Add option to skip prerelease versions.

Replace release sorting by tag with release sorting by creation date.

Author: BrOleg5

README.rst

@@ -125,10 +125,11 @@ CLI Help output::
                             keychain that holds the personal access or OAuth token
       --releases            include release information, not including assets or
                             binaries
-      --assets              include assets alongside release information; only
-                            applies if including releases
       --latest-releases INCLUDE_LATEST_RELEASES
-                            include certain number of the latest releases; only
+                            include certain number of the latest releases;
+                            only applies if including releases
+      --skip-prerelease     skip prerelease and draft versions; only applies if including releases
+      --assets              include assets alongside release information; only
                             applies if including releases
       --exclude [REPOSITORY [REPOSITORY ...]]
                             names of repositories to exclude from backup.

github_backup/github_backup.py

@@ -23,7 +23,7 @@
 from urllib.parse import quote as urlquote
 from urllib.parse import urlencode, urlparse
 from urllib.request import HTTPRedirectHandler, Request, build_opener, urlopen
-from operator import itemgetter
+from datetime import datetime
 
 try:
     from . import __version__
@@ -377,19 +377,25 @@ def parse_args(args=None):
         dest="include_releases",
         help="include release information, not including assets or binaries",
     )
-    parser.add_argument(
-        "--assets",
-        action="store_true",
-        dest="include_assets",
-        help="include assets alongside release information; only applies if including releases",
-    )
     parser.add_argument(
         "--latest-releases",
         type=int,
         default=0,
         dest="include_latest_releases",
         help="include certain number of the latest releases; only applies if including releases",
     )
+    parser.add_argument(
+        "--skip-prerelease",
+        action="store_true",
+        dest="skip_prerelease",
+        help="skip prerelease and draft versions; only applies if including releases",
+    )
+    parser.add_argument(
+        "--assets",
+        action="store_true",
+        dest="include_assets",
+        help="include assets alongside release information; only applies if including releases",
+    )
     parser.add_argument(
         "--throttle-limit",
         dest="throttle_limit",
@@ -1214,8 +1220,12 @@ def backup_releases(args, repo_cwd, repository, repos_template, include_assets=F
     release_template = "{0}/{1}/releases".format(repos_template, repository_fullname)
     releases = retrieve_data(args, release_template, query_args=query_args)
 
+    if args.skip_prerelease:
+        releases = [r for r in releases if r["prerelease"] == False and r["draft"] == False]
+
     if args.include_latest_releases and args.include_latest_releases < len(releases):
-        releases = sorted(releases, key=itemgetter('tag_name'), reverse=True)
+        releases.sort(key=lambda item: datetime.strptime(item["created_at"], "%Y-%m-%dT%H:%M:%SZ"), \
+                      reverse=True)
         releases = releases[:args.include_latest_releases]
         logger.info("Saving the latest {0} releases to disk".format(len(releases)))
     else: