Hotfix supervisor infinite log recursion if no LogMonitor

Console

.pylintrc

@@ -2,4 +2,4 @@
 
 ignored-modules = zmq
 max-line-length = 150
-disable = missing-docstring, too-few-public-methods
+disable = missing-docstring, too-few-public-methods, invalid-name

Dockerfile

@@ -11,7 +11,8 @@ RUN curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash -
         libzmq5                                \
         nginx                                  \
         gettext-base                                                                                   &&\
-    rm -rf /var/lib/apt/lists/*
+    rm -rf /var/lib/apt/lists/*                                                                        &&\
+    ln -sf /bin/bash /bin/sh
 
 COPY requirements.txt /tmp
 RUN pip3 install -r /tmp/requirements.txt
@@ -26,7 +27,7 @@ ENV TFW_PUBLIC_PORT=8888          \
 
 EXPOSE ${TFW_PUBLIC_PORT}
 
-ENV PYTHONPATH="/usr/local/lib/"                                           \
+ENV PYTHONPATH="/usr/local/lib"                                            \
     TFW_SUPERVISOR_HTTP_URI="http://localhost:${TFW_SUPERVISOR_HTTP_PORT}" \
     TFW_SUPERVISORD_CONF="/etc/supervisor/supervisord.conf"                \
     TFW_SUPERVISORD_COMPONENTS="/etc/supervisor/conf"                      \
@@ -39,22 +40,17 @@ ENV PYTHONPATH="/usr/local/lib/"                                           \
     TFW_HISTFILE="/home/${AVATAO_USER}/.bash_history"                      \
     PROMPT_COMMAND="history -a"
 
-RUN echo "shopt -s cmdhist\n"                 \
+COPY bashrc /tmp
-         "shopt -s histappend\n"              \
+RUN echo "export HISTFILE=${TFW_HISTFILE}" >> /tmp/bashrc &&\
-         "unset HISTCONTROL\n"                \
+    cat /tmp/bashrc >> /home/${AVATAO_USER}/.bashrc
-         "export HISTFILE=$TFW_HISTFILE\n"    \
-         "export HISTFILESIZE=1000\n"         \
-         "export HISTSIZE=1000\n"             \
-         'PROMPT_COMMAND="history -a"\n'      \
-    >> /home/${AVATAO_USER}/.bashrc
 
 COPY supervisor/supervisord.conf ${TFW_SUPERVISORD_CONF}
 COPY nginx/nginx.conf ${TFW_NGINX_CONF}
 COPY nginx/default.conf ${TFW_NGINX_DEFAULT}
 COPY nginx/components/ ${TFW_NGINX_COMPONENTS}
-COPY lib ${TFW_LIB_DIR}
+COPY lib LICENSE ${TFW_LIB_DIR}
 
-RUN for dir in "${TFW_LIB_DIR}" "/etc/nginx" "/etc/supervisor"; do \
+RUN for dir in "${TFW_LIB_DIR}"/{tfw,tao,envvars} "/etc/nginx" "/etc/supervisor"; do \
         chown -R root:root "$dir" && chmod -R 700 "$dir";                               \
     done
 

README.md

@@ -3,11 +3,11 @@
 This is the beating heart of TFW – the Docker baseimage containing the internals of the framework.
 
 Every tutorial-framework based challenge has a `solvable` Docker image based on this one: their `Dockerfile`s begin with `FROM eu.gcr.io/avatao-challengestore/tutorial-framework`.
-Note that TFW is not avaliable on Docker Hub due to legal reasons and is only accessible through local builds (dont't worry, we've got you covered with build scripts in the `test-tutorial-framework` repo).
+Note that TFW is not avaliable on Docker Hub due to legal reasons and is only accessible through local builds (don't worry, we've got you covered with build scripts in the [test-tutorial-framework](https://github.com/avatao-content/test-tutorial-framework) repo).
 
 This document explains the general concepts of TFW and should be the first thing you read before getting started with development.
 
-For more on building and running you should consult the `test-tutorial-framework` repo.
+For more on building and running you should check the [test-tutorial-framework](https://github.com/avatao-content/test-tutorial-framework) repo.
 
 ## The framework
 
@@ -22,9 +22,9 @@ Frontend components use websockets to connect to the TFW server, to which you ca
 
 ### Event handlers
 
-Imagine event handlers as callbacks that are invoked when TFW receives a specific type of message. For instance you could send a message to the framework when the user does something of note.
+Imagine event handlers as callbacks that are invoked when TFW receives a specific type of message. For instance, you could send a message to the framework when the user does something of note.
 
-This allows you to define actions triggered on the backend when the user presses a button on the frontend, moves the cursor to a specific area or anything like that.
+Event handler allow you to define actions triggered on the backend when the user presses a button on the frontend or moves the cursor to a specific area, etc.
 
 Event handlers use ZeroMQ to connect to the framework. Due to this they are as loosely-coupled as possible: usually they are running in separate processes and only communicate with TFW through ZMQ.
 
@@ -38,9 +38,9 @@ Inside Avatao this means that any of the content teams can use the framework wit
 Another unique feature of the framework is the FSM – finite state machine – representing the state of your challenge.
 This allows you to track users progressing with the tasks you've defined for them to complete.
 
-For instance you could represent whether the user managed to create a malicious user with a state called `user_registered` and subscribe callbacks to events regarding that state (like entering or leaving).
+For instance, you could represent whether the user managed to create a malicious user with a state called `user_registered` and subscribe callbacks to events regarding that state (like entering or leaving).
 
-You could create challenges that can be completed in several different ways: imagine a state called `challenge_complete`, which represents when the challenge is completed. Several series of actions (triggers) could lead to this state.
+You could create challenges that can be completed in several different ways: imagine a state called `challenge_complete`, which indicates if the challenge is completed. Several series of actions (triggers) could lead to this state.
 
 This enables you to guide your users through the experience you've envisioned with your tutorial.
 We can provide a whole new level of interactivity in our challenges because we know what the user is doing.
@@ -48,10 +48,36 @@ This includes context-dependent hints and the automatic typing of commands to a
 
 ### Frontend
 
-Note that our frontend implementation is written in Angular. It is maintained and documented in the `frontend-tutorial-framework` repository.
+Note that our frontend implementation is written in Angular. It is maintained and documented in the [frontend-tutorial-framework](https://github.com/avatao-content/frontend-tutorial-framework) repository.
+
+### Messaging format
+
+The framework uses JSON messages internally and in exposed APIs as well.
+These messages must comply with some rules.
+Don't worry, we are not too fond of rules around these parts.
+
+The TFW message format:
+
+```text
+{
+    "key: "some identifier used for addressing",
+    "data":
+    {
+        ...
+        JSON object carrying anything, preferably cats
+        ...
+    },
+    "trigger": "FSM action"
+}
+```
+
+- The `key` field is used by TFW for addressing and every message must have one (it can be an empty string though)
+- The `data` object can contain anything you might want to send
+- The `trigger` key is an optional field that triggers an FSM action with that name from the current state (whatever that might be)
+
 
 ## Where to go next
 
 Most of the components you need have docstrings included (hang on tight, this is work in progress) – refer to them for usage info.
 
-To get started you should take a look at the `test-tutorial-framework` repository, which serves as an example project as well.
+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.

bashrc

@@ -0,0 +1,20 @@
+_postcmd() 
+{
+    AT_PROMPT=1
+    history -a
+}
+PROMPT_COMMAND="_postcmd"
+
+_precmd()
+{
+    [ -z "$AT_PROMPT" ] && return
+    unset AT_PROMPT
+    history -a
+}
+trap _precmd DEBUG
+
+shopt -s cmdhist
+shopt -s histappend
+unset HISTCONTROL
+export HISTFILESIZE=1000
+export HISTSIZE=1000

lib/tfw/__init__.py

@@ -1,6 +1,6 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from .event_handler_base import TriggerlessEventHandler, TriggeredEventHandler
+from .event_handler_base import EventHandlerBase, TriggeredEventHandler
 from .fsm_base import FSMBase
 from .linear_fsm import LinearFSM

lib/tfw/components/__init__.py

@@ -3,7 +3,8 @@
 
 from .directory_monitoring_event_handler import DirectoryMonitoringEventHandler
 from .process_managing_event_handler import ProcessManagingEventHandler
-from .terminado_event_handler import TerminadoEventHandler
+from .terminal_event_handler import TerminalEventHandler
-from .webide_event_handler import WebideEventHandler
+from .ide_event_handler import IdeEventHandler
 from .history_monitor import HistoryMonitor, BashMonitor, GDBMonitor
 from .terminal_commands import TerminalCommands
+from .log_monitoring_event_handler import LogMonitoringEventHandler

lib/tfw/components/directory_monitor.py

@@ -15,10 +15,12 @@ LOG = logging.getLogger(__name__)
 
 
 class DirectoryMonitor(ObserverMixin):
-    def __init__(self, directory):
+    def __init__(self, directories):
         ObserverMixin.__init__(self)
-        self.eventhandler = WebideReloadWatchdogEventHandler()
+        self.eventhandler = IdeReloadWatchdogEventHandler()
+        for directory in directories:
             self.observer.schedule(self.eventhandler, directory, recursive=True)
+
         self.pause, self.resume = self.eventhandler.pause, self.eventhandler.resume
 
     @property
@@ -42,7 +44,7 @@ class DirectoryMonitor(ObserverMixin):
             self.directorymonitor.resume()
 
 
-class WebideReloadWatchdogEventHandler(FileSystemWatchdogEventHandler):
+class IdeReloadWatchdogEventHandler(FileSystemWatchdogEventHandler):
     def __init__(self):
         super().__init__()
         self.uplink = ServerUplinkConnector()
@@ -63,7 +65,7 @@ class WebideReloadWatchdogEventHandler(FileSystemWatchdogEventHandler):
             self.ignore = self.ignore - 1
             return
         LOG.debug(event)
-        self.uplink.send({'key': 'webide',
+        self.uplink.send({'key': 'ide',
                           'data': {'command': 'reload'}})
 
 

lib/tfw/components/directory_monitoring_event_handler.py

@@ -3,7 +3,7 @@
 
 from os.path import isdir, exists
 
-from tfw import TriggerlessEventHandler
+from tfw import EventHandlerBase
 from tfw.config.logs import logging
 from tfw.mixins import MonitorManagerMixin
 from .directory_monitor import DirectoryMonitor
@@ -11,7 +11,7 @@ from .directory_monitor import DirectoryMonitor
 LOG = logging.getLogger(__name__)
 
 
-class DirectoryMonitoringEventHandler(TriggerlessEventHandler, MonitorManagerMixin):
+class DirectoryMonitoringEventHandler(EventHandlerBase, MonitorManagerMixin):
     def __init__(self, key, directory):
         super().__init__(key)
         self._directory = directory

lib/tfw/components/history_monitor.py

@@ -24,6 +24,17 @@ class CallbackEventHandler(PatternMatchingEventHandler, ABC):
 
 
 class HistoryMonitor(CallbackMixin, ObserverMixin, ABC):
+    """
+    Abstract class capable of monitoring and parsing a history file such as
+    bash HISTFILEs. Monitoring means detecting when the file was changed and
+    notifying subscribers about new content in the file.
+
+    This is useful for monitoring CLI sessions.
+
+    To specify a custom HistoryMonitor inherit from this class and override the
+    command pattern property and optionally the sanitize_command method.
+    See examples below.
+    """
     def __init__(self, histfile):
         CallbackMixin.__init__(self)
         ObserverMixin.__init__(self)
@@ -61,6 +72,15 @@ class HistoryMonitor(CallbackMixin, ObserverMixin, ABC):
 
 
 class BashMonitor(HistoryMonitor):
+    """
+    HistoryMonitor for monitoring bash CLI sessions.
+    This requires the following to be set in bash
+    (note that this is done automatically by TFW):
+        PROMPT_COMMAND="history -a"
+        shopt -s cmdhist
+        shopt -s histappend
+        unset HISTCONTROL
+    """
     @property
     def command_pattern(self):
         return r'.+'
@@ -70,6 +90,10 @@ class BashMonitor(HistoryMonitor):
 
 
 class GDBMonitor(HistoryMonitor):
+    """
+    HistoryMonitor to monitor GDB sessions.
+    For this to work "set trace-commands on" must be set in GDB.
+    """
     @property
     def command_pattern(self):
         return r'(?<=\n)\+(.+)\n'

lib/tfw/components/ide_event_handler.py

@@ -6,7 +6,7 @@ from glob import glob
 from fnmatch import fnmatchcase
 from collections import Iterable
 
-from tfw import TriggerlessEventHandler
+from tfw import EventHandlerBase
 from tfw.mixins import MonitorManagerMixin
 from tfw.config.logs import logging
 from .directory_monitor import DirectoryMonitor
@@ -40,9 +40,9 @@ class FileManager:  # pylint: disable=too-many-instance-attributes
     @workdir.setter
     def workdir(self, directory):
         if not exists(directory) or not isdir(directory):
-            raise EnvironmentError('"{}" is not a directory!'.format(directory))
+            raise EnvironmentError(f'"{directory}" is not a directory!')
         if not self._is_in_whitelisted_dir(directory):
-            raise EnvironmentError('Directory "{}" is not in whitelist!'.format(directory))
+            raise EnvironmentError(f'Directory "{directory}" is not in whitelist!')
         self._workdir = directory
 
     @property
@@ -91,13 +91,43 @@ class FileManager:  # pylint: disable=too-many-instance-attributes
         return relpath(self._filepath(filename), start=self._workdir)
 
 
-class WebideEventHandler(TriggerlessEventHandler, MonitorManagerMixin):
+class IdeEventHandler(EventHandlerBase, MonitorManagerMixin):
     # pylint: disable=too-many-arguments
-    def __init__(self, key, directory, allowed_directories, selected_file=None, exclude=None):
+    """
+    Event handler implementing the backend of our browser based IDE.
+    By default all files in the directory specified in __init__ are displayed
+    on the fontend. Note that this is a stateful component.
+
+    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
+    a command to be executed.
+    The API of each command is documented in their respective handlers.
+    """
+    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 selected_file: file that is selected by default
+        :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,
                                            selected_file=selected_file, exclude=exclude)
-        MonitorManagerMixin.__init__(self, DirectoryMonitor, self.filemanager.workdir)
+        except IndexError:
+            raise EnvironmentError(f'No file(s) in IdeEventHandler working_directory "{directory}"!')
+
+        self.watched_directories = [self.filemanager.workdir]
+        if additional_watched_directories:
+            self.watched_directories.extend(additional_watched_directories)
+        MonitorManagerMixin.__init__(self, DirectoryMonitor, self.watched_directories)
 
         self.commands = {'read':      self.read,
                          'write':     self.write,
@@ -106,6 +136,11 @@ class WebideEventHandler(TriggerlessEventHandler, MonitorManagerMixin):
                          'exclude':   self.exclude}
 
     def read(self, data):
+        """
+        Read the currently selected file.
+
+        :return: message with the contents of the file in data['content']
+        """
         try:
             data['content'] = self.filemanager.file_contents
         except PermissionError:
@@ -117,6 +152,12 @@ class WebideEventHandler(TriggerlessEventHandler, MonitorManagerMixin):
         return data
 
     def write(self, data):
+        """
+        Overwrites a file with the desired string.
+
+        :param data: TFW message data containing keys:
+               |-string: containing the desired file contents
+        """
         self.monitor.ignore = self.monitor.ignore + 1
         try:
             self.filemanager.file_contents = data['content']
@@ -126,6 +167,12 @@ class WebideEventHandler(TriggerlessEventHandler, MonitorManagerMixin):
         return data
 
     def select(self, data):
+        """
+        Selects a file from the current directory.
+
+        :param data: TFW message data containing keys:
+               |-filename: name of file to select relative to the current directory
+        """
         try:
             self.filemanager.filename = data['filename']
         except EnvironmentError:
@@ -133,6 +180,14 @@ class WebideEventHandler(TriggerlessEventHandler, MonitorManagerMixin):
         return data
 
     def select_dir(self, data):
+        """
+        Select a new working directory to display files from.
+
+        :param data: TFW message data containing keys:
+               |-directory: absolute path of diretory to select.
+                            must be a path whitelisted in
+                            self.allowed_directories
+        """
         try:
             self.filemanager.workdir = data['directory']
             self.reload_monitor()
@@ -146,6 +201,12 @@ class WebideEventHandler(TriggerlessEventHandler, MonitorManagerMixin):
         return data
 
     def exclude(self, data):
+        """
+        Overwrite list of excluded files
+
+        :param data: TFW message data containing keys:
+               |-exclude: list of filename patterns to be excluded, e.g.: ["*.pyc", "*.o"]
+        """
         try:
             self.filemanager.exclude = list(data['exclude'])
         except TypeError:
@@ -153,6 +214,9 @@ class WebideEventHandler(TriggerlessEventHandler, MonitorManagerMixin):
         return data
 
     def attach_fileinfo(self, data):
+        """
+        Basic information included in every response to the frontend.
+        """
         data['filename'] = self.filemanager.filename
         data['files'] = self.filemanager.files
         data['directory'] = self.filemanager.workdir

lib/tfw/components/log_monitor.py

@@ -0,0 +1,52 @@
+# Copyright (C) 2018 Avatao.com Innovative Learning Kft.
+# All Rights Reserved. See LICENSE file for details.
+
+import logging
+from os.path import dirname
+
+from watchdog.events import PatternMatchingEventHandler as PatternMatchingWatchdogEventHandler
+
+from tfw.networking.event_handlers import ServerUplinkConnector
+from tfw.decorators import RateLimiter
+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(process_name, log_tail=log_tail)
+        self.observer.schedule(
+            event_handler,
+            event_handler.path
+        )
+
+    @staticmethod
+    def prevent_log_recursion():
+        # This is done to prevent inotify event logs triggering themselves (infinite log recursion)
+        logging.getLogger('watchdog.observers.inotify_buffer').propagate = False
+
+
+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']])
+        self.uplink = ServerUplinkConnector()
+        self.log_tail = log_tail
+
+    @property
+    def path(self):
+        return dirname(self.procinfo['stdout_logfile'])
+
+    @RateLimiter(rate_per_second=5)
+    def on_modified(self, event):
+        self.uplink.send({
+            'key': 'processlog',
+            'data': {
+                'command': 'new_log',
+                'stdout': self.read_stdout(self.process_name, tail=self.log_tail),
+                'stderr': self.read_stderr(self.process_name, tail=self.log_tail)
+            }
+        })

lib/tfw/components/log_monitoring_event_handler.py

@@ -0,0 +1,37 @@
+# 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
+from .log_monitor import LogMonitor
+
+LOG = logging.getLogger(__name__)
+
+
+class LogMonitoringEventHandler(EventHandlerBase, MonitorManagerMixin):
+    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)
+
+        self.command_handlers = {
+            'process_name': self.handle_process_name,
+            'log_tail':     self.handle_log_tail
+        }
+
+    def handle_event(self, message):
+        try:
+            data = message['data']
+            self.command_handlers[data['command']](data)
+            self.reload_monitor()
+        except KeyError:
+            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)
+
+    def handle_log_tail(self, data):
+        self.set_monitor_args(self.process_name, data['log_tail'])

lib/tfw/components/process_managing_event_handler.py

@@ -3,41 +3,55 @@
 
 from xmlrpc.client import Fault as SupervisorFault
 
-from tfw import TriggerlessEventHandler
+from tfw import EventHandlerBase
-from tfw.mixins import SupervisorMixin
+from tfw.mixins import SupervisorMixin, SupervisorLogMixin
 from tfw.config.logs import logging
 from .directory_monitor import with_monitor_paused
 
 LOG = logging.getLogger(__name__)
 
 
-class ProcessManager(SupervisorMixin):
+class ProcessManager(SupervisorMixin, SupervisorLogMixin):
     def __init__(self):
         self.commands = {'start':      self.start_process,
                          'stop':       self.stop_process,
-                         'restart': self.restart_process,
+                         'restart':    self.restart_process}
-                         'readlog': self.read_log}
 
     def __call__(self, command, process_name):
         return self.commands[command](process_name)
 
 
-class ProcessManagingEventHandler(TriggerlessEventHandler):
+class ProcessManagingEventHandler(EventHandlerBase):
-    def __init__(self, key, dirmonitor=None):
+    """
+    Event handler that can manage processes managed by supervisor.
+
+    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
+    process to manage. This is the name specified in supervisor config files like so:
+    [program:someprogram]
+
+    Commands available: start, stop, restart, readlog
+    (the names are as self-documenting as it gets)
+    """
+    def __init__(self, key, dirmonitor=None, log_tail=0):
         super().__init__(key)
         self.key = key
         self.monitor = dirmonitor
         self.processmanager = ProcessManager()
+        self.log_tail = log_tail
 
     @with_monitor_paused
     def handle_event(self, message):
         try:
             data = message['data']
+            try:
                 self.processmanager(data['command'], data['process_name'])
+            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']['stderr'] = self.processmanager.read_stderr(data['process_name'], self.log_tail)
             return message
         except KeyError:
             LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
-        except SupervisorFault as fault:
-            message['data']['error'] = fault.faultString
-            message['data']['log'] = self.processmanager.read_log(message['data']['process_name'])
-            return message

lib/tfw/components/terminal_commands.py

@@ -3,6 +3,7 @@
 
 from abc import ABC
 from re import match
+from shlex import split
 
 from tfw.config.logs import logging
 
@@ -10,6 +11,24 @@ LOG = logging.getLogger(__name__)
 
 
 class TerminalCommands(ABC):
+    """
+    A class you can use to define hooks for terminal commands. This means that you can
+    have python code executed when the user enters a specific command to the terminal on
+    our frontend.
+
+    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
+    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
+    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 can also use this class to create new commands similarly.
+    """
     def __init__(self, bashrc=None):
         self._command_method_regex = r'^command_(.+)$'
         self.command_implemetations = self._build_command_to_implementation_dict()
@@ -22,7 +41,7 @@ class TerminalCommands(ABC):
 
     def _setup_bashrc_aliases(self, bashrc):
         with open(bashrc, 'a') as ofile:
-            alias_template = 'alias {0}="{0} > /dev/null 2>&1"\n'
+            alias_template = 'type {0} &> /dev/null || alias {0}="{0} &> /dev/null"\n'
             for command in self.command_implemetations.keys():
                 ofile.write(alias_template.format(command))
 
@@ -39,10 +58,10 @@ class TerminalCommands(ABC):
         return match(self._command_method_regex, string)
 
     def callback(self, history):
-        parts = history[-1].split()
+        parts = split(history[-1])
         command = parts[0]
         if command in self.command_implemetations.keys():
             try:
                 self.command_implemetations[command](*parts[1:])
-            except IndexError:
+            except Exception: # pylint: disable=broad-except
-                LOG.debug('Command "%s" failed!', command)
+                LOG.exception('Command "%s" failed:', command)

lib/tfw/components/terminal_event_handler.py

@@ -1,7 +1,7 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from tfw import TriggerlessEventHandler
+from tfw import EventHandlerBase
 from tfw.config import TFWENV
 from tfw.config.logs import logging
 from tao.config import TAOENV
@@ -10,8 +10,21 @@ from .terminado_mini_server import TerminadoMiniServer
 LOG = logging.getLogger(__name__)
 
 
-class TerminadoEventHandler(TriggerlessEventHandler):
+class TerminalEventHandler(EventHandlerBase):
+    """
+    Event handler responsible for managing terminal sessions for frontend xterm
+    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
+    a command to be executed.
+    The API of each command is documented in their respective handlers.
+    """
     def __init__(self, key, monitor):
+        """
+        :param key: key this EventHandler listens to
+        :param monitor: tfw.components.HistoryMonitor instance to read command history from
+        """
         super().__init__(key)
         self.working_directory = TFWENV.TERMINADO_DIR
         self._historymonitor = monitor
@@ -37,9 +50,23 @@ class TerminadoEventHandler(TriggerlessEventHandler):
             LOG.error('IGNORING MESSAGE: Invalid message received: %s', message)
 
     def write(self, data):
+        """
+        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:
+               |-shellcmd: command to be written to the pty
+        """
         self.terminado_server.pty.write(data['shellcmd'])
 
     def read(self, data):
+        """
+        Reads the history of commands executed.
+
+        :param data: TFW message data containing keys:
+               |-count: the number of history elements to return
+        :return: message with list of commands in data['history']
+        """
         data['count'] = int(data.get('count', 1))
         if self.historymonitor:
             data['history'] = self.historymonitor.history[-data['count']:]

lib/tfw/event_handler_base.py

@@ -8,75 +8,97 @@ from tfw.networking.event_handlers import ServerConnector
 
 
 class EventHandlerBase(ABC):
+    """
+    Abstract base class for all Python based EventHandlers. Useful implementation template
+    for other languages.
+
+    Derived classes must implement the handle_event() method
+    """
     def __init__(self, key):
         self.server_connector = ServerConnector()
         self.key = key
-        self.subscriptions = set()
+        self.subscribe(self.key, 'reset')
-        self.subscribe(self.key)
-        self.subscribe('reset')
         self.server_connector.register_callback(self.event_handler_callback)
 
     def event_handler_callback(self, msg_parts):
+        """
+        Callback that is invoked when receiving a message.
+        Dispatches messages to handler methods and sends
+        a response back in case the handler returned something.
+        This is subscribed in __init__().
+        """
         message = deserialize_tfw_msg(*msg_parts)
         response = self.dispatch_handling(message)
+        if response:
             response['key'] = message['key']
-        if response is None:
-            return
             self.server_connector.send(response)
 
-    @abstractmethod
     def dispatch_handling(self, message):
-        raise NotImplementedError
+        """
-
+        Used to dispatch messages to their specific handlers.
-    def _dispatch_handling(self, message):
+        """
-        # pylint: disable=no-else-return
         if message['key'] != 'reset':
             return self.handle_event(message)
-        else:
         return self.handle_reset(message)
 
     @abstractmethod
     def handle_event(self, message):
+        """
+        Abstract method that implements the handling of messages.
+
+        :param message: the message received
+        """
         raise NotImplementedError
 
     def handle_reset(self, message):
         # pylint: disable=unused-argument,no-self-use
+        """
+        Usually 'reset' events receive some sort of special treatment.
+
+        :param message: the message received
+        """
         return None
 
-    def cleanup(self):
+    def subscribe(self, *keys):
-        pass
+        """
+        Subscribe this EventHandler to receive events for given keys.
+        Note that you can subscribe to the same key several times in which
+        case you will need to unsubscribe multiple times in order to stop
+        receiving events.
         
-    def subscribe(self, key):
+        :param keys: list of keys to subscribe to
-        if key not in self.subscriptions:
+        """
-            self.subscriptions.add(key)
+        for key in keys:
             self.server_connector.subscribe(key)
 
-    def unsubscribe(self, key):
+    def unsubscribe(self, *keys):
-        try:
+        """
-            self.subscriptions.remove(key)
+        Unsubscribe this eventhandler from the given keys.
+
+        :param keys: list of keys to unsubscribe from
+        """
+        for key in keys:
             self.server_connector.unsubscribe(key)
-        except KeyError:
+
+    def cleanup(self):
+        """
+        Perform cleanup actions such as releasing database
+        connections and stuff like that.
+        """
         pass
 
-    def unsubscribe_all(self):
-        for sub in self.subscriptions:
-            self.server_connector.unsubscribe(key=sub)
-        self.subscriptions.clear()
-
-
-class TriggerlessEventHandler(EventHandlerBase, ABC):
-    # pylint: disable=abstract-method
-    def dispatch_handling(self, message):
-        return self._dispatch_handling(message)
-
 
 class TriggeredEventHandler(EventHandlerBase, ABC):
     # pylint: disable=abstract-method
+    """
+    Abstract base class for EventHandlers which are only triggered in case
+    TFWServer has successfully triggered an FSM step defined in __init__.
+    """
     def __init__(self, key, trigger):
         super().__init__(key)
         self.trigger = trigger
 
     def dispatch_handling(self, message):
         if message.get('trigger') == self.trigger:
-            return self._dispatch_handling(message)
+            return super().dispatch_handling(message)
         return None

lib/tfw/fsm_base.py

@@ -9,6 +9,13 @@ from tfw.mixins import CallbackMixin
 
 
 class FSMBase(CallbackMixin):
+    """
+    A general FSM base class you can inherit from to track user progress.
+    See linear_fsm.py for an example use-case.
+    TFW the transitions library for state machines, please refer to their
+    documentation for more information on creating your own machines:
+    https://github.com/pytransitions/transitions
+    """
     states, transitions = [], []
 
     def __init__(self, initial: str = None, accepted_states: List[str] = None):

lib/tfw/linear_fsm.py

@@ -5,8 +5,18 @@ from .fsm_base import FSMBase
 
 
 class LinearFSM(FSMBase):
+    # pylint: disable=anomalous-backslash-in-string
+    """
+    This is a state machine for challenges with linear progression, consisting of
+    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 = [{'trigger': 'step_{}'.format(int(index)+1), 'source': index, 'dest': str(int(index)+1)}
+        self.transitions = []
-                            for index in self.states[:-1]]
+        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({'trigger': 'step_next', 'source': index, 'dest': str(int(index)+1)})
         super(LinearFSM, self).__init__()

lib/tfw/mixins/__init__.py

@@ -1,7 +1,7 @@
 # Copyright (C) 2018 Avatao.com Innovative Learning Kft.
 # All Rights Reserved. See LICENSE file for details.
 
-from .supervisor_mixin import SupervisorMixin
+from .supervisor_mixin import SupervisorMixin, SupervisorLogMixin
 from .callback_mixin import CallbackMixin
 from .observer_mixin import ObserverMixin
 from .monitor_manager_mixin import MonitorManagerMixin

lib/tfw/mixins/callback_mixin.py

@@ -9,6 +9,12 @@ class CallbackMixin:
         self._callbacks = []
 
     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 **kwargs: kwargs passed to callable
+        """
         fun = partial(callback, *args, **kwargs)
         self._callbacks.append(fun)
 

lib/tfw/mixins/monitor_manager_mixin.py

@@ -7,21 +7,24 @@ LOG = logging.getLogger(__name__)
 
 
 class MonitorManagerMixin:
-    def __init__(self, monitor_type, directory):
+    def __init__(self, monitor_type, *monitor_args):
         self._monitor_type = monitor_type
         self._monitor = None
-        self._monitored_directory = directory
+        self.monitor_args = monitor_args
         self.reload_monitor()
 
     @property
     def monitor(self):
         return self._monitor
 
+    def set_monitor_args(self, *monitor_args):
+        self.monitor_args = monitor_args
+
     def reload_monitor(self):
         if self._monitor:
             try:
                 self._monitor.stop()
             except KeyError:
                 LOG.debug('Working directory was removed – ignoring...')
-        self._monitor = self._monitor_type(self._monitored_directory)
+        self._monitor = self._monitor_type(*self.monitor_args)
         self._monitor.watch()   # This runs on a separate thread

lib/tfw/mixins/supervisor_mixin.py

@@ -9,9 +9,21 @@ from os import remove
 from tfw.config import TFWENV
 
 
-class SupervisorMixin:
+def get_supervisor_instance():
-    supervisor = xmlrpc.client.ServerProxy(TFWENV.SUPERVISOR_HTTP_URI).supervisor
+    return xmlrpc.client.ServerProxy(TFWENV.SUPERVISOR_HTTP_URI).supervisor
 
+
+class SupervisorBaseMixin:
+    supervisor = get_supervisor_instance()
+
+    def acquire_own_supervisor_instance(self):
+        """
+        Give this instance non-static, local xmlrpc client
+        """
+        self.supervisor = get_supervisor_instance()
+
+
+class SupervisorMixin(SupervisorBaseMixin):
     def stop_process(self, process_name):
         with suppress(SupervisorFault):
             self.supervisor.stopProcess(process_name)
@@ -19,12 +31,20 @@ class SupervisorMixin:
     def start_process(self, process_name):
         self.supervisor.startProcess(process_name)
 
-    def read_log(self, process_name):
-        logs = self.supervisor.readProcessStderrLog(process_name, 0, 0)
-        remove(self.supervisor.getProcessInfo(process_name)['stderr_logfile'])
-        self.supervisor.clearProcessLogs(process_name)
-        return logs
-
     def restart_process(self, process_name):
         self.stop_process(process_name)
         self.start_process(process_name)
+
+
+class SupervisorLogMixin(SupervisorBaseMixin):
+    def read_stdout(self, process_name, tail=0):
+        return self.supervisor.readProcessStdoutLog(process_name, -tail, 0)
+
+    def read_stderr(self, process_name, tail=0):
+        return self.supervisor.readProcessStderrLog(process_name, -tail, 0)
+
+    def clear_logs(self, process_name):
+        for logfile in ('stdout_logfile', 'stderr_logfile'):
+            with suppress(FileNotFoundError):
+                remove(self.supervisor.getProcessInfo(process_name)[logfile])
+        self.supervisor.clearProcessLogs(process_name)

lib/tfw/networking/controller_connector.py

@@ -12,7 +12,7 @@ class ControllerConnector(ZMQConnectorBase):
     def __init__(self, zmq_context=None):
         super(ControllerConnector, self).__init__(zmq_context)
         self._zmq_rep_socket = self._zmq_context.socket(zmq.REP)
-        self._zmq_rep_socket.connect('tcp://localhost:{}'.format(TFWENV.CONTROLLER_PORT))
+        self._zmq_rep_socket.connect(f'tcp://localhost:{TFWENV.CONTROLLER_PORT}')
         self._zmq_rep_stream = ZMQStream(self._zmq_rep_socket)
 
         self.register_callback = self._zmq_rep_stream.on_recv_stream

lib/tfw/networking/event_handlers/server_connector.py

@@ -15,7 +15,7 @@ class ServerDownlinkConnector(ZMQConnectorBase):
     def __init__(self, zmq_context=None):
         super(ServerDownlinkConnector, self).__init__(zmq_context)
         self._zmq_sub_socket = self._zmq_context.socket(zmq.SUB)
-        self._zmq_sub_socket.connect('tcp://localhost:{}'.format(TFWENV.PUBLISHER_PORT))
+        self._zmq_sub_socket.connect(f'tcp://localhost:{TFWENV.PUBLISHER_PORT}')
         self._zmq_sub_stream = ZMQStream(self._zmq_sub_socket)
 
         self.subscribe = partial(self._zmq_sub_socket.setsockopt_string, zmq.SUBSCRIBE)
@@ -24,18 +24,34 @@ class ServerDownlinkConnector(ZMQConnectorBase):
 
 
 class ServerUplinkConnector(ZMQConnectorBase):
+    """
+    Class capable of sending messages to the TFW server and event handlers.
+    """
     def __init__(self, zmq_context=None):
         super(ServerUplinkConnector, self).__init__(zmq_context)
         self._zmq_push_socket = self._zmq_context.socket(zmq.PUSH)
-        self._zmq_push_socket.connect('tcp://localhost:{}'.format(TFWENV.RECEIVER_PORT))
+        self._zmq_push_socket.connect(f'tcp://localhost:{TFWENV.RECEIVER_PORT}')
 
     def send_to_eventhandler(self, message):
+        """
+        Send a message to an event handler.
+        This envelopes the desired message in the 'data' field of the message to
+        TFWServer, which will mirror it to event handlers.
+
+        :param message: JSON message you want to send
+        :param message['key']: key of event handler you want to address
+        """
         nested_message = {'key': message['key'], 'data': message.pop('data')}
         message['key'] = 'mirror'
         message['data'] = nested_message
         self.send(message)
 
     def send(self, message):
+        """
+        Send a message to the TFW server
+
+        :param message: JSON message you want to send
+        """
         self._zmq_push_socket.send_multipart(serialize_tfw_msg(message))
 
 

lib/tfw/networking/message_sender.py

@@ -7,11 +7,20 @@ from tfw.networking.event_handlers import ServerUplinkConnector
 
 
 class MessageSender:
+    """
+    Provides a mechanism to send messages to our frontend messaging component which
+    displays messages with the key "message".
+    """
     def __init__(self, custom_key: str = None):
         self.server_connector = ServerUplinkConnector()
         self.key = custom_key or 'message'
 
     def send(self, originator, message):
+        """
+        Sends a message to the key specified in __init__.
+        :param originator: name of sender to be displayed on the frontend
+        :param message: message to send
+        """
         data = {
             'originator': originator,
             'timestamp': datetime.now().isoformat(),

lib/tfw/networking/serialization.py

@@ -29,10 +29,16 @@ def validate_message(message):
 
 
 def serialize_tfw_msg(message):
+    """
+    Create TFW multipart data from message dict
+    """
     return _serialize_all(message['key'], message)
 
 
 def deserialize_tfw_msg(*args):
+    """
+    Return message from TFW multipart data
+    """
     return _deserialize_all(*args)[1]
 
 
@@ -45,12 +51,20 @@ def _deserialize_all(*args):
 
 
 def _serialize_single(data):
+    """
+    Return input as bytes
+    (serialize input if it is JSON)
+    """
     if not isinstance(data, str):
         data = json.dumps(data)
     return _encode_if_needed(data)
 
 
 def _deserialize_single(data):
+    """
+    Try parsing input as JSON, return it as
+    string if parsing fails.
+    """
     try:
         return json.loads(data)
     except ValueError:
@@ -58,12 +72,20 @@ def _deserialize_single(data):
 
 
 def _encode_if_needed(value):
+    """
+    Return input as bytes
+    (encode if input is string)
+    """
     if isinstance(value, str):
         value = value.encode('utf-8')
     return value
 
 
 def _decode_if_needed(value):
+    """
+    Return input as string
+    (decode if input is bytes)
+    """
     if isinstance(value, (bytes, bytearray)):
         value = value.decode('utf-8')
     return value

lib/tfw/networking/server/event_handler_connector.py

@@ -16,7 +16,7 @@ class EventHandlerDownlinkConnector(ZMQConnectorBase):
         super(EventHandlerDownlinkConnector, self).__init__(zmq_context)
         self._zmq_pull_socket = self._zmq_context.socket(zmq.PULL)
         self._zmq_pull_stream = ZMQStream(self._zmq_pull_socket)
-        address = 'tcp://*:{}'.format(TFWENV.RECEIVER_PORT)
+        address = f'tcp://*:{TFWENV.RECEIVER_PORT}'
         self._zmq_pull_socket.bind(address)
         LOG.debug('Pull socket bound to %s', address)
 
@@ -25,7 +25,7 @@ class EventHandlerUplinkConnector(ZMQConnectorBase):
     def __init__(self, zmq_context=None):
         super(EventHandlerUplinkConnector, self).__init__(zmq_context)
         self._zmq_pub_socket = self._zmq_context.socket(zmq.PUB)
-        address = 'tcp://*:{}'.format(TFWENV.PUBLISHER_PORT)
+        address = f'tcp://*:{TFWENV.PUBLISHER_PORT}'
         self._zmq_pub_socket.bind(address)
         LOG.debug('Pub socket bound to %s', address)
 

lib/tfw/networking/server/tfw_server.py

@@ -15,7 +15,15 @@ LOG = logging.getLogger(__name__)
 
 
 class TFWServer:
+    """
+    This class handles the proxying of messages between the frontend and event handers.
+    It proxies messages from the "/ws" route to all event handlers subscribed to a ZMQ
+    SUB socket. It also manages an FSM you can define as a constructor argument.
+    """
     def __init__(self, fsm_type):
+        """
+        :param fsm_type: the type of FSM you want TFW to use
+        """
         self._fsm = fsm_type()
         self._fsm_updater = FSMUpdater(self._fsm)
         self._fsm_manager = FSMManager(self._fsm)

nginx/default.conf

@@ -4,6 +4,7 @@ server {
     proxy_connect_timeout 7d;
     proxy_send_timeout 7d;
     proxy_read_timeout 7d;
+    absolute_redirect off;
 
     location = /ws {
         proxy_pass http://127.0.0.1:${TFW_WEB_PORT};

setup.py

@@ -0,0 +1,23 @@
+from os.path import dirname, realpath, join
+
+from setuptools import setup, find_packages
+
+
+here = dirname(realpath(__file__))
+
+with open(join(here, 'VERSION'), 'r') as ifile:
+    version = ifile.read().strip('\n')
+with open(join(here, 'requirements.txt'), 'r') as ifile:
+    requirements = ifile.read().splitlines()
+
+setup(name='tfw',
+      version=version,
+      description='Avatao tutorial-framework',
+      url='https://github.com/avatao-content/baseimage-tutorial-framework',
+      author='Avatao.com Innovative Learning Kft.',
+      author_email='support@avatao.com',
+      license='custom',
+      packages=find_packages('lib'),
+      package_dir={'': 'lib'},
+      install_requires=requirements,
+      zip_safe=False)

supervisor/supervisord.conf

@@ -1,6 +1,7 @@
 [supervisord]
 user=root
-logfile = /tmp/supervisord.log
+logfile=/dev/null
+logfile_maxbytes=0
 loglevel = debug
 pidfile = /tmp/supervisord.pid