#!/usr/bin/python
# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright 2012 Michael Still and Canonical Inc
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.


import cStringIO
import hashlib
import logging
import os
import shutil
import tempfile
import time

from nova import test

from nova import db
from nova import flags
from nova import log
from nova import utils
from nova.virt.libvirt import imagecache
from nova.virt.libvirt import utils as virtutils


flags.DECLARE('instances_path', 'nova.compute.manager')
FLAGS = flags.FLAGS

LOG = log.getLogger(__name__)


class ImageCacheManagerTestCase(test.TestCase):

    def setUp(self):
        super(ImageCacheManagerTestCase, self).setUp()
        self.stock_instance_names = {'instance-00000001': '123',
                                     'instance-00000002': '456',
                                     'instance-00000003': '789',
                                     'banana-42-hamster': '444'}

    def test_read_stored_checksum_missing(self):
        self.stubs.Set(os.path, 'exists', lambda x: False)

        csum = imagecache.read_stored_checksum('/tmp/foo')
        self.assertEquals(csum, None)

    def test_read_stored_checksum(self):
        try:
            dirname = tempfile.mkdtemp()
            fname = os.path.join(dirname, 'aaa')

            csum_input = 'fdghkfhkgjjksfdgjksjkghsdf'
            f = open('%s.sha1' % fname, 'w')
            f.write('%s\n' % csum_input)
            f.close()

            csum_output = imagecache.read_stored_checksum(fname)

            self.assertEquals(csum_input, csum_output)

        finally:
            shutil.rmtree(dirname)

    def test_list_base_images(self):
        listing = ['00000001',
                   'ephemeral_0_20_None',
                   'e97222e91fc4241f49a7f520d1dcf446751129b3_sm',
                   'e09c675c2d1cfac32dae3c2d83689c8c94bc693b_sm',
                   'e97222e91fc4241f49a7f520d1dcf446751129b3',
                   '17d1b00b81642842e514494a78e804e9a511637c',
                   '17d1b00b81642842e514494a78e804e9a511637c_5368709120',
                   '17d1b00b81642842e514494a78e804e9a511637c_10737418240',
                   '00000004']

        self.stubs.Set(os, 'listdir', lambda x: listing)
        self.stubs.Set(os.path, 'isfile', lambda x: True)

        base_dir = '/var/lib/nova/instances/_base'
        image_cache_manager = imagecache.ImageCacheManager()
        image_cache_manager._list_base_images(base_dir)

        self.assertEquals(len(image_cache_manager.unexplained_images), 6)

        expected = os.path.join(base_dir,
                                'e97222e91fc4241f49a7f520d1dcf446751129b3')
        self.assertTrue(expected in image_cache_manager.unexplained_images)

        expected = os.path.join(base_dir,
                                '17d1b00b81642842e514494a78e804e9a511637c_'
                                '10737418240')
        self.assertTrue(expected in image_cache_manager.unexplained_images)

        unexpected = os.path.join(base_dir, '00000004')
        self.assertFalse(unexpected in image_cache_manager.unexplained_images)

        for ent in image_cache_manager.unexplained_images:
            self.assertTrue(ent.startswith(base_dir))

        self.assertEquals(len(image_cache_manager.originals), 2)

        expected = os.path.join(base_dir,
                                '17d1b00b81642842e514494a78e804e9a511637c')
        self.assertTrue(expected in image_cache_manager.originals)

        unexpected = os.path.join(base_dir,
                                  '17d1b00b81642842e514494a78e804e9a511637c_'
                                '10737418240')
        self.assertFalse(unexpected in image_cache_manager.originals)

    def test_list_running_instances(self):
        self.stubs.Set(db, 'instance_get_all',
                       lambda x: [{'image_ref': 'image-1',
                                   'host': FLAGS.host,
                                   'name': 'inst-1',
                                   'uuid': '123'},
                                  {'image_ref': 'image-2',
                                   'host': FLAGS.host,
                                   'name': 'inst-2',
                                   'uuid': '456'},
                                  {'image_ref': 'image-2',
                                   'host': 'remotehost',
                                   'name': 'inst-3',
                                   'uuid': '789'}])

        image_cache_manager = imagecache.ImageCacheManager()

        # The argument here should be a context, but its mocked out
        image_cache_manager._list_running_instances(None)

        self.assertEqual(len(image_cache_manager.used_images), 2)
        self.assertTrue(image_cache_manager.used_images['image-1'] ==
                        (1, 0, ['inst-1']))
        self.assertTrue(image_cache_manager.used_images['image-2'] ==
                        (1, 1, ['inst-2', 'inst-3']))

        self.assertEqual(len(image_cache_manager.image_popularity), 2)
        self.assertEqual(image_cache_manager.image_popularity['image-1'], 1)
        self.assertEqual(image_cache_manager.image_popularity['image-2'], 2)

    def test_list_backing_images_small(self):
        self.stubs.Set(os, 'listdir',
                       lambda x: ['_base', 'instance-00000001',
                                  'instance-00000002', 'instance-00000003'])
        self.stubs.Set(os.path, 'exists',
                       lambda x: x.find('instance-') != -1)
        self.stubs.Set(virtutils, 'get_disk_backing_file',
                       lambda x: 'e97222e91fc4241f49a7f520d1dcf446751129b3_sm')

        found = os.path.join(FLAGS.instances_path, '_base',
                             'e97222e91fc4241f49a7f520d1dcf446751129b3_sm')

        image_cache_manager = imagecache.ImageCacheManager()
        image_cache_manager.unexplained_images = [found]
        image_cache_manager.instance_names = self.stock_instance_names

        inuse_images = image_cache_manager._list_backing_images()

        self.assertEquals(inuse_images, [found])
        self.assertEquals(len(image_cache_manager.unexplained_images), 0)

    def test_list_backing_images_resized(self):
        self.stubs.Set(os, 'listdir',
                       lambda x: ['_base', 'instance-00000001',
                                  'instance-00000002', 'instance-00000003'])
        self.stubs.Set(os.path, 'exists',
                       lambda x: x.find('instance-') != -1)
        self.stubs.Set(virtutils, 'get_disk_backing_file',
                       lambda x: ('e97222e91fc4241f49a7f520d1dcf446751129b3_'
                                  '10737418240'))

        found = os.path.join(FLAGS.instances_path, '_base',
                             'e97222e91fc4241f49a7f520d1dcf446751129b3_'
                             '10737418240')

        image_cache_manager = imagecache.ImageCacheManager()
        image_cache_manager.unexplained_images = [found]
        image_cache_manager.instance_names = self.stock_instance_names

        inuse_images = image_cache_manager._list_backing_images()

        self.assertEquals(inuse_images, [found])
        self.assertEquals(len(image_cache_manager.unexplained_images), 0)

    def test_list_backing_images_instancename(self):
        self.stubs.Set(os, 'listdir',
                       lambda x: ['_base', 'banana-42-hamster'])
        self.stubs.Set(os.path, 'exists',
                       lambda x: x.find('banana-42-hamster') != -1)
        self.stubs.Set(virtutils, 'get_disk_backing_file',
                       lambda x: 'e97222e91fc4241f49a7f520d1dcf446751129b3_sm')

        found = os.path.join(FLAGS.instances_path, '_base',
                             'e97222e91fc4241f49a7f520d1dcf446751129b3_sm')

        image_cache_manager = imagecache.ImageCacheManager()
        image_cache_manager.unexplained_images = [found]
        image_cache_manager.instance_names = self.stock_instance_names

        inuse_images = image_cache_manager._list_backing_images()

        self.assertEquals(inuse_images, [found])
        self.assertEquals(len(image_cache_manager.unexplained_images), 0)

    def test_find_base_file_nothing(self):
        self.stubs.Set(os.path, 'exists', lambda x: False)

        base_dir = '/var/lib/nova/instances/_base'
        fingerprint = '549867354867'
        image_cache_manager = imagecache.ImageCacheManager()
        res = list(image_cache_manager._find_base_file(base_dir, fingerprint))

        self.assertEqual(0, len(res))

    def test_find_base_file_small(self):
        fingerprint = '968dd6cc49e01aaa044ed11c0cce733e0fa44a6a'
        self.stubs.Set(os.path, 'exists',
                       lambda x: x.endswith('%s_sm' % fingerprint))

        base_dir = '/var/lib/nova/instances/_base'
        image_cache_manager = imagecache.ImageCacheManager()
        res = list(image_cache_manager._find_base_file(base_dir, fingerprint))

        base_file = os.path.join(base_dir, fingerprint + '_sm')
        self.assertTrue(res == [(base_file, True, False)])

    def test_find_base_file_resized(self):
        fingerprint = '968dd6cc49e01aaa044ed11c0cce733e0fa44a6a'
        listing = ['00000001',
                   'ephemeral_0_20_None',
                   '968dd6cc49e01aaa044ed11c0cce733e0fa44a6a_10737418240',
                   '00000004']

        self.stubs.Set(os, 'listdir', lambda x: listing)
        self.stubs.Set(os.path, 'exists',
                       lambda x: x.endswith('%s_10737418240' % fingerprint))
        self.stubs.Set(os.path, 'isfile', lambda x: True)

        base_dir = '/var/lib/nova/instances/_base'
        image_cache_manager = imagecache.ImageCacheManager()
        image_cache_manager._list_base_images(base_dir)
        res = list(image_cache_manager._find_base_file(base_dir, fingerprint))

        base_file = os.path.join(base_dir, fingerprint + '_10737418240')
        self.assertTrue(res == [(base_file, False, True)])

    def test_find_base_file_all(self):
        fingerprint = '968dd6cc49e01aaa044ed11c0cce733e0fa44a6a'
        listing = ['00000001',
                   'ephemeral_0_20_None',
                   '968dd6cc49e01aaa044ed11c0cce733e0fa44a6a_sm',
                   '968dd6cc49e01aaa044ed11c0cce733e0fa44a6a_10737418240',
                   '00000004']

        self.stubs.Set(os, 'listdir', lambda x: listing)
        self.stubs.Set(os.path, 'exists', lambda x: True)
        self.stubs.Set(os.path, 'isfile', lambda x: True)

        base_dir = '/var/lib/nova/instances/_base'
        image_cache_manager = imagecache.ImageCacheManager()
        image_cache_manager._list_base_images(base_dir)
        res = list(image_cache_manager._find_base_file(base_dir, fingerprint))

        base_file1 = os.path.join(base_dir, fingerprint)
        base_file2 = os.path.join(base_dir, fingerprint + '_sm')
        base_file3 = os.path.join(base_dir, fingerprint + '_10737418240')
        print res
        self.assertTrue(res == [(base_file1, False, False),
                                (base_file2, True, False),
                                (base_file3, False, True)])

    def _intercept_log_messages(self):
        mylog = log.getLogger()
        stream = cStringIO.StringIO()
        handler = logging.StreamHandler(stream)
        handler.setFormatter(log.LegacyNovaFormatter())
        mylog.logger.addHandler(handler)
        return mylog, handler, stream

    def test_verify_checksum(self):
        testdata = ('OpenStack Software delivers a massively scalable cloud '
                    'operating system.')
        img = {'container_format': 'ami', 'id': '42'}

        self.flags(checksum_base_images=True)
        mylog, handler, stream = self._intercept_log_messages()

        try:
            dirname = tempfile.mkdtemp()
            fname = os.path.join(dirname, 'aaa')

            f = open(fname, 'w')
            f.write(testdata)
            f.close()

            # Checksum is valid
            f = open('%s.sha1' % fname, 'w')
            csum = hashlib.sha1()
            csum.update(testdata)
            f.write(csum.hexdigest())
            f.close()

            image_cache_manager = imagecache.ImageCacheManager()
            res = image_cache_manager._verify_checksum(img, fname)
            self.assertTrue(res)

            # Checksum is invalid
            f = open('%s.sha1' % fname, 'w')
            f.write('banana')
            f.close()

            image_cache_manager = imagecache.ImageCacheManager()
            res = image_cache_manager._verify_checksum(img, fname)
            self.assertFalse(res)
            self.assertNotEqual(stream.getvalue().find('image verification '
                                                       'failed'), -1)

            # Checksum file missing
            os.remove('%s.sha1' % fname)
            image_cache_manager = imagecache.ImageCacheManager()
            res = image_cache_manager._verify_checksum(img, fname)
            self.assertEquals(res, None)

            # Checksum requests for a file with no checksum now have the
            # side effect of creating the checksum
            self.assertTrue(os.path.exists('%s.sha1' % fname))

        finally:
            shutil.rmtree(dirname)
            mylog.logger.removeHandler(handler)

    def _make_base_file(checksum=True):
        """Make a base file for testing."""

        dirname = tempfile.mkdtemp()
        fname = os.path.join(dirname, 'aaa')

        base_file = open(fname, 'w')
        base_file.write('data')
        base_file.close()
        base_file = open(fname, 'r')

        if checksum:
            checksum_file = open('%s.sha1' % fname, 'w')
            checksum_file.write(utils.hash_file(base_file))
            checksum_file.close()

        base_file.close()
        return dirname, fname

    def test_remove_base_file(self):
        dirname, fname = self._make_base_file()
        try:
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager._remove_base_file(fname)

            # Files are initially too new to delete
            self.assertTrue(os.path.exists(fname))
            self.assertTrue(os.path.exists('%s.sha1' % fname))

            # Old files get cleaned up though
            os.utime(fname, (-1, time.time() - 3601))
            image_cache_manager._remove_base_file(fname)

            self.assertFalse(os.path.exists(fname))
            self.assertFalse(os.path.exists('%s.sha1' % fname))

        finally:
            shutil.rmtree(dirname)

    def test_remove_base_file_original(self):
        dirname, fname = self._make_base_file()
        try:
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager.originals = [fname]
            image_cache_manager._remove_base_file(fname)

            # Files are initially too new to delete
            self.assertTrue(os.path.exists(fname))
            self.assertTrue(os.path.exists('%s.sha1' % fname))

            # This file should stay longer than a resized image
            os.utime(fname, (-1, time.time() - 3601))
            image_cache_manager._remove_base_file(fname)

            self.assertTrue(os.path.exists(fname))
            self.assertTrue(os.path.exists('%s.sha1' % fname))

            # Originals don't stay forever though
            os.utime(fname, (-1, time.time() - 3600 * 25))
            image_cache_manager._remove_base_file(fname)

            self.assertFalse(os.path.exists(fname))
            self.assertFalse(os.path.exists('%s.sha1' % fname))

        finally:
            shutil.rmtree(dirname)

    def test_remove_base_file_dne(self):
        # This test is solely to execute the "does not exist" code path. We
        # don't expect the method being tested to do anything in this case.
        dirname = tempfile.mkdtemp()
        try:
            fname = os.path.join(dirname, 'aaa')
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager._remove_base_file(fname)

        finally:
            shutil.rmtree(dirname)

    def test_remove_base_file_oserror(self):
        dirname = tempfile.mkdtemp()
        fname = os.path.join(dirname, 'aaa')
        mylog, handler, stream = self._intercept_log_messages()

        try:
            os.mkdir(fname)
            os.utime(fname, (-1, time.time() - 3601))

            # This will raise an OSError because of file permissions
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager._remove_base_file(fname)

            self.assertTrue(os.path.exists(fname))
            self.assertNotEqual(stream.getvalue().find('Failed to remove'),
                                -1)

        finally:
            shutil.rmtree(dirname)
            mylog.logger.removeHandler(handler)

    def test_handle_base_image_unused(self):
        img = {'container_format': 'ami',
               'id': '123',
               'uuid': '1234-4567-2378'}

        dirname, fname = self._make_base_file()
        os.utime(fname, (-1, time.time() - 3601))

        try:
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager.unexplained_images = [fname]
            image_cache_manager._handle_base_image(img, fname)

            self.assertEquals(image_cache_manager.unexplained_images, [])
            self.assertEquals(image_cache_manager.removable_base_files,
                              [fname])
            self.assertEquals(image_cache_manager.corrupt_base_files, [])

        finally:
            shutil.rmtree(dirname)

    def test_handle_base_image_used(self):
        img = {'container_format': 'ami',
               'id': '123',
               'uuid': '1234-4567-2378'}

        dirname, fname = self._make_base_file()
        os.utime(fname, (-1, time.time() - 3601))

        try:
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager.unexplained_images = [fname]
            image_cache_manager.used_images = {'123': (1, 0, ['banana-42'])}
            image_cache_manager._handle_base_image(img, fname)

            self.assertEquals(image_cache_manager.unexplained_images, [])
            self.assertEquals(image_cache_manager.removable_base_files, [])
            self.assertEquals(image_cache_manager.corrupt_base_files, [])

        finally:
            shutil.rmtree(dirname)

    def test_handle_base_image_used_remotely(self):
        img = {'container_format': 'ami',
               'id': '123',
               'uuid': '1234-4567-2378'}

        dirname, fname = self._make_base_file()
        os.utime(fname, (-1, time.time() - 3601))

        try:
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager.used_images = {'123': (0, 1, ['banana-42'])}
            image_cache_manager._handle_base_image(img, None)

            self.assertEquals(image_cache_manager.unexplained_images, [])
            self.assertEquals(image_cache_manager.removable_base_files, [])
            self.assertEquals(image_cache_manager.corrupt_base_files, [])

        finally:
            shutil.rmtree(dirname)

    def test_handle_base_image_absent(self):
        """Ensure we warn for use of a missing base image."""

        img = {'container_format': 'ami',
               'id': '123',
               'uuid': '1234-4567-2378'}

        mylog, handler, stream = self._intercept_log_messages()

        try:
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager.used_images = {'123': (1, 0, ['banana-42'])}
            image_cache_manager._handle_base_image(img, None)

            self.assertEquals(image_cache_manager.unexplained_images, [])
            self.assertEquals(image_cache_manager.removable_base_files, [])
            self.assertEquals(image_cache_manager.corrupt_base_files, [])
            self.assertNotEqual(stream.getvalue().find('an absent base file'),
                                -1)

        finally:
            mylog.logger.removeHandler(handler)

    def test_handle_base_image_used_missing(self):
        img = {'container_format': 'ami',
               'id': '123',
               'uuid': '1234-4567-2378'}

        dirname = tempfile.mkdtemp()
        fname = os.path.join(dirname, 'aaa')

        try:
            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager.unexplained_images = [fname]
            image_cache_manager.used_images = {'123': (1, 0, ['banana-42'])}
            image_cache_manager._handle_base_image(img, fname)

            self.assertEquals(image_cache_manager.unexplained_images, [])
            self.assertEquals(image_cache_manager.removable_base_files, [])
            self.assertEquals(image_cache_manager.corrupt_base_files, [])

        finally:
            shutil.rmtree(dirname)

    def test_handle_base_image_checksum_fails(self):
        img = {'container_format': 'ami',
               'id': '123',
               'uuid': '1234-4567-2378'}

        dirname, fname = self._make_base_file()

        try:
            f = open(fname, 'w')
            f.write('banana')
            f.close()

            image_cache_manager = imagecache.ImageCacheManager()
            image_cache_manager.unexplained_images = [fname]
            image_cache_manager.used_images = {'123': (1, 0, ['banana-42'])}
            image_cache_manager._handle_base_image(img, fname)

            self.assertEquals(image_cache_manager.unexplained_images, [])
            self.assertEquals(image_cache_manager.removable_base_files, [])
            self.assertEquals(image_cache_manager.corrupt_base_files,
                              [fname])

        finally:
            shutil.rmtree(dirname)
