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# Excerpt from twisted.enterprise.adbapi.py |
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# Demonstrates a patch of the __init__ constructor to share threadpools for Twisted |
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# Confirmed that this actually works |
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# TODO: benchmark various threadpool sizes |
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def __init__(self, dbapiName, *connargs, **connkw): |
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"""Create a new ConnectionPool. |
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Any positional or keyword arguments other than those documented here |
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are passed to the DB-API object when connecting. Use these arguments to |
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pass database names, usernames, passwords, etc. |
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@param dbapiName: an import string to use to obtain a DB-API compatible |
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module (e.g. 'pyPgSQL.PgSQL') |
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@param cp_min: the minimum number of connections in pool (default 3) |
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@param cp_max: the maximum number of connections in pool (default 5) |
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@param cp_noisy: generate informational log messages during operation |
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(default False) |
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@param cp_openfun: a callback invoked after every connect() on the |
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underlying DB-API object. The callback is passed a |
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new DB-API connection object. This callback can |
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setup per-connection state such as charset, |
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timezone, etc. |
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@param cp_reconnect: detect connections which have failed and reconnect |
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(default False). Failed connections may result in |
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ConnectionLost exceptions, which indicate the |
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query may need to be re-sent. |
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@param cp_good_sql: an sql query which should always succeed and change |
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no state (default 'select 1') |
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@param cp_reactor: use this reactor instead of the global reactor |
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(added in Twisted 10.2). |
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@type cp_reactor: L{IReactorCore} provider |
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""" |
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self.dbapiName = dbapiName |
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self.dbapi = reflect.namedModule(dbapiName) |
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if getattr(self.dbapi, 'apilevel', None) != '2.0': |
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log.msg('DB API module not DB API 2.0 compliant.') |
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if getattr(self.dbapi, 'threadsafety', 0) < 1: |
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log.msg('DB API module not sufficiently thread-safe.') |
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reactor = connkw.pop('cp_reactor', None) |
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if reactor is None: |
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from twisted.internet import reactor |
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self._reactor = reactor |
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self.connargs = connargs |
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self.connkw = connkw |
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for arg in self.CP_ARGS: |
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cp_arg = 'cp_%s' % arg |
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if cp_arg in connkw: |
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setattr(self, arg, connkw[cp_arg]) |
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del connkw[cp_arg] |
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self.min = min(self.min, self.max) |
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self.max = max(self.min, self.max) |
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self.connections = {} # all connections, hashed on thread id |
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# these are optional so import them here |
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from twisted.python import threadpool |
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import thread |
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# 1. To share one threadpool: grab a reference to the reactor |
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from twisted.internet import reactor |
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self.threadID = thread.get_ident |
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#self.threadpool = threadpool.ThreadPool(self.min, self.max) |
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# 2. set each connections threadpool equal to that of the reactors threadpool |
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self.threadpool = reactor.getThreadPool() |
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self.startID = self._reactor.callWhenRunning(self._start) |
