Il 01/01/2021 04:14, 2qdxy4rzwzuui...@potatochowder.com ha scritto:
On 2021-01-01 at 03:43:43 +0100,
Regarding "Re: Control stript which is runing in background.,"
jak <nos...@please.ty> wrote:
Il 01/01/2021 01:43, Cameron Simpson ha scritto:
On 01Jan2021 01:21, jak <nos...@please.ty> wrote:
Il 01/01/2021 00:58, 2qdxy4rzwzuui...@potatochowder.com ha scritto:
Most of the time, I have several shells open, often with their own
background jobs running. Limiting write permission on the pipe to "me"
wouldn't prevent concurrent access.
This is true but there would be no difference if this happened through
a socket.
Accessing a socket makes a distinct separate data connection - other
openers do not conflict with it. That's the critical difference between
a socket and a pipe in terms of functionality, and why sockets have a
connect/accept step.
Cheers,
Cameron Simpson <c...@cskk.id.au>
Maybe the fact that I'm not English and I don't know the language well
doesn't allow me to express myself clearly. Try it one more time:
The OP would like to give some command to a script that is running. How?
With a script that sends commands to it. One of the ways, as mentioned,
is by using a mini socket server. Given the needs of the OP and the fact
that sockets are a limited resource in a system, I took the liberty of
proposing a simple alternative: using a named pipe, also because, IMO,
sockets, in this case, are an overkill. with a few lines of code in a
thread in the running script they can allow it to receive commands:
#-----------------
import os, errno
fnpipe = 'cmdpipe'
try:
os.mkfifo(fnpipe)
except OSError as e:
if e.errno != errno.EEXIST:
raise
while True:
with open(fnpipe, 'rt', 1) as fifo:
for line in fifo:
print(line, ends='')
#-----------------
Running the command:
$ cat bible.txt > cmdpipe & cat bible.txt > cmdpipe & cat bible.txt >
cmdpipe
the three texts do not mix. IMO, the OP should be enough. after that, I
know that a pipe is more like a queue than a soket and in this case a
socket, IMO, is wasted.
Only the OP knows for sure. :-) Does the server send data back to the
client that made the request? Are the requests (and the responses, if
any) small enough to be sent/received atomically? *If* the answers are
no and yes, then you're right, a named pipe would be good enough. If
not, then a socket *might* be better. Until the OP clarifies, we can't
tell.
greetings, hoping to have been clearer than before.
I think you were clear enough before, but you may not have considered
things the OP did not specify. One of the hardest parts of software
development is understanding and specifying the actual problem to be
solved. I've never done that in a second language (I'm nowhere near
fluent in anything other than English); I can only imagine the extra
layers of complexity.
This is the OP's initial request:
Hi.
I would like to make something like this:
A python script would run headlessly in the background.
I would like to control the script from the command line using other python
scripts or from the python shell.
From time to time I would ask the main script to create a popup window with an
image or a plot.
What would be the proper way to approach it. How to make communication between
two scripts?
Thank you.
Petro.
I have suggested an alternative way for his necessity.
It will be up to him to decide which one he should adopt. That way he
has a choice, at least.
I don't know where you work. I know, however, that in these zones, if
you do more than necessary wasting their time, they will kick you away.
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