Bump metadata version to 2.0, add support for tzdata mirrors.

1 files changed, 24 insertions, 4 deletions

diff --git a/updatezinfo.py b/updatezinfo.py
index 591118e..e767366 100644
--- a/updatezinfo.py
+++ b/updatezinfo.py
@@ -5,6 +5,7 @@ import json
 import io
 
 from six.moves.urllib import request
+from six.moves.urllib import error as urllib_error
 
 from dateutil.zoneinfo import rebuild
 
@@ -15,11 +16,30 @@ def main():
     with io.open(METADATA_FILE, 'r') as f:
         metadata = json.load(f)
 
+    releases_urls = metadata['releases_url']
+    if metadata['metadata_version'] < 2.0:
+        # In later versions the releases URL is a mirror URL
+        releases_urls = [releases_urls]
+
     if not os.path.isfile(metadata['tzdata_file']):
-        print("Downloading tz file from iana")
-        request.urlretrieve(os.path.join(metadata['releases_url'],
-                                         metadata['tzdata_file']),
-                            metadata['tzdata_file'])
+
+        for ii, releases_url in enumerate(releases_urls):
+            print("Downloading tz file from mirror {ii}".format(ii=ii))
+            try:
+                request.urlretrieve(os.path.join(releases_url,
+                                                 metadata['tzdata_file']),
+                                    metadata['tzdata_file'])
+            except urllib_error.URLError as e:
+                print("Download failed, trying next mirror.")
+                last_error = e
+                continue
+
+            last_error = None
+            break
+
+        if last_error is not None:
+            raise last_error
+
     with open(metadata['tzdata_file'], 'rb') as tzfile:
         sha_hasher = hashlib.sha512()
         sha_hasher.update(tzfile.read())