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<h1>Source code for horizon.exceptions</h1><div class="highlight"><pre>
<span class="c"># vim: tabstop=4 shiftwidth=4 softtabstop=4</span>
<span class="c"># Copyright 2012 Nebula, Inc.</span>
<span class="c">#</span>
<span class="c"># Licensed under the Apache License, Version 2.0 (the "License"); you may</span>
<span class="c"># not use this file except in compliance with the License. You may obtain</span>
<span class="c"># a copy of the License at</span>
<span class="c">#</span>
<span class="c"># http://www.apache.org/licenses/LICENSE-2.0</span>
<span class="c">#</span>
<span class="c"># Unless required by applicable law or agreed to in writing, software</span>
<span class="c"># distributed under the License is distributed on an "AS IS" BASIS, WITHOUT</span>
<span class="c"># WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the</span>
<span class="c"># License for the specific language governing permissions and limitations</span>
<span class="c"># under the License.</span>
<span class="sd">"""</span>
<span class="sd">Exceptions raised by the Horizon code and the machinery for handling them.</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">logging</span>
<span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">sys</span>
<span class="kn">from</span> <span class="nn">django.conf</span> <span class="kn">import</span> <span class="n">settings</span>
<span class="kn">from</span> <span class="nn">django.contrib.auth</span> <span class="kn">import</span> <span class="n">logout</span>
<span class="kn">from</span> <span class="nn">django.http</span> <span class="kn">import</span> <span class="n">HttpRequest</span>
<span class="kn">from</span> <span class="nn">django.utils</span> <span class="kn">import</span> <span class="n">termcolors</span>
<span class="kn">from</span> <span class="nn">django.utils.translation</span> <span class="kn">import</span> <span class="n">ugettext</span> <span class="k">as</span> <span class="n">_</span>
<span class="kn">from</span> <span class="nn">django.views.debug</span> <span class="kn">import</span> <span class="n">SafeExceptionReporterFilter</span><span class="p">,</span> <span class="n">CLEANSED_SUBSTITUTE</span>
<span class="kn">from</span> <span class="nn">horizon</span> <span class="kn">import</span> <span class="n">messages</span>
<span class="n">LOG</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>
<span class="n">PALETTE</span> <span class="o">=</span> <span class="n">termcolors</span><span class="o">.</span><span class="n">PALETTES</span><span class="p">[</span><span class="n">termcolors</span><span class="o">.</span><span class="n">DEFAULT_PALETTE</span><span class="p">]</span>
<div class="viewcode-block" id="HorizonReporterFilter"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.HorizonReporterFilter">[docs]</a><span class="k">class</span> <span class="nc">HorizonReporterFilter</span><span class="p">(</span><span class="n">SafeExceptionReporterFilter</span><span class="p">):</span>
<span class="sd">""" Error report filter that's always active, even in DEBUG mode. """</span>
<div class="viewcode-block" id="HorizonReporterFilter.is_active"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.HorizonReporterFilter.is_active">[docs]</a> <span class="k">def</span> <span class="nf">is_active</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">request</span><span class="p">):</span>
<span class="k">return</span> <span class="bp">True</span>
<span class="c"># TODO(gabriel): This bugfix is cribbed from Django's code. When 1.4.1</span>
<span class="c"># is available we can remove this code.</span></div>
<div class="viewcode-block" id="HorizonReporterFilter.get_traceback_frame_variables"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.HorizonReporterFilter.get_traceback_frame_variables">[docs]</a> <span class="k">def</span> <span class="nf">get_traceback_frame_variables</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">request</span><span class="p">,</span> <span class="n">tb_frame</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Replaces the values of variables marked as sensitive with</span>
<span class="sd"> stars (*********).</span>
<span class="sd"> """</span>
<span class="c"># Loop through the frame's callers to see if the sensitive_variables</span>
<span class="c"># decorator was used.</span>
<span class="n">current_frame</span> <span class="o">=</span> <span class="n">tb_frame</span><span class="o">.</span><span class="n">f_back</span>
<span class="n">sensitive_variables</span> <span class="o">=</span> <span class="bp">None</span>
<span class="k">while</span> <span class="n">current_frame</span> <span class="ow">is</span> <span class="ow">not</span> <span class="bp">None</span><span class="p">:</span>
<span class="k">if</span> <span class="p">(</span><span class="n">current_frame</span><span class="o">.</span><span class="n">f_code</span><span class="o">.</span><span class="n">co_name</span> <span class="o">==</span> <span class="s">'sensitive_variables_wrapper'</span>
<span class="ow">and</span> <span class="s">'sensitive_variables_wrapper'</span>
<span class="ow">in</span> <span class="n">current_frame</span><span class="o">.</span><span class="n">f_locals</span><span class="p">):</span>
<span class="c"># The sensitive_variables decorator was used, so we take note</span>
<span class="c"># of the sensitive variables' names.</span>
<span class="n">wrapper</span> <span class="o">=</span> <span class="n">current_frame</span><span class="o">.</span><span class="n">f_locals</span><span class="p">[</span><span class="s">'sensitive_variables_wrapper'</span><span class="p">]</span>
<span class="n">sensitive_variables</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">wrapper</span><span class="p">,</span>
<span class="s">'sensitive_variables'</span><span class="p">,</span>
<span class="bp">None</span><span class="p">)</span>
<span class="k">break</span>
<span class="n">current_frame</span> <span class="o">=</span> <span class="n">current_frame</span><span class="o">.</span><span class="n">f_back</span>
<span class="n">cleansed</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">is_active</span><span class="p">(</span><span class="n">request</span><span class="p">)</span> <span class="ow">and</span> <span class="n">sensitive_variables</span><span class="p">:</span>
<span class="k">if</span> <span class="n">sensitive_variables</span> <span class="o">==</span> <span class="s">'__ALL__'</span><span class="p">:</span>
<span class="c"># Cleanse all variables</span>
<span class="k">for</span> <span class="n">name</span><span class="p">,</span> <span class="n">value</span> <span class="ow">in</span> <span class="n">tb_frame</span><span class="o">.</span><span class="n">f_locals</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
<span class="n">cleansed</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">name</span><span class="p">,</span> <span class="n">CLEANSED_SUBSTITUTE</span><span class="p">))</span>
<span class="k">return</span> <span class="n">cleansed</span>
<span class="k">else</span><span class="p">:</span>
<span class="c"># Cleanse specified variables</span>
<span class="k">for</span> <span class="n">name</span><span class="p">,</span> <span class="n">value</span> <span class="ow">in</span> <span class="n">tb_frame</span><span class="o">.</span><span class="n">f_locals</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
<span class="k">if</span> <span class="n">name</span> <span class="ow">in</span> <span class="n">sensitive_variables</span><span class="p">:</span>
<span class="n">value</span> <span class="o">=</span> <span class="n">CLEANSED_SUBSTITUTE</span>
<span class="k">elif</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">value</span><span class="p">,</span> <span class="n">HttpRequest</span><span class="p">):</span>
<span class="c"># Cleanse the request's POST parameters.</span>
<span class="n">value</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_request_repr</span><span class="p">(</span><span class="n">value</span><span class="p">)</span>
<span class="n">cleansed</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">name</span><span class="p">,</span> <span class="n">value</span><span class="p">))</span>
<span class="k">return</span> <span class="n">cleansed</span>
<span class="k">else</span><span class="p">:</span>
<span class="c"># Potentially cleanse only the request if it's one of the</span>
<span class="c"># frame variables.</span>
<span class="k">for</span> <span class="n">name</span><span class="p">,</span> <span class="n">value</span> <span class="ow">in</span> <span class="n">tb_frame</span><span class="o">.</span><span class="n">f_locals</span><span class="o">.</span><span class="n">items</span><span class="p">():</span>
<span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">value</span><span class="p">,</span> <span class="n">HttpRequest</span><span class="p">):</span>
<span class="c"># Cleanse the request's POST parameters.</span>
<span class="n">value</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_request_repr</span><span class="p">(</span><span class="n">value</span><span class="p">)</span>
<span class="n">cleansed</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">name</span><span class="p">,</span> <span class="n">value</span><span class="p">))</span>
<span class="k">return</span> <span class="n">cleansed</span>
</div></div>
<div class="viewcode-block" id="HorizonException"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.HorizonException">[docs]</a><span class="k">class</span> <span class="nc">HorizonException</span><span class="p">(</span><span class="ne">Exception</span><span class="p">):</span>
<span class="sd">""" Base exception class for distinguishing our own exception classes. """</span>
<span class="k">pass</span>
</div>
<div class="viewcode-block" id="Http302"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.Http302">[docs]</a><span class="k">class</span> <span class="nc">Http302</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Error class which can be raised from within a handler to cause an</span>
<span class="sd"> early bailout and redirect at the middleware level.</span>
<span class="sd"> """</span>
<span class="n">status_code</span> <span class="o">=</span> <span class="mi">302</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">location</span><span class="p">,</span> <span class="n">message</span><span class="o">=</span><span class="bp">None</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">location</span> <span class="o">=</span> <span class="n">location</span>
<span class="bp">self</span><span class="o">.</span><span class="n">message</span> <span class="o">=</span> <span class="n">message</span>
</div>
<div class="viewcode-block" id="NotAuthorized"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.NotAuthorized">[docs]</a><span class="k">class</span> <span class="nc">NotAuthorized</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Raised whenever a user attempts to access a resource which they do not</span>
<span class="sd"> have permission-based access to (such as when failing the</span>
<span class="sd"> :func:`~horizon.decorators.require_perms` decorator).</span>
<span class="sd"> The included :class:`~horizon.middleware.HorizonMiddleware` catches</span>
<span class="sd"> ``NotAuthorized`` and handles it gracefully by displaying an error</span>
<span class="sd"> message and redirecting the user to a login page.</span>
<span class="sd"> """</span>
<span class="n">status_code</span> <span class="o">=</span> <span class="mi">401</span>
</div>
<div class="viewcode-block" id="NotAuthenticated"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.NotAuthenticated">[docs]</a><span class="k">class</span> <span class="nc">NotAuthenticated</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Raised when a user is trying to make requests and they are not logged in.</span>
<span class="sd"> The included :class:`~horizon.middleware.HorizonMiddleware` catches</span>
<span class="sd"> ``NotAuthenticated`` and handles it gracefully by displaying an error</span>
<span class="sd"> message and redirecting the user to a login page.</span>
<span class="sd"> """</span>
<span class="n">status_code</span> <span class="o">=</span> <span class="mi">403</span>
</div>
<div class="viewcode-block" id="NotFound"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.NotFound">[docs]</a><span class="k">class</span> <span class="nc">NotFound</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">""" Generic error to replace all "Not Found"-type API errors. """</span>
<span class="n">status_code</span> <span class="o">=</span> <span class="mi">404</span>
</div>
<div class="viewcode-block" id="RecoverableError"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.RecoverableError">[docs]</a><span class="k">class</span> <span class="nc">RecoverableError</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">""" Generic error to replace any "Recoverable"-type API errors. """</span>
<span class="n">status_code</span> <span class="o">=</span> <span class="mi">100</span> <span class="c"># HTTP status code "Continue"</span>
</div>
<div class="viewcode-block" id="ServiceCatalogException"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.ServiceCatalogException">[docs]</a><span class="k">class</span> <span class="nc">ServiceCatalogException</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Raised when a requested service is not available in the ``ServiceCatalog``</span>
<span class="sd"> returned by Keystone.</span>
<span class="sd"> """</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">service_name</span><span class="p">):</span>
<span class="n">message</span> <span class="o">=</span> <span class="s">'Invalid service catalog service: </span><span class="si">%s</span><span class="s">'</span> <span class="o">%</span> <span class="n">service_name</span>
<span class="nb">super</span><span class="p">(</span><span class="n">ServiceCatalogException</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="n">__init__</span><span class="p">(</span><span class="n">message</span><span class="p">)</span>
</div>
<div class="viewcode-block" id="AlreadyExists"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.AlreadyExists">[docs]</a><span class="k">class</span> <span class="nc">AlreadyExists</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Exception to be raised when trying to create an API resource which</span>
<span class="sd"> already exists.</span>
<span class="sd"> """</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">name</span><span class="p">,</span> <span class="n">resource_type</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">attrs</span> <span class="o">=</span> <span class="p">{</span><span class="s">"name"</span><span class="p">:</span> <span class="n">name</span><span class="p">,</span> <span class="s">"resource"</span><span class="p">:</span> <span class="n">resource_type</span><span class="p">}</span>
<span class="bp">self</span><span class="o">.</span><span class="n">msg</span> <span class="o">=</span> <span class="s">'A </span><span class="si">%(resource)s</span><span class="s"> with the name "</span><span class="si">%(name)s</span><span class="s">" already exists.'</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="bp">self</span><span class="o">.</span><span class="n">msg</span> <span class="o">%</span> <span class="bp">self</span><span class="o">.</span><span class="n">attrs</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="bp">self</span><span class="o">.</span><span class="n">msg</span> <span class="o">%</span> <span class="bp">self</span><span class="o">.</span><span class="n">attrs</span>
<span class="k">def</span> <span class="nf">__unicode__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="n">_</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">msg</span><span class="p">)</span> <span class="o">%</span> <span class="bp">self</span><span class="o">.</span><span class="n">attrs</span>
</div>
<div class="viewcode-block" id="WorkflowError"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.WorkflowError">[docs]</a><span class="k">class</span> <span class="nc">WorkflowError</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">""" Exception to be raised when something goes wrong in a workflow. """</span>
<span class="k">pass</span>
</div>
<div class="viewcode-block" id="WorkflowValidationError"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.WorkflowValidationError">[docs]</a><span class="k">class</span> <span class="nc">WorkflowValidationError</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Exception raised during workflow validation if required data is missing,</span>
<span class="sd"> or existing data is not valid.</span>
<span class="sd"> """</span>
<span class="k">pass</span>
</div>
<div class="viewcode-block" id="HandledException"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.HandledException">[docs]</a><span class="k">class</span> <span class="nc">HandledException</span><span class="p">(</span><span class="n">HorizonException</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Used internally to track exceptions that have gone through</span>
<span class="sd"> :func:`horizon.exceptions.handle` more than once.</span>
<span class="sd"> """</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">wrapped</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">wrapped</span> <span class="o">=</span> <span class="n">wrapped</span>
</div>
<span class="n">HORIZON_CONFIG</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">settings</span><span class="p">,</span> <span class="s">"HORIZON_CONFIG"</span><span class="p">,</span> <span class="p">{})</span>
<span class="n">EXCEPTION_CONFIG</span> <span class="o">=</span> <span class="n">HORIZON_CONFIG</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s">"exceptions"</span><span class="p">,</span> <span class="p">{})</span>
<span class="n">UNAUTHORIZED</span> <span class="o">=</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">EXCEPTION_CONFIG</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s">'unauthorized'</span><span class="p">,</span> <span class="p">[]))</span>
<span class="n">NOT_FOUND</span> <span class="o">=</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">EXCEPTION_CONFIG</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s">'not_found'</span><span class="p">,</span> <span class="p">[]))</span>
<span class="n">RECOVERABLE</span> <span class="o">=</span> <span class="p">(</span><span class="n">AlreadyExists</span><span class="p">,)</span>
<span class="n">RECOVERABLE</span> <span class="o">+=</span> <span class="nb">tuple</span><span class="p">(</span><span class="n">EXCEPTION_CONFIG</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s">'recoverable'</span><span class="p">,</span> <span class="p">[]))</span>
<div class="viewcode-block" id="error_color"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.error_color">[docs]</a><span class="k">def</span> <span class="nf">error_color</span><span class="p">(</span><span class="n">msg</span><span class="p">):</span>
<span class="k">return</span> <span class="n">termcolors</span><span class="o">.</span><span class="n">colorize</span><span class="p">(</span><span class="n">msg</span><span class="p">,</span> <span class="o">**</span><span class="n">PALETTE</span><span class="p">[</span><span class="s">'ERROR'</span><span class="p">])</span>
</div>
<div class="viewcode-block" id="check_message"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.check_message">[docs]</a><span class="k">def</span> <span class="nf">check_message</span><span class="p">(</span><span class="n">keywords</span><span class="p">,</span> <span class="n">message</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Checks an exception for given keywords and raises a new ``ActionError``</span>
<span class="sd"> with the desired message if the keywords are found. This allows selective</span>
<span class="sd"> control over API error messages.</span>
<span class="sd"> """</span>
<span class="n">exc_type</span><span class="p">,</span> <span class="n">exc_value</span><span class="p">,</span> <span class="n">exc_traceback</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="k">if</span> <span class="nb">set</span><span class="p">(</span><span class="nb">str</span><span class="p">(</span><span class="n">exc_value</span><span class="p">)</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s">" "</span><span class="p">))</span><span class="o">.</span><span class="n">issuperset</span><span class="p">(</span><span class="nb">set</span><span class="p">(</span><span class="n">keywords</span><span class="p">)):</span>
<span class="n">exc_value</span><span class="o">.</span><span class="n">_safe_message</span> <span class="o">=</span> <span class="n">message</span>
<span class="k">raise</span>
</div>
<div class="viewcode-block" id="handle"><a class="viewcode-back" href="../../sourcecode/horizon/horizon.exceptions.html#horizon.exceptions.handle">[docs]</a><span class="k">def</span> <span class="nf">handle</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="n">message</span><span class="o">=</span><span class="bp">None</span><span class="p">,</span> <span class="n">redirect</span><span class="o">=</span><span class="bp">None</span><span class="p">,</span> <span class="n">ignore</span><span class="o">=</span><span class="bp">False</span><span class="p">,</span>
<span class="n">escalate</span><span class="o">=</span><span class="bp">False</span><span class="p">,</span> <span class="n">log_level</span><span class="o">=</span><span class="bp">None</span><span class="p">,</span> <span class="n">force_log</span><span class="o">=</span><span class="bp">None</span><span class="p">):</span>
<span class="sd">""" Centralized error handling for Horizon.</span>
<span class="sd"> Because Horizon consumes so many different APIs with completely</span>
<span class="sd"> different ``Exception`` types, it's necessary to have a centralized</span>
<span class="sd"> place for handling exceptions which may be raised.</span>
<span class="sd"> Exceptions are roughly divided into 3 types:</span>
<span class="sd"> #. ``UNAUTHORIZED``: Errors resulting from authentication or authorization</span>
<span class="sd"> problems. These result in being logged out and sent to the login screen.</span>
<span class="sd"> #. ``NOT_FOUND``: Errors resulting from objects which could not be</span>
<span class="sd"> located via the API. These generally result in a user-facing error</span>
<span class="sd"> message, but are otherwise returned to the normal code flow. Optionally</span>
<span class="sd"> a redirect value may be passed to the error handler so users are</span>
<span class="sd"> returned to a different view than the one requested in addition to the</span>
<span class="sd"> error message.</span>
<span class="sd"> #. RECOVERABLE: Generic API errors which generate a user-facing message</span>
<span class="sd"> but drop directly back to the regular code flow.</span>
<span class="sd"> All other exceptions bubble the stack as normal unless the ``ignore``</span>
<span class="sd"> argument is passed in as ``True``, in which case only unrecognized</span>
<span class="sd"> errors are bubbled.</span>
<span class="sd"> If the exception is not re-raised, an appropriate wrapper exception</span>
<span class="sd"> class indicating the type of exception that was encountered will be</span>
<span class="sd"> returned.</span>
<span class="sd"> """</span>
<span class="n">exc_type</span><span class="p">,</span> <span class="n">exc_value</span><span class="p">,</span> <span class="n">exc_traceback</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="n">log_method</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">LOG</span><span class="p">,</span> <span class="n">log_level</span> <span class="ow">or</span> <span class="s">"exception"</span><span class="p">)</span>
<span class="n">force_log</span> <span class="o">=</span> <span class="n">force_log</span> <span class="ow">or</span> <span class="n">os</span><span class="o">.</span><span class="n">environ</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s">"HORIZON_TEST_RUN"</span><span class="p">,</span> <span class="bp">False</span><span class="p">)</span>
<span class="n">force_silence</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">exc_value</span><span class="p">,</span> <span class="s">"silence_logging"</span><span class="p">,</span> <span class="bp">False</span><span class="p">)</span>
<span class="c"># Because the same exception may travel through this method more than</span>
<span class="c"># once (if it's re-raised) we may want to treat it differently</span>
<span class="c"># the second time (e.g. no user messages/logging).</span>
<span class="n">handled</span> <span class="o">=</span> <span class="nb">issubclass</span><span class="p">(</span><span class="n">exc_type</span><span class="p">,</span> <span class="n">HandledException</span><span class="p">)</span>
<span class="n">wrap</span> <span class="o">=</span> <span class="bp">False</span>
<span class="c"># Restore our original exception information, but re-wrap it at the end</span>
<span class="k">if</span> <span class="n">handled</span><span class="p">:</span>
<span class="n">exc_type</span><span class="p">,</span> <span class="n">exc_value</span><span class="p">,</span> <span class="n">exc_traceback</span> <span class="o">=</span> <span class="n">exc_value</span><span class="o">.</span><span class="n">wrapped</span>
<span class="n">wrap</span> <span class="o">=</span> <span class="bp">True</span>
<span class="c"># We trust messages from our own exceptions</span>
<span class="k">if</span> <span class="nb">issubclass</span><span class="p">(</span><span class="n">exc_type</span><span class="p">,</span> <span class="n">HorizonException</span><span class="p">):</span>
<span class="n">message</span> <span class="o">=</span> <span class="n">exc_value</span>
<span class="c"># Check for an override message</span>
<span class="k">elif</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">exc_value</span><span class="p">,</span> <span class="s">"_safe_message"</span><span class="p">,</span> <span class="bp">None</span><span class="p">):</span>
<span class="n">message</span> <span class="o">=</span> <span class="n">exc_value</span><span class="o">.</span><span class="n">_safe_message</span>
<span class="c"># If the message has a placeholder for the exception, fill it in</span>
<span class="k">elif</span> <span class="n">message</span> <span class="ow">and</span> <span class="s">"</span><span class="si">%(exc)s</span><span class="s">"</span> <span class="ow">in</span> <span class="n">message</span><span class="p">:</span>
<span class="n">message</span> <span class="o">=</span> <span class="n">message</span> <span class="o">%</span> <span class="p">{</span><span class="s">"exc"</span><span class="p">:</span> <span class="n">exc_value</span><span class="p">}</span>
<span class="k">if</span> <span class="nb">issubclass</span><span class="p">(</span><span class="n">exc_type</span><span class="p">,</span> <span class="n">UNAUTHORIZED</span><span class="p">):</span>
<span class="k">if</span> <span class="n">ignore</span><span class="p">:</span>
<span class="k">return</span> <span class="n">NotAuthorized</span>
<span class="n">logout</span><span class="p">(</span><span class="n">request</span><span class="p">)</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">force_silence</span> <span class="ow">and</span> <span class="ow">not</span> <span class="n">handled</span><span class="p">:</span>
<span class="n">log_method</span><span class="p">(</span><span class="n">error_color</span><span class="p">(</span><span class="s">"Unauthorized: </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span> <span class="n">exc_value</span><span class="p">))</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">handled</span><span class="p">:</span>
<span class="c"># We get some pretty useless error messages back from</span>
<span class="c"># some clients, so let's define our own fallback.</span>
<span class="n">fallback</span> <span class="o">=</span> <span class="n">_</span><span class="p">(</span><span class="s">"Unauthorized. Please try logging in again."</span><span class="p">)</span>
<span class="n">messages</span><span class="o">.</span><span class="n">error</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="n">message</span> <span class="ow">or</span> <span class="n">fallback</span><span class="p">,</span> <span class="n">extra_tags</span><span class="o">=</span><span class="s">"login"</span><span class="p">)</span>
<span class="k">raise</span> <span class="n">NotAuthorized</span> <span class="c"># Redirect handled in middleware</span>
<span class="k">if</span> <span class="nb">issubclass</span><span class="p">(</span><span class="n">exc_type</span><span class="p">,</span> <span class="n">NOT_FOUND</span><span class="p">):</span>
<span class="n">wrap</span> <span class="o">=</span> <span class="bp">True</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">force_silence</span> <span class="ow">and</span> <span class="ow">not</span> <span class="n">handled</span> <span class="ow">and</span> <span class="p">(</span><span class="ow">not</span> <span class="n">ignore</span> <span class="ow">or</span> <span class="n">force_log</span><span class="p">):</span>
<span class="n">log_method</span><span class="p">(</span><span class="n">error_color</span><span class="p">(</span><span class="s">"Not Found: </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span> <span class="n">exc_value</span><span class="p">))</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">ignore</span> <span class="ow">and</span> <span class="ow">not</span> <span class="n">handled</span><span class="p">:</span>
<span class="n">messages</span><span class="o">.</span><span class="n">error</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="n">message</span> <span class="ow">or</span> <span class="n">exc_value</span><span class="p">)</span>
<span class="k">if</span> <span class="n">redirect</span><span class="p">:</span>
<span class="k">raise</span> <span class="n">Http302</span><span class="p">(</span><span class="n">redirect</span><span class="p">)</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">escalate</span><span class="p">:</span>
<span class="k">return</span> <span class="n">NotFound</span> <span class="c"># return to normal code flow</span>
<span class="k">if</span> <span class="nb">issubclass</span><span class="p">(</span><span class="n">exc_type</span><span class="p">,</span> <span class="n">RECOVERABLE</span><span class="p">):</span>
<span class="n">wrap</span> <span class="o">=</span> <span class="bp">True</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">force_silence</span> <span class="ow">and</span> <span class="ow">not</span> <span class="n">handled</span> <span class="ow">and</span> <span class="p">(</span><span class="ow">not</span> <span class="n">ignore</span> <span class="ow">or</span> <span class="n">force_log</span><span class="p">):</span>
<span class="n">log_method</span><span class="p">(</span><span class="n">error_color</span><span class="p">(</span><span class="s">"Recoverable error: </span><span class="si">%s</span><span class="s">"</span> <span class="o">%</span> <span class="n">exc_value</span><span class="p">))</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">ignore</span> <span class="ow">and</span> <span class="ow">not</span> <span class="n">handled</span><span class="p">:</span>
<span class="n">messages</span><span class="o">.</span><span class="n">error</span><span class="p">(</span><span class="n">request</span><span class="p">,</span> <span class="n">message</span> <span class="ow">or</span> <span class="n">exc_value</span><span class="p">)</span>
<span class="k">if</span> <span class="n">redirect</span><span class="p">:</span>
<span class="k">raise</span> <span class="n">Http302</span><span class="p">(</span><span class="n">redirect</span><span class="p">)</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">escalate</span><span class="p">:</span>
<span class="k">return</span> <span class="n">RecoverableError</span> <span class="c"># return to normal code flow</span>
<span class="c"># If we've gotten here, time to wrap and/or raise our exception.</span>
<span class="k">if</span> <span class="n">wrap</span><span class="p">:</span>
<span class="k">raise</span> <span class="n">HandledException</span><span class="p">([</span><span class="n">exc_type</span><span class="p">,</span> <span class="n">exc_value</span><span class="p">,</span> <span class="n">exc_traceback</span><span class="p">])</span>
<span class="k">raise</span> <span class="n">exc_type</span><span class="p">,</span> <span class="n">exc_value</span><span class="p">,</span> <span class="n">exc_traceback</span></div>
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