Add ability to INCLUDE specific cameras instead of EXCLUDE (#179)

Co-authored-by: Sebastian Goscik <sebastian.goscik@live.co.uk>

unifi_protect_backup/cli.py

@@ -1,5 +1,6 @@
 """Console script for unifi_protect_backup."""
 
+import sys
 import re
 
 import click
@@ -108,6 +109,16 @@ def parse_rclone_retention(ctx, param, retention) -> relativedelta:
     "Alternatively, use a Unifi user with a role which has access restricted to the subset of cameras "
     "that you wish to backup.",
 )
+@click.option(
+    "--camera",
+    "cameras",
+    multiple=True,
+    envvar="ONLY_CAMERAS",
+    help="IDs of *ONLY* cameras for which events should be backed up. Use multiple times to include "
+    "multiple IDs. If being set as an environment variable the IDs should be separated by whitespace. "
+    "Alternatively, use a Unifi user with a role which has access restricted to the subset of cameras "
+    "that you wish to backup.",
+)
 @click.option(
     "--file-structure-format",
     envvar="FILE_STRUCTURE_FORMAT",
@@ -228,8 +239,25 @@ a lot of failed downloads with the default downloader.
 )
 def main(**kwargs):
     """A Python based tool for backing up Unifi Protect event clips as they occur."""
-    event_listener = UnifiProtectBackup(**kwargs)
-    run(event_listener.start(), stop_on_unhandled_errors=True)
+
+    try:
+        # Validate only one of the camera select arguments was given
+        if kwargs.get("cameras") and kwargs.get("ignore_cameras"):
+            click.echo(
+                "Error: --camera and --ignore-camera options are mutually exclusive. "
+                "Please use only one of these options.",
+                err=True,
+            )
+            raise SystemExit(200)  # throw 200 = arg error, service will not be restarted (docker)
+
+        # Only create the event listener and run if validation passes
+        event_listener = UnifiProtectBackup(**kwargs)
+        run(event_listener.start(), stop_on_unhandled_errors=True)
+    except SystemExit as e:
+        sys.exit(e.code)
+    except Exception as e:
+        click.echo(f"Error: {str(e)}", err=True)
+        sys.exit(1)
 
 
 if __name__ == "__main__":