move downloader into its own class

Signed-off-by: Doug Hellmann <doug@doughellmann.com>

aerostat/app.py

@@ -37,13 +37,15 @@ def main():
 
     cloud_config = config.get_one_cloud(options=parsed_options)
     cloud = shade.OpenStackCloud(cloud_config=cloud_config)
-    res = resolver.Resolver(cloud)
+    downloader = download.Downloader('.', cloud)
+    res = resolver.Resolver(cloud, downloader)
 
     tasks = []
 
     # for server in cloud.list_servers():
     #     tasks.extend(res.server(server))
     tasks.extend(res.server(cloud.get_server('dev1')))
+    tasks.extend(res.image(cloud.get_image('testvol1-img1')))
 
     playbook = [
         {'hosts': 'localhost',
@@ -54,10 +56,13 @@ def main():
 
     print(yaml.dump(playbook, default_flow_style=False, explicit_start=True))
 
-    print('downloading snapshot')
-    image = cloud.get_image('dev1-sn1')
-    with download.ProgressBarDownloader('dev1-sn1.dat', image.size) as out:
-        cloud.download_image('dev1-sn1', output_file=out)
+    downloader.start()
+
+    # print('downloading volume snapshot')
+    # snapshot = cloud.get_volume_snapshot('testvol1-sn1')
+    # pprint.pprint(snapshot)
+    # # with download.ProgressBarDownloader('testvol1-sn1.dat', snapshot.size) as out:
+    # #     cloud.download_image('dev1-sn1', output_file=out)
 
     # for volume in dev1.volumes:
     #     vol = cloud.get_volume(volume.id)

aerostat/download.py

@@ -15,6 +15,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import os.path
+
 import progressbar
 
 
@@ -31,6 +33,7 @@ class ProgressBarDownloader:
         self.bar = progressbar.ProgressBar(
             widgets=[
                 progressbar.Percentage(),
+                ' ',
                 progressbar.Bar(),
                 progressbar.FileTransferSpeed(),
                 ' ',
@@ -51,3 +54,34 @@ class ProgressBarDownloader:
             self.fd.write(block)
             self.amt_read += len(block)
             self.bar.update(self.amt_read)
+
+
+class Downloader:
+
+    def __init__(self, output_dir, cloud):
+        self.output_dir = output_dir
+        self.cloud = cloud
+        self._tasks = []
+
+    def _add(self, resource_type, resource, output_path):
+        self._tasks.append((resource_type, resource, output_path))
+
+    def add_image(self, image):
+        base = image.name + '.dat'
+        output_path = os.path.join(self.output_dir, base)
+        self._add('image', image, output_path)
+        return base
+
+    def start(self):
+        # FIXME(dhellmann): start downloads in a separate thread or process
+        for resource_type, resource, output_path in self._tasks:
+            if os.path.exists(output_path):
+                print('output file {} already exists, skipping download'.format(output_path))
+                continue
+            if resource_type == 'image':
+                print('downloading image {} to {}'.format(
+                    resource.name,
+                    output_path,
+                ))
+                with ProgressBarDownloader(output_path, resource.size) as out:
+                    self.cloud.download_image(resource.name, output_file=out)

aerostat/resolver.py

@@ -20,9 +20,10 @@ import pprint
 
 class Resolver:
 
-    def __init__(self, cloud):
+    def __init__(self, cloud, downloader):
         self.cloud = cloud
         self._memo = set()
+        self._downloader = downloader
 
     def security_group(self, group):
         if ('security_group', group.id) in self._memo:
@@ -106,3 +107,20 @@ class Resolver:
             'name': 'Creating server {}'.format(server.name),
             'os_server': server_data,
         }
+
+    def image(self, image):
+        filename = self._downloader.add_image(image)
+        image_data = {
+            'name': image.name,
+            'container_format': image.container_format,
+            'disk_format': image.disk_format,
+            'min_disk': image.min_disk,
+            'min_ram': image.min_ram,
+        }
+        # FIXME(dhellmann): handle ramdisk property?
+        if filename:
+            image_data['filename'] = filename
+        yield {
+            'name': 'Creating image {}'.format(image.name),
+            'os_image': image_data,
+        }