Merge lp:~ltrager/maas-images/limit_imports into lp:maas-images

[Lee Trager]

Allow limiting the number of CentOS images imported

Previously all CentOS images found were imported. If the image already existed in the stream it was skipped. This meant if you wanted to test building a CentOS image you had to build all images ever published. This limits the images imported to only the latest.

[lp:~ltrager/maas-images/limit_imports]

355. By Lee Trager on 2017-02-13

Limit the number of CentOS images imported

=== modified file 'meph2/commands/mimport.py'
--- meph2/commands/mimport.py	2017-02-11 01:29:31 +0000
+++ meph2/commands/mimport.py	2017-02-13 21:27:33 +0000
@@ -36,7 +36,7 @@
         product_id = cfgdata['product_id'].format(
             version=release_info['version'], arch=arch)
         url = cfgdata['sha256_meta_data_path'].format(version=path_version)
-        images = get_sha256_meta_images(url)
+        images = get_sha256_meta_images(url, args.max)
         base_url = os.path.dirname(url)
 
         if product_tree['products'].get(product_id) is None:
@@ -173,7 +173,7 @@
         }
 
 
-def get_sha256_meta_images(url):
+def get_sha256_meta_images(url, max_items=0):
     """ Given a URL to a SHA256SUM file return a dictionary of filenames and
         SHA256 checksums keyed off the file version found as a date string in
         the filename. This is used in cases where simplestream data isn't
@@ -214,7 +214,13 @@
             'img_name': img_name,
             'sha256': sha256,
             }
-    return ret
+    if max_items == 0:
+        return ret
+    else:
+        return {
+            key: ret[key]
+            for key in sorted(ret.keys(), reverse=True)[:max_items]
+        }
 
 
 def import_qcow2(url, expected_sha256, out, curtin_files=None, packages=None):
@@ -297,6 +303,11 @@
     for (args, kwargs) in COMMON_ARGS:
         parser.add_argument(*args, **kwargs)
 
+    parser.add_argument('--max', type=int, default=1,
+                        help=(
+                            'Import at most MAX CentOS images in the target, '
+                            '0 for no limit, defaults to 1.'))
+
     for (args, kwargs) in subc['opts']:
         if isinstance(args, str):
             args = [args]