Start daemon process within BaseHTTPServer

Question

In order to allow helpdesk to restart an Oracle Instance, we are trying to implement a small python webserver that would start a shell script that starts the Oracle instance.

The code is done and it starts the instance but there is a problem: the instance is connected to the webserver, so the buffer to the browser is not closed until the instance has been stopped, and there is a ora_pmon_INSTANCE process listening on the webserver port.

I tried to launch the script with:

process = os.system("/home/oracle/scripts/webservice/prueba.sh TFINAN")

and

process = subprocess.Popen(["/home/oracle/scripts/webservice/prueba.sh", "TFINAN"], shell=False, stdout=subprocess.PIPE)`

but it happens the same.

I also tried to launch a script with daemon (using daemon function from redhat's init scripts). The script starts the Oracle instance with the same result.

This is my code:

#!/usr/bin/python

from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
from SocketServer import ThreadingMixIn
import threading
import argparse, urlparse
import re
import cgi, sys, time
import os, subprocess

class HTTPRequestHandler(BaseHTTPRequestHandler):

    def do_POST(self):
        self.send_response(403)
        self.send_header('Content-Type', 'text/html')
        self.end_headers()

        return

    def do_GET(self):
        ko = False
        respuesta = ""
        params = {}
        myProc = -1
        parsed_path = urlparse.urlparse(self.path)
        try:
            params = dict([p.split('=') for p in parsed_path[4].split('&')])
        except:
            params = {}

        elif None != re.search('/prueba/*', self.path):
            self.send_response(200)
            respuesta = "Hola Mundo! -->" + str( params['database'] )

        elif None != re.search('/startup/*', self.path):
            self.send_response(200)
            self.send_header('Content-Type', 'text/html')
            self.end_headers()
            cmd = """ <html>
                        <body><H2> Iniciando instancia oracle: """ + str( params["database"]) + '. Espere un momento, por favor ...</H2>'

            self.wfile.write(cmd)

            #process = os.system("/home/oracle/scripts/webservice/prueba.sh INSTANCE")
            process = subprocess.Popen(["/home/oracle/scripts/webservice/prueba.sh", "INSTANCE"], shell=False, stdout=subprocess.PIPE)
            # wait for the process to terminate
            out, err = process.communicate()
            errcode = process.returncode
            if errcode == 0:
                self.wfile.write("""<H1> Instancia iniciada correctamente
                                </H1>
                            </body> </html>""")
                self.wfile.close()
            else:
                respuestaok = "Error inicializando la instancia: " + str( params['database']) + " Intentelo de nuevo pasados unos minutos y si vuelve a fallar escale la incidencia al siguiente nivel de soporte"

        else:
            self.send_response(403, 'Bad Request: pagina no existe')
            respuesta = "Solicitud no autorizada"

        if respuesta != "":
            self.send_response(200)
            self.send_header('Content-Type', 'text/html')
            self.end_headers()
            self.wfile.write(respuesta)
            self.wfile.close()

        if ko:
            server.stop()           

        return


class ThreadedHTTPServer(ThreadingMixIn, HTTPServer):
    allow_reuse_address = True

    def shutdown(self):
        self.socket.close()
        sys.exit(0)

class SimpleHttpServer(object):
    def __init__(self, ip, port):
        self.server = ThreadedHTTPServer((ip,port), HTTPRequestHandler)

    def start(self):
        self.server_thread = threading.Thread(target=self.server.serve_forever)
        self.server_thread.daemon = True
        self.server_thread.start()

    def waitForThread(self):
        self.server_thread.join()

    def stop(self):
        self.server.shutdown()

if __name__=='__main__':
    parser = argparse.ArgumentParser(description='HTTP Server')
    parser.add_argument('port', type=int, help='Listening port for HTTP Server')
    parser.add_argument('ip', help='HTTP Server IP')
    args = parser.parse_args()

    server = SimpleHttpServer(args.ip, args.port)
    print 'HTTP Server Running...........'
    server.start()
    server.waitForThread()

Can any of you help me?

score 0 · Answer 1 · answered Apr 17 '14 at 20:00

Your problem is not related much to HTTP server. You seem to have general problem to control Oracle daemon from Python code.

Try first writing a simple python script, which does what you need.

My guess is, that your attempts are having problems with reading output from daemon control script.

See also Popen.communicate() for reading output from the command. Other option could be to call subrocess.call()

There are many tutorials for calling system command from Python, e.g. this one

Apart of purely Python related problems you may run into problems with permission - if your user, running the script/HTTP server is not allowed to call oracle control script, you have another problem (which might have a solution, on Linux adding that user into sudoers).

After you resolve problems with calling the script, it shall be easy to make it working inside of your HTTP server.

Start daemon process within BaseHTTPServer

1 Answers1