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<h1>Source code for django.db.utils</h1><div class="highlight"><pre>
<span></span><span class="kn">import</span> <span class="nn">os</span>
<span class="kn">import</span> <span class="nn">pkgutil</span>
<span class="kn">from</span> <span class="nn">importlib</span> <span class="k">import</span> <span class="n">import_module</span>
<span class="kn">from</span> <span class="nn">threading</span> <span class="k">import</span> <span class="n">local</span>
<span class="kn">from</span> <span class="nn">django.conf</span> <span class="k">import</span> <span class="n">settings</span>
<span class="kn">from</span> <span class="nn">django.core.exceptions</span> <span class="k">import</span> <span class="n">ImproperlyConfigured</span>
<span class="kn">from</span> <span class="nn">django.utils</span> <span class="k">import</span> <span class="n">six</span>
<span class="kn">from</span> <span class="nn">django.utils._os</span> <span class="k">import</span> <span class="n">npath</span><span class="p">,</span> <span class="n">upath</span>
<span class="kn">from</span> <span class="nn">django.utils.functional</span> <span class="k">import</span> <span class="n">cached_property</span>
<span class="kn">from</span> <span class="nn">django.utils.module_loading</span> <span class="k">import</span> <span class="n">import_string</span>
<span class="n">DEFAULT_DB_ALIAS</span> <span class="o">=</span> <span class="s1">'default'</span>
<span class="n">DJANGO_VERSION_PICKLE_KEY</span> <span class="o">=</span> <span class="s1">'_django_version'</span>
<div class="viewcode-block" id="Error"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.Error">[docs]</a><span class="k">class</span> <span class="nc">Error</span><span class="p">(</span><span class="ne">Exception</span> <span class="k">if</span> <span class="n">six</span><span class="o">.</span><span class="n">PY3</span> <span class="k">else</span> <span class="n">StandardError</span><span class="p">):</span> <span class="c1"># NOQA: StandardError undefined on PY3</span>
<span class="k">pass</span></div>
<div class="viewcode-block" id="InterfaceError"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.InterfaceError">[docs]</a><span class="k">class</span> <span class="nc">InterfaceError</span><span class="p">(</span><span class="n">Error</span><span class="p">):</span>
<span class="k">pass</span></div>
<div class="viewcode-block" id="DatabaseError"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.DatabaseError">[docs]</a><span class="k">class</span> <span class="nc">DatabaseError</span><span class="p">(</span><span class="n">Error</span><span class="p">):</span>
<span class="k">pass</span></div>
<div class="viewcode-block" id="DataError"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.DataError">[docs]</a><span class="k">class</span> <span class="nc">DataError</span><span class="p">(</span><span class="n">DatabaseError</span><span class="p">):</span>
<span class="k">pass</span></div>
<div class="viewcode-block" id="OperationalError"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.OperationalError">[docs]</a><span class="k">class</span> <span class="nc">OperationalError</span><span class="p">(</span><span class="n">DatabaseError</span><span class="p">):</span>
<span class="k">pass</span></div>
<div class="viewcode-block" id="IntegrityError"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.IntegrityError">[docs]</a><span class="k">class</span> <span class="nc">IntegrityError</span><span class="p">(</span><span class="n">DatabaseError</span><span class="p">):</span>
<span class="k">pass</span></div>
<div class="viewcode-block" id="InternalError"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.InternalError">[docs]</a><span class="k">class</span> <span class="nc">InternalError</span><span class="p">(</span><span class="n">DatabaseError</span><span class="p">):</span>
<span class="k">pass</span></div>
<div class="viewcode-block" id="ProgrammingError"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.ProgrammingError">[docs]</a><span class="k">class</span> <span class="nc">ProgrammingError</span><span class="p">(</span><span class="n">DatabaseError</span><span class="p">):</span>
<span class="k">pass</span></div>
<div class="viewcode-block" id="NotSupportedError"><a class="viewcode-back" href="../../../ref/exceptions.html#django.db.NotSupportedError">[docs]</a><span class="k">class</span> <span class="nc">NotSupportedError</span><span class="p">(</span><span class="n">DatabaseError</span><span class="p">):</span>
<span class="k">pass</span></div>
<span class="k">class</span> <span class="nc">DatabaseErrorWrapper</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Context manager and decorator that re-throws backend-specific database</span>
<span class="sd"> exceptions using Django's common wrappers.</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">wrapper</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> wrapper is a database wrapper.</span>
<span class="sd"> It must have a Database attribute defining PEP-249 exceptions.</span>
<span class="sd"> """</span>
<span class="bp">self</span><span class="o">.</span><span class="n">wrapper</span> <span class="o">=</span> <span class="n">wrapper</span>
<span class="k">def</span> <span class="nf">__enter__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">pass</span>
<span class="k">def</span> <span class="nf">__exit__</span><span class="p">(</span><span class="bp">self</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">traceback</span><span class="p">):</span>
<span class="k">if</span> <span class="n">exc_type</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
<span class="k">return</span>
<span class="k">for</span> <span class="n">dj_exc_type</span> <span class="ow">in</span> <span class="p">(</span>
<span class="n">DataError</span><span class="p">,</span>
<span class="n">OperationalError</span><span class="p">,</span>
<span class="n">IntegrityError</span><span class="p">,</span>
<span class="n">InternalError</span><span class="p">,</span>
<span class="n">ProgrammingError</span><span class="p">,</span>
<span class="n">NotSupportedError</span><span class="p">,</span>
<span class="n">DatabaseError</span><span class="p">,</span>
<span class="n">InterfaceError</span><span class="p">,</span>
<span class="n">Error</span><span class="p">,</span>
<span class="p">):</span>
<span class="n">db_exc_type</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">wrapper</span><span class="o">.</span><span class="n">Database</span><span class="p">,</span> <span class="n">dj_exc_type</span><span class="o">.</span><span class="vm">__name__</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">db_exc_type</span><span class="p">):</span>
<span class="n">dj_exc_value</span> <span class="o">=</span> <span class="n">dj_exc_type</span><span class="p">(</span><span class="o">*</span><span class="n">exc_value</span><span class="o">.</span><span class="n">args</span><span class="p">)</span>
<span class="n">dj_exc_value</span><span class="o">.</span><span class="n">__cause__</span> <span class="o">=</span> <span class="n">exc_value</span>
<span class="k">if</span> <span class="ow">not</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">exc_value</span><span class="p">,</span> <span class="s1">'__traceback__'</span><span class="p">):</span>
<span class="n">exc_value</span><span class="o">.</span><span class="n">__traceback__</span> <span class="o">=</span> <span class="n">traceback</span>
<span class="c1"># Only set the 'errors_occurred' flag for errors that may make</span>
<span class="c1"># the connection unusable.</span>
<span class="k">if</span> <span class="n">dj_exc_type</span> <span class="ow">not</span> <span class="ow">in</span> <span class="p">(</span><span class="n">DataError</span><span class="p">,</span> <span class="n">IntegrityError</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">wrapper</span><span class="o">.</span><span class="n">errors_occurred</span> <span class="o">=</span> <span class="kc">True</span>
<span class="n">six</span><span class="o">.</span><span class="n">reraise</span><span class="p">(</span><span class="n">dj_exc_type</span><span class="p">,</span> <span class="n">dj_exc_value</span><span class="p">,</span> <span class="n">traceback</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">func</span><span class="p">):</span>
<span class="c1"># Note that we are intentionally not using @wraps here for performance</span>
<span class="c1"># reasons. Refs #21109.</span>
<span class="k">def</span> <span class="nf">inner</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span>
<span class="k">with</span> <span class="bp">self</span><span class="p">:</span>
<span class="k">return</span> <span class="n">func</span><span class="p">(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span>
<span class="k">return</span> <span class="n">inner</span>
<span class="k">def</span> <span class="nf">load_backend</span><span class="p">(</span><span class="n">backend_name</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Return a database backend's "base" module given a fully qualified database</span>
<span class="sd"> backend name, or raise an error if it doesn't exist.</span>
<span class="sd"> """</span>
<span class="c1"># This backend was renamed in Django 1.9.</span>
<span class="k">if</span> <span class="n">backend_name</span> <span class="o">==</span> <span class="s1">'django.db.backends.postgresql_psycopg2'</span><span class="p">:</span>
<span class="n">backend_name</span> <span class="o">=</span> <span class="s1">'django.db.backends.postgresql'</span>
<span class="k">try</span><span class="p">:</span>
<span class="k">return</span> <span class="n">import_module</span><span class="p">(</span><span class="s1">'</span><span class="si">%s</span><span class="s1">.base'</span> <span class="o">%</span> <span class="n">backend_name</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">ImportError</span> <span class="k">as</span> <span class="n">e_user</span><span class="p">:</span>
<span class="c1"># The database backend wasn't found. Display a helpful error message</span>
<span class="c1"># listing all possible (built-in) database backends.</span>
<span class="n">backend_dir</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</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">dirname</span><span class="p">(</span><span class="n">upath</span><span class="p">(</span><span class="vm">__file__</span><span class="p">)),</span> <span class="s1">'backends'</span><span class="p">)</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">builtin_backends</span> <span class="o">=</span> <span class="p">[</span>
<span class="n">name</span> <span class="k">for</span> <span class="n">_</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">ispkg</span> <span class="ow">in</span> <span class="n">pkgutil</span><span class="o">.</span><span class="n">iter_modules</span><span class="p">([</span><span class="n">npath</span><span class="p">(</span><span class="n">backend_dir</span><span class="p">)])</span>
<span class="k">if</span> <span class="n">ispkg</span> <span class="ow">and</span> <span class="n">name</span> <span class="ow">not</span> <span class="ow">in</span> <span class="p">{</span><span class="s1">'base'</span><span class="p">,</span> <span class="s1">'dummy'</span><span class="p">,</span> <span class="s1">'postgresql_psycopg2'</span><span class="p">}</span>
<span class="p">]</span>
<span class="k">except</span> <span class="ne">EnvironmentError</span><span class="p">:</span>
<span class="n">builtin_backends</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">if</span> <span class="n">backend_name</span> <span class="ow">not</span> <span class="ow">in</span> <span class="p">[</span><span class="s1">'django.db.backends.</span><span class="si">%s</span><span class="s1">'</span> <span class="o">%</span> <span class="n">b</span> <span class="k">for</span> <span class="n">b</span> <span class="ow">in</span>
<span class="n">builtin_backends</span><span class="p">]:</span>
<span class="n">backend_reprs</span> <span class="o">=</span> <span class="nb">map</span><span class="p">(</span><span class="nb">repr</span><span class="p">,</span> <span class="nb">sorted</span><span class="p">(</span><span class="n">builtin_backends</span><span class="p">))</span>
<span class="n">error_msg</span> <span class="o">=</span> <span class="p">(</span><span class="s2">"</span><span class="si">%r</span><span class="s2"> isn't an available database backend.</span><span class="se">\n</span><span class="s2">"</span>
<span class="s2">"Try using 'django.db.backends.XXX', where XXX "</span>
<span class="s2">"is one of:</span><span class="se">\n</span><span class="s2"> </span><span class="si">%s</span><span class="se">\n</span><span class="s2">Error was: </span><span class="si">%s</span><span class="s2">"</span> <span class="o">%</span>
<span class="p">(</span><span class="n">backend_name</span><span class="p">,</span> <span class="s2">", "</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">backend_reprs</span><span class="p">),</span> <span class="n">e_user</span><span class="p">))</span>
<span class="k">raise</span> <span class="n">ImproperlyConfigured</span><span class="p">(</span><span class="n">error_msg</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="c1"># If there's some other error, this must be an error in Django</span>
<span class="k">raise</span>
<span class="k">class</span> <span class="nc">ConnectionDoesNotExist</span><span class="p">(</span><span class="ne">Exception</span><span class="p">):</span>
<span class="k">pass</span>
<span class="k">class</span> <span class="nc">ConnectionHandler</span><span class="p">(</span><span class="nb">object</span><span class="p">):</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">databases</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> databases is an optional dictionary of database definitions (structured</span>
<span class="sd"> like settings.DATABASES).</span>
<span class="sd"> """</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_databases</span> <span class="o">=</span> <span class="n">databases</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_connections</span> <span class="o">=</span> <span class="n">local</span><span class="p">()</span>
<span class="nd">@cached_property</span>
<span class="k">def</span> <span class="nf">databases</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">_databases</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_databases</span> <span class="o">=</span> <span class="n">settings</span><span class="o">.</span><span class="n">DATABASES</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">_databases</span> <span class="o">==</span> <span class="p">{}:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_databases</span> <span class="o">=</span> <span class="p">{</span>
<span class="n">DEFAULT_DB_ALIAS</span><span class="p">:</span> <span class="p">{</span>
<span class="s1">'ENGINE'</span><span class="p">:</span> <span class="s1">'django.db.backends.dummy'</span><span class="p">,</span>
<span class="p">},</span>
<span class="p">}</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">_databases</span><span class="p">[</span><span class="n">DEFAULT_DB_ALIAS</span><span class="p">]</span> <span class="o">==</span> <span class="p">{}:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_databases</span><span class="p">[</span><span class="n">DEFAULT_DB_ALIAS</span><span class="p">][</span><span class="s1">'ENGINE'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'django.db.backends.dummy'</span>
<span class="k">if</span> <span class="n">DEFAULT_DB_ALIAS</span> <span class="ow">not</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_databases</span><span class="p">:</span>
<span class="k">raise</span> <span class="n">ImproperlyConfigured</span><span class="p">(</span><span class="s2">"You must define a '</span><span class="si">%s</span><span class="s2">' database"</span> <span class="o">%</span> <span class="n">DEFAULT_DB_ALIAS</span><span class="p">)</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_databases</span>
<span class="k">def</span> <span class="nf">ensure_defaults</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">alias</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Puts the defaults into the settings dictionary for a given connection</span>
<span class="sd"> where no settings is provided.</span>
<span class="sd"> """</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">conn</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">databases</span><span class="p">[</span><span class="n">alias</span><span class="p">]</span>
<span class="k">except</span> <span class="ne">KeyError</span><span class="p">:</span>
<span class="k">raise</span> <span class="n">ConnectionDoesNotExist</span><span class="p">(</span><span class="s2">"The connection </span><span class="si">%s</span><span class="s2"> doesn't exist"</span> <span class="o">%</span> <span class="n">alias</span><span class="p">)</span>
<span class="n">conn</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s1">'ATOMIC_REQUESTS'</span><span class="p">,</span> <span class="kc">False</span><span class="p">)</span>
<span class="n">conn</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s1">'AUTOCOMMIT'</span><span class="p">,</span> <span class="kc">True</span><span class="p">)</span>
<span class="n">conn</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s1">'ENGINE'</span><span class="p">,</span> <span class="s1">'django.db.backends.dummy'</span><span class="p">)</span>
<span class="k">if</span> <span class="n">conn</span><span class="p">[</span><span class="s1">'ENGINE'</span><span class="p">]</span> <span class="o">==</span> <span class="s1">'django.db.backends.'</span> <span class="ow">or</span> <span class="ow">not</span> <span class="n">conn</span><span class="p">[</span><span class="s1">'ENGINE'</span><span class="p">]:</span>
<span class="n">conn</span><span class="p">[</span><span class="s1">'ENGINE'</span><span class="p">]</span> <span class="o">=</span> <span class="s1">'django.db.backends.dummy'</span>
<span class="n">conn</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s1">'CONN_MAX_AGE'</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span>
<span class="n">conn</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s1">'OPTIONS'</span><span class="p">,</span> <span class="p">{})</span>
<span class="n">conn</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s1">'TIME_ZONE'</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
<span class="k">for</span> <span class="n">setting</span> <span class="ow">in</span> <span class="p">[</span><span class="s1">'NAME'</span><span class="p">,</span> <span class="s1">'USER'</span><span class="p">,</span> <span class="s1">'PASSWORD'</span><span class="p">,</span> <span class="s1">'HOST'</span><span class="p">,</span> <span class="s1">'PORT'</span><span class="p">]:</span>
<span class="n">conn</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="n">setting</span><span class="p">,</span> <span class="s1">''</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">prepare_test_settings</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">alias</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Makes sure the test settings are available in the 'TEST' sub-dictionary.</span>
<span class="sd"> """</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">conn</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">databases</span><span class="p">[</span><span class="n">alias</span><span class="p">]</span>
<span class="k">except</span> <span class="ne">KeyError</span><span class="p">:</span>
<span class="k">raise</span> <span class="n">ConnectionDoesNotExist</span><span class="p">(</span><span class="s2">"The connection </span><span class="si">%s</span><span class="s2"> doesn't exist"</span> <span class="o">%</span> <span class="n">alias</span><span class="p">)</span>
<span class="n">test_settings</span> <span class="o">=</span> <span class="n">conn</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s1">'TEST'</span><span class="p">,</span> <span class="p">{})</span>
<span class="k">for</span> <span class="n">key</span> <span class="ow">in</span> <span class="p">[</span><span class="s1">'CHARSET'</span><span class="p">,</span> <span class="s1">'COLLATION'</span><span class="p">,</span> <span class="s1">'NAME'</span><span class="p">,</span> <span class="s1">'MIRROR'</span><span class="p">]:</span>
<span class="n">test_settings</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="n">key</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__getitem__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">alias</span><span class="p">):</span>
<span class="k">if</span> <span class="nb">hasattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_connections</span><span class="p">,</span> <span class="n">alias</span><span class="p">):</span>
<span class="k">return</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_connections</span><span class="p">,</span> <span class="n">alias</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">ensure_defaults</span><span class="p">(</span><span class="n">alias</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">prepare_test_settings</span><span class="p">(</span><span class="n">alias</span><span class="p">)</span>
<span class="n">db</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">databases</span><span class="p">[</span><span class="n">alias</span><span class="p">]</span>
<span class="n">backend</span> <span class="o">=</span> <span class="n">load_backend</span><span class="p">(</span><span class="n">db</span><span class="p">[</span><span class="s1">'ENGINE'</span><span class="p">])</span>
<span class="n">conn</span> <span class="o">=</span> <span class="n">backend</span><span class="o">.</span><span class="n">DatabaseWrapper</span><span class="p">(</span><span class="n">db</span><span class="p">,</span> <span class="n">alias</span><span class="p">)</span>
<span class="nb">setattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_connections</span><span class="p">,</span> <span class="n">alias</span><span class="p">,</span> <span class="n">conn</span><span class="p">)</span>
<span class="k">return</span> <span class="n">conn</span>
<span class="k">def</span> <span class="nf">__setitem__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">key</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span>
<span class="nb">setattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_connections</span><span class="p">,</span> <span class="n">key</span><span class="p">,</span> <span class="n">value</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__delitem__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">key</span><span class="p">):</span>
<span class="nb">delattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_connections</span><span class="p">,</span> <span class="n">key</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__iter__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="nb">iter</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">databases</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">all</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="p">[</span><span class="bp">self</span><span class="p">[</span><span class="n">alias</span><span class="p">]</span> <span class="k">for</span> <span class="n">alias</span> <span class="ow">in</span> <span class="bp">self</span><span class="p">]</span>
<span class="k">def</span> <span class="nf">close_all</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">for</span> <span class="n">alias</span> <span class="ow">in</span> <span class="bp">self</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">connection</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_connections</span><span class="p">,</span> <span class="n">alias</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">AttributeError</span><span class="p">:</span>
<span class="k">continue</span>
<span class="n">connection</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="k">class</span> <span class="nc">ConnectionRouter</span><span class="p">(</span><span class="nb">object</span><span class="p">):</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">routers</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> If routers is not specified, will default to settings.DATABASE_ROUTERS.</span>
<span class="sd"> """</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_routers</span> <span class="o">=</span> <span class="n">routers</span>
<span class="nd">@cached_property</span>
<span class="k">def</span> <span class="nf">routers</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">_routers</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_routers</span> <span class="o">=</span> <span class="n">settings</span><span class="o">.</span><span class="n">DATABASE_ROUTERS</span>
<span class="n">routers</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">_routers</span><span class="p">:</span>
<span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">r</span><span class="p">,</span> <span class="n">six</span><span class="o">.</span><span class="n">string_types</span><span class="p">):</span>
<span class="n">router</span> <span class="o">=</span> <span class="n">import_string</span><span class="p">(</span><span class="n">r</span><span class="p">)()</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">router</span> <span class="o">=</span> <span class="n">r</span>
<span class="n">routers</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">router</span><span class="p">)</span>
<span class="k">return</span> <span class="n">routers</span>
<span class="k">def</span> <span class="nf">_router_func</span><span class="p">(</span><span class="n">action</span><span class="p">):</span>
<span class="k">def</span> <span class="nf">_route_db</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">,</span> <span class="o">**</span><span class="n">hints</span><span class="p">):</span>
<span class="n">chosen_db</span> <span class="o">=</span> <span class="kc">None</span>
<span class="k">for</span> <span class="n">router</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">routers</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">method</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">router</span><span class="p">,</span> <span class="n">action</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">AttributeError</span><span class="p">:</span>
<span class="c1"># If the router doesn't have a method, skip to the next one.</span>
<span class="k">pass</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">chosen_db</span> <span class="o">=</span> <span class="n">method</span><span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="o">**</span><span class="n">hints</span><span class="p">)</span>
<span class="k">if</span> <span class="n">chosen_db</span><span class="p">:</span>
<span class="k">return</span> <span class="n">chosen_db</span>
<span class="n">instance</span> <span class="o">=</span> <span class="n">hints</span><span class="o">.</span><span class="n">get</span><span class="p">(</span><span class="s1">'instance'</span><span class="p">)</span>
<span class="k">if</span> <span class="n">instance</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span> <span class="ow">and</span> <span class="n">instance</span><span class="o">.</span><span class="n">_state</span><span class="o">.</span><span class="n">db</span><span class="p">:</span>
<span class="k">return</span> <span class="n">instance</span><span class="o">.</span><span class="n">_state</span><span class="o">.</span><span class="n">db</span>
<span class="k">return</span> <span class="n">DEFAULT_DB_ALIAS</span>
<span class="k">return</span> <span class="n">_route_db</span>
<span class="n">db_for_read</span> <span class="o">=</span> <span class="n">_router_func</span><span class="p">(</span><span class="s1">'db_for_read'</span><span class="p">)</span>
<span class="n">db_for_write</span> <span class="o">=</span> <span class="n">_router_func</span><span class="p">(</span><span class="s1">'db_for_write'</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">allow_relation</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">obj1</span><span class="p">,</span> <span class="n">obj2</span><span class="p">,</span> <span class="o">**</span><span class="n">hints</span><span class="p">):</span>
<span class="k">for</span> <span class="n">router</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">routers</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">method</span> <span class="o">=</span> <span class="n">router</span><span class="o">.</span><span class="n">allow_relation</span>
<span class="k">except</span> <span class="ne">AttributeError</span><span class="p">:</span>
<span class="c1"># If the router doesn't have a method, skip to the next one.</span>
<span class="k">pass</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">allow</span> <span class="o">=</span> <span class="n">method</span><span class="p">(</span><span class="n">obj1</span><span class="p">,</span> <span class="n">obj2</span><span class="p">,</span> <span class="o">**</span><span class="n">hints</span><span class="p">)</span>
<span class="k">if</span> <span class="n">allow</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="k">return</span> <span class="n">allow</span>
<span class="k">return</span> <span class="n">obj1</span><span class="o">.</span><span class="n">_state</span><span class="o">.</span><span class="n">db</span> <span class="o">==</span> <span class="n">obj2</span><span class="o">.</span><span class="n">_state</span><span class="o">.</span><span class="n">db</span>
<span class="k">def</span> <span class="nf">allow_migrate</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">db</span><span class="p">,</span> <span class="n">app_label</span><span class="p">,</span> <span class="o">**</span><span class="n">hints</span><span class="p">):</span>
<span class="k">for</span> <span class="n">router</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">routers</span><span class="p">:</span>
<span class="k">try</span><span class="p">:</span>
<span class="n">method</span> <span class="o">=</span> <span class="n">router</span><span class="o">.</span><span class="n">allow_migrate</span>
<span class="k">except</span> <span class="ne">AttributeError</span><span class="p">:</span>
<span class="c1"># If the router doesn't have a method, skip to the next one.</span>
<span class="k">continue</span>
<span class="n">allow</span> <span class="o">=</span> <span class="n">method</span><span class="p">(</span><span class="n">db</span><span class="p">,</span> <span class="n">app_label</span><span class="p">,</span> <span class="o">**</span><span class="n">hints</span><span class="p">)</span>
<span class="k">if</span> <span class="n">allow</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span>
<span class="k">return</span> <span class="n">allow</span>
<span class="k">return</span> <span class="kc">True</span>
<span class="k">def</span> <span class="nf">allow_migrate_model</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">db</span><span class="p">,</span> <span class="n">model</span><span class="p">):</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">allow_migrate</span><span class="p">(</span>
<span class="n">db</span><span class="p">,</span>
<span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">app_label</span><span class="p">,</span>
<span class="n">model_name</span><span class="o">=</span><span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">model_name</span><span class="p">,</span>
<span class="n">model</span><span class="o">=</span><span class="n">model</span><span class="p">,</span>
<span class="p">)</span>
<span class="k">def</span> <span class="nf">get_migratable_models</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">app_config</span><span class="p">,</span> <span class="n">db</span><span class="p">,</span> <span class="n">include_auto_created</span><span class="o">=</span><span class="kc">False</span><span class="p">):</span>
<span class="sd">"""</span>
<span class="sd"> Return app models allowed to be synchronized on provided db.</span>
<span class="sd"> """</span>
<span class="n">models</span> <span class="o">=</span> <span class="n">app_config</span><span class="o">.</span><span class="n">get_models</span><span class="p">(</span><span class="n">include_auto_created</span><span class="o">=</span><span class="n">include_auto_created</span><span class="p">)</span>
<span class="k">return</span> <span class="p">[</span><span class="n">model</span> <span class="k">for</span> <span class="n">model</span> <span class="ow">in</span> <span class="n">models</span> <span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">allow_migrate_model</span><span class="p">(</span><span class="n">db</span><span class="p">,</span> <span class="n">model</span><span class="p">)]</span>
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