[ovs-discuss] [nic19-2 5/5] xenserver: Fix "brctl show" compatibility by introducing "brctl" wrapper.
Justin Pettit
jpettit at nicira.com
Wed Aug 19 07:04:27 UTC 2009
On Aug 18, 2009, at 11:59 PM, Justin Pettit wrote:
> This code will barf if the file can't be read, since the exception
> is still raised from the "finally" clause. Even if the exception
> were caught, it would still return None, which will make callers
> like get_bridge_id() raise an exception. What if y
>
> def read_first_line_of_file(name):
> file = None
> line = ""
> try:
> file = open(name, 'r')
> line = file.readline().rstrip('\n')
> finally:
> if file:
> file.close()
> return line
Sorry, that went off prematurely. I meant to finish the sentence
saying that you may want to try something like that. Obviously, this
raises its own set of problems, since the bridge id will be garbage.
However, I think a bad value is better than the program returning a
traceback. Obviously, with a bit more coding, the entire device entry
could be skipped if a bad hardware address is returned. (Which is
likely the correct behavior, since the reason for a missing sysfs
entry is probably that it was going away.)
--Justin
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