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<h1>Source code for Bcfg2.Server.FileMonitor</h1><div class="highlight"><pre>
<span class="sd">""" Bcfg2.Server.FileMonitor provides the support for monitoring</span>
<span class="sd">files. The FAM acts as a dispatcher for events: An event is detected</span>
<span class="sd">on a file (e.g., the file content is changed), and then that event is</span>
<span class="sd">dispatched to the ``HandleEvent`` method of an object that knows how</span>
<span class="sd">to handle the event. Consequently,</span>
<span class="sd">:func:`Bcfg2.Server.FileMonitor.FileMonitor.AddMonitor` takes two</span>
<span class="sd">arguments: the path to monitor, and the object that handles events</span>
<span class="sd">detected on that event.</span>
<span class="sd">``HandleEvent`` is called with a single argument, the</span>
<span class="sd">:class:`Bcfg2.Server.FileMonitor.Event` object to be handled.</span>
<span class="sd">Assumptions</span>
<span class="sd">-----------</span>
<span class="sd">The FAM API Bcfg2 uses is based on the API of SGI's `File Alteration</span>
<span class="sd">Monitor <http://oss.sgi.com/projects/fam/>`_ (also called "FAM").</span>
<span class="sd">Consequently, a few assumptions apply:</span>
<span class="sd">* When a file or directory is monitored for changes, we call that a</span>
<span class="sd"> "monitor"; other backends my use the term "watch," but for</span>
<span class="sd"> consistency we will use "monitor."</span>
<span class="sd">* Monitors can be set on files or directories.</span>
<span class="sd">* A monitor set on a directory monitors all files within that</span>
<span class="sd"> directory, non-recursively. If the object that requested the</span>
<span class="sd"> monitor wishes to monitor recursively, it must implement that</span>
<span class="sd"> itself.</span>
<span class="sd">* Setting a monitor immediately produces "exists" and "endExist"</span>
<span class="sd"> events for the monitored file or directory and all files or</span>
<span class="sd"> directories contained within it (non-recursively).</span>
<span class="sd">* An event on a file or directory that is monitored directly yields</span>
<span class="sd"> the full path to the file or directory.</span>
<span class="sd">* An event on a file or directory that is *only* contained within a</span>
<span class="sd"> monitored directory yields the relative path to the file or</span>
<span class="sd"> directory within the monitored parent. It is the responsibility of</span>
<span class="sd"> the handler to reconstruct full paths as necessary.</span>
<span class="sd">* Each monitor that is set must have a unique ID that identifies it,</span>
<span class="sd"> in order to make it possible to reconstruct full paths as</span>
<span class="sd"> necessary. This ID will be stored in</span>
<span class="sd"> :attr:`Bcfg2.Server.FileMonitor.FileMonitor.handles`. It may be any</span>
<span class="sd"> hashable value; some FAM backends use monotonically increasing</span>
<span class="sd"> integers, while others use the path to the monitor.</span>
<span class="sd">Base Classes</span>
<span class="sd">------------</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">import</span> <span class="nn">fnmatch</span>
<span class="kn">import</span> <span class="nn">logging</span>
<span class="kn">from</span> <span class="nn">time</span> <span class="kn">import</span> <span class="n">sleep</span><span class="p">,</span> <span class="n">time</span>
<span class="kn">from</span> <span class="nn">Bcfg2.Server.Plugin</span> <span class="kn">import</span> <span class="n">Debuggable</span>
<span class="n">LOGGER</span> <span class="o">=</span> <span class="n">logging</span><span class="o">.</span><span class="n">getLogger</span><span class="p">(</span><span class="n">__name__</span><span class="p">)</span>
<div class="viewcode-block" id="Event"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.Event">[docs]</a><span class="k">class</span> <span class="nc">Event</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="sd">""" Base class for all FAM events. """</span>
<span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">request_id</span><span class="p">,</span> <span class="n">filename</span><span class="p">,</span> <span class="n">code</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> :param request_id: The handler ID of the monitor that produced</span>
<span class="sd"> this event</span>
<span class="sd"> :type request_id: Varies</span>
<span class="sd"> :param filename: The file or directory on which the event was</span>
<span class="sd"> detected. An event on a file or directory</span>
<span class="sd"> that is monitored directly yields the full</span>
<span class="sd"> path to the file or directory; an event on a</span>
<span class="sd"> file or directory that is *only* contained</span>
<span class="sd"> within a monitored directory yields the</span>
<span class="sd"> relative path to the file or directory within</span>
<span class="sd"> the monitored parent.</span>
<span class="sd"> :type filename: string</span>
<span class="sd"> :param code: The :ref:`event code</span>
<span class="sd"> <development-fam-event-codes>` produced. I.e.,</span>
<span class="sd"> the type of event.</span>
<span class="sd"> :type code: string</span>
<span class="sd"> """</span>
<span class="c">#: The handler ID of the monitor that produced this event</span>
<span class="bp">self</span><span class="o">.</span><span class="n">requestID</span> <span class="o">=</span> <span class="n">request_id</span>
<span class="c">#: The file or directory on which the event was detected. An</span>
<span class="c">#: event on a file or directory that is monitored directly</span>
<span class="c">#: yields the full path to the file or directory; an event on</span>
<span class="c">#: a file or directory that is *only* contained within a</span>
<span class="c">#: monitored directory yields the relative path to the file or</span>
<span class="c">#: directory within the monitored parent.</span>
<span class="bp">self</span><span class="o">.</span><span class="n">filename</span> <span class="o">=</span> <span class="n">filename</span>
<span class="c">#: The :ref:`event code <development-fam-event-codes>`</span>
<span class="c">#: produced. I.e., the type of event.</span>
<span class="bp">self</span><span class="o">.</span><span class="n">action</span> <span class="o">=</span> <span class="n">code</span>
<div class="viewcode-block" id="Event.code2str"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.Event.code2str">[docs]</a> <span class="k">def</span> <span class="nf">code2str</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">""" Return the :ref:`event code <development-fam-event-codes>`</span>
<span class="sd"> for this event. This is just an alias for :attr:`action`. """</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">action</span>
</div>
<span class="k">def</span> <span class="nf">__str__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s">"</span><span class="si">%s</span><span class="s">: </span><span class="si">%s</span><span class="s"> </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">__class__</span><span class="o">.</span><span class="n">__name__</span><span class="p">,</span>
<span class="bp">self</span><span class="o">.</span><span class="n">filename</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">action</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__repr__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s">"</span><span class="si">%s</span><span class="s"> (request ID </span><span class="si">%s</span><span class="s">)"</span> <span class="o">%</span> <span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="bp">self</span><span class="p">),</span> <span class="bp">self</span><span class="o">.</span><span class="n">requestID</span><span class="p">)</span>
</div>
<div class="viewcode-block" id="FileMonitor"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor">[docs]</a><span class="k">class</span> <span class="nc">FileMonitor</span><span class="p">(</span><span class="n">Debuggable</span><span class="p">):</span>
<span class="sd">""" The base class that all FAM implementions must inherit.</span>
<span class="sd"> The simplest instance of a FileMonitor subclass needs only to add</span>
<span class="sd"> monitor objects to :attr:`handles` and received events to</span>
<span class="sd"> :attr:`events`; the basic interface will handle the rest. """</span>
<span class="c">#: The relative priority of this FAM backend. Better backends</span>
<span class="c">#: should have higher priorities.</span>
<span class="n">__priority__</span> <span class="o">=</span> <span class="o">-</span><span class="mi">1</span>
<span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">ignore</span><span class="o">=</span><span class="bp">None</span><span class="p">,</span> <span class="n">debug</span><span class="o">=</span><span class="bp">False</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> :param ignore: A list of filename globs describing events that</span>
<span class="sd"> should be ignored (i.e., not processed by any</span>
<span class="sd"> object)</span>
<span class="sd"> :type ignore: list of strings (filename globs)</span>
<span class="sd"> :param debug: Produce debugging information about the events</span>
<span class="sd"> received and handled.</span>
<span class="sd"> :type debug: bool</span>
<span class="sd"> .. -----</span>
<span class="sd"> .. autoattribute:: __priority__</span>
<span class="sd"> """</span>
<span class="n">Debuggable</span><span class="o">.</span><span class="n">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">debug_flag</span> <span class="o">=</span> <span class="n">debug</span>
<span class="c">#: A dict that records which objects handle which events.</span>
<span class="c">#: Keys are monitor handle IDs and values are objects whose</span>
<span class="c">#: ``HandleEvent`` method will be called to handle an event</span>
<span class="bp">self</span><span class="o">.</span><span class="n">handles</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">()</span>
<span class="c">#: Queue of events to handle</span>
<span class="bp">self</span><span class="o">.</span><span class="n">events</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">if</span> <span class="n">ignore</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span>
<span class="n">ignore</span> <span class="o">=</span> <span class="p">[]</span>
<span class="c">#: List of filename globs to ignore events for. For events</span>
<span class="c">#: that include the full path, both the full path and the bare</span>
<span class="c">#: filename will be checked against ``ignore``.</span>
<span class="bp">self</span><span class="o">.</span><span class="n">ignore</span> <span class="o">=</span> <span class="n">ignore</span>
<span class="c">#: Whether or not the FAM has been started. See :func:`start`.</span>
<span class="bp">self</span><span class="o">.</span><span class="n">started</span> <span class="o">=</span> <span class="bp">False</span>
<span class="k">def</span> <span class="nf">__str__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s">"</span><span class="si">%s</span><span class="s">: </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span> <span class="p">(</span><span class="n">__name__</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">__class__</span><span class="o">.</span><span class="n">__name__</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__repr__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s">"</span><span class="si">%s</span><span class="s"> (</span><span class="si">%s</span><span class="s"> events, fd </span><span class="si">%s</span><span class="s">)"</span> <span class="o">%</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">__class__</span><span class="o">.</span><span class="n">__name__</span><span class="p">,</span>
<span class="nb">len</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">events</span><span class="p">),</span>
<span class="bp">self</span><span class="o">.</span><span class="n">fileno</span><span class="p">())</span>
<div class="viewcode-block" id="FileMonitor.start"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.start">[docs]</a> <span class="k">def</span> <span class="nf">start</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">""" Start threads or anything else that needs to be done after</span>
<span class="sd"> the server forks and daemonizes. Note that monitors may (and</span>
<span class="sd"> almost certainly will) be added before ``start()`` is called,</span>
<span class="sd"> so if a backend depends on being started to add monitors,</span>
<span class="sd"> those requests will need to be enqueued and added after</span>
<span class="sd"> ``start()``. See</span>
<span class="sd"> :class:`Bcfg2.Server.FileMonitor.Inotify.Inotify` for an</span>
<span class="sd"> example of this. """</span>
<span class="bp">self</span><span class="o">.</span><span class="n">started</span> <span class="o">=</span> <span class="bp">True</span>
</div>
<div class="viewcode-block" id="FileMonitor.should_ignore"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.should_ignore">[docs]</a> <span class="k">def</span> <span class="nf">should_ignore</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">event</span><span class="p">):</span>
<span class="sd">""" Returns True if an event should be ignored, False</span>
<span class="sd"> otherwise. For events that include the full path, both the</span>
<span class="sd"> full path and the bare filename will be checked against</span>
<span class="sd"> :attr:`ignore`. If the event is ignored, a debug message will</span>
<span class="sd"> be logged with :func:`debug_log`.</span>
<span class="sd"> :param event: Check if this event matches :attr:`ignore`</span>
<span class="sd"> :type event: Bcfg2.Server.FileMonitor.Event</span>
<span class="sd"> :returns: bool - Whether not to ignore the event</span>
<span class="sd"> """</span>
<span class="k">for</span> <span class="n">pattern</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">ignore</span><span class="p">:</span>
<span class="k">if</span> <span class="p">(</span><span class="n">fnmatch</span><span class="o">.</span><span class="n">fnmatch</span><span class="p">(</span><span class="n">event</span><span class="o">.</span><span class="n">filename</span><span class="p">,</span> <span class="n">pattern</span><span class="p">)</span> <span class="ow">or</span>
<span class="n">fnmatch</span><span class="o">.</span><span class="n">fnmatch</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="n">event</span><span class="o">.</span><span class="n">filename</span><span class="p">)[</span><span class="o">-</span><span class="mi">1</span><span class="p">],</span> <span class="n">pattern</span><span class="p">)):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">debug_log</span><span class="p">(</span><span class="s">"Ignoring </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span> <span class="n">event</span><span class="p">)</span>
<span class="k">return</span> <span class="bp">True</span>
<span class="k">return</span> <span class="bp">False</span>
</div>
<div class="viewcode-block" id="FileMonitor.pending"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.pending">[docs]</a> <span class="k">def</span> <span class="nf">pending</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">""" Returns True if there are pending events (i.e., events in</span>
<span class="sd"> :attr:`events` that have not been processed), False</span>
<span class="sd"> otherwise. """</span>
<span class="k">return</span> <span class="nb">bool</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">events</span><span class="p">)</span>
</div>
<div class="viewcode-block" id="FileMonitor.get_event"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.get_event">[docs]</a> <span class="k">def</span> <span class="nf">get_event</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">""" Get the oldest pending event in :attr:`events`.</span>
<span class="sd"> :returns: :class:`Bcfg2.Server.FileMonitor.Event`</span>
<span class="sd"> """</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">events</span><span class="o">.</span><span class="n">pop</span><span class="p">(</span><span class="mi">0</span><span class="p">)</span>
</div>
<div class="viewcode-block" id="FileMonitor.fileno"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.fileno">[docs]</a> <span class="k">def</span> <span class="nf">fileno</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">""" Get the file descriptor of the file monitor thread.</span>
<span class="sd"> :returns: int - The FD number</span>
<span class="sd"> """</span>
<span class="k">return</span> <span class="mi">0</span>
</div>
<div class="viewcode-block" id="FileMonitor.handle_one_event"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.handle_one_event">[docs]</a> <span class="k">def</span> <span class="nf">handle_one_event</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">event</span><span class="p">):</span>
<span class="sd">""" Handle the given event by dispatching it to the object</span>
<span class="sd"> that handles it. This is only called by</span>
<span class="sd"> :func:`handle_event_set`, so if a backend overrides that</span>
<span class="sd"> method it does not necessarily need to implement this</span>
<span class="sd"> function.</span>
<span class="sd"> :param event: The event to handle.</span>
<span class="sd"> :type event: Bcfg2.Server.FileMonitor.Event</span>
<span class="sd"> :returns: None</span>
<span class="sd"> """</span>
<span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">started</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">start</span><span class="p">()</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">should_ignore</span><span class="p">(</span><span class="n">event</span><span class="p">):</span>
<span class="k">return</span>
<span class="k">if</span> <span class="n">event</span><span class="o">.</span><span class="n">requestID</span> <span class="ow">not</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">handles</span><span class="p">:</span>
<span class="n">LOGGER</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s">"Got event for unexpected id </span><span class="si">%s</span><span class="s">, file </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span>
<span class="p">(</span><span class="n">event</span><span class="o">.</span><span class="n">requestID</span><span class="p">,</span> <span class="n">event</span><span class="o">.</span><span class="n">filename</span><span class="p">))</span>
<span class="k">return</span>
<span class="bp">self</span><span class="o">.</span><span class="n">debug_log</span><span class="p">(</span><span class="s">"Dispatching event </span><span class="si">%s</span><span class="s"> </span><span class="si">%s</span><span class="s"> to obj </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span>
<span class="p">(</span><span class="n">event</span><span class="o">.</span><span class="n">code2str</span><span class="p">(),</span> <span class="n">event</span><span class="o">.</span><span class="n">filename</span><span class="p">,</span>
<span class="bp">self</span><span class="o">.</span><span class="n">handles</span><span class="p">[</span><span class="n">event</span><span class="o">.</span><span class="n">requestID</span><span class="p">]))</span>
<span class="k">try</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">handles</span><span class="p">[</span><span class="n">event</span><span class="o">.</span><span class="n">requestID</span><span class="p">]</span><span class="o">.</span><span class="n">HandleEvent</span><span class="p">(</span><span class="n">event</span><span class="p">)</span>
<span class="k">except</span><span class="p">:</span> <span class="c"># pylint: disable=W0702</span>
<span class="n">err</span> <span class="o">=</span> <span class="n">sys</span><span class="o">.</span><span class="n">exc_info</span><span class="p">()[</span><span class="mi">1</span><span class="p">]</span>
<span class="n">LOGGER</span><span class="o">.</span><span class="n">error</span><span class="p">(</span><span class="s">"Error in handling of event </span><span class="si">%s</span><span class="s"> for </span><span class="si">%s</span><span class="s">: </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span>
<span class="p">(</span><span class="n">event</span><span class="o">.</span><span class="n">code2str</span><span class="p">(),</span> <span class="n">event</span><span class="o">.</span><span class="n">filename</span><span class="p">,</span> <span class="n">err</span><span class="p">))</span>
</div>
<div class="viewcode-block" id="FileMonitor.handle_event_set"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.handle_event_set">[docs]</a> <span class="k">def</span> <span class="nf">handle_event_set</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">lock</span><span class="o">=</span><span class="bp">None</span><span class="p">):</span>
<span class="sd">""" Handle all pending events.</span>
<span class="sd"> :param lock: A thread lock to use while handling events. If</span>
<span class="sd"> None, then no thread locking will be performed.</span>
<span class="sd"> This can possibly lead to race conditions in</span>
<span class="sd"> event handling, although it's unlikely to cause</span>
<span class="sd"> any real problems.</span>
<span class="sd"> :type lock: threading.Lock</span>
<span class="sd"> :returns: None</span>
<span class="sd"> """</span>
<span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">started</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">start</span><span class="p">()</span>
<span class="n">count</span> <span class="o">=</span> <span class="mi">0</span>
<span class="n">start</span> <span class="o">=</span> <span class="n">time</span><span class="p">()</span>
<span class="k">if</span> <span class="n">lock</span><span class="p">:</span>
<span class="n">lock</span><span class="o">.</span><span class="n">acquire</span><span class="p">()</span>
<span class="k">while</span> <span class="bp">self</span><span class="o">.</span><span class="n">pending</span><span class="p">():</span>
<span class="bp">self</span><span class="o">.</span><span class="n">handle_one_event</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">get_event</span><span class="p">())</span>
<span class="n">count</span> <span class="o">+=</span> <span class="mi">1</span>
<span class="k">if</span> <span class="n">lock</span><span class="p">:</span>
<span class="n">lock</span><span class="o">.</span><span class="n">release</span><span class="p">()</span>
<span class="n">end</span> <span class="o">=</span> <span class="n">time</span><span class="p">()</span>
<span class="k">if</span> <span class="n">count</span> <span class="o">></span> <span class="mi">0</span><span class="p">:</span>
<span class="n">LOGGER</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s">"Handled </span><span class="si">%d</span><span class="s"> events in </span><span class="si">%.03f</span><span class="s">s"</span> <span class="o">%</span> <span class="p">(</span><span class="n">count</span><span class="p">,</span> <span class="p">(</span><span class="n">end</span> <span class="o">-</span> <span class="n">start</span><span class="p">)))</span>
</div>
<div class="viewcode-block" id="FileMonitor.handle_events_in_interval"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.handle_events_in_interval">[docs]</a> <span class="k">def</span> <span class="nf">handle_events_in_interval</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">interval</span><span class="p">):</span>
<span class="sd">""" Handle events for the specified period of time (in</span>
<span class="sd"> seconds). This call will block for ``interval`` seconds and</span>
<span class="sd"> handle all events received during that period by calling</span>
<span class="sd"> :func:`handle_event_set`.</span>
<span class="sd"> :param interval: The interval, in seconds, during which events</span>
<span class="sd"> should be handled. Any events that are</span>
<span class="sd"> already pending when</span>
<span class="sd"> :func:`handle_events_in_interval` is called</span>
<span class="sd"> will also be handled.</span>
<span class="sd"> :type interval: int</span>
<span class="sd"> :returns: None</span>
<span class="sd"> """</span>
<span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">started</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">start</span><span class="p">()</span>
<span class="n">end</span> <span class="o">=</span> <span class="n">time</span><span class="p">()</span> <span class="o">+</span> <span class="n">interval</span>
<span class="k">while</span> <span class="n">time</span><span class="p">()</span> <span class="o"><</span> <span class="n">end</span><span class="p">:</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">pending</span><span class="p">():</span>
<span class="bp">self</span><span class="o">.</span><span class="n">handle_event_set</span><span class="p">()</span>
<span class="n">end</span> <span class="o">=</span> <span class="n">time</span><span class="p">()</span> <span class="o">+</span> <span class="n">interval</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">sleep</span><span class="p">(</span><span class="mf">0.5</span><span class="p">)</span>
</div>
<div class="viewcode-block" id="FileMonitor.shutdown"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.shutdown">[docs]</a> <span class="k">def</span> <span class="nf">shutdown</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="sd">""" Handle any tasks required to shut down the monitor. """</span>
<span class="bp">self</span><span class="o">.</span><span class="n">started</span> <span class="o">=</span> <span class="bp">False</span>
</div>
<div class="viewcode-block" id="FileMonitor.AddMonitor"><a class="viewcode-back" href="../../../development/fam.html#Bcfg2.Server.FileMonitor.FileMonitor.AddMonitor">[docs]</a> <span class="k">def</span> <span class="nf">AddMonitor</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">path</span><span class="p">,</span> <span class="n">obj</span><span class="p">,</span> <span class="n">handleID</span><span class="o">=</span><span class="bp">None</span><span class="p">):</span>
<span class="sd">""" Monitor the specified path, alerting obj to events. This</span>
<span class="sd"> method must be overridden by a subclass of</span>
<span class="sd"> :class:`Bcfg2.Server.FileMonitor.FileMonitor`.</span>
<span class="sd"> :param path: The path to monitor</span>
<span class="sd"> :type path: string</span>
<span class="sd"> :param obj: The object whose ``HandleEvent`` method will be</span>
<span class="sd"> called when an event is produced.</span>
<span class="sd"> :type obj: Varies</span>
<span class="sd"> :param handleID: The handle ID to use for the monitor. This</span>
<span class="sd"> is useful when requests to add a monitor must</span>
<span class="sd"> be enqueued and the actual monitors added</span>
<span class="sd"> after :func:`start` is called.</span>
<span class="sd"> :type handleID: Varies</span>
<span class="sd"> :returns: Varies - The handler ID for the newly created</span>
<span class="sd"> monitor</span>
<span class="sd"> """</span>
<span class="k">raise</span> <span class="ne">NotImplementedError</span>
<span class="c">#: A dict of all available FAM backends. Keys are the human-readable</span>
<span class="c">#: names of the backends, which are used in bcfg2.conf to select a</span>
<span class="c">#: backend; values are the backend classes. In addition, the</span>
<span class="c">#: ``default`` key will be set to the best FAM backend as determined</span>
<span class="c">#: by :attr:`Bcfg2.Server.FileMonitor.FileMonitor.__priority__`</span></div></div>
<span class="n">available</span> <span class="o">=</span> <span class="nb">dict</span><span class="p">()</span> <span class="c"># pylint: disable=C0103</span>
<span class="c"># TODO: loading the monitor drivers should be automatic</span>
<span class="kn">from</span> <span class="nn">Bcfg2.Server.FileMonitor.Pseudo</span> <span class="kn">import</span> <span class="n">Pseudo</span>
<span class="n">available</span><span class="p">[</span><span class="s">'pseudo'</span><span class="p">]</span> <span class="o">=</span> <span class="n">Pseudo</span>
<span class="k">try</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">Bcfg2.Server.FileMonitor.Fam</span> <span class="kn">import</span> <span class="n">Fam</span>
<span class="n">available</span><span class="p">[</span><span class="s">'fam'</span><span class="p">]</span> <span class="o">=</span> <span class="n">Fam</span>
<span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
<span class="k">pass</span>
<span class="k">try</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">Bcfg2.Server.FileMonitor.Gamin</span> <span class="kn">import</span> <span class="n">Gamin</span>
<span class="n">available</span><span class="p">[</span><span class="s">'gamin'</span><span class="p">]</span> <span class="o">=</span> <span class="n">Gamin</span>
<span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
<span class="k">pass</span>
<span class="k">try</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">Bcfg2.Server.FileMonitor.Inotify</span> <span class="kn">import</span> <span class="n">Inotify</span>
<span class="n">available</span><span class="p">[</span><span class="s">'inotify'</span><span class="p">]</span> <span class="o">=</span> <span class="n">Inotify</span>
<span class="k">except</span> <span class="ne">ImportError</span><span class="p">:</span>
<span class="k">pass</span>
<span class="k">for</span> <span class="n">fdrv</span> <span class="ow">in</span> <span class="nb">reversed</span><span class="p">(</span><span class="nb">sorted</span><span class="p">(</span><span class="n">available</span><span class="o">.</span><span class="n">keys</span><span class="p">(),</span>
<span class="n">key</span><span class="o">=</span><span class="k">lambda</span> <span class="n">k</span><span class="p">:</span> <span class="n">available</span><span class="p">[</span><span class="n">k</span><span class="p">]</span><span class="o">.</span><span class="n">__priority__</span><span class="p">)):</span>
<span class="k">if</span> <span class="n">fdrv</span> <span class="ow">in</span> <span class="n">available</span><span class="p">:</span>
<span class="n">available</span><span class="p">[</span><span class="s">'default'</span><span class="p">]</span> <span class="o">=</span> <span class="n">available</span><span class="p">[</span><span class="n">fdrv</span><span class="p">]</span>
<span class="k">break</span>
</pre></div>
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