Add early channel permission check

ricecooker/commands.py

@@ -134,6 +134,19 @@ def uploadchannel(  # noqa: C901
         config.PROGRESS_MANAGER.set_tree(create_initial_tree(channel))
     tree = config.PROGRESS_MANAGER.tree
 
+    # Early permission check: Try creating the channel before downloading/uploading files
+    # This will fail fast if the user lacks edit permissions
+    # Fixes issues #95 and #434 by avoiding wasted downloads/uploads
+    if (
+        config.PROGRESS_MANAGER.get_status_val() <= Status.CREATE_TREE.value
+        and command != "dryrun"
+    ):
+        config.LOGGER.info("Checking channel permissions...")
+        try:
+            tree.root_id, tree.channel_id = tree.add_channel()
+        except Exception:
+            sys.exit(1)
+
     # Download files if they haven't been downloaded already
     if config.PROGRESS_MANAGER.get_status_val() <= Status.DOWNLOAD_FILES.value:
         config.LOGGER.info("")

ricecooker/managers/tree.py

@@ -30,6 +30,8 @@ def __init__(self, channel):
         self.failed_uploads = {}
         self.file_map = {}
         self.all_nodes = []
+        self.root_id = None  # Will be set during early permission check
+        self.channel_id = None  # Will be set during early permission check
 
     def validate(self):
         """validate: checks if tree structure is valid
@@ -269,7 +271,11 @@ def upload_tree(self):
         from datetime import datetime
 
         start_time = datetime.now()
-        root, channel_id = self.add_channel()
+        # Use cached root_id and channel_id if already set (from early permission check)
+        if self.root_id is not None and self.channel_id is not None:
+            root, channel_id = self.root_id, self.channel_id
+        else:
+            root, channel_id = self.add_channel()
         self.node_count_dict = {"upload_count": 0, "total_count": self.channel.count()}
 
         config.LOGGER.info("\tPreparing fields...")