Remote Debugging with PyCharm

Complete the following preparation tasks:

1. On the local machine, create a pure Python project, as described in the section Create a Python project.

2. Add a Python file to this project (Alt+Insert - Python File).

3. Add the following code to the Python File:

   import math class Solver: def demo(self, a, b, c): d = b ** 2 - 4 * a * c if d > 0: disc = math.sqrt(d) root1 = (-b + disc) / (2 * a) root2 = (-b - disc) / (2 * a) return root1, root2 elif d == 0: return -b / (2 * a) else: return "This equation has no roots" if __name__ == '__main__': solver = Solver() while True: a = int(input("a: ")) b = int(input("b: ")) c = int(input("c: ")) result = solver.demo(a, b, c) print(result)

Configure a remote interpreter

1. Ensure that you have SSH access to the remote machine.

2. Add a new remote interpreter to the project as described in Configure an interpreter using SSH specifying the credentials to connect to the remote machine.

3. Once you create the remote interpreter for your project, the corresponding deployment configuration is created. To preview it, press Ctrl+Alt+S to open the Settings dialog window on the local machine, then click the Build, Execution, Deployment node and the Deployment node.

   

4. You can accept all default settings or alter them, if needed. For this example, let's use a meaningful name for your deployment configuration, for example, "MySFTPConnection".

5. Ensure that the Root path value reflects the path specified in the corresponding settings of the created SSH interpreter.

   

   To check the Path Interpreter in the Project | Python Interpreter Settings, expand the list of the available interpreters in Project | Python Interpreter, select Show All..., and click . The existing paths of the selected interpreter show up in the Interpreter Paths dialog.

Now your deployment configuration is ready.

Deploy your application to a remote host

Next, your application must be deployed to the remote host.

1. On the Tools menu, select Deployment | Upload to MySFTPConnection.

2. File Transfer tool window appears. Verify the number of transferred files.

   

Debug your application

1. Right-click the editor background and choose the Debug <name> (here Debug 'quadratic_equation').

2. Review the debugging output. Note that debugging actually takes place on the specified remote server.

   

Create a run/debug configuration

1. Go to Run| Edit Configuration.... The Run/debug configurations dialog opens. You have to click on the toolbar, and from the list of available configurations, select Python Debug Server.

   

2. Enter the name of this run/debug configuration – let it be MyRemoteServer. Specify the port number (here 12345) and the IDE host name (here 172.20.208.95) of the machine where the IDE is running. These parameters will be used by the remote debug server to access it.

3. Map the path on the local machine to the path on the remote machine:

   

4. Inspect the Update your script instructions. You can use the pydevd-pycharm.egg from the PyCharm installation (<PyCharm directory>/debug-egg/pydevd-pycharm.egg) or install the pydevd-pycharm package using pip.

   Depending on your choice, perform the following changes:

   • Install the pydevd-pycharm package on the remote machine by running the following command:

     pip install pydevd-pycharm~=<version of PyCharm on the local machine>

     for example, pip install pydevd-pycharm~=191.3490)

   • Modify the source code file as follows:

   import math #==============this code added==================================================================: import pydevd_pycharm pydevd_pycharm.settrace('172.20.208.95', port=12345, stdoutToServer=True, stderrToServer=True) #================================================================================================ class Solver: def demo(self, a, b, c): d = b ** 2 - 4 * a * c if d > 0: disc = math.sqrt(d) root1 = (-b + disc) / (2 * a) root2 = (-b - disc) / (2 * a) return root1, root2 elif d == 0: return -b / (2 * a) else: return "This equation has no roots" if __name__ == '__main__': solver = Solver() while True: a = int(input("a: ")) b = int(input("b: ")) c = int(input("c: ")) result = solver.demo(a, b, c) print(result)

   Modify the code as follows:

   import math #==============this code added==================================================================: import sys sys.path.append("<PyCharm directory>/debug-egg/pydevd-pycharm.egg") import pydevd_pycharm pydevd_pycharm.settrace('172.20.208.95', port=12345, stdoutToServer=True, stderrToServer=True) #================================================================================================ class Solver: def demo(self, a, b, c): d = b ** 2 - 4 * a * c if d > 0: disc = math.sqrt(d) root1 = (-b + disc) / (2 * a) root2 = (-b - disc) / (2 * a) return root1, root2 elif d == 0: return -b / (2 * a) else: return "This equation has no roots" if __name__ == '__main__': solver = Solver() while True: a = int(input("a: ")) b = int(input("b: ")) c = int(input("c: ")) result = solver.demo(a, b, c) print(result)

Create a SFTP connection

1. On the remote machine, create a directory where the file quadratic_equation.py should be uploaded. You can do it in the Terminal window:

   $cd /tmp $mkdir pycharm_project_986

2. On the local machine, create a connection profile. Go to Tools | Deployment - Configuration.... In the dialog that opens, click , and in the Add Server dialog select the connection type (here SFTP) and enter its name (here MySFTPConnection).

3. In the Connection tab, specify the SFTP host (address of the remote machine), username and password for that machine.

   Note that the specified user should have SSH access to the remote host.

4. Click Mappings tab, and enter the deployment path in server. The server is MySFTPConnection, so click the browse button and select the required folder /tmp/pycharm_project_986. Note that the browse button shows the contents of the remote host. Apply the changes and close the dialog.

Deploy files to the remote machine

1. Deploy the following files to the remote machine: pydevd-pycharm.egg and quadratic_equation.py.

   On the local machine, in the Project tool window, select the files, right-click the selection and choose Deployment | Upload to MySFTPConnection.

2. Inspect the File Transfer dialog window to ensure that the files from the local machine are uploaded to the remote server.

   

Launch the Debug Server

1. Choose the created run/debug configuration, and click :

   

2. Ensure that the Debug window shows the Waiting for process connection.. message. This message will be shown until you launch your script on the remote machine, and this script will connect to the Debug Server.

Execute the Python file on the remote machine

1. On the remote machine, navigate to the tmp/pycharm_project_986 directory.

2. Launch the quadratic_equation.py file on the remote host. To do that, in the Terminal window, enter the following command:

   $python3 quadratic_equation.py

   $python quadratic_equation.py

   The most helpful aspect of this debugging method is that you can run execution the Python file using any of your bash scripts when remote debugging is part of a scheduled task or when you need to execute some preparation steps before running the Python script. If that's the case, add the following lines to the appropriate place of your bash script:

   cd /tmp/pycharm_project_986 python3 quadratic_equation.py

   cd /tmp/pycharm_project_986 python quadratic_equation.py

Debug your application

• On your local machine, switch to the Debug window. It should show the connection to the pydev debugger.

  

  Your code is actually executed on the remote host, but debugged on the local machine.