From 24d998f0b69db87df4a622091c7fd3765bd580ff Mon Sep 17 00:00:00 2001
From: Cian Hatton <cianhatton@gmail.com>
Date: Sat, 3 Sep 2022 16:57:07 +0100
Subject: [PATCH] Switch to filter plugin instead of python script (#14)

---
 plugins/filter/filters.py                     | 15 +++++++++++++
 .../files/determine-s3-keys-to-delete.py      | 21 -------------------
 .../scripts/determine-s3-keys-to-delete.py    | 21 -------------------
 roles/docker_s3_backup/tasks/main.yml         | 13 ++++--------
 tests/ansible.cfg                             |  1 +
 5 files changed, 20 insertions(+), 51 deletions(-)
 create mode 100644 plugins/filter/filters.py
 delete mode 100644 roles/docker_s3_backup/files/determine-s3-keys-to-delete.py
 delete mode 100644 roles/docker_s3_backup/files/scripts/determine-s3-keys-to-delete.py

diff --git a/plugins/filter/filters.py b/plugins/filter/filters.py
new file mode 100644
index 0000000..d58572e
--- /dev/null
+++ b/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
diff --git a/roles/docker_s3_backup/files/determine-s3-keys-to-delete.py b/roles/docker_s3_backup/files/determine-s3-keys-to-delete.py
deleted file mode 100644
index 44435b0..0000000
--- a/roles/docker_s3_backup/files/determine-s3-keys-to-delete.py
+++ /dev/null
@@ -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()
diff --git a/roles/docker_s3_backup/files/scripts/determine-s3-keys-to-delete.py b/roles/docker_s3_backup/files/scripts/determine-s3-keys-to-delete.py
deleted file mode 100644
index 44435b0..0000000
--- a/roles/docker_s3_backup/files/scripts/determine-s3-keys-to-delete.py
+++ /dev/null
@@ -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()
diff --git a/roles/docker_s3_backup/tasks/main.yml b/roles/docker_s3_backup/tasks/main.yml
index 41cd190..68372e7 100644
--- a/roles/docker_s3_backup/tasks/main.yml
+++ b/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 }}"
diff --git a/tests/ansible.cfg b/tests/ansible.cfg
index a99d3fe..9acce73 100644
--- a/tests/ansible.cfg
+++ b/tests/ansible.cfg
@@ -1,3 +1,4 @@
 [defaults]
 roles_path = roles
 vault_password_file=tests/vault_key.sh
+filter_plugins = plugins/filter