Run/Debug Configuration: Flask Server

Use this dialog to create run/debug configuration for Flask server and customize the way PyCharm executes your Flask application.

See Creating web applications with Flask for more details on using Flask in PyCharm.

Select Run | Edit Configurations from the main menu, then click and select the Flask template.

Fill in the following parameters:

Configuration tab

Item	Description
Module name/Script path/Custom	Choose one of the following methods to construct and pass the `FLASK_APP` variable to Flask: Module name – by using a Python module name and a `Flask` class instance. Script path – by using a path to a Python file. Custom – by using an arbitrary combination of paths, modules, and `Flask` class instances. For more information about the `FLASK_APP` variable, refer to Flask CLI documentation.
Target	Depending on the selected Target type, you can specify the following values: Path to the Python file, for example, /Users/jetbrains/MyFlaskProject/app.py. You can type in the path or click the button to locate the file in the project structure. Name of the module in the Flask project, for example, `access_management`. You can type in the module name or click the button to search the target module by its name or to locate it in the project structure. Custom combination of modules, scripts, and `Flask` class instances, for example, `access_management.access:app2`, where: `access_management` – the module name `access` – the target file in the module `app2` – the `Flask` class instance in `access`.
Application	The target `Flask` class instance to be executed. This value will be put into the `FLASK_APP` variable during the execution. For example, you've declared the following instance of the `Flask` class in your application: `app = Flask(__name__);` Then you can add `app` into the Application field. It is typically used for the Module name target type. For Script path, the `Application` field is enabled only for the Flask version 0.13 and later. The field is disabled for the Custom target type, because you can specify the required instance in the combination added to the Target field.
Additional options	Parameters of the `flask run` command. `--host` – the IP address of the web server to run your Flask application on. The default value is '127.0.0.1'. To make your web server externally visible, use the '0.0.0.0' value for this parameter. `--port` – the port of the web server. The default value is 5000 or it is the port number set in the `SERVER_NAME` config variable. Example: `--host=127.0.0.2 --port=1234`.
FLASK_ENV	An environment variable set to one of possible environments. The default value is 'development'.
FLASK_DEBUG	Select this checkbox to enable the built-in Flask debug mode. With this mode, the development server will be automatically reloaded on any code change enabling continuous debugging. For more information about Flask debugger, refer to Flask Debug Mode.
Project	Click this list to select one of the projects, opened in the same PyCharm window, where this run/debug configuration should be used. If there is only one open project, this field is not displayed.
Environment variables	This field shows the list of environment variables. If the list contains several variables, they are delimited with semicolons. By default, the field contains the variable `PYTHONUNBUFFERED` set to 1. To fill in the list, click the browse button, or press `Shift+Enter` and specify the desired set of environment variables in the Environment Variables dialog. To create a new variable, click , and type the desired name and value. You might want to populate the list with the variables stored as a series of records in a text file, for example: Variable1 = Value1 Variable2 = Value2 Just copy the list of variables from the text file and click Paste () in the Environmental Variables dialog. The variables will be added to the table. Click Ok to complete the task. At any time, you can select all variables in the Environment Variables dialog, click Copy , and paste them into a text file.
Python Interpreter	Select one of the pre-configured Python interpreters from the list. Note that you can select a remote interpreter as well as the local one.
Interpreter options	In this field, specify the string to be passed to the interpreter. If necessary, click , and type the string in the editor.
Working directory	Specify a directory to be used by the running task. When a default run/debug configuration is created by the keyboard shortcut `Ctrl+Shift+F10`, or by choosing Run from the context menu of a script, the working directory is the one that contains the executable script. This directory may differ from the project directory. When this field is left blank, the bin directory of the PyCharm installation will be used.
Add content roots to PYTHONPATH	Select this checkbox to add all content roots of your project to the environment variable PYTHONPATH;
Add source roots to PYTHONPATH	Select this checkbox to add all source roots of your project to the environment variable PYTHONPATH;

Logs tab

Use this tab to specify which log files generated while running or debugging should be displayed in the console, that is, on the dedicated tabs of the Run or Debug tool window.

Item	Description
Is Active	Select checkboxes in this column to have the log entries displayed in the corresponding tabs in the Run tool window or Debug tool window.
Log File Entry	The read-only fields in this column list the log files to show. The list can contain: Full paths to specific files. Aliases to substitute for full paths or patterns. These aliases are also displayed in the headers of the tabs where the corresponding log files are shown. If a log entry pattern defines more than one file, the tab header shows the name of the file instead of the log entry alias.
Skip Content	Select this checkbox to have the previous content of the selected log skipped.
Save console output to file	Select this checkbox to save the console output to the specified location. Type the path manually, or click the browse button and point to the desired location in the dialog that opens.
Show console when a message is printed to standard output stream	Select this checkbox to activate the output console and bring it forward if an associated process writes to Standard.out.
Show console when a message is printed to standard error stream	Select this checkbox to activate the output console and bring it forward if an associated process writes to Standard.err.
	Click this button to open the Edit Log Files Aliases dialog where you can select a new log entry and specify an alias for it.
	Click this button to edit the properties of the selected log file entry in the Edit Log Files Aliases dialog.
	Click this button to remove the selected log entry from the list.
	Click this button to edit the select log file entry. The button is available only when an entry is selected.

Common settings

When you edit a run configuration (but not a run configuration template), you can specify the following options:


Name	Specify a name for the run/debug configuration to quickly identify it when editing or running the configuration, for example, from the Run popup `Alt+Shift+F10`.
Allow parallel run	Select to allow running multiple instances of this run configuration in parallel. By default, it is disabled, and when you start this configuration while another instance is still running, PyCharm suggests to stop the running instance and start another one. This is helpful when a run/debug configuration consumes a lot of resources and there is no good reason to run multiple instances.
Store as project file	Save the file with the run configuration settings to share it with other team members. The default location is .idea/runConfigurations. However, if you do not want to share the .idea directory, you can save the configuration to any other directory within the project. By default, it is disabled, and PyCharm stores run configuration settings in .idea/workspace.xml.

Name

Specify a name for the run/debug configuration to quickly identify it when editing or running the configuration, for example, from the Run popup Alt+Shift+F10.

Allow parallel run

Select to allow running multiple instances of this run configuration in parallel.

By default, it is disabled, and when you start this configuration while another instance is still running, PyCharm suggests to stop the running instance and start another one. This is helpful when a run/debug configuration consumes a lot of resources and there is no good reason to run multiple instances.

Store as project file

Save the file with the run configuration settings to share it with other team members. The default location is .idea/runConfigurations. However, if you do not want to share the .idea directory, you can save the configuration to any other directory within the project.

By default, it is disabled, and PyCharm stores run configuration settings in .idea/workspace.xml.

The tree view of run/debug configurations has a toolbar that helps you manage configurations available in your project as well as adjust default configurations templates.

Item	Shortcut	Description
	`Alt+Insert`	Create a run/debug configuration.
	`Alt+Delete`	Delete the selected run/debug configuration. Note that you cannot delete default configurations.
	`Ctrl+D`	Create a copy of the selected run/debug configuration. Note that you create copies of default configurations.
		The button is displayed only when you select a temporary configuration. Click this button to save a temporary configuration as permanent.
		Move into new folder / Create new folder. You can group run/debug configurations by placing them into folders. To create a folder, select the configurations within a category, click , and specify the folder name. If only a category is in focus, an empty folder is created. Then, to move a configuration into a folder, between the folders or out of a folder, use drag or and buttons. To remove grouping, select a folder and click .
		Click this button to sort configurations in the alphabetical order.

Before launch

In this area, you can specify tasks to be performed before starting the selected run/debug configuration. The tasks are performed in the order they appear in the list.

Item	Shortcut	Description
	`Alt+Insert`	Click this icon to add one of the following available tasks: Run External tool: select to run an external application. In the dialog that opens, select one or multiple applications you want to run. If it is not defined in PyCharm yet, add its definition. For more information, see External tools and External Tools. Run Another Configuration: select to execute another run/debug configuration and wait until it finishes before starting the current configuration. If you want to run several configurations in parallel, use a compound run configuration. Launch Web Browser: select this option to have a browser started. In the dialog that opens, select the type of the browser and provide the start URL. Also, specify if you want the browser be launched with JavaScript debugger. Run File Watchers: select this option to have PyCharm apply all the currently active File Watchers. Run Grunt task: select this option to run a Grunt task. In the Grunt task dialog that opens, specify the Gruntfile.js where the required task is defined, select the task to execute, and specify the arguments to pass to the Grunt tool. Specify the location of the Node.js interpreter, the parameters to pass to it, and the path to the grunt-cli package. Run gulp task: select this option to run a Gulp task. In the Gulp task dialog that opens, specify the Gulpfile.js where the required task is defined, select the task to execute, and specify the arguments to pass to the Gulp tool. Specify the location of the Node.js interpreter, the parameters to pass to it, and the path to the gulp package. Run npm script: select this option to execute an npm script. In the NPM Script dialog that opens, specify the npm run/debug configuration settings. Start React Native Bundler: select this option to run the bundler automatically, as part of a running or debugging session. By default, this is done through `react-native start`. If your application uses Expo, you need to run the development server via the `start` npm task. To do that, click , then in the Configure React Native dialog, choose npm script and select start from the list. Compile TypeScript: select to run the built-in TypeScript compiler and thus make sure that all the changes you made to your TypeScript code are reflected in the generated JavaScript files. In the TypeScript Compile Settings dialog that opens, select or clear the Check errors checkbox to configure the behaviour of the compiler in case any errors are detected: If the Check errors checkbox is selected, the compiler will show all the errors and the run configuration will not start. If the Check errors checkbox is cleared, the compiler will show all the detected errors but the run configuration still will be launched. Generate CoffeeScript Source Maps: select this option to generate the source maps for your CoffeeScript sources. In the dialog that opens, specify where your CoffeeScript source files are located. Run Remote External Tool: adds a remote SSH external tool.
	`Alt+Delete`	Click this icon to remove the selected task from the list.
	`Enter`	Click this icon to edit the selected task. Make the necessary changes in the dialog that opens.
/	`Alt+Up`/`Alt+Down`	Click these icons to move the selected task one line up or down in the list. The tasks are performed in the order that they appear in the list.
Show this page		Select this checkbox to show the run/debug configuration settings prior to actually starting the run/debug configuration.
Activate tool window		By default this checkbox is selected and the Run or the Debug tool window opens when you start the run/debug configuration. Otherwise, if the checkbox is cleared, the tool window is hidden. However, when the configuration is running, you can open the corresponding tool window for it yourself by pressing `Alt+4` or `Alt+5`.

Last modified: 17 March 2022

Run/Debug Configuration: Flask Server

Configuration tab

Logs tab

Common settings

Toolbar

Before launch