[Tutor] Python Daemons

[Steven D'Aprano]

Hi Daniel,

My responses below.

On Tue, Aug 01, 2017 at 02:48:19PM -0400, Daniel Bosah wrote:
> I'm following an online tutorial about threading. This is the code I've
> used so far:

Can you give us a link to the tutorial?

[...]
> def portscan(port):
>     s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
>     try:
>        con = s.connect((target,port)) # con for connect
>        with print_lock: # if sucessful run with statement
>           print 'port', port, 'is open'
>        con.close() # closes connection
>     except:
>            pass #if it doesn't work pass the method

I'm very concerned about that bare "except" line. I'm not absolutely 
saying that it is wrong, but in general bare excepts are a terrible 
idea.

https://realpython.com/blog/python/the-most-diabolical-python-antipattern/


> def threader():
>     while True:
>         worker = q.get()
>         portscan(worker)
>         q.task_done
> q = Queue()
> for x in range(30):
>     t = threading.Thread(target = threader() #creates a thread, gets
> workers from q, set them to work on portscanning
>     t.daemon() = True # want it to be a daemon
>     t.start()
>     #jobs = ports
> for worker in range(1,101): # port zero invalid port
>     q.put(worker) # puts worker to work
> q.join() #waits till thread terminiates
> 
> 
>     I don't know what a Daemon is, 

https://en.wikipedia.org/wiki/Daemon_(computing)




> and I also don't know how to use it in
> Python 2.7. Apparently its built in Python 3, but  I don't know how to use
> it in Python 2.7. Any help would be appreciated.

What happens when you try?



-- 
Steve