Switch to filter plugin instead of python script (#14)

plugins/filter/filters.py

@@ -0,0 +1,15 @@
+#!/usr/bin/python
+class FilterModule(object):
+    def filters(self):
+        return {
+            'keep_last': self._keep_last,
+        }
+
+    """
+    _keep_last keeps the last n items of a list of lists
+    """
+    def _keep_last(self, list_of_lists, num_to_keep):
+        lists_to_return = []
+        for list_items in list_of_lists:
+            lists_to_return.append(list_items[0:-num_to_keep])
+        return lists_to_return

roles/docker_s3_backup/files/determine-s3-keys-to-delete.py

@@ -1,21 +0,0 @@
-#!/usr/bin/python
-import os
-
-
-def main():
-    s3_result = eval(os.getenv("S3_RESULTS"))
-    num_backups_to_keep = int(os.getenv("NUM_BACKUPS_TO_KEEP"))
-
-    items_to_delete = []
-    for res in s3_result:
-        s3_keys = res["s3_keys"]
-        # fetch all of the backups before the desired number.
-        # these are the ones we want to delete.
-        items_to_delete.extend(s3_keys[0:-num_backups_to_keep])
-
-    for item in items_to_delete:
-        print(item)
-
-
-if __name__ == "__main__":
-    main()

roles/docker_s3_backup/files/scripts/determine-s3-keys-to-delete.py

@@ -1,21 +0,0 @@
-#!/usr/bin/python
-import os
-
-
-def main():
-    s3_result = eval(os.getenv("S3_RESULTS"))
-    num_backups_to_keep = int(os.getenv("NUM_BACKUPS_TO_KEEP"))
-
-    items_to_delete = []
-    for res in s3_result:
-        s3_keys = res["s3_keys"]
-        # fetch all of the backups before the desired number.
-        # these are the ones we want to delete.
-        items_to_delete.extend(s3_keys[0:-num_backups_to_keep])
-
-    for item in items_to_delete:
-        print(item)
-
-
-if __name__ == "__main__":
-    main()

roles/docker_s3_backup/tasks/main.yml

@@ -69,14 +69,9 @@
   register: s3_list_outputs
   with_items: "{{ volume_mounts }}"
 
-# TODO: do this in a more native way rather than a python script reading env vars.
-- name: Determine which backups should be deleted.
-  ansible.builtin.script: determine-s3-keys-to-delete.py
-  environment:
-    S3_RESULTS: "{{ s3_list_outputs.results }}"
-    NUM_BACKUPS_TO_KEEP: "{{ docker_backup_retain_count }}"
-  register: python_output
-  changed_when: false
+- name: Find keys to delete.
+  ansible.builtin.set_fact:
+    s3_keys_to_delete: "{{ s3_list_outputs.results | map(attribute='s3_keys') | keep_last(docker_backup_retain_count) | flatten }}"
 
 - name: Delete old backups.
   amazon.aws.aws_s3:
@@ -87,4 +82,4 @@
     s3_url: "{{ docker_backup_aws_s3_url }}"
     object: "{{ item }}"
     mode: delobj
-  with_items: "{{ python_output.stdout_lines }}"
+  with_items: "{{ s3_keys_to_delete }}"

tests/ansible.cfg

@@ -1,3 +1,4 @@
 [defaults]
 roles_path = roles
 vault_password_file=tests/vault_key.sh
+filter_plugins = plugins/filter