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## Hrishi Hiraskar
## 23 October 2016
import gevent
import time
import subprocess
from gevent import monkey
from gevent.pywsgi import WSGIServer
from flask import Flask, request, Response, render_template, send_from_directory
monkey.patch_all()
app = Flask(__name__, static_folder='')
# Delay time to look for new line (in s)
LOOK_DELAY = 0.1
# States of the line
INITIALIZATION = 0
ENDING = 1
DATA = 2
NOLINE = -1
# List to store figure IDs
figure_list = []
class line_and_state:
# Class to store the line and its state
line = None
state = NOLINE
def __init__(self, line, state):
self.line = line
self.state = state
def set(self, line_state):
self.line = line_state[0]
self.state = line_state[1]
return False
def get_line(self):
return self.line
def get_state(self):
return self.state
def parse_line(line):
# Function to parse the line
# Returns tuple of figure ID and state
# state = INITIALIZATION if new figure is created
# ENDING if current fig end
# DATA otherwise
line_words = line.split(' ')
if line_words[2] == "Initialization":
# New figure created
# Get fig id
figure_id = int(line_words[-1])
return (figure_id, INITIALIZATION)
elif line_words[2] == "Ending":
# Current figure end
# Get fig id
figure_id = int(line_words[-1])
return (figure_id, ENDING)
else:
# Current figure coordinates
figure_id = int(line_words[2])
return (figure_id, DATA)
def get_line_and_state(file):
# Function to get a new line from file
# This also parses the line and appends new figures to figure List
global figure_list
line = file.readline()
if not line:
return (None, NOLINE)
parse_result = parse_line(line)
figure_id = parse_result[0]
state = parse_result[1]
if state == INITIALIZATION:
# New figure created
# Add figure ID to list
figure_list.append(figure_id)
return (None, INITIALIZATION)
elif state == ENDING:
# End of figure
# Remove figure ID from list
figure_list.remove(figure_id)
return (None, ENDING)
return (line, DATA)
def event_stream():
global figure_list
# Get previously running scilab process IDs
proc = subprocess.Popen("pgrep scilab", stdout=subprocess.PIPE, shell=True)
# out will contain output of command, the list of process IDs of scilab
(out, err) = proc.communicate()
_l = len(out)
# Run xcos
subprocess.Popen("./../../bin/xcos")
# Wait till xcos is launched
while len(out) == _l:
# If length of out equals _l,
# it means scilab hasn't launched yet
# Wait
gevent.sleep(LOOK_DELAY)
# Get process IDs of scilab instances
proc = subprocess.Popen("pgrep scilab", stdout=subprocess.PIPE, shell=True)
# out will contain output of command, the list of process IDs of scilab
(out, err) = proc.communicate()
# out will contain output of command, the list of process IDs of scilab
# Get the latest process ID of scilab
pid = out.split()[-1]
# Log file directory
# As the scilab process is spawned by this script
# the log directory is same as that of this script
log_dir = ""
# Log file name
log_name = "scilab-log-"+pid+".txt"
# Open the log file
log_file = open(log_dir + log_name, "a+")
# Seek the file pointer to the end of file
# 0 signifies the displacement index relative to given position and
# 2 signifies the position (here, end of file; 0 is for start of file and 1 is for current position)
# Refer https://www.tutorialspoint.com/python/file_seek.htm for more
log_file.seek(0,2)
# Start sending log
line = line_and_state(None, NOLINE)
while line.set(get_line_and_state(log_file)) or (line.get_state() != ENDING or len(figure_list) > 0):
# Get the line and loop until the state is ENDING and figure_list empty
if line.get_state() != DATA:
gevent.sleep(LOOK_DELAY)
else:
yield "event: log\ndata: "+line.get_line()+"\n\n";
# Reset line
line = line_and_state(None, NOLINE)
# Finished Sending Log
# Exit xcos
subprocess.Popen(["kill","-9",pid])
# Remove log file, so server won't send same line twice
subprocess.Popen(["rm",log_dir+log_name])
# Notify Client
yield "event: DONE\ndata: None\n\n";
@app.route('/SendLog')
def sse_request():
# Set response method to event-stream
return Response(event_stream(), mimetype='text/event-stream')
@app.route('/<path:path>')
def static_file(path):
return app.send_static_file(path)
@app.route('/')
def page():
return app.send_static_file('index.html')
if __name__ == '__main__':
# Set server address 127.0.0.1:8001/
http_server = WSGIServer(('127.0.0.1', 8001), app)
http_server.serve_forever()
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