Output from beanstalkd - beanstalkd

I want to monitor what jobs are flowing through a beanstalkd queue. Is there a way I can do this through command line. On running beanstalkd on command line no output is displayed. Essentially I am looking for a debug or a verbose option.

beanstalkd doesn't ship with any management tools as far as I know. But if you install one of the python/ruby/perl libraries you can write something to emit server status pretty easily.
Here's an example using python and the beanstalkc client package:
#!/usr/bin/python
import beanstalkc
b = beanstalkc.Connection(host='localhost', port=11300)
for tube in b.tubes():
print "Tube: %s" % tube
stats = b.stats_tube(tube)
for k, v in stats.items():
print " %s: %s" % (k, v)

Related

running subprocesses in parallel with Python

I am trying to understand how can I build a parallel computing pipeline for multiple subprocesses.
As I see, each subprocess block waits for the previous code block to run, whereas I have a pipeline which does not have a dependency for the previous run, and it can be handled in parallel. I want to understand whether this is possible, and if so, a sample syntax for showing how to do that would be a great help! Thanks in advance.
import sys
import os
import subprocess
subprocess.run("python pipelinecode1.py".split() +
[run_date, this_wk, last_wk, prev_wk], shell=True)
subprocess.run("python pipelinecode2.py".split() +
[run_date, this_wk, last_wk, prev_wk], shell=True)
subprocess.run("python pipelinecode3.py".split() +
[run_date, this_wk, last_wk, prev_wk], shell=True)
The MCVE as-is shows zero dependency on the python-interpreter, so the most efficient step for running a set of mutualy independent tasks ( not a pipeline, where one-step-after-another order of processing steps "forms" the "pipeline" ) is GNU parallel:
$ parallel python {} run_date this_wk last_wk prev_wk ::: pipelinecode1.py \
pipelinecode2.py \
pipelinecode3.py
This way you do not waste CPU / cache resources and escape from the blocking and GIL-lock re-introduced re-[SERIAL]-isation of the code-execution without any add-on overhead costs.
For all configurables available read respective details in man parallel

How to run code in a debugging session from VS code on a remote using an interactive session?

I am using a cluster (similar to slurm but using condor) and I wanted to run my code using VS code (its debugger specially) and it's remote sync extension.
I tried running it using my debugger in VS code but it didn't quite work as expected.
First I logged in to the cluster using VS code and remote sync as usual and that works just fine. Then I go ahead an get an interactive job with the command:
condor_submit -i request_cpus=4 request_gpus=1
then that successfully gives a node/gpu to use.
Once I have that I try to run the debugger but somehow it logs me out from the remote session (and it looks like it goes to the head node from the print statements). That's NOT what I want. I want to run my job in the interactive session in the node/gpu I was allocated. Why is VS code running it in the wrong place? How can I run it in the right place?
Some of the output from the integrated terminal:
source /home/miranda9/miniconda3/envs/automl-meta-learning/bin/activate
/home/miranda9/miniconda3/envs/automl-meta-learning/bin/python /home/miranda9/.vscode-server/extensions/ms-python.python-2020.2.60897-dev/pythonFiles/lib/python/new_ptvsd/wheels/ptvsd/launcher /home/miranda9/automl-meta-learning/automl/automl/meta_optimizers/differentiable_SGD.py
conda activate base
(automl-meta-learning) miranda9~/automl-meta-learning $ source /home/miranda9/miniconda3/envs/automl-meta-learning/bin/activate
(automl-meta-learning) miranda9~/automl-meta-learning $ /home/miranda9/miniconda3/envs/automl-meta-learning/bin/python /home/miranda9/.vscode-server/extensions/ms-python.python-2020.2.60897-dev/pythonFiles/lib/python/new_ptvsd/wheels/ptvsd/launcher /home/miranda9/automl-meta-learning/automl/automl/meta_optimizers/differentiable_SGD.py
--> main in differentiable SGD
hello world torch_utils!
vision-sched.cs.illinois.edu
Files already downloaded and verified
Files already downloaded and verified
Files already downloaded and verified
-> initialization of DiMO done!
---> i = 0, iteration/it 1 about to start
lp_norms(mdl) = 18.43514633178711
lp_norms(meta_optimized mdl) = 18.43514633178711
[e=0,it=1], train_loss: 2.304989814758301, train error: -1, test loss: -1, test error: -1
---> i = 1, iteration/it 2 about to start
lp_norms(mdl) = 18.470401763916016
lp_norms(meta_optimized mdl) = 18.470401763916016
[e=0,it=2], train_loss: 2.3068909645080566, train error: -1, test loss: -1, test error: -1
---> i = 2, iteration/it 3 about to start
lp_norms(mdl) = 18.548133850097656
lp_norms(meta_optimized mdl) = 18.548133850097656
[e=0,it=3], train_loss: 2.3019633293151855, train error: -1, test loss: -1, test error: -1
---> i = 0, iteration/it 1 about to start
lp_norms(mdl) = 18.65604019165039
lp_norms(meta_optimized mdl) = 18.65604019165039
[e=1,it=1], train_loss: 2.308889150619507, train error: -1, test loss: -1, test error: -1
---> i = 1, iteration/it 2 about to start
lp_norms(mdl) = 18.441967010498047
lp_norms(meta_optimized mdl) = 18.441967010498047
[e=1,it=2], train_loss: 2.300947666168213, train error: -1, test loss: -1, test error: -1
---> i = 2, iteration/it 3 about to start
lp_norms(mdl) = 18.545459747314453
lp_norms(meta_optimized mdl) = 18.545459747314453
[e=1,it=3], train_loss: 2.30662202835083, train error: -1, test loss: -1, test error: -1
-> DiMO done training!
--> Done with Main
(automl-meta-learning) miranda9~/automl-meta-learning $ conda activate base
(automl-meta-learning) miranda9~/automl-meta-learning $ hostname vision-sched.cs.illinois.edu
Doesn't even run without debugging mode
The problem is more serious than I thought. I can't run the debugger in the interactive session but I can't even "Run Without Debugging" without it switching to the Python Debug Console on it's own. So that means I have to run things manually with python main.py but that won't allow me to use the variable pane...which is a big loss!
What I am doing is switching my terminal to the conoder_ssh_to_job and then clicking the button Run Without Debugging (or ^F5 or Control + fn + f5) and although I made sure to be on the interactive session at the bottom in my integrated window it goes by itself to the Python Debugger window/pane which is not connected to the interactive session I requested from my cluster...
related:
gitissue: https://github.com/microsoft/vscode-remote-release/issues/1722
quora: https://qr.ae/TqCiu8
reddit: https://www.reddit.com/r/vscode/comments/f1giwi/how_to_run_code_in_a_debugging_session_from_vs/
You can try reversing the order of operations; first submitting the job, obtaining the name of the compute node allocated to you, then instructing VSCode to connect to the compute node rather than the login node.
So first would be
condor_submit -i request_cpus=4 request_gpus=1
and noting the name of the compute node. Assuming node001 in the following.
Then, open VSCode on your laptop, click on the Remote Development extension icon and choose "Remote SSH: Connect to Host...". Choose "+ Add new SSH host...". In the "Enter SSH command" box, add the following:
ssh -J vision-sched.cs.illinois.edu miranda9#node001
The VSCode will ask you which SSH configuration file it should update. Make sure to review that configuration: specify the SSH keys if needed, the user name, etc. Also make sure you have the vision-sched.cs.illinois.edu correctly configured in that file.
Then you can choose that host to connect to. VSCode will then execute on the compute node, and will be disconnected when the allocation finishes.
I stumbled upon a related issue recently (I wanted to use VsCode interactive Python capabilities on a compute node) and the above weren't working but this solved it:
ssh to the remote cluster ssh cluster
inside the remote cluster, add my public key to the authorized keys, so typically append the content of ~/.ssh/id_rsa.pub (local machine) to .ssh/authorized_keys (remote cluster)
allocate some resources inside the cluster (this particular cluster uses slurm and not condor so in this case I use something like srun --pty bash)
get the name of the compute node, typically visible in the command line as username#nodename). For argument's sake, let's imagine I get a generic name like node001
for simplicity on my local machine, modify the ~/.ssh/config file and edit it as:
Host cluster
# stuff written
Host node*
HostName %h
ProxyJump cluster
User $USERNAME
Now I'm able to ssh to it from my local machine (as long as the compute node is running) with ssh node001.
In VsCode this boils down to
CTRL+P > Remote-SSH: Connect to Host...
type in the name of the node, here node001
you get connected to the node, now every interactive python you run (including jupyter and jupytext) will have access to your allocated resources
I don't know how generic this solution is, I hope it'll help at least somebody !
Here is a simpler workaround:
on the remote server create a file named bash somewhere for example /home/myuser/pathto/bash
make it executable using chmod +x bash
write salloc [your desired options for the interactive job] in the bash file
In vscode Settings search for Automation Shell: Linux and click on the "Edit in settings.js"
change the line to "terminal.integrated.automationShell.linux": "/home/myuser/pathto/bash" and save it (use the absolute path. for example ~/pathto/bash didn't work for me)
Done :)
now every time you run the debugger it will first ask for the interactive job and the debugger will run on it. but take in to consider that this is also applied to tasks you run in tasks.json.
also you can use srun instead of salloc. for example srun --pty -t 2:00:00 --mem=8G bash

Efficient way of sending the same data to multiple dynamic processes

I have a stream of line-buffered data, and many readers from other processes
The readers need to attach to the system dynamically, they are not known to the process writing the stream
First i tried to read every line and simply send them to a lot of pipes
#writer
command | while read -r line; do
printf '%s\n' "$line" | tee listeners/*
done
#reader
mkfifo listeners/1
cat listeners/1
But that's consume a lot of CPU
So i though about writing to a file and cleaning it repeatedly
#writer
command >> file &
while true; do
: > file
sleep 1
done
#reader
tail -f -n0 file
But sometimes, a line is not read by one or more readers before truncation, making a race condition
Is there a better way on how i could implement this?
Sounds like pub/sub to me - see Wikipedia.
Basically, new interested parties come along whenever they like and "subscribe" to your channel. The process receiving the data then "publishes" it, line by line, to that channel.
You can do it with MQTT using mosquitto or with Redis. Both have command-line interfaces/bindings, as well as Python, C/C++, Ruby, PHP etc. Client and server need not be on same machine, some clients could be elsewhere on the network.
Mosquitto example here.
I did a few tests on my Mac with Redis pub/sub. The client code in Terminal to subscribe to a channel called myStream looks like this:
redis-cli SUBSCRIBE myStream
I then ran a process to synthesise 10,000 lines like this:
time seq 10000 | while read a ; do redis-cli PUBLISH myStream "$a" >/dev/null 2>&1 ; done
And that takes 40s, so it does around 250 lines per second, but it has to start a whole new process for each line and create and tear down the connection to Redis... and we don't want to send your CPU mad.
More appropriately for your situation then, here is how you can create a file with 100,000 lines, and read them one at a time, and send them to all your subscribers in Python:
# Make a "BigFile" with 100,000 lines
seq 100000 > BigFile
and read the lines and publish them with:
#!/usr/bin/env python3
import redis
if __name__ == '__main__':
# Redis connection
r = redis.Redis(host='localhost', port=6379, db=0)
# Read file line by line...
with open('BigFile', 'r') as infile:
for line in infile:
# Publish the current line to subscribers
r.publish('myStream', line)
The entire 100,000 lines were sent and received in 4s, so 25,000 lines per second. Here is a little recording of it in action. At the top you can see the CPU is not unduly troubled by it. The second window from the top is a client, receiving 100,000 lines and the next window down is a second client. The bottom window shows the server running the Python code above and sending all 100,000 lines in 4s.
Keywords: Redis, mosquitto, pub/sub, publish, subscribe.

Send data by network and plot with octave

I am working on a robot and my goal is to plot the state of the robot.
For now, my workflow is this:
Launch the program
Redirect the output in a file (robot/bash): rosrun explo explo_node > states.txt
Send the file to my local machine (robot/bash): scp states.txt my_desktop:/home/user
Plot the states with octave (desktop/octave): plot_data('states.txt')
Is there a simple solution to have the data in "real time"? For the octave side. I think that I can with not so much difficulty read from a file as an input and plot the data when data is added.
The problem is how do I send the data to a file?
I am opened to other solutions than octave. The thing is that I need to have 2d plot with arrows for the orientation of the robot.
Here's an example of how you could send the data over the network (as Andy suggested) and plot as it is generated (i.e. realtime). I also think this approach is the most flexible / appropriate.
To demonstrate, I will use a bash script that generates an
pair every 10th of a second, for the
function, in the range
:
#!/bin/bash
# script: sin.sh
for i in `seq 0 0.01 31.4`;
do
printf "$i, `echo "s($i)" | bc -l`\n"
sleep 0.1
done
(Don't forget to make this script executable!)
Prepare the following octave script (requires the sockets package!):
% in visualiseRobotData.m
pkg load sockets
s = socket();
bind(s, 9000);
listen(s, 1);
c = accept(s);
figure; hold on;
while ! isempty (a = str2num (char (recv (c, inf))))
plot (a(:,1), a(:,2), '*'); drawnow;
end
hold off;
Now execute things in the following order:
Run the visualiseRobotData script from the octave terminal.
(Note: this will block until a connection is established)
From your bash terminal run: ./sin.sh | nc localhost 9000
And watch the datapoints get plotted as they come in from your sin.sh script.
It's a bit crude, but you can just reload the file in a loop. This one runs for 5 minutes:
for i = 1:300
load Test/sine.txt
plot (sine(:,1), sine(:,2))
sleep (1)
endfor
You can mount remote directory via sshfs:
sshfs user#remote:/path/to/remote_dir local_dir
so you wouldn't have to load remote file. If sshfs is not installed, install it. To unmount remote directory later, execute
fusermount -u local_dir
To get a robot's data from Octave, execute (Octave code)
system("ssh user#host 'cd remote_dir; rosrun explo explo_node > states.txt'")
%% then plot picture from the data in local_dir
%% that is defacto the directory on the remote server

Synchronizing between multiple pexpect processes

I am writing an application that requires to ssh and telnet to a device at the same time.
The pseudo code goes something like this.
p1 = pexpect.spawn("ssh to the device")
p1.send("run some command")
p1.expect("..")
p2 = pexpect.spawn("telnet to same device")
p2.send("run a command that can be run only through telnet")
p2.expect("..")
p1.send("run some other command")
p1.expect("..")
p2.send("run another command that can be run only through telnet")
p2.expect("..")`
If you notice, I need synchronization between two pexpect children
in order to run them one after the other.
I searched a lot but could not find any information.
please help.
thanks

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