Question
Answer and Explanation
Debugging Python with Proxychains in VSCode can be tricky because of how Proxychains operates and how VSCode handles debugging. Here's why you might encounter issues:
1. Proxychains Mechanism: Proxychains primarily works by hooking system-level network calls of an application. However, the way VSCode communicates with its Python debug adapter is more complex; it's often through inter-process communication rather than direct network connections. Proxychains is designed to intercept network calls but will not generally intercept these.
2. VSCode's Debug Adapter: VSCode's Python debugger relies on a debug adapter process (`debugpy`). The connection between the VSCode front-end and the debug adapter process is done by localhost socket connections. Proxychains isn’t designed to proxy these sorts of localhost socket connections.
3. Process Tree: VSCode might spawn several processes or subprocesses (like the Python interpreter itself, and potentially other spawned helpers by your Python script). It is hard for Proxychains to guarantee all the connections will go through the proxy; it may affect how sub-processes resolve their addresses. Proxychains only impacts the launched process network operations.
4. Debugger’s Internal Communication: Debuggers frequently set up sockets between themselves and the process they're debugging on the localhost; Proxychains is designed to change external connections to another network. Usually, Proxychains does not re-route connections in a similar way that proxy programs such as Squid do, meaning that debugging may just bypass the proxy.
5. OS Limitations: How Proxychains does its job heavily relies on specific operating system mechanisms which often require special permissions to function correctly, while Python interpreters or debuggers may not. Issues can occur where a debugger running on a different platform/with different system permissions may behave differently to normal applications that utilize system resources for their network functions.
6. Python Interpreter Version Proxychains may have different outcomes with different python versions or debuggers
Potential Workarounds (But often unreliable):
- You may try wrapping `code` to run via `proxychains code --proxy-server
Better Solutions:
- Instead of using Proxychains with VSCode’s debugger for specific situations, it may be more convenient to launch your target server or program via proxy settings within Python, through something like requests, for when using libraries that rely on network functionality.
- For remote debugging where a server is available only via a proxy, you should debug directly on that server, rather than try to use `proxychains` locally
- Utilize VSCode’s configuration where proxy settings or proxy configuration can be set on project level or for workspace using .vscode/settings.json with specific settings "http.proxy" "https.proxy" variables. These settings can be checked by accessing settings, which you can do via keyboard shortcuts of either Ctrl+, or Cmd+,.
Debugging Process Explanation:
When VSCode’s debugging process is initiated a debugging instance is created in another thread in parallel with running instance. The program executes with debugger support, and will establish a TCP socket (by default on the localhost). When breakpoints or an error occurs in execution process pauses. You interact with the execution process in VSCode as a proxy, sending commands and evaluating responses on paused instance via TCP connections to local or localhost instance.
In Summary, you would face a number of limitations attempting to use proxychains, rather using more specific solutions via environment, python script modifications and vscode settings will usually yield more robust result in resolving issues for debugging Python applications with restricted access due to firewall/proxy setup issues