Enable client V2 to download images

Added the CLI option image-download to download an image via API V2.
Added utility function to save an image.
Added common iterator to validate the checksum.

Related to bp glance-client-v2

Change-Id: I0247f5a3462142dc5e9f3dc16cbe00c8e3d42f42

glanceclient/common/utils.py

@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import errno
+import hashlib
 import os
 import sys
 import uuid
@@ -130,3 +132,39 @@ def exit(msg=''):
     if msg:
         print >> sys.stderr, msg
     sys.exit(1)
+
+
+def save_image(data, path):
+    """
+    Save an image to the specified path.
+
+    :param data: binary data of the image
+    :param path: path to save the image to
+    """
+    if path is None:
+        image = sys.stdout
+    else:
+        image = open(path, 'wb')
+    try:
+        for chunk in data:
+            image.write(chunk)
+    finally:
+        if path is not None:
+            image.close()
+
+
+def integrity_iter(iter, checksum):
+    """
+    Check image data integrity.
+
+    :raises: IOError
+    """
+    md5sum = hashlib.md5()
+    for chunk in iter:
+        yield chunk
+        md5sum.update(chunk)
+    md5sum = md5sum.hexdigest()
+    if md5sum != checksum:
+        raise IOError(errno.EPIPE,
+                      'Corrupt image download. Checksum was %s expected %s' %
+                      (md5sum, checksum))

glanceclient/v1/images.py

@@ -20,6 +20,7 @@ import os
 import urllib
 
 from glanceclient.common import base
+from glanceclient.common import utils
 
 UPDATE_PARAMS = ('name', 'disk_format', 'container_format', 'min_disk',
                  'min_ram', 'owner', 'size', 'is_public', 'protected',
@@ -40,8 +41,8 @@ class Image(base.Resource):
     def delete(self):
         return self.manager.delete(self)
 
-    def data(self):
+    def data(self, **kwargs):
-        return self.manager.data(self)
+        return self.manager.data(self, **kwargs)
 
 
 class ImageManager(base.Manager):
@@ -77,15 +78,20 @@ class ImageManager(base.Manager):
         meta = self._image_meta_from_headers(dict(resp.getheaders()))
         return Image(self, meta)
 
-    def data(self, image):
+    def data(self, image, do_checksum=True):
         """Get the raw data for a specific image.
 
         :param image: image object or id to look up
+        :param do_checksum: Enable/disable checksum validation
         :rtype: iterable containing image data
         """
         image_id = base.getid(image)
-        _, body = self.api.raw_request('GET', '/v1/images/%s' % image_id)
+        resp, body = self.api.raw_request('GET', '/v1/images/%s' % image_id)
-        return body
+        checksum = resp.getheader('x-image-meta-checksum', None)
+        if do_checksum and checksum is not None:
+            return utils.integrity_iter(body, checksum)
+        else:
+            return body
 
     def list(self, **kwargs):
         """Get a list of images.

glanceclient/v2/images.py

@@ -13,6 +13,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from glanceclient.common import utils
+
 DEFAULT_PAGE_SIZE = 20
 
 
@@ -54,3 +56,18 @@ class Controller(object):
         # way to pass it into the model constructor without conflict
         body.pop('self', None)
         return self.model(**body)
+
+    def data(self, image_id, do_checksum=True):
+        """
+        Retrieve data of an image.
+
+        :param image_id:    ID of the image to download.
+        :param do_checksum: Enable/disable checksum validation.
+        """
+        url = '/v2/images/%s/file' % image_id
+        resp, body = self.http_client.raw_request('GET', url)
+        checksum = resp.getheader('content-md5', None)
+        if do_checksum and checksum is not None:
+            return utils.integrity_iter(body, checksum)
+        else:
+            return body

glanceclient/v2/shell.py

@@ -49,3 +49,14 @@ def do_explain(gc, args):
         formatters = {'Attribute': lambda m: m.name}
         columns = ['Attribute', 'Description']
         utils.print_list(schema.properties, columns, formatters)
+
+
+@utils.arg('--file', metavar='<FILE>',
+           help='Local file to save downloaded image data to. '
+                'If this is not specified the image data will be '
+                'written to stdout.')
+@utils.arg('id', metavar='<IMAGE_ID>', help='ID of image to download.')
+def do_image_download(gc, args):
+    """Download a specific image."""
+    body = gc.images.data(args.id)
+    utils.save_image(body, args.file)

tests/test_utils.py

@@ -0,0 +1,45 @@
+# Copyright 2012 OpenStack LLC.
+# 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 errno
+import unittest
+
+from glanceclient.common import utils
+
+
+class TestUtils(unittest.TestCase):
+
+    def test_integrity_iter_without_checksum(self):
+        try:
+            data = ''.join([f for f in utils.integrity_iter('A', None)])
+            self.fail('integrity checked passed without checksum.')
+        except IOError, e:
+            self.assertEqual(errno.EPIPE, e.errno)
+            msg = 'was 7fc56270e7a70fa81a5935b72eacbe29 expected None'
+            self.assertTrue(msg in str(e))
+
+    def test_integrity_iter_with_wrong_checksum(self):
+        try:
+            data = ''.join([f for f in utils.integrity_iter('BB', 'wrong')])
+            self.fail('integrity checked passed with wrong checksum')
+        except IOError, e:
+            self.assertEqual(errno.EPIPE, e.errno)
+            msg = 'was 9d3d9048db16a7eee539e93e3618cbe7 expected wrong'
+            self.assertTrue('expected wrong' in str(e))
+
+    def test_integrity_iter_with_checksum(self):
+        fixture = 'CCC'
+        checksum = 'defb99e69a9f1f6e06f15006b1f166ae'
+        data = ''.join([f for f in utils.integrity_iter(fixture, checksum)])

tests/utils.py

@@ -45,3 +45,6 @@ class FakeResponse(object):
 
     def getheaders(self):
         return copy.deepcopy(self.headers).items()
+
+    def getheader(self, key, default):
+        return self.headers.get(key, default)

tests/v1/test_images.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import errno
 import json
 import StringIO
 import unittest
@@ -164,7 +165,34 @@ fixtures = {
         ),
         'DELETE': ({}, None),
     },
-
+    '/v1/images/2': {
+       'HEAD': (
+            {
+                'x-image-meta-id': '2'
+            },
+            None,
+        ),
+        'GET': (
+            {
+                'x-image-meta-checksum': 'wrong'
+            },
+            'YYY',
+        ),
+    },
+    '/v1/images/3': {
+       'HEAD': (
+            {
+                'x-image-meta-id': '3'
+            },
+            None,
+        ),
+        'GET': (
+            {
+                'x-image-meta-checksum': '0745064918b49693cca64d6b6a13d28a'
+            },
+            'ZZZ',
+        ),
+    },
 }
 
 
@@ -220,11 +248,44 @@ class ImageManagerTest(unittest.TestCase):
         self.assertEqual(image.name, 'image-1')
 
     def test_data(self):
-        data = ''.join([b for b in self.mgr.data('1')])
+        data = ''.join([b for b in self.mgr.data('1', do_checksum=False)])
         expect = [('GET', '/v1/images/1', {}, None)]
         self.assertEqual(self.api.calls, expect)
         self.assertEqual(data, 'XXX')
 
+        expect += [('GET', '/v1/images/1', {}, None)]
+        data = ''.join([b for b in self.mgr.data('1')])
+        self.assertEqual(self.api.calls, expect)
+        self.assertEqual(data, 'XXX')
+
+    def test_data_with_wrong_checksum(self):
+        data = ''.join([b for b in self.mgr.data('2', do_checksum=False)])
+        expect = [('GET', '/v1/images/2', {}, None)]
+        self.assertEqual(self.api.calls, expect)
+        self.assertEqual(data, 'YYY')
+
+        expect += [('GET', '/v1/images/2', {}, None)]
+        data = self.mgr.data('2')
+        self.assertEqual(self.api.calls, expect)
+        try:
+            data = ''.join([b for b in data])
+            self.fail('data did not raise an error.')
+        except IOError, e:
+            self.assertEqual(errno.EPIPE, e.errno)
+            msg = 'was fd7c5c4fdaa97163ee4ba8842baa537a expected wrong'
+            self.assertTrue(msg in str(e))
+
+    def test_data_with_checksum(self):
+        data = ''.join([b for b in self.mgr.data('3', do_checksum=False)])
+        expect = [('GET', '/v1/images/3', {}, None)]
+        self.assertEqual(self.api.calls, expect)
+        self.assertEqual(data, 'ZZZ')
+
+        expect += [('GET', '/v1/images/3', {}, None)]
+        data = ''.join([b for b in self.mgr.data('3')])
+        self.assertEqual(self.api.calls, expect)
+        self.assertEqual(data, 'ZZZ')
+
     def test_delete(self):
         self.mgr.delete('1')
         expect = [('DELETE', '/v1/images/1', {}, None)]
@@ -352,3 +413,44 @@ class ImageTest(unittest.TestCase):
         ]
         self.assertEqual(self.api.calls, expect)
         self.assertEqual(data, 'XXX')
+
+        data = ''.join([b for b in image.data(do_checksum=False)])
+        expect += [('GET', '/v1/images/1', {}, None)]
+        self.assertEqual(self.api.calls, expect)
+        self.assertEqual(data, 'XXX')
+
+    def test_data_with_wrong_checksum(self):
+        image = self.mgr.get('2')
+        data = ''.join([b for b in image.data(do_checksum=False)])
+        expect = [
+            ('HEAD', '/v1/images/2', {}, None),
+            ('GET', '/v1/images/2', {}, None),
+        ]
+        self.assertEqual(self.api.calls, expect)
+        self.assertEqual(data, 'YYY')
+
+        data = image.data()
+        expect += [('GET', '/v1/images/2', {}, None)]
+        self.assertEqual(self.api.calls, expect)
+        try:
+            data = ''.join([b for b in image.data()])
+            self.fail('data did not raise an error.')
+        except IOError, e:
+            self.assertEqual(errno.EPIPE, e.errno)
+            msg = 'was fd7c5c4fdaa97163ee4ba8842baa537a expected wrong'
+            self.assertTrue(msg in str(e))
+
+    def test_data_with_checksum(self):
+        image = self.mgr.get('3')
+        data = ''.join([b for b in image.data(do_checksum=False)])
+        expect = [
+            ('HEAD', '/v1/images/3', {}, None),
+            ('GET', '/v1/images/3', {}, None),
+        ]
+        self.assertEqual(self.api.calls, expect)
+        self.assertEqual(data, 'ZZZ')
+
+        data = ''.join([b for b in image.data()])
+        expect += [('GET', '/v1/images/3', {}, None)]
+        self.assertEqual(self.api.calls, expect)
+        self.assertEqual(data, 'ZZZ')

tests/v2/test_images.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import errno
 import unittest
 
 import warlock
@@ -72,6 +73,28 @@ fixtures = {
             },
         ),
     },
+    '/v2/images/5cc4bebc-db27-11e1-a1eb-080027cbe205/file': {
+        'GET': (
+            {},
+            'A',
+        ),
+    },
+    '/v2/images/66fb18d6-db27-11e1-a1eb-080027cbe205/file': {
+        'GET': (
+            {
+                'content-md5': 'wrong'
+            },
+            'BB',
+        ),
+    },
+    '/v2/images/1b1c6366-dd57-11e1-af0f-02163e68b1d8/file': {
+        'GET': (
+            {
+                'content-md5': 'defb99e69a9f1f6e06f15006b1f166ae'
+            },
+            'CCC',
+        ),
+    }
 }
 
 
@@ -105,3 +128,38 @@ class TestController(unittest.TestCase):
         image = self.controller.get('3a4560a1-e585-443e-9b39-553b46ec92d1')
         self.assertEqual(image.id, '3a4560a1-e585-443e-9b39-553b46ec92d1')
         self.assertEqual(image.name, 'image-1')
+
+    def test_data_without_checksum(self):
+        body = self.controller.data('5cc4bebc-db27-11e1-a1eb-080027cbe205',
+                                    do_checksum=False)
+        body = ''.join([b for b in body])
+        self.assertEqual(body, 'A')
+
+        body = self.controller.data('5cc4bebc-db27-11e1-a1eb-080027cbe205')
+        body = ''.join([b for b in body])
+        self.assertEqual(body, 'A')
+
+    def test_data_with_wrong_checksum(self):
+        body = self.controller.data('66fb18d6-db27-11e1-a1eb-080027cbe205',
+                                    do_checksum=False)
+        body = ''.join([b for b in body])
+        self.assertEqual(body, 'BB')
+
+        body = self.controller.data('66fb18d6-db27-11e1-a1eb-080027cbe205')
+        try:
+            body = ''.join([b for b in body])
+            self.fail('data did not raise an error.')
+        except IOError, e:
+            self.assertEqual(errno.EPIPE, e.errno)
+            msg = 'was 9d3d9048db16a7eee539e93e3618cbe7 expected wrong'
+            self.assertTrue(msg in str(e))
+
+    def test_data_with_checksum(self):
+        body = self.controller.data('1b1c6366-dd57-11e1-af0f-02163e68b1d8',
+                                    do_checksum=False)
+        body = ''.join([b for b in body])
+        self.assertEqual(body, 'CCC')
+
+        body = self.controller.data('1b1c6366-dd57-11e1-af0f-02163e68b1d8')
+        body = ''.join([b for b in body])
+        self.assertEqual(body, 'CCC')