[FEATURE] Add keep_versions to remove older versions after set threshold

out

@@ -1,4 +1,5 @@
 #!/usr/bin/env python3
+#pylint: disable=invalid-name
 '''
 aptly-resource out
 
@@ -14,9 +15,11 @@ import json
 import sys
 import os
 import hashlib
+import functools
 from pprint import pprint
 from aptly_api import Client
 from aptly_api.base import AptlyAPIException
+import semver
 
 BLOCK_SIZE = 65536
 
@@ -83,6 +86,41 @@ aptly.publish.update(
     force_overwrite = True
     )
 
+if 'keep_versions' in config['source'] \
+    and config['source']['keep_versions'] > 0:
+    packages_delete = aptly.repos.search_packages(
+        'datentonne',
+        config['source']['package'] + ' (<= ' + archive_filename_parts[1] + ')'
+        )
+
+    versions_delete = []
+    for package in packages_delete:
+        package_data = package.key.split(' ')
+        versions_delete.append({
+            'version': package_data[2],
+            'key':     package.key,
+            })
+
+    def compare_func(a, b):
+        return semver.compare(a['version'], b['version'])
+
+    versions_delete.sort(key=functools.cmp_to_key(compare_func))
+    versions_delete.reverse()
+
+    for i, package in enumerate(versions_delete):
+        if i >= config['source']['keep_versions']:
+            aptly.repos.delete_packages_by_key(
+                config['source']['repo'],
+                package['key'],
+                )
+
+    aptly.publish.update(
+        prefix          = config['source']['repo'],
+        distribution    = config['source']['distribution'],
+        force_overwrite = True
+        )
+
+
 print(json.dumps({
     'version': {'version': archive_filename_parts[1]},
     'metadata': [