fetch-stage3: Download Gentoo stage3 tarballs using mkvm

fetch-stage3.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+from mkvm import stage3
+import argparse
+import os
+import sys
+
+
+def parse_args():
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        '--arch',
+        help='Architecture to use when fetching a stage3 tarball'
+    )
+    parser.add_argument(
+        '--subtype',
+        help='stage3 subtype/profile (e.g. nomultilib)'
+    )
+    parser.add_argument(
+        '--cache-dir',
+        metavar='PATH',
+        help='Cache location for fetched stage3 tarballs'
+    )
+    return parser.parse_args()
+
+
+def main():
+    args = parse_args()
+
+    try:
+        fetcher = stage3.Fetcher(args.cache_dir)
+        stagetbz = fetcher.fetch_stage(args.arch, args.subtype)
+        fetcher.verify(stagetbz + '.DIGESTS.asc')
+    except KeyboardInterrupt:
+        print('')
+        raise SystemExit(os.EX_TEMPFAIL)
+    except (OSError, stage3.FetchError, stage3.VerifyError) as e:
+        sys.stderr.write('Failed to fetch stage3 tarball: {}\n'.format(e))
+        raise SystemExit(os.EX_UNAVAILABLE)
+
+
+if __name__ == '__main__':
+    main()