From f11bea36ec9df8d34e4edc07398cb6df6fccaca1 Mon Sep 17 00:00:00 2001
From: Thomas Oettli <spacefreak@noop.ch>
Date: Tue, 3 Nov 2020 15:11:29 +0100
Subject: [PATCH] change README.md, warn on empty dest path

---
 README.md     | 42 +++++++++++++++++++++++++-----------------
 pyinotifyd.py |  5 ++++-
 2 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/README.md b/README.md
index bcb7c92..2f70070 100644
--- a/README.md
+++ b/README.md
@@ -13,13 +13,15 @@ pip install pyinotifyd
 The config file **/etc/pyinotifyd/config.py** is written in Python syntax. pyinotifyd reads and executes its content, that means you can add your custom Python code to the config file.
 
 ## Tasks
-Tasks are Python methods that are called in case an event occurs. 
-This is a very simple example task that just logs the task_id and the event:
+Tasks are Python methods that are called in case an event occurs. They can be bound directly to an event type in an event map. Although this is the easiest and quickest way, it is usually better to use a scheduler to schedule the task execution.
+
+### Simple
+This is a very basic example task that just logs each event and task_id:
 ```python
-async def custom_task(event, task_id):
+async def task(event, task_id):
     logging.info(f"{task_id}: execute example task: {event}")
 ```
-This task can be directly bound to an event in an event map. Although this is the easiest and quickest way, it is usually better to use a scheduler to schedule the task execution.
+### FileManager
 
 ## Schedulers
 pyinotifyd has different schedulers to schedule tasks with an optional delay. The advantages of using a scheduler are consistent logging and the possibility to cancel delayed tasks. Furthermore, schedulers have the ability to differentiate between files and directories.
@@ -28,7 +30,7 @@ pyinotifyd has different schedulers to schedule tasks with an optional delay. Th
 TaskScheduler to schedule *task* with an optional *delay* in seconds. Use the *files* and *dirs* arguments to schedule tasks only for files and/or directories. 
 The *logname* argument is used to set a custom name for log messages. All arguments except for *task* are optional.
 ```python
-s = TaskScheduler(task=custom_task, files=True, dirs=False, delay=0, logname="TaskScheduler")
+s = TaskScheduler(task=task, files=True, dirs=False, delay=0, logname="TaskScheduler")
 ```
 TaskScheduler provides two tasks which can be bound to an event in an event map.
 * **s.schedule** 
@@ -65,12 +67,12 @@ pyinotifyd_config = PyinotifydConfig(watches=[watch], loglevel=logging.INFO, shu
 
 ## Schedule Python task for all events
 ```python
-async def custom_task(event, task_id):
+async def task(event, task_id):
     logging.info(f"{task_id}: execute example task: {event}")
 
-s = TaskScheduler(task=custom_task, files=True, dirs=True)
+s = TaskScheduler(task=task, files=True, dirs=True)
 
-event_map = EventMap(default_task=custom_task)
+event_map = EventMap(default_task=task)
 watch = Watch(path="/tmp", event_map=event_map, rec=True, auto_add=True)
 
 pyinotifyd_config = PyinotifydConfig(
@@ -92,15 +94,21 @@ pyinotifyd_config = PyinotifydConfig(
 
 ## Move, copy or delete newly created files after a delay
 ```python
-rules = [{"action": "move",
-          "src_re": "^/src_path/(?P<path>.*)\.to_move$",
-          "dst_re": "/dst_path/\g<path"},
-         {"action": "copy",
-          "src_re": "^/src_path/(?P<path>.*)\.to_copy$",
-          "dst_re": "/dst_path/\g<path"},
-         {"action": "delete",
-          "src_re": "^/src_path/(?P<path>.*)\.to_delete$"}]
-fm = FileManager(rules=rules, auto_create=True)
+move_rule = Rule(action="move",
+    src_re="^/src_path/(?P<path>.*)\.to_move$",
+    dst_re="/dst_path/\g<path>",
+    auto_create=True)
+
+copy_rule = Rule(action="copy",
+    src_re="^/src_path/(?P<path>.*)\.to_copy$",
+    dst_re="/dst_path/\g<path>",
+    auto_create=True)
+
+delete_rule = Rule(action="delete",
+    src_re="^/src_path/(?P<path>.*)\.to_delete$",
+    rec=False)
+
+fm = FileManager(rules=[move_rule, copy_rule, delete_rule])
 
 s = TaskScheduler(task=fm.task, delay=30, files=True, dirs=False)
 
diff --git a/pyinotifyd.py b/pyinotifyd.py
index 84f35ea..da90233 100755
--- a/pyinotifyd.py
+++ b/pyinotifyd.py
@@ -249,7 +249,6 @@ class Rule:
 
     def __init__(self, action, src_re, dst_re="", auto_create=False,
             rec=False):
-
         assert action in self.valid_actions, \
             f"action: expected [{Rule.valid_actions.join(', ')}], got{action}"
         self.action = action
@@ -292,6 +291,10 @@ class FileManager:
             try:
                 if rule.action in ["copy", "move"]:
                     dest = src_re.sub(rule.dst_re, path)
+                    if not dest:
+                        raise RuntimeError(
+                            f"unable to {rule.action} '{path}', "
+                            f"resulting destination path is empty")
                     dest_dir = os.path.dirname(dest)
                     if not os.path.isdir(dest_dir) and rule.auto_create:
                         self._log.info(