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path: root/kpov_judge/create_disk_images.py
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#!/usr/bin/env python
# -*- coding: utf-8 -*-

import pymongo
import sys
import inspect
import kpov_random_helpers
import settings
import guestfs
import os
import glob
import subprocess
import fcntl

def get_prepare_disks(db, task_id):
    prepare_disks_source = db.prepare_disks.find_one({'task_id':task_id})['source']
    prepare_disks_code = compile(prepare_disks_source, 'prepare_disks.py', 'exec')
    exec(prepare_disks_code)
    return prepare_disks

def create_snapshot(task_id, student_id, disk_name, overwrite = True, cow = False):
    print(os.path.join(settings.DISK_TEMPLATE_PATH, task_id, disk_name) + '.*')
    template_paths = glob.glob(os.path.join(settings.DISK_TEMPLATE_PATH, task_id, disk_name) + '.*')
    filtered_paths = filter((lambda x: os.path.splitext(x)[1] == '.' + settings.STUDENT_DISK_FORMAT), template_paths)
    if filtered_paths:
      template_path = filtered_paths[0]
    else:
      template_path = template_paths[0]
    if cow:
        d = os.path.join(student_id, task_id, disk_name) + os.path.splitext(template_path)[1]
    else:
        d = os.path.join(student_id, task_id, disk_name) + '.qcow2'
    try:
        os.makedirs(os.path.join(settings.STUDENT_DISK_PATH, student_id, task_id))
    except:
        pass
    disk_file = os.path.join(settings.STUDENT_DISK_PATH, d)
    if overwrite or not os.path.exists(disk_file):
        if cow:
            subprocess.call(['cp', '--reflink=always', template_path, disk_file])
        else:
            subprocess.call(['qemu-img', 'create', '-f', 'qcow2', '-o', 'backing_file=' + template_path,
                     disk_file])
    return d

def publish_snapshot(d):
    if os.path.splitext(d)[1][1:] != settings.STUDENT_DISK_FORMAT:
        snap_name = os.path.splitext(d)[0] + '.' + settings.STUDENT_DISK_FORMAT
        disk_file = os.path.join(settings.STUDENT_DISK_PATH, d)
        snap_file = os.path.join(settings.STUDENT_DISK_PATH, snap_name)
        subprocess.call(['qemu-img', 'convert', '-f', 'qcow2', '-O', settings.STUDENT_DISK_FORMAT, disk_file,
            snap_file])
        url = settings.STUDENT_DISK_URL + snap_name
    else:
        url = settings.STUDENT_DISK_URL + d
    return url
  
if __name__ == '__main__':
    if len(sys.argv) != 1:
        print "Usage: {0}"
        print "Create the neccessarry disk images"
    db = pymongo.Connection(settings.DB_HOST).kpov
    try:
        db.authenticate(settings.USERNAME, settings.PASSWORD)
    except Exception, e:
        print str(e)
    dev_prefix = settings.GUESTFS_DEV_PREFIX
    l = db.student_computers.find({"disk_urls": {"$exists": False}})
    computers_by_task_student = dict()
    for computer in l:
        student_id, task_id = computer['student_id'], computer['task_id']
        if (task_id, student_id) not in computers_by_task_student:
            computers_by_task_student[(task_id, student_id)] = list()
        computers_by_task_student[(task_id, student_id)].append(computer)
    for (task_id, student_id), computers in computers_by_task_student.iteritems():
    	l = db.student_computers.find_one({'task_id': task_id, 'student_id':student_id, "disk_urls": {"$exists": False}})
        if l is None:
            continue
        lock_file = os.path.join(settings.STUDENT_LOCKFILE_PATH, 
            '{0}-{1}.lock'.format(student_id, task_id))
        lock_fp = open(lock_file, 'w')
        try:
            fcntl.lockf(lock_fp, fcntl.LOCK_EX | fcntl.LOCK_NB)
        except IOError:
            continue
        params = db.task_params.find_one({'task_id': task_id, 'student_id': student_id})['params']
        prepare_disks = get_prepare_disks(db, task_id)
        # tule odpri, ustvari snapshote za vajo
        templates = dict()
        all_disks = dict()
        parts = dict()
        for computer in computers:
            lock_fp.write('creating computer ' + computer['name'] + '\n')
            all_disks[computer['name']] = dict()
            manual_disks = list()
            this_computers_disks = set()
            try_automount = False
            g = guestfs.GuestFS()
            for disk in computer['disks']:
                lock_fp.write("register " + disk['name'] + '\n')
                snap = create_snapshot(task_id, student_id, disk['name'],
                    cow = settings.STUDENT_DISK_COW)
                snap_file = os.path.join(settings.STUDENT_DISK_PATH, snap)
                if 'options' in disk:
                    g.add_drive_opts(snap_file, **(disk['options']))
                else:
                    g.add_drive(snap_file)
                if 'parts' in disk:
                    for p in disk['parts']:
                        manual_disks.append((dev_prefix + p['dev'],
                            p['path'], p.get('options', None)))
                else:
                    try_automount = True
                templates[disk['name']] = g
                all_disks[computer['name']][disk['name']] = snap
            g.launch()
            mounted = set()
            if try_automount:
                roots = g.inspect_os()
                for root in roots:
                    mps = g.inspect_get_mountpoints(root)
                    lock_fp.write("detected:"+str(mps)+'\n')
                    for mountpoint, device in sorted(mps):
                        if mountpoint not in mounted:
                            try:
                                g.mount(device, mountpoint, )
                                lock_fp.write( 'mounted ' + device + ' on ' + mountpoint + '\n')
                            except RuntimeError as msg:
                                lock_fp.write( "%s (ignored)\n" % msg)
                            mounted.add(mountpoint)
            for device, mountpoint, opts in manual_disks:
                try:
                    if opts is not None:
                        g.mount_options(opts, device, mountpoint)
                    else:
                        g.mount(device, mountpoint)
                    lock_fp.write('manually mounted ' + device + " on " + mountpoint + '\n')
                except RuntimeError as msg:
                    lock_fp.write( "%s (ignored)\n" % msg)
        lock_fp.write("preparing disks\n")
        prepare_disks(templates, params)
        # pospravi za seboj.
        lock_fp.write("unmounting\n")
        for g in set(templates.values()):
            g.umount_all()
            g.close()
        lock_fp.write("saving URLs\n")
        for comp_name, d_dict in all_disks.iteritems():
            disk_urls = list()
            for d_name, d in d_dict.iteritems():
                lock_fp.write('publishing '+ str(d) + '\n')
                url = publish_snapshot(d)
                lock_fp.write('published as '+ url + '\n')
                disk_urls.append({'name': d_name, 'url': url})
            lock_fp.write('urls: '+ str(disk_urls) + '\n')
            l = db.student_computers.update({
                "disk_urls": {"$exists": False}, 
                'student_id': student_id, 
                'task_id': task_id,
                'name': comp_name},
                {'$set': { 'disk_urls': disk_urls }})
        # print "done for ", student_id, task_id
        os.unlink(lock_file)
        lock_fp.close()