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    <p>Approximately:</p> <pre><code>attempts = [ { 'database'='postgres', 'user'='pgsql', ...}, { 'database'='postgres', 'user'='postgres', 'host'='localhost', 'password'=getpass()}, ... ] conn = None for attempt in attempts: try: conn = psycopg2.connect(**attempt) break except psycopg2.OperationalError: pass if conn is None: raise a ruckus CURSOR = conn.cursor() </code></pre> <p>Now, if you don't want to call <code>getpass()</code> unless it is necessary, you'd want to check <code>if 'password' in attempt: attempt['password'] = getpass()</code> or so.</p> <p>Now about that global....</p> <pre><code>class MyCursor: def __init__(self): self.CURSOR = None def __call__(self): if self.CURSOR is None: &lt;insert logic here&gt; return self.CURSOR get_cursor = MyCursor() </code></pre> <p>... though I think there are a couple of other ways to accomplish the same thing.</p> <p>Bringing it all together:</p> <pre><code>class MyCursor: def __init__(self): self.CURSOR = None def __call__(self): if self.CURSOR is None: attempts = [ {'database'='postgres', 'user'='postgres'}, {'database'='postgres', 'user'='pgsql'}, {'database'='postgres', 'user'='postgres', 'host'='localhost', 'password'=True}, {'database'='postgres', 'user'='pgsql', 'host'='localhost', 'password'=True}, ] conn = None for attempt in attempts: if 'password' in attempt: attempt['password'] = getpass() try: conn = psycopg2.connect(**attempt) break # that didn't throw an exception, we're done except psycopg2.OperationalError: pass if conn is None: raise a ruckus # nothin' worked self.CURSOR = conn.cursor() return self.CURSOR get_cursor = MyCursor() </code></pre> <p><sub>Note: completely untested</sub></p>
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    1. POPython idiom for 'Try until no exception is raised'
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    1. POPython idiom for 'Try until no exception is raised'
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    1. COInstead of initialising `conn` to `None`, you can just use the `else` clause on the `for`
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      1. USJohn La Rooy
    2. CO+1 @David: The break ensures that the first connection that worked is returned. This solution will scale well with an increased number of databases, and the connection strings have been nicely abstracted from the code.
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    3. CO@gnibbler - Woah, I forgot Python had that awesome feature (http://docs.python.org/reference/compound_stmts.html#the-for-statement)
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