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diff --git a/app/static/doc/flask-docs/errorhandling.html b/app/static/doc/flask-docs/errorhandling.html deleted file mode 100644 index 9698707..0000000 --- a/app/static/doc/flask-docs/errorhandling.html +++ /dev/null @@ -1,347 +0,0 @@ - -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" - "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> - - -<html xmlns="http://www.w3.org/1999/xhtml"> - <head> - <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> - - <title>Handling Application Errors — Flask 0.8 documentation</title> - - <link rel="stylesheet" href="_static/flasky.css" type="text/css" /> - <link rel="stylesheet" href="_static/pygments.css" type="text/css" /> - - <script type="text/javascript"> - var DOCUMENTATION_OPTIONS = { - URL_ROOT: '', - VERSION: '0.8', - COLLAPSE_INDEX: false, - FILE_SUFFIX: '.html', - HAS_SOURCE: true - }; - </script> - <script type="text/javascript" src="_static/jquery.js"></script> - <script type="text/javascript" src="_static/underscore.js"></script> - <script type="text/javascript" src="_static/doctools.js"></script> - <link rel="top" title="Flask 0.8 documentation" href="index.html" /> - <link rel="next" title="Configuration Handling" href="config.html" /> - <link rel="prev" title="Testing Flask Applications" href="testing.html" /> - - - <link rel="apple-touch-icon" href="_static/touch-icon.png" /> - - <link media="only screen and (max-device-width: 480px)" href="_static/small_flask.css" type= "text/css" rel="stylesheet" /> - - </head> - <body> - <div class="related"> - <h3>Navigation</h3> - <ul> - <li class="right" style="margin-right: 10px"> - <a href="genindex.html" title="General Index" - accesskey="I">index</a></li> - <li class="right" > - <a href="config.html" title="Configuration Handling" - accesskey="N">next</a> |</li> - <li class="right" > - <a href="testing.html" title="Testing Flask Applications" - accesskey="P">previous</a> |</li> - <li><a href="index.html">Flask 0.8 documentation</a> »</li> - </ul> - </div> - - <div class="document"> - <div class="documentwrapper"> - <div class="bodywrapper"> - <div class="body"> - - <div class="section" id="handling-application-errors"> -<span id="application-errors"></span><h1>Handling Application Errors<a class="headerlink" href="#handling-application-errors" title="Permalink to this headline">¶</a></h1> -<p class="versionadded"> -<span class="versionmodified">New in version 0.3.</span></p> -<p>Applications fail, servers fail. Sooner or later you will see an exception -in production. Even if your code is 100% correct, you will still see -exceptions from time to time. Why? Because everything else involved will -fail. Here some situations where perfectly fine code can lead to server -errors:</p> -<ul class="simple"> -<li>the client terminated the request early and the application was still -reading from the incoming data.</li> -<li>the database server was overloaded and could not handle the query.</li> -<li>a filesystem is full</li> -<li>a harddrive crashed</li> -<li>a backend server overloaded</li> -<li>a programming error in a library you are using</li> -<li>network connection of the server to another system failed.</li> -</ul> -<p>And that’s just a small sample of issues you could be facing. So how do we -deal with that sort of problem? By default if your application runs in -production mode, Flask will display a very simple page for you and log the -exception to the <a class="reference internal" href="api.html#flask.Flask.logger" title="flask.Flask.logger"><tt class="xref py py-attr docutils literal"><span class="pre">logger</span></tt></a>.</p> -<p>But there is more you can do, and we will cover some better setups to deal -with errors.</p> -<div class="section" id="error-mails"> -<h2>Error Mails<a class="headerlink" href="#error-mails" title="Permalink to this headline">¶</a></h2> -<p>If the application runs in production mode (which it will do on your -server) you won’t see any log messages by default. Why is that? Flask -tries to be a zero-configuration framework. Where should it drop the logs -for you if there is no configuration? Guessing is not a good idea because -chances are, the place it guessed is not the place where the user has -permission to create a logfile. Also, for most small applications nobody -will look at the logs anyways.</p> -<p>In fact, I promise you right now that if you configure a logfile for the -application errors you will never look at it except for debugging an issue -when a user reported it for you. What you want instead is a mail the -second the exception happened. Then you get an alert and you can do -something about it.</p> -<p>Flask uses the Python builtin logging system, and it can actually send -you mails for errors which is probably what you want. Here is how you can -configure the Flask logger to send you mails for exceptions:</p> -<div class="highlight-python"><div class="highlight"><pre><span class="n">ADMINS</span> <span class="o">=</span> <span class="p">[</span><span class="s">'yourname@example.com'</span><span class="p">]</span> -<span class="k">if</span> <span class="ow">not</span> <span class="n">app</span><span class="o">.</span><span class="n">debug</span><span class="p">:</span> - <span class="kn">import</span> <span class="nn">logging</span> - <span class="kn">from</span> <span class="nn">logging.handlers</span> <span class="kn">import</span> <span class="n">SMTPHandler</span> - <span class="n">mail_handler</span> <span class="o">=</span> <span class="n">SMTPHandler</span><span class="p">(</span><span class="s">'127.0.0.1'</span><span class="p">,</span> - <span class="s">'server-error@example.com'</span><span class="p">,</span> - <span class="n">ADMINS</span><span class="p">,</span> <span class="s">'YourApplication Failed'</span><span class="p">)</span> - <span class="n">mail_handler</span><span class="o">.</span><span class="n">setLevel</span><span class="p">(</span><span class="n">logging</span><span class="o">.</span><span class="n">ERROR</span><span class="p">)</span> - <span class="n">app</span><span class="o">.</span><span class="n">logger</span><span class="o">.</span><span class="n">addHandler</span><span class="p">(</span><span class="n">mail_handler</span><span class="p">)</span> -</pre></div> -</div> -<p>So what just happened? We created a new -<a class="reference external" href="http://docs.python.org/dev/library/logging.handlers.html#logging.handlers.SMTPHandler" title="(in Python v3.3)"><tt class="xref py py-class docutils literal"><span class="pre">SMTPHandler</span></tt></a> that will send mails with the mail -server listening on <tt class="docutils literal"><span class="pre">127.0.0.1</span></tt> to all the <cite>ADMINS</cite> from the address -<em>server-error@example.com</em> with the subject “YourApplication Failed”. If -your mail server requires credentials, these can also be provided. For -that check out the documentation for the -<a class="reference external" href="http://docs.python.org/dev/library/logging.handlers.html#logging.handlers.SMTPHandler" title="(in Python v3.3)"><tt class="xref py py-class docutils literal"><span class="pre">SMTPHandler</span></tt></a>.</p> -<p>We also tell the handler to only send errors and more critical messages. -Because we certainly don’t want to get a mail for warnings or other -useless logs that might happen during request handling.</p> -<p>Before you run that in production, please also look at <a class="reference internal" href="#logformat"><em>Controlling the Log Format</em></a> to -put more information into that error mail. That will save you from a lot -of frustration.</p> -</div> -<div class="section" id="logging-to-a-file"> -<h2>Logging to a File<a class="headerlink" href="#logging-to-a-file" title="Permalink to this headline">¶</a></h2> -<p>Even if you get mails, you probably also want to log warnings. It’s a -good idea to keep as much information around that might be required to -debug a problem. Please note that Flask itself will not issue any -warnings in the core system, so it’s your responsibility to warn in the -code if something seems odd.</p> -<p>There are a couple of handlers provided by the logging system out of the -box but not all of them are useful for basic error logging. The most -interesting are probably the following:</p> -<ul class="simple"> -<li><a class="reference external" href="http://docs.python.org/dev/library/logging.handlers.html#logging.FileHandler" title="(in Python v3.3)"><tt class="xref py py-class docutils literal"><span class="pre">FileHandler</span></tt></a> - logs messages to a file on the -filesystem.</li> -<li><a class="reference external" href="http://docs.python.org/dev/library/logging.handlers.html#logging.handlers.RotatingFileHandler" title="(in Python v3.3)"><tt class="xref py py-class docutils literal"><span class="pre">RotatingFileHandler</span></tt></a> - logs messages to a file -on the filesystem and will rotate after a certain number of messages.</li> -<li><a class="reference external" href="http://docs.python.org/dev/library/logging.handlers.html#logging.handlers.NTEventLogHandler" title="(in Python v3.3)"><tt class="xref py py-class docutils literal"><span class="pre">NTEventLogHandler</span></tt></a> - will log to the system -event log of a Windows system. If you are deploying on a Windows box, -this is what you want to use.</li> -<li><a class="reference external" href="http://docs.python.org/dev/library/logging.handlers.html#logging.handlers.SysLogHandler" title="(in Python v3.3)"><tt class="xref py py-class docutils literal"><span class="pre">SysLogHandler</span></tt></a> - sends logs to a UNIX -syslog.</li> -</ul> -<p>Once you picked your log handler, do like you did with the SMTP handler -above, just make sure to use a lower setting (I would recommend -<cite>WARNING</cite>):</p> -<div class="highlight-python"><div class="highlight"><pre><span class="k">if</span> <span class="ow">not</span> <span class="n">app</span><span class="o">.</span><span class="n">debug</span><span class="p">:</span> - <span class="kn">import</span> <span class="nn">logging</span> - <span class="kn">from</span> <span class="nn">themodule</span> <span class="kn">import</span> <span class="n">TheHandlerYouWant</span> - <span class="n">file_handler</span> <span class="o">=</span> <span class="n">TheHandlerYouWant</span><span class="p">(</span><span class="o">...</span><span class="p">)</span> - <span class="n">file_handler</span><span class="o">.</span><span class="n">setLevel</span><span class="p">(</span><span class="n">logging</span><span class="o">.</span><span class="n">WARNING</span><span class="p">)</span> - <span class="n">app</span><span class="o">.</span><span class="n">logger</span><span class="o">.</span><span class="n">addHandler</span><span class="p">(</span><span class="n">file_handler</span><span class="p">)</span> -</pre></div> -</div> -</div> -<div class="section" id="controlling-the-log-format"> -<span id="logformat"></span><h2>Controlling the Log Format<a class="headerlink" href="#controlling-the-log-format" title="Permalink to this headline">¶</a></h2> -<p>By default a handler will only write the message string into a file or -send you that message as mail. A log record stores more information, -and it makes a lot of sense to configure your logger to also contain that -information so that you have a better idea of why that error happened, and -more importantly, where it did.</p> -<p>A formatter can be instantiated with a format string. Note that -tracebacks are appended to the log entry automatically. You don’t have to -do that in the log formatter format string.</p> -<p>Here some example setups:</p> -<div class="section" id="email"> -<h3>Email<a class="headerlink" href="#email" title="Permalink to this headline">¶</a></h3> -<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">logging</span> <span class="kn">import</span> <span class="n">Formatter</span> -<span class="n">mail_handler</span><span class="o">.</span><span class="n">setFormatter</span><span class="p">(</span><span class="n">Formatter</span><span class="p">(</span><span class="s">'''</span> -<span class="s">Message type: </span><span class="si">%(levelname)s</span><span class="s"></span> -<span class="s">Location: </span><span class="si">%(pathname)s</span><span class="s">:</span><span class="si">%(lineno)d</span><span class="s"></span> -<span class="s">Module: </span><span class="si">%(module)s</span><span class="s"></span> -<span class="s">Function: </span><span class="si">%(funcName)s</span><span class="s"></span> -<span class="s">Time: </span><span class="si">%(asctime)s</span><span class="s"></span> - -<span class="s">Message:</span> - -<span class="si">%(message)s</span><span class="s"></span> -<span class="s">'''</span><span class="p">))</span> -</pre></div> -</div> -</div> -<div class="section" id="file-logging"> -<h3>File logging<a class="headerlink" href="#file-logging" title="Permalink to this headline">¶</a></h3> -<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">logging</span> <span class="kn">import</span> <span class="n">Formatter</span> -<span class="n">file_handler</span><span class="o">.</span><span class="n">setFormatter</span><span class="p">(</span><span class="n">Formatter</span><span class="p">(</span> - <span class="s">'</span><span class="si">%(asctime)s</span><span class="s"> </span><span class="si">%(levelname)s</span><span class="s">: </span><span class="si">%(message)s</span><span class="s"> '</span> - <span class="s">'[in </span><span class="si">%(pathname)s</span><span class="s">:</span><span class="si">%(lineno)d</span><span class="s">]'</span> -<span class="p">))</span> -</pre></div> -</div> -</div> -<div class="section" id="complex-log-formatting"> -<h3>Complex Log Formatting<a class="headerlink" href="#complex-log-formatting" title="Permalink to this headline">¶</a></h3> -<p>Here is a list of useful formatting variables for the format string. Note -that this list is not complete, consult the official documentation of the -<a class="reference external" href="http://docs.python.org/dev/library/logging.html#logging" title="(in Python v3.3)"><tt class="xref py py-mod docutils literal"><span class="pre">logging</span></tt></a> package for a full list.</p> -<table border="1" class="docutils"> -<colgroup> -<col width="26%" /> -<col width="74%" /> -</colgroup> -<thead valign="bottom"> -<tr class="row-odd"><th class="head">Format</th> -<th class="head">Description</th> -</tr> -</thead> -<tbody valign="top"> -<tr class="row-even"><td><tt class="docutils literal"><span class="pre">%(levelname)s</span></tt></td> -<td>Text logging level for the message -(<tt class="docutils literal"><span class="pre">'DEBUG'</span></tt>, <tt class="docutils literal"><span class="pre">'INFO'</span></tt>, <tt class="docutils literal"><span class="pre">'WARNING'</span></tt>, -<tt class="docutils literal"><span class="pre">'ERROR'</span></tt>, <tt class="docutils literal"><span class="pre">'CRITICAL'</span></tt>).</td> -</tr> -<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">%(pathname)s</span></tt></td> -<td>Full pathname of the source file where the -logging call was issued (if available).</td> -</tr> -<tr class="row-even"><td><tt class="docutils literal"><span class="pre">%(filename)s</span></tt></td> -<td>Filename portion of pathname.</td> -</tr> -<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">%(module)s</span></tt></td> -<td>Module (name portion of filename).</td> -</tr> -<tr class="row-even"><td><tt class="docutils literal"><span class="pre">%(funcName)s</span></tt></td> -<td>Name of function containing the logging call.</td> -</tr> -<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">%(lineno)d</span></tt></td> -<td>Source line number where the logging call was -issued (if available).</td> -</tr> -<tr class="row-even"><td><tt class="docutils literal"><span class="pre">%(asctime)s</span></tt></td> -<td>Human-readable time when the LogRecord` was -created. By default this is of the form -<tt class="docutils literal"><span class="pre">"2003-07-08</span> <span class="pre">16:49:45,896"</span></tt> (the numbers after -the comma are millisecond portion of the time). -This can be changed by subclassing the formatter -and overriding the -<a class="reference external" href="http://docs.python.org/dev/library/logging.html#logging.Formatter.formatTime" title="(in Python v3.3)"><tt class="xref py py-meth docutils literal"><span class="pre">formatTime()</span></tt></a> method.</td> -</tr> -<tr class="row-odd"><td><tt class="docutils literal"><span class="pre">%(message)s</span></tt></td> -<td>The logged message, computed as <tt class="docutils literal"><span class="pre">msg</span> <span class="pre">%</span> <span class="pre">args</span></tt></td> -</tr> -</tbody> -</table> -<p>If you want to further customize the formatting, you can subclass the -formatter. The formatter has three interesting methods:</p> -<dl class="docutils"> -<dt><a class="reference external" href="http://docs.python.org/dev/library/logging.html#logging.Formatter.format" title="(in Python v3.3)"><tt class="xref py py-meth docutils literal"><span class="pre">format()</span></tt></a>:</dt> -<dd>handles the actual formatting. It is passed a -<a class="reference external" href="http://docs.python.org/dev/library/logging.html#logging.LogRecord" title="(in Python v3.3)"><tt class="xref py py-class docutils literal"><span class="pre">LogRecord</span></tt></a> object and has to return the formatted -string.</dd> -<dt><a class="reference external" href="http://docs.python.org/dev/library/logging.html#logging.Formatter.formatTime" title="(in Python v3.3)"><tt class="xref py py-meth docutils literal"><span class="pre">formatTime()</span></tt></a>:</dt> -<dd>called for <cite>asctime</cite> formatting. If you want a different time format -you can override this method.</dd> -<dt><a class="reference external" href="http://docs.python.org/dev/library/logging.html#logging.Formatter.formatException" title="(in Python v3.3)"><tt class="xref py py-meth docutils literal"><span class="pre">formatException()</span></tt></a></dt> -<dd>called for exception formatting. It is passed an <tt class="xref py py-attr docutils literal"><span class="pre">exc_info</span></tt> -tuple and has to return a string. The default is usually fine, you -don’t have to override it.</dd> -</dl> -<p>For more information, head over to the official documentation.</p> -</div> -</div> -<div class="section" id="other-libraries"> -<h2>Other Libraries<a class="headerlink" href="#other-libraries" title="Permalink to this headline">¶</a></h2> -<p>So far we only configured the logger your application created itself. -Other libraries might log themselves as well. For example, SQLAlchemy uses -logging heavily in its core. While there is a method to configure all -loggers at once in the <a class="reference external" href="http://docs.python.org/dev/library/logging.html#logging" title="(in Python v3.3)"><tt class="xref py py-mod docutils literal"><span class="pre">logging</span></tt></a> package, I would not recommend using -it. There might be a situation in which you want to have multiple -separate applications running side by side in the same Python interpreter -and then it becomes impossible to have different logging setups for those.</p> -<p>Instead, I would recommend figuring out which loggers you are interested -in, getting the loggers with the <a class="reference external" href="http://docs.python.org/dev/library/logging.html#logging.getLogger" title="(in Python v3.3)"><tt class="xref py py-func docutils literal"><span class="pre">getLogger()</span></tt></a> function and -iterating over them to attach handlers:</p> -<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">logging</span> <span class="kn">import</span> <span class="n">getLogger</span> -<span class="n">loggers</span> <span class="o">=</span> <span class="p">[</span><span class="n">app</span><span class="o">.</span><span class="n">logger</span><span class="p">,</span> <span class="n">getLogger</span><span class="p">(</span><span class="s">'sqlalchemy'</span><span class="p">),</span> - <span class="n">getLogger</span><span class="p">(</span><span class="s">'otherlibrary'</span><span class="p">)]</span> -<span class="k">for</span> <span class="n">logger</span> <span class="ow">in</span> <span class="n">loggers</span><span class="p">:</span> - <span class="n">logger</span><span class="o">.</span><span class="n">addHandler</span><span class="p">(</span><span class="n">mail_handler</span><span class="p">)</span> - <span class="n">logger</span><span class="o">.</span><span class="n">addHandler</span><span class="p">(</span><span class="n">file_handler</span><span class="p">)</span> -</pre></div> -</div> -</div> -</div> - - - </div> - </div> - </div> - <div class="sphinxsidebar"> - <div class="sphinxsidebarwrapper"><p class="logo"><a href="index.html"> - <img class="logo" src="_static/flask.png" alt="Logo"/> -</a></p> - <h3><a href="index.html">Table Of Contents</a></h3> - <ul> -<li><a class="reference internal" href="#">Handling Application Errors</a><ul> -<li><a class="reference internal" href="#error-mails">Error Mails</a></li> -<li><a class="reference internal" href="#logging-to-a-file">Logging to a File</a></li> -<li><a class="reference internal" href="#controlling-the-log-format">Controlling the Log Format</a><ul> -<li><a class="reference internal" href="#email">Email</a></li> -<li><a class="reference internal" href="#file-logging">File logging</a></li> -<li><a class="reference internal" href="#complex-log-formatting">Complex Log Formatting</a></li> -</ul> -</li> -<li><a class="reference internal" href="#other-libraries">Other Libraries</a></li> -</ul> -</li> -</ul> -<h3>Related Topics</h3> -<ul> - <li><a href="index.html">Documentation overview</a><ul> - <li>Previous: <a href="testing.html" title="previous chapter">Testing Flask Applications</a></li> - <li>Next: <a href="config.html" title="next chapter">Configuration Handling</a></li> - </ul></li> -</ul> - <h3>This Page</h3> - <ul class="this-page-menu"> - <li><a href="_sources/errorhandling.txt" - rel="nofollow">Show Source</a></li> - </ul> -<div id="searchbox" style="display: none"> - <h3>Quick search</h3> - <form class="search" action="search.html" method="get"> - <input type="text" name="q" /> - <input type="submit" value="Go" /> - <input type="hidden" name="check_keywords" value="yes" /> - <input type="hidden" name="area" value="default" /> - </form> - <p class="searchtip" style="font-size: 90%"> - Enter search terms or a module, class or function name. - </p> -</div> -<script type="text/javascript">$('#searchbox').show(0);</script> - </div> - </div> - <div class="clearer"></div> - </div> - <div class="footer"> - © Copyright 2010, Armin Ronacher. - Created using <a href="http://sphinx.pocoo.org/">Sphinx</a>. - </div> - </body> -</html>
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