Previously compute_id was typed as str, so 'local' would pass MCP validation
and reach the controller API where it crashed. Now uuid.UUID type ensures
Pydantic rejects any non-UUID string before the handler runs.
The end /v3/computes/{compute_id} expects the compute_id to be a
valid UUID. Previously the MCP tool defaulted to the string 'local',
which caused a ValueError in the database layer. Now compute_id is
required and callers must use compute_list first to resolve names to UUIDs.
- Move node file operations (list_files, delete_file) from Gns3Connector to Node class
- Add link capture/reset operations (reset, start_capture, stop_capture) to Link class
- Convert all MCP handlers to use conn.http_call() directly instead of
Gns3Connector/Node/Link abstraction methods
- Register 4 new MCP tools: reset_link, start_capture, stop_capture,
download_capture_file
- Add list_node_files, get_node_file, write_node_file, delete_node_file methods to Gns3Connector
- Add MCP handlers with offset/limit line-based reading for get_node_file
- Auto-truncate files >50KB with truncated flag in response
- Rich metadata returned (total_lines, total_bytes, has_more, etc.)
- Tool docstrings guide AI to check file sizes before reading chunked
Rootful Docker recreates volume mount points as root on start,
preventing the GNS3 process from writing files into node directories
while the container is running. self._fix_permissions() would resolve
this but is currently only called at container stop time.
- _fix_permissions: capture stderr, check returncode, only set
_permissions_fixed on success instead of silently marking as fixed
- list_node_files: wrap os.scandir in try-except to handle
PermissionError gracefully
Create async_iterable_to_stream() in gns3server.utils.asyncio that
converts an async iterable to an aiohttp StreamReader via a background
feeder task. This bypasses aiohttp's AsyncIterablePayload which can
cause 'Connection reset by peer' with certain HTTP servers.
Use it in _run_http_query for the __aiter__ data path.
Both is_safe_path rejection and PermissionError were returning 403
without a detail message, making them indistinguishable in logs.
Add specific detail strings to each:
- is_safe_path: 'Path is outside the project directory'
- PermissionError (write): 'Permission denied writing to ...'
- PermissionError (delete): 'Permission denied deleting ...'
The inner try-except caught OSError/UnicodeEncodeError with 'pass',
silently swallowing all write failures and returning HTTP 204 as if
the file was written successfully.
Remove the nested try-except and let errors propagate properly:
- OSError → 500 with error detail
- PermissionError → 403 (already handled)
- FileNotFoundError → 404 (already handled)
- Stream file GET/POST through controller without buffering in memory
- Add recursive and subdirectory filtering to node file listing
- Replace file extension with magic-based file type detection
- Add DELETE endpoint for node and project files
- Include directories in listing response
- Add params and stream support to http_query
- Fix lambda closures, streamer exception scope, and delete error codes
Only description strings changed to tell AI the content is Markdown
format (.md). The actual handler still reads/writes README.txt for
Web UI compatibility.
Updated the actual MCP tool definitions in __init__.py with detailed
filter parameter descriptions. The previous update to links.py was incorrect
because MCP tools are defined via @mcp.tool() decorators in __init__.py.
Changes:
- Updated update_link tool docstring with comprehensive filter information
- Updated create_link tool filters parameter description
- Added all 5 filter types with proper array format requirements
- Added parameter ranges and usage examples
Filters now properly documented:
- frequency_drop: [N] (N: -1 to 32767)
- packet_loss: [rate] (rate: 0 to 100)
- delay: [ms, jitter] (milliseconds)
- corrupt: [rate] (rate: 0 to 100)
- bpf: [expression] (BPF syntax)
This will prevent TypeError: 'int' object is not iterable errors and
help users understand the correct filter format.
Updated the filters parameter description in create_link and update_link
MCP tools to specify the required array format and provide examples.
Changes:
- Updated create_link filters description with array format requirements
- Updated update_link filters description with array format and example
- Added specific filter types: frequency_drop, packet_loss, delay, corrupt, bpf
This helps users understand the correct format:
- frequency_drop: [N] (drop every Nth packet)
- packet_loss: [rate] (packet loss percentage)
- delay: [ms, jitter] (latency and jitter in milliseconds)
- corrupt: [rate] (packet corruption percentage)
- bpf: [expression] (Berkeley Packet Filter)
Prevents TypeError: 'int' object is not iterable errors.
Extended the kwargs parameter handling fix to nodes and links MCP tools,
which had the same nested kwargs structure issue as templates.
Changes:
- Modified update_node_handler to extract params from nested kwargs
- Modified update_link_handler to extract params from nested kwargs
This ensures that node and link updates through MCP tools work correctly,
allowing proper modification of node and link properties.
Fixed an issue where MCP template tools (update_template, create_template)
were not correctly handling nested kwargs parameter structure from MCP clients.
The problem occurred when MCP clients passed parameters in the format:
{'template_id': 'xxx', 'kwargs': {'adapters': 3}}
The original code was passing the entire kwargs dictionary as a parameter,
instead of extracting the actual update parameters from within it.
Changes:
- Modified update_template_handler to extract params from nested kwargs
- Modified create_template_handler to handle the same issue
This fix ensures that template updates through MCP tools now work correctly,
allowing proper modification of template properties like adapters count.
Replace the global variable + lock + polling mechanism with asyncio.Event
pattern for MCP server ready state tracking.
Benefits:
- Eliminates race conditions (Event.set() is thread-safe)
- Event-driven notification instead of polling (no 50x sleep overhead)
- Fixes test contamination from global state
- Reduces code from 54 lines to 30 lines
- Uses standard asyncio primitive for this pattern
YueGuobin
grossmj
Guobin Yue
Cristi