File watchers

In the Settings/Preferences dialog Ctrl+Alt+S, click File Watchers under Tools. The File Watchers page opens showing a list of File Watchers that are already configured in this project and in the IDE.

Click and choose the predefined template from which you want to create a File Watcher. The choice depends on the tool you are going to use. To use a tool that is not on the list, choose Custom. The New Watcher dialog opens.

In the Name field, type the name of the File Watcher. By default, PyCharm suggests the name of the selected predefined template.

From the File type list, choose the expected type of input files. The File Watcher will consider only files of this type as subject for analyzing and processing. File types are recognised based on associations between file types and file extensions.

By default, the field shows the file type in accordance with the chosen predefined template.

Select the Scope in which the File Watcher is applicable.

Changes in these files will invoke the File Watcher either immediately or upon save or frame deactivation, depending on the status of the Auto-save edited files to trigger the watcher checkbox.

Select one of the predefined scopes from the list. For a project-level File Watcher, you can also click to configure a custom scope in the Scopes dialog that opens.

• All Places: all the scopes listed below.

• Project Files: all the files within the project content roots (see Configuring Project Structure).

• Project Production Files: all the files within the project content roots excluding test sources.

• Project Test Files: all the files within the project test source roots.

• Scratches and Consoles: all the files from the Scratches and Consoles directory located in the Project tool window.

• Open Files: all the files that are currently opened in the editor.

• Current File: the file opened in the active editor tab.

VCS Scopes: these scopes are only available if your project is under version control.

• All Changed Files: all changed files, that is, all files associated with all existing changelists.

• Default Changelist: all the files associated with the changelist  Default.

Alternatively, click and configure a custom scope in the Scopes dialog that opens.

See Scopes and file colors for details.

Optionally: specify how you want the File Watcher to deal with dependencies. A root file is a file that is not included (for example via import) in any other file within the specified scope.

• To run the File Watcher only against root files, select the Track only root files checkbox.

• Clear the checkbox to run the File Watcher against the file from which it is invoked and against all the files in which this file is recursively included within the specified scope.

Note that the Scope setting overrides the Track only root files checkbox setting: if a dependency is outside the specified scope, the File Watcher is not applied to it.

In the Program field, specify the path to the executable file of the tool (.exe, .cmd, .bat, or other depending on the specific tool).

In the Arguments field, define the arguments to pass to the tool.

Arguments are usually specified using macros, for example, $FileName$ or $FileNameWithoutExtension$, that will be replaced with actual file names.

Type the macros manually or click and select the relevant pattern fom the list in the Macros dialog that opens.

In the Output paths to refresh field, specify the files where the tool stores its output: the resulting source code, source maps, and dependencies. Based on these settings, PyCharm recognizes the files generated through compilation.

Note, that changing the value in the Output paths to refresh field does not make the tool store its output in another place. If you still need to do that, specify the desired custom output location in the Arguments field: type the output paths with colons as separators and use macros.

Output paths are usually specified using macros. Type the path manually or click and select the relevant pattern from the list.

Expand the Working Directory and Environment Variables hidden area.

Define the environment variables. For example, specify the PATH variable for the tools that are required for starting the tool you are configuring but are not referenced in the path to it. In most cases it is Node.js or ruby.exe. Such situation may result from custom manual installation instead of installation through the Node Package Manager (npm) or gem manager.

In the Working Directory field, specify the directory to which the tool will be applied.
Because the tool is always invoked in the context of a file, the default working directory is the directory of the current file. The default working directory is specified in all predefined templates through a $FileDir$ macros. To specify a custom working directory, type the path to it in the field, or click and select the directory in the Select Path dialog, or click and select the desired macro from the list in the Macros dialog.

Specify the events that will invoke the File Watcher:

• To invoke the File Watcher as soon as any changes are made to the source code, select the Auto-save edited files to trigger the watcher checkbox.
  When the checkbox is cleared, the File Watcher starts upon save (File | Save All) or when you move the focus from PyCharm (on frame deactivation).

• By default, the File Watcher wakes up on any saved change, including the updates received from you version control system when you, for example, check out a branch. To ignore such changes and invoke the File Watcher only when you update your code in PyCharm, clear the Trigger the watcher on external changes checkbox.

Specify whether you want the File Watcher to interact with the PyCharm syntax parser:

• When the Trigger watcher regardless of syntax errors checkbox is selected, the File Watcher start regardless of the syntactical correctness of a file. The File Watcher will start upon update, save, or frame deactivation, depending on the status of the Auto-save edited files to trigger the watcher checkbox.

• When the Trigger watcher regardless of syntax errors checkbox is cleared, the File Watcher ignores all triggers in files that are syntactically invalid and starts only in error-free files.

Use the Create output file from stdout checkbox to specify how you want to generate the output file.

• When the checkbox is selected, PyCharm reads the native tool's output standard output stream (stdout) and generates the resulting files from it.

• When the checkbox is cleared, the tool writes its output directly to the files specified in the Output paths to refresh field.

In the Show console list, choose when you want the File Watcher to open the console.

• Always: with this option, the console always opens after the tool execution is completed.

• On error: with this option, the console opens after the tool execution only when the Exit code is different from 0.

• Never: choose this option to suppress opening the console at all.