Added management command to update course images

This command downloads images from the course's card_image_url field
value, and stores them in the image field.

LEARNER-2463

course_discovery/apps/course_metadata/management/commands/download_course_images.py

+import logging
+
+import requests
+from django.core.files.base import ContentFile
+from django.core.management import BaseCommand
+
+from course_discovery.apps.course_metadata.models import Course
+
+logger = logging.getLogger(__name__)
+
+IMAGE_TYPES = {
+    'image/jpeg': 'jpg',
+    'image/png': 'png',
+}
+
+
+class Command(BaseCommand):
+    help = 'Download course images to this server. This is intended to migrate image data from the edx.org ' \
+           'marketing site to Discovery.'
+
+    def add_arguments(self, parser):
+        super().add_arguments(parser)
+        parser.add_argument(
+            '--overwrite',
+            action='store_true',
+            dest='overwrite_existing',
+            help='Overwrite existing image content'
+        )
+
+    def handle(self, *args, **options):
+        courses = Course.objects.filter(card_image_url__isnull=False).exclude(card_image_url='').order_by('key')
+
+        if not options['overwrite_existing']:
+            courses = courses.filter(image='')
+
+        count = courses.count()
+        if count < 1:
+            logger.info('All courses are up to date.')
+            return
+
+        logger.info('Retrieving images for [%d] courses...', count)
+
+        for course in courses:
+            logger.info('Retrieving image for course [%s] from [%s]...', course.key, course.card_image_url)
+            response = requests.get(course.card_image_url)
+
+            if response.status_code == requests.codes.ok:  # pylint: disable=no-member
+                content_type = response.headers['Content-Type'].lower()
+                extension = IMAGE_TYPES.get(content_type)
+
+                if extension:
+                    filename = '{uuid}.{extension}'.format(uuid=str(course.uuid), extension=extension)
+                    course.image.save(filename, ContentFile(response.content))
+                    logger.info('Image for course [%s] successfully updated.', course.key)
+                else:
+                    # pylint: disable=line-too-long
+                    msg = 'Image retrieved for course [%s] from [%s] has an unknown content type [%s] and will not be saved.'
+                    logger.error(msg, course.key, course.card_image_url, content_type)
+
+            else:
+                msg = 'Failed to download image for course [%s] from [%s]! Response was [%d]:\n%s'
+                logger.error(msg, course.key, course.card_image_url, response.status_code, response.content)

course_discovery/apps/course_metadata/management/commands/tests/test_download_course_images.py

+import mock
+import pytest
+import responses
+from django.core.management import call_command
+
+from course_discovery.apps.course_metadata.tests.factories import CourseFactory
+
+
+@pytest.mark.django_db
+class TestDownloadCourseImages:
+    LOGGER_PATH = 'course_discovery.apps.course_metadata.management.commands.download_course_images.logger'
+
+    def mock_image_response(self, status=200, body=None, content_type='image/jpeg'):
+        # PNG. Single black pixel
+        body = body or b'\x89PNG\r\n\x1a\n\x00\x00\x00\rIHDR\x00\x00\x00\x01\x00\x00\x00\x01\x08\x02\x00\x00\x00' \
+                       b'\x90wS\xde\x00\x00\x00\x0cIDATx\x9cc```\x00\x00\x00\x04\x00\x01\xf6\x178U\x00\x00\x00\x00' \
+                       b'IEND\xaeB`\x82'
+        image_url = 'https://example.com/image.jpg'
+        responses.add(
+            responses.GET,
+            image_url,
+            body=body,
+            status=status,
+            content_type=content_type
+        )
+        return image_url, body
+
+    @responses.activate
+    def test_download(self):
+        image_url, image_content = self.mock_image_response()
+        course = CourseFactory(card_image_url=image_url, image=None)
+
+        call_command('download_course_images')
+
+        assert len(responses.calls) == 1
+
+        course.refresh_from_db()
+        assert course.image.read() == image_content
+
+    @responses.activate
+    def test_download_with_overwrite_of_existing_data(self):
+        image_url, image_content = self.mock_image_response()
+        course = CourseFactory(card_image_url=image_url)
+        assert course.image.read() != image_content
+
+        call_command('download_course_images', '--overwrite')
+
+        assert len(responses.calls) == 1
+
+        course.refresh_from_db()
+        assert course.image.read() == image_content
+
+    @responses.activate
+    def test_download_with_invalid_content_type(self):
+        content_type = 'text/plain'
+        image_url, __ = self.mock_image_response(content_type=content_type)
+        course = CourseFactory(card_image_url=image_url, image=None)
+
+        with mock.patch(self.LOGGER_PATH) as mock_logger:
+            call_command('download_course_images')
+            mock_logger.error.assert_called_with(
+                'Image retrieved for course [%s] from [%s] has an unknown content type [%s] and will not be saved.',
+                course.key,
+                image_url,
+                content_type
+            )
+
+        assert len(responses.calls) == 1
+
+        course.refresh_from_db()
+        assert not bool(course.image)
+
+    @responses.activate
+    def test_download_with_invalid_status_code(self):
+        status = 500
+        body = b'Oops!'
+        image_url, __ = self.mock_image_response(status=status, body=body)
+        course = CourseFactory(card_image_url=image_url, image=None)
+
+        with mock.patch(self.LOGGER_PATH) as mock_logger:
+            call_command('download_course_images')
+            mock_logger.error.assert_called_with(
+                'Failed to download image for course [%s] from [%s]! Response was [%d]:\n%s',
+                course.key,
+                image_url,
+                status,
+                body
+            )
+
+        assert len(responses.calls) == 1
+
+        course.refresh_from_db()
+        assert not bool(course.image)
+
+    def test_download_without_courses(self):
+        with mock.patch(self.LOGGER_PATH) as mock_logger:
+            call_command('download_course_images')
+            mock_logger.info.assert_called_with('All courses are up to date.')

course_discovery/apps/course_metadata/tests/factories.py

@@ -72,6 +72,7 @@ class CourseFactory(factory.DjangoModelFactory):
     prerequisites_raw = FuzzyText()
     syllabus_raw = FuzzyText()
     outcome = FuzzyText()
+    image = factory.django.ImageField()
 
     class Meta:
         model = Course