debugpy - a debugger for Python
This debugger implements the Debug Adapter Protocol: debugProtocol.json
debugpy CLI Usage
Debugging a script file
To run a script file with debugging enabled, but without waiting for the client to attach (i.e. code starts executing immediately):
-m debugpy --listen localhost:5678 myfile.py
To wait until the client attaches before running your code, use the
-m debugpy --listen localhost:5678 --wait-for-client myfile.py
The hostname passed to
--listen specifies the interface on which the debug adapter will be listening for connections from DAP clients. It can be omitted, with only the port number specified:
-m debugpy --listen 5678 ...
in which case the default interface is 127.0.0.1.
To be able to attach from another machine, make sure that the adapter is listening on a public interface - using
0.0.0.0 will make it listen on all available interfaces:
-m debugpy --listen 0.0.0.0:5678 myfile.py
This should only be done on secure networks, since anyone who can connect to the specified port can then execute arbitrary code within the debugged process.
To pass arguments to the script, just specify them after the filename. This works the same as with Python itself - everything up to the filename is processed by debugpy, but everything after that becomes
sys.argv of the running process.
Debugging a module
To run a module, use the
-m switch instead of filename:
-m debugpy --listen localhost:5678 -m mymodule
Same as with scripts, command line arguments can be passed to the module by specifying them after the module name. All other debugpy switches work identically in this mode; in particular,
--wait-for-client can be used to block execution until the client attaches.
Attaching to a running process by ID
The following command injects the debugger into a process with a given PID that is running Python code. Once the command returns, a debugpy server is running within the process, as if that process was launched via
-m debugpy itself.
-m debugpy --listen localhost:5678 --pid 12345
debugpy Import usage
At the beginning of your script, import debugpy, and call
debugpy.listen() to start the debug adapter, passing a
(host, port) tuple as the first argument.
import debugpy debugpy.listen(("localhost", 5678)) ...
As with the
--listen command line switch, hostname can be omitted, and defaults to
Waiting for the client to attach
debugpy.wait_for_client() function to block program execution until the client is attached.
import debugpy debugpy.listen(5678) debugpy.wait_for_client() # blocks execution until client is attached ...
In Python 3.7 and above,
debugpy supports the standard
breakpoint() function. Use
debugpy.breakpoint() function for similar behavior and compatibility with older versions of Python. If the debugger is attached when either of these functions is invoked, it will pause execution on the calling line, as if it had a breakpoint set. If there's no client attached, the functions do nothing, and the code continues to execute normally.
import debugpy debugpy.listen(...) while True: ... breakpoint() # or debugpy.breakpoint() on 3.6 and below ...
To enable debugger internal logging via CLI, the
--log-to switch can be used:
-m debugpy --log-to path/to/logs ...
When using the API, the same can be done with
In both cases, the environment variable
DEBUGPY_LOG_DIR can also be set to the same effect.
When logging is enabled, debugpy will create several log files with names matching
debugpy*.log in the specified directory, corresponding to different components of the debugger. When subprocess debugging is enabled, separate logs are created for every subprocess.