the framework is based on and stuff you will need to develop your own challenges.
+
+.. toctree::
+    :glob:
+
+    foundations/*
+
+Networking
+----------
+
+You can use these to send messages to the frontend or the event handlers through TFWServer.
+
+.. toctree::
+    :glob:
+
+    networking/*
+
+Components
+----------
+
+These are pre-written components for you to use, such as our IDE, terminal or console.
+
+.. toctree::
+    :glob:
+
+    components/*
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`

docs/source/networking/networking.rst

@@ -0,0 +1,17 @@
+Networking
+----------
+
+.. automodule:: tfw.networking
+
+.. autoclass:: TFWServerConnector
+    :members:
+
+.. automodule:: tfw.networking.event_handlers
+
+.. autoclass:: ServerUplinkConnector
+    :members:
+
+.. automodule:: tfw.networking
+
+.. autoclass:: MessageSender
+    :members:

lib/envvars/__init__.py

@@ -4,9 +4,22 @@
 from collections import namedtuple
 from os import environ
 
+from tfw.decorators import lazy_property
 
-def prefixed_envvars_to_namedtuple(prefix: str, tuple_name: str):
+
-    envvars = {envvar.replace(prefix, '', 1): environ.get(envvar)
+class LazyEnvironment:
+    def __init__(self, prefix, tuple_name):
+        self._prefix = prefix
+        self._tuple_name = tuple_name
+
+    @lazy_property
+    def environment(self):
+        return self.prefixed_envvars_to_namedtuple()
+
+    def prefixed_envvars_to_namedtuple(self):
+        envvars = {
+            envvar.replace(self._prefix, '', 1): environ.get(envvar)
             for envvar in environ.keys()
-               if envvar.startswith(prefix)}
+            if envvar.startswith(self._prefix)
-    return namedtuple(tuple_name, envvars)(**envvars)
+        }
+        return namedtuple(self._tuple_name, envvars)(**envvars)

lib/tao/config/envvars.py

@@ -1,6 +1,6 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from envvars import prefixed_envvars_to_namedtuple
+from envvars import LazyEnvironment
 
-TAOENV = prefixed_envvars_to_namedtuple('AVATAO_', 'taoenvtuple')
+TAOENV = LazyEnvironment('AVATAO_', 'taoenvtuple').environment

lib/tfw/components/directory_monitor.py

@@ -16,7 +16,6 @@ LOG = logging.getLogger(__name__)
 
 class DirectoryMonitor(ObserverMixin):
     def __init__(self, directories):
-        ObserverMixin.__init__(self)
         self.eventhandler = IdeReloadWatchdogEventHandler()
         for directory in directories:
             self.observer.schedule(self.eventhandler, directory, recursive=True)
@@ -65,8 +64,10 @@ class IdeReloadWatchdogEventHandler(FileSystemWatchdogEventHandler):
             self.ignore = self.ignore - 1
             return
         LOG.debug(event)
-        self.uplink.send({'key': 'ide',
+        self.uplink.send({
-                          'data': {'command': 'reload'}})
+            'key': 'ide',
+            'data': {'command': 'reload'}
+        })
 
 
 def with_monitor_paused(fun):

lib/tfw/components/directory_monitoring_event_handler.py

@@ -17,10 +17,12 @@ class DirectoryMonitoringEventHandler(EventHandlerBase, MonitorManagerMixin):
         self._directory = directory
         MonitorManagerMixin.__init__(self, DirectoryMonitor, self._directory)
 
-        self.commands = {'pause':     self.pause,
+        self.commands = {
+            'pause':     self.pause,
             'resume':    self.resume,
             'ignore':    self.ignore,
-                         'selectdir': self.selectdir}
+            'selectdir': self.selectdir
+        }
 
     @property
     def directory(self):

lib/tfw/components/history_monitor.py

@@ -36,15 +36,17 @@ class HistoryMonitor(CallbackMixin, ObserverMixin, ABC):
     See examples below.
     """
     def __init__(self, histfile):
-        CallbackMixin.__init__(self)
-        ObserverMixin.__init__(self)
         self.histfile = histfile
         self._history = []
         self._last_length = len(self._history)
-        self.observer.schedule(CallbackEventHandler([self.histfile],
+        self.observer.schedule(
+            CallbackEventHandler(
+                [self.histfile],
                 self._fetch_history,
-                                                    self._invoke_callbacks),
+                self._invoke_callbacks
-                               dirname(self.histfile))
+            ),
+            dirname(self.histfile)
+        )
 
     @property
     def history(self):
@@ -55,7 +57,10 @@ class HistoryMonitor(CallbackMixin, ObserverMixin, ABC):
         with open(self.histfile, 'r') as ifile:
             pattern = compileregex(self.command_pattern)
             data = ifile.read()
-            self._history = [self.sanitize_command(command) for command in findall(pattern, data)]
+            self._history = [
+                self.sanitize_command(command)
+                for command in findall(pattern, data)
+            ]
 
     @property
     @abstractmethod

lib/tfw/components/ide_event_handler.py

@@ -41,8 +41,8 @@ class FileManager:  # pylint: disable=too-many-instance-attributes
     def workdir(self, directory):
         if not exists(directory) or not isdir(directory):
             raise EnvironmentError(f'"{directory}" is not a directory!')
-        if not self._is_in_whitelisted_dir(directory):
+        if not self._is_in_allowed_dir(directory):
-            raise EnvironmentError(f'Directory "{directory}" is not in whitelist!')
+            raise EnvironmentError(f'Directory "{directory}" is not allowed!')
         self._workdir = directory
 
     @property
@@ -65,8 +65,13 @@ class FileManager:  # pylint: disable=too-many-instance-attributes
 
     @property
     def files(self):
-        return [self._relpath(file) for file in glob(join(self._workdir, '**/*'), recursive=True)
+        return [
-                if isfile(file) and self._is_in_whitelisted_dir(file) and not self._is_blacklisted(file)]
+            self._relpath(file)
+            for file in glob(join(self._workdir, '**/*'), recursive=True)
+            if isfile(file)
+            and self._is_in_allowed_dir(file)
+            and not self._is_blacklisted(file)
+        ]
 
     @property
     def file_contents(self):
@@ -78,11 +83,17 @@ class FileManager:  # pylint: disable=too-many-instance-attributes
         with open(self._filepath(self.filename), 'w', errors='surrogateescape') as ofile:
             ofile.write(value)
 
-    def _is_in_whitelisted_dir(self, path):
+    def _is_in_allowed_dir(self, path):
-        return any(realpath(path).startswith(allowed_dir) for allowed_dir in self.allowed_directories)
+        return any(
+            realpath(path).startswith(allowed_dir)
+            for allowed_dir in self.allowed_directories
+        )
 
     def _is_blacklisted(self, file):
-        return any(fnmatchcase(file, blacklisted) for blacklisted in self.exclude)
+        return any(
+            fnmatchcase(file, blacklisted)
+            for blacklisted in self.exclude
+        )
 
     def _filepath(self, filename):
         return join(self._workdir, filename)
@@ -101,45 +112,51 @@ class IdeEventHandler(EventHandlerBase, MonitorManagerMixin):
     When any file in the selected directory changes they are automatically refreshed
     on the frontend (this is done by listening to inotify events).
 
-    This EventHandler accepts messages that have a data["command"] key specifying
+    This EventHandler accepts messages that have a data['command'] key specifying
     a command to be executed.
-    The API of each command is documented in their respective handlers.
+
+    The API of each command is documented in their respective handler.
     """
-    def __init__(self, key, directory, allowed_directories, selected_file=None, exclude=None,
+    def __init__(self, key, directory, allowed_directories, selected_file=None, exclude=None):
-                 additional_watched_directories=None):
         """
         :param key: the key this instance should listen to
         :param directory: working directory which the EventHandler should serve files from
-        :param allowed_directories: list of directories that can be switched to using the selectdir command
+        :param allowed_directories: list of directories that can be switched to using selectdir
         :param selected_file: file that is selected by default
-        :param exclude: list of filenames that should not appear between files (for *.o, *.pyc, etc.)
+        :param exclude: list of filenames that should not appear between files (for .o, .pyc, etc.)
-        :param additional_watched_directories: refresh the selected file when files change in these directories
-                                               (the working directory is watched by default, this is useful for
-                                               symlinks and such)
         """
         super().__init__(key)
         try:
-            self.filemanager = FileManager(allowed_directories=allowed_directories, working_directory=directory,
+            self.filemanager = FileManager(
-                                           selected_file=selected_file, exclude=exclude)
+                allowed_directories=allowed_directories,
+                working_directory=directory,
+                selected_file=selected_file,
+                exclude=exclude
+            )
         except IndexError:
-            raise EnvironmentError(f'No file(s) in IdeEventHandler working_directory "{directory}"!')
+            raise EnvironmentError(
+                f'No file(s) in IdeEventHandler working_directory "{directory}"!'
+            )
 
-        self.watched_directories = [self.filemanager.workdir]
+        MonitorManagerMixin.__init__(
-        if additional_watched_directories:
+            self,
-            self.watched_directories.extend(additional_watched_directories)
+            DirectoryMonitor,
-        MonitorManagerMixin.__init__(self, DirectoryMonitor, self.watched_directories)
+            self.filemanager.allowed_directories
+        )
 
-        self.commands = {'read':      self.read,
+        self.commands = {
+            'read':      self.read,
             'write':     self.write,
             'select':    self.select,
             'selectdir': self.select_dir,
-                         'exclude':   self.exclude}
+            'exclude':   self.exclude
+        }
 
     def read(self, data):
         """
         Read the currently selected file.
 
-        :return: message with the contents of the file in data['content']
+        :return dict: message with the contents of the file in data['content']
         """
         try:
             data['content'] = self.filemanager.file_contents
@@ -155,8 +172,9 @@ class IdeEventHandler(EventHandlerBase, MonitorManagerMixin):
         """
         Overwrites a file with the desired string.
 
-        :param data: TFW message data containing keys:
+        :param data: TFW message data containing key 'content'
-               |-string: containing the desired file contents
+                     (new file content)
+
         """
         self.monitor.ignore = self.monitor.ignore + 1
         try:
@@ -170,8 +188,8 @@ class IdeEventHandler(EventHandlerBase, MonitorManagerMixin):
         """
         Selects a file from the current directory.
 
-        :param data: TFW message data containing keys:
+        :param data: TFW message data containing 'filename'
-               |-filename: name of file to select relative to the current directory
+                     (name of file to select relative to the current directory)
         """
         try:
             self.filemanager.filename = data['filename']
@@ -183,10 +201,10 @@ class IdeEventHandler(EventHandlerBase, MonitorManagerMixin):
         """
         Select a new working directory to display files from.
 
-        :param data: TFW message data containing keys:
+        :param data: TFW message data containing 'directory'
-               |-directory: absolute path of diretory to select.
+                     (absolute path of diretory to select.
                      must be a path whitelisted in
-                            self.allowed_directories
+                     self.allowed_directories)
         """
         try:
             self.filemanager.workdir = data['directory']
@@ -204,8 +222,9 @@ class IdeEventHandler(EventHandlerBase, MonitorManagerMixin):
         """
         Overwrite list of excluded files
 
-        :param data: TFW message data containing keys:
+        :param data: TFW message data containing 'exclude'
-               |-exclude: list of filename patterns to be excluded, e.g.: ["*.pyc", "*.o"]
+                     (list of unix-style filename patterns to be excluded,
+                     e.g.: ["\*.pyc", "\*.o")
         """
         try:
             self.filemanager.exclude = list(data['exclude'])

lib/tfw/components/log_monitor.py

@@ -14,8 +14,10 @@ from tfw.mixins import ObserverMixin, SupervisorLogMixin
 class LogMonitor(ObserverMixin):
     def __init__(self, process_name, log_tail=0):
         self.prevent_log_recursion()
-        ObserverMixin.__init__(self)
+        event_handler = SendLogWatchdogEventHandler(
-        event_handler = SendLogWatchdogEventHandler(process_name, log_tail=log_tail)
+            process_name,
+            log_tail=log_tail
+        )
         self.observer.schedule(
             event_handler,
             event_handler.path
@@ -29,10 +31,12 @@ class LogMonitor(ObserverMixin):
 
 class SendLogWatchdogEventHandler(PatternMatchingWatchdogEventHandler, SupervisorLogMixin):
     def __init__(self, process_name, log_tail=0):
-        self.acquire_own_supervisor_instance()  # This thread-localises the xmlrpc client
         self.process_name = process_name
         self.procinfo = self.supervisor.getProcessInfo(self.process_name)
-        super().__init__([self.procinfo['stdout_logfile'], self.procinfo['stderr_logfile']])
+        super().__init__([
+            self.procinfo['stdout_logfile'],
+            self.procinfo['stderr_logfile']
+        ])
         self.uplink = ServerUplinkConnector()
         self.log_tail = log_tail
 

lib/tfw/components/log_monitoring_event_handler.py

@@ -1,7 +1,6 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-
 from tfw import EventHandlerBase
 from tfw.mixins import MonitorManagerMixin
 from tfw.config.logs import logging
@@ -11,11 +10,25 @@ LOG = logging.getLogger(__name__)
 
 
 class LogMonitoringEventHandler(EventHandlerBase, MonitorManagerMixin):
+    """
+    Monitors the output of a supervisor process (stdout, stderr) and
+    sends the results to the frontend.
+
+    Accepts messages that have a data['command'] key specifying
+    a command to be executed.
+
+    The API of each command is documented in their respective handler.
+    """
     def __init__(self, key, process_name, log_tail=0):
         super().__init__(key)
         self.process_name = process_name
         self.log_tail = log_tail
-        MonitorManagerMixin.__init__(self, LogMonitor, self.process_name, self.log_tail)
+        MonitorManagerMixin.__init__(
+            self,
+            LogMonitor,
+            self.process_name,
+            self.log_tail
+        )
 
         self.command_handlers = {
             'process_name': self.handle_process_name,
@@ -31,7 +44,24 @@ class LogMonitoringEventHandler(EventHandlerBase, MonitorManagerMixin):
             LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
 
     def handle_process_name(self, data):
-        self.set_monitor_args(data['process_name'], self.log_tail)
+        """
+        Changes the monitored process.
+
+        :param data: TFW message data containing 'value'
+                     (name of the process to monitor)
+        """
+        self.set_monitor_args(data['value'], self.log_tail)
 
     def handle_log_tail(self, data):
-        self.set_monitor_args(self.process_name, data['log_tail'])
+        """
+        Sets tail length of the log the monitor will send
+        to the frontend (the monitor will send back the last
+        'value' characters of the log).
+
+        :param data: TFW message data containing 'value'
+                     (new tail length)
+        """
+        self.set_monitor_args(self.process_name, data['value'])
+
+    def cleanup(self):
+        self.monitor.stop()

lib/tfw/components/process_managing_event_handler.py

@@ -13,9 +13,11 @@ LOG = logging.getLogger(__name__)
 
 class ProcessManager(SupervisorMixin, SupervisorLogMixin):
     def __init__(self):
-        self.commands = {'start':      self.start_process,
+        self.commands = {
+            'start':   self.start_process,
             'stop':    self.stop_process,
-                         'restart':    self.restart_process}
+            'restart': self.restart_process
+        }
 
     def __call__(self, command, process_name):
         return self.commands[command](process_name)
@@ -25,9 +27,9 @@ class ProcessManagingEventHandler(EventHandlerBase):
     """
     Event handler that can manage processes managed by supervisor.
 
-    This EventHandler accepts messages that have a data["command"] key specifying
+    This EventHandler accepts messages that have a data['command'] key specifying
     a command to be executed.
-    Every message must contain a data["process_name"] field with the name of the
+    Every message must contain a data['process_name'] field with the name of the
     process to manage. This is the name specified in supervisor config files like so:
     [program:someprogram]
 
@@ -50,8 +52,14 @@ class ProcessManagingEventHandler(EventHandlerBase):
             except SupervisorFault as fault:
                 message['data']['error'] = fault.faultString
             finally:
-                message['data']['stdout'] = self.processmanager.read_stdout(data['process_name'], self.log_tail)
+                message['data']['stdout'] = self.processmanager.read_stdout(
-                message['data']['stderr'] = self.processmanager.read_stderr(data['process_name'], self.log_tail)
+                    data['process_name'],
+                    self.log_tail
+                )
+                message['data']['stderr'] = self.processmanager.read_stderr(
+                    data['process_name'],
+                    self.log_tail
+                )
             return message
         except KeyError:
             LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)

lib/tfw/components/terminado_mini_server.py

@@ -14,15 +14,15 @@ LOG = logging.getLogger(__name__)
 class TerminadoMiniServer:
     def __init__(self, url, port, workdir, shellcmd):
         self.port = port
-        self._term_manager = SingleTermManager(shell_command=shellcmd,
+        self._term_manager = SingleTermManager(
-                                               term_settings={'cwd': workdir})
+            shell_command=shellcmd,
-        self.application = Application(
+            term_settings={'cwd': workdir}
-            [(
+        )
+        self.application = Application([(
             url,
             TerminadoMiniServer.ResetterTermSocket,
             {'term_manager': self._term_manager}
-            )]
+        )])
-        )
 
     @property
     def term_manager(self):
@@ -46,5 +46,10 @@ class TerminadoMiniServer:
 
 if __name__ == '__main__':
     LOG.info('Terminado Mini Server listening on %s', TFWENV.TERMINADO_PORT)
-    TerminadoMiniServer('/terminal', TFWENV.TERMINADO_PORT, TFWENV.TERMINADO_WD, ['bash']).listen()
+    TerminadoMiniServer(
+        '/terminal',
+        TFWENV.TERMINADO_PORT,
+        TFWENV.TERMINADO_WD,
+        ['bash']
+    ).listen()
     IOLoop.instance().start()

lib/tfw/components/terminal_commands.py

@@ -19,13 +19,13 @@ class TerminalCommands(ABC):
     To receive events you need to subscribe TerminalCommand.callback to a HistoryMonitor
     instance.
 
-    Inherit from this class and define methods which start with "command_". When the user
+    Inherit from this class and define methods which start with "command\_". When the user
     executes the command specified after the underscore, your method will be invoked. All
-    such commands must expect the parameter *args which will contain the arguments of the
+    such commands must expect the parameter \*args which will contain the arguments of the
     command.
 
     For example to define a method that runs when someone starts vim in the terminal
-    you have to define a method like: "def command_vim(self, *args)"
+    you have to define a method like: "def command_vim(self, \*args)"
 
     You can also use this class to create new commands similarly.
     """
@@ -36,8 +36,12 @@ class TerminalCommands(ABC):
             self._setup_bashrc_aliases(bashrc)
 
     def _build_command_to_implementation_dict(self):
-        return {self._parse_command_name(fun): getattr(self, fun) for fun in dir(self)
+        return {
-                if callable(getattr(self, fun)) and self._is_command_implementation(fun)}
+            self._parse_command_name(fun): getattr(self, fun)
+            for fun in dir(self)
+            if callable(getattr(self, fun))
+            and self._is_command_implementation(fun)
+        }
 
     def _setup_bashrc_aliases(self, bashrc):
         with open(bashrc, 'a') as ofile:

lib/tfw/components/terminal_event_handler.py

@@ -16,9 +16,9 @@ class TerminalEventHandler(EventHandlerBase):
     sessions to connect to. You need to instanciate this in order for frontend
     terminals to work.
 
-    This EventHandler accepts messages that have a data["command"] key specifying
+    This EventHandler accepts messages that have a data['command'] key specifying
     a command to be executed.
-    The API of each command is documented in their respective handlers.
+    The API of each command is documented in their respective handler.
     """
     def __init__(self, key, monitor):
         """
@@ -29,9 +29,19 @@ class TerminalEventHandler(EventHandlerBase):
         self.working_directory = TFWENV.TERMINADO_DIR
         self._historymonitor = monitor
         bash_as_user_cmd = ['sudo', '-u', TAOENV.USER, 'bash']
-        self.terminado_server = TerminadoMiniServer('/terminal', TFWENV.TERMINADO_PORT, TFWENV.TERMINADO_WD, bash_as_user_cmd)
+
-        self.commands = {'write': self.write,
+        self.terminado_server = TerminadoMiniServer(
-                         'read': self.read}
+            '/terminal',
+            TFWENV.TERMINADO_PORT,
+            TFWENV.TERMINADO_WD,
+            bash_as_user_cmd
+        )
+
+        self.commands = {
+            'write': self.write,
+            'read': self.read
+        }
+
         if self._historymonitor:
             self._historymonitor.watch()
         self.terminado_server.listen()
@@ -54,18 +64,18 @@ class TerminalEventHandler(EventHandlerBase):
         Writes a string to the terminal session (on the pty level).
         Useful for pre-typing and executing commands for the user.
 
-        :param data: TFW message data containing keys:
+        :param data: TFW message data containing 'value'
-               |-shellcmd: command to be written to the pty
+                     (command to be written to the pty)
         """
-        self.terminado_server.pty.write(data['shellcmd'])
+        self.terminado_server.pty.write(data['value'])
 
     def read(self, data):
         """
         Reads the history of commands executed.
 
-        :param data: TFW message data containing keys:
+        :param data: TFW message data containing 'count'
-               |-count: the number of history elements to return
+                     (the number of history elements to return)
-        :return: message with list of commands in data['history']
+        :return dict: message with list of commands in data['history']
         """
         data['count'] = int(data.get('count', 1))
         if self.historymonitor:

lib/tfw/config/envvars.py

@@ -1,6 +1,6 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from envvars import prefixed_envvars_to_namedtuple
+from envvars import LazyEnvironment
 
-TFWENV = prefixed_envvars_to_namedtuple('TFW_', 'tfwenvtuple')
+TFWENV = LazyEnvironment('TFW_', 'tfwenvtuple').environment

lib/tfw/decorators/__init__.py

@@ -2,3 +2,4 @@
 # All Rights Reserved. See LICENSE file for details.
 
 from .rate_limiter import RateLimiter
+from .lazy_property import lazy_property

lib/tfw/decorators/lazy_property.py

@@ -0,0 +1,19 @@
+# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
+# All Rights Reserved. See LICENSE file for details.
+
+
+class lazy_property:
+    """
+    Decorator that replaces a function with the value
+    it calculates on the first call.
+    """
+    def __init__(self, func):
+        self.func = func
+        self.__doc__ = func.__doc__
+
+    def __get__(self, instance, owner):
+        if instance is None:
+            return self  # avoids potential __new__ TypeError
+        value = self.func(instance)
+        setattr(instance, self.func.__name__, value)
+        return value

lib/tfw/fsm_base.py

@@ -19,15 +19,16 @@ class FSMBase(CallbackMixin):
     states, transitions = [], []
 
     def __init__(self, initial: str = None, accepted_states: List[str] = None):
-        CallbackMixin.__init__(self)
         self.accepted_states = accepted_states or [self.states[-1]]
-        self.machine = Machine(model=self,
+        self.machine = Machine(
+            model=self,
             states=self.states,
             transitions=self.transitions,
             initial=initial or self.states[0],
             send_event=True,
             ignore_invalid_triggers=True,
-                               after_state_change='execute_callbacks')
+            after_state_change='execute_callbacks'
+        )
 
     def execute_callbacks(self, event_data):
         self._execute_callbacks(event_data.kwargs)

lib/tfw/linear_fsm.py

@@ -11,12 +11,19 @@ class LinearFSM(FSMBase):
     a number of steps specified in the constructor. It automatically sets up 2
     actions (triggers) between states as such:
     (0) --  step_1  --> (1) --  step_2  --> (2) --  step_3  --> (3) ... and so on
-        \-step_next-/       \-step_next-/       \-step_next-/
     """
     def __init__(self, number_of_steps):
         self.states = list(map(str, range(number_of_steps)))
         self.transitions = []
         for index in self.states[:-1]:
-            self.transitions.append({'trigger': f'step_{int(index)+1}', 'source': index, 'dest': str(int(index)+1)})
+            self.transitions.append({
-            self.transitions.append({'trigger': 'step_next', 'source': index, 'dest': str(int(index)+1)})
+                'trigger': f'step_{int(index)+1}',
+                'source': index,
+                'dest': str(int(index)+1)
+            })
+            self.transitions.append({
+                'trigger': 'step_next',
+                'source': index,
+                'dest': str(int(index)+1)
+            })
         super(LinearFSM, self).__init__()

lib/tfw/mixins/callback_mixin.py

@@ -3,17 +3,20 @@
 
 from functools import partial
 
+from tfw.decorators import lazy_property
+
 
 class CallbackMixin:
-    def __init__(self):
+    @lazy_property
-        self._callbacks = []
+    def _callbacks(self):
+        return []
 
     def subscribe_callback(self, callback, *args, **kwargs):
         """
         Subscribe a callable to invoke once an event is triggered.
         :param callback: callable to be executed on events
-        :param *args: arguments passed to callable
+        :param args: arguments passed to callable
-        :param **kwargs: kwargs passed to callable
+        :param kwargs: kwargs passed to callable
         """
         fun = partial(callback, *args, **kwargs)
         self._callbacks.append(fun)

lib/tfw/mixins/observer_mixin.py

@@ -3,10 +3,13 @@
 
 from watchdog.observers import Observer
 
+from tfw.decorators import lazy_property
+
 
 class ObserverMixin:
-    def __init__(self):
+    @lazy_property
-        self.observer = Observer()
+    def observer(self):
+        return Observer()
 
     def watch(self):
         self.observer.start()

lib/tfw/mixins/supervisor_mixin.py

@@ -6,21 +6,14 @@ from xmlrpc.client import Fault as SupervisorFault
 from contextlib import suppress
 from os import remove
 
+from tfw.decorators import lazy_property
 from tfw.config import TFWENV
 
 
-def get_supervisor_instance():
-    return xmlrpc.client.ServerProxy(TFWENV.SUPERVISOR_HTTP_URI).supervisor
-
-
 class SupervisorBaseMixin:
-    supervisor = get_supervisor_instance()
+    @lazy_property
-
+    def supervisor(self):
-    def acquire_own_supervisor_instance(self):
+        return xmlrpc.client.ServerProxy(TFWENV.SUPERVISOR_HTTP_URI).supervisor
-        """
-        Give this instance non-static, local xmlrpc client
-        """
-        self.supervisor = get_supervisor_instance()
 
 
 class SupervisorMixin(SupervisorBaseMixin):

lib/tfw/networking/message_sender.py

@@ -26,5 +26,7 @@ class MessageSender:
             'timestamp': datetime.now().isoformat(),
             'message': message
         }
-        self.server_connector.send({'key': self.key,
+        self.server_connector.send({
-                                    'data': data})
+            'key': self.key,
+            'data': data
+        })

lib/tfw/networking/serialization.py

@@ -43,11 +43,17 @@ def deserialize_tfw_msg(*args):
 
 
 def _serialize_all(*args):
-    return tuple(_serialize_single(arg) for arg in args)
+    return tuple(
+        _serialize_single(arg)
+        for arg in args
+    )
 
 
 def _deserialize_all(*args):
-    return tuple(_deserialize_single(arg) for arg in args)
+    return tuple(
+        _deserialize_single(arg)
+        for arg in args
+    )
 
 
 def _serialize_single(data):

lib/tfw/networking/server/tfw_server.py

@@ -30,13 +30,16 @@ class TFWServer:
         self._fsm.subscribe_callback(self._fsm_updater.update)
         self._event_handler_connector = EventHandlerConnector()
 
-        self.application = Application(
+        self.application = Application([(
-            [(r'/ws', ZMQWebSocketProxy, {'make_eventhandler_message': self.make_eventhandler_message,
+            r'/ws', ZMQWebSocketProxy,{
+                'make_eventhandler_message': self.make_eventhandler_message,
                 'proxy_filter': self.proxy_filter,
                 'handle_trigger': self.handle_trigger,
-                                          'event_handler_connector': self._event_handler_connector})]
+                'event_handler_connector': self._event_handler_connector
+            })]
         )
-        #self.controller_responder = ControllerResponder(self.fsm) TODO: add this once controller stuff is resolved
+        # self.controller_responder = ControllerResponder(self.fsm)
+        # TODO: add this once controller stuff is resolved
 
     @property
     def fsm(self):
@@ -97,8 +100,11 @@ class FSMManager:
         self.trigger_predicates[trigger].extend(predicates)
 
     def unsubscribe_predicate(self, trigger, *predicates):
-        self.trigger_predicates[trigger] = [predicate for predicate in self.trigger_predicates[trigger]
+        self.trigger_predicates[trigger] = [
-                                            not in predicates]
+            predicate
+            for predicate in self.trigger_predicates[trigger]
+            not in predicates
+        ]
 
 
 class FSMUpdater:
@@ -111,10 +117,18 @@ class FSMUpdater:
         self.uplink.send(self.generate_fsm_update())
 
     def generate_fsm_update(self):
-        return {'key': 'FSMUpdate',
+        return {
-                'data': self.get_fsm_state_and_transitions()}
+            'key': 'FSMUpdate',
+            'data': self.get_fsm_state_and_transitions()
+        }
 
     def get_fsm_state_and_transitions(self):
         state = self.fsm.state
-        valid_transitions = [{'trigger': trigger} for trigger in self.fsm.machine.get_triggers(self.fsm.state)]
+        valid_transitions = [
-        return {'current_state': state, 'valid_transitions': valid_transitions}
+            {'trigger': trigger}
+            for trigger in self.fsm.machine.get_triggers(self.fsm.state)
+        ]
+        return {
+            'current_state': state,
+            'valid_transitions': valid_transitions
+        }