add aws secret handling (#161)

* add aws secret handling

* make it look go-ish

* fix tests

* whitespace

* sleep a bit

test/secret/docker-compose.yml

@@ -0,0 +1,89 @@
+# Copyright 2020-2021 - Offen Authors <hioffen@posteo.de>
+# SPDX-License-Identifier: Unlicense
+
+version: '3.8'
+
+services:
+  minio_setup:
+    image: alpine:latest
+    deploy:
+      restart_policy:
+        condition: none
+    volumes:
+      - backup_data:/data
+    command: mkdir -p /data/backup
+    
+  minio:
+    image: minio/minio:RELEASE.2021-12-20T22-07-16Z
+    deploy:
+      restart_policy:
+        condition: on-failure
+    environment:
+      MINIO_ROOT_USER_FILE: /run/secrets/minio_root_user
+      MINIO_ROOT_PASSWORD_FILE: /run/secrets/minio_root_password
+    command: minio server /data
+    volumes:
+      - backup_data:/data
+    secrets:
+      - minio_root_user
+      - minio_root_password
+    depends_on:
+      - minio_setup
+
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    depends_on:
+      - minio
+    deploy:
+      restart_policy:
+        condition: on-failure
+    environment:
+      AWS_ACCESS_KEY_ID_FILE: /run/secrets/minio_root_user
+      AWS_SECRET_ACCESS_KEY_FILE: /run/secrets/minio_root_password
+      AWS_ENDPOINT: minio:9000
+      AWS_ENDPOINT_PROTO: http
+      AWS_S3_BUCKET_NAME: backup
+      BACKUP_FILENAME: test.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      BACKUP_RETENTION_DAYS: 7
+      BACKUP_PRUNING_LEEWAY: 5s
+    volumes:
+      - pg_data:/backup/pg_data:ro
+      - /var/run/docker.sock:/var/run/docker.sock
+    secrets:
+      - minio_root_user
+      - minio_root_password
+
+  offen:
+    image: offen/offen:latest
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    healthcheck:
+      disable: true
+    deploy:
+      replicas: 2
+      restart_policy:
+        condition: on-failure
+
+  pg:
+    image: postgres:14-alpine
+    environment:
+      POSTGRES_PASSWORD: example
+    labels:
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - pg_data:/var/lib/postgresql/data
+    deploy:
+      restart_policy:
+        condition: on-failure
+
+volumes:
+  backup_data:
+    name: backup_data
+  pg_data:
+
+secrets:
+  minio_root_user:
+    external: true
+  minio_root_password:
+    external: true