# Source: https://trigger.dev/docs/config/extensions/pythonExtension.md

> ## Documentation Index
> Fetch the complete documentation index at: https://trigger.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Python

> Use the python build extension to add support for executing Python scripts in your project

If you need to execute Python scripts in your Trigger.dev project, you can use the `pythonExtension` build extension via the `@trigger.dev/python` package.

First, you'll need to install the `@trigger.dev/python` package:

```bash  theme={"theme":"css-variables"}
npm add @trigger.dev/python
```

Then, you can use the `pythonExtension` build extension in your `trigger.config.ts` file:

```ts  theme={"theme":"css-variables"}
import { defineConfig } from "@trigger.dev/sdk";
import { pythonExtension } from "@trigger.dev/python/extension";

export default defineConfig({
  project: "<project ref>",
  build: {
    extensions: [pythonExtension()],
  },
});
```

This will take care of adding python to the build image and setting up the necessary environment variables to execute Python scripts. You can then use our `python` utilities in the `@trigger.dev/python` package to execute Python scripts in your tasks. For example, running a Python script inline in a task:

```ts  theme={"theme":"css-variables"}
import { task } from "@trigger.dev/sdk";
import { python } from "@trigger.dev/python";

export const myScript = task({
  id: "my-python-script",
  run: async () => {
    const result = await python.runInline(`print("Hello, world!")`);
    return result.stdout;
  },
});
```

## Adding python scripts

You can automatically add python scripts to your project using the `scripts` option in the `pythonExtension` function. This will copy the specified scripts to the build directory during the deploy process. For example:

```ts  theme={"theme":"css-variables"}
import { defineConfig } from "@trigger.dev/sdk";
import { pythonExtension } from "@trigger.dev/python/extension";

export default defineConfig({
  project: "<project ref>",
  build: {
    extensions: [
      pythonExtension({
        scripts: ["./python/**/*.py"],
      }),
    ],
  },
});
```

This will copy all Python files in the `python` directory to the build directory during the deploy process. You can then execute these scripts using the `python.runScript` function:

```ts  theme={"theme":"css-variables"}
import { task } from "@trigger.dev/sdk";
import { python } from "@trigger.dev/python";

export const myScript = task({
  id: "my-python-script",
  run: async () => {
    const result = await python.runScript("./python/my_script.py", ["hello", "world"]);
    return result.stdout;
  },
});
```

<Note>
  The pythonExtension will also take care of moving the scripts to the correct location during `dev`
  mode, so you can use the same exact path in development as you do in production.
</Note>

## Using requirements files

If you have a `requirements.txt` file in your project, you can use the `requirementsFile` option in the `pythonExtension` function to install the required packages during the build process. For example:

```ts  theme={"theme":"css-variables"}
import { defineConfig } from "@trigger.dev/sdk";
import { pythonExtension } from "@trigger.dev/python/extension";

export default defineConfig({
  project: "<project ref>",
  build: {
    extensions: [
      pythonExtension({
        requirementsFile: "./requirements.txt",
      }),
    ],
  },
});
```

This will install the packages specified in the `requirements.txt` file during the build process. You can then use these packages in your Python scripts.

<Note>
  The `requirementsFile` option is only available in production mode. In development mode, you can
  install the required packages manually using the `pip` command.
</Note>

## Virtual environments

If you are using a virtual environment in your project, you can use the `devPythonBinaryPath` option in the `pythonExtension` function to specify the path to the Python binary in the virtual environment. For example:

```ts  theme={"theme":"css-variables"}
import { defineConfig } from "@trigger.dev/sdk";
import { pythonExtension } from "@trigger.dev/python/extension";

export default defineConfig({
  project: "<project ref>",
  build: {
    extensions: [
      pythonExtension({
        devPythonBinaryPath: ".venv/bin/python",
      }),
    ],
  },
});
```

This has no effect in production mode, but in development mode, it will use the specified Python binary to execute Python scripts.

## Streaming output

All of the `python` functions have a streaming version that allows you to stream the output of the Python script as it runs. For example:

```ts  theme={"theme":"css-variables"}
import { task } from "@trigger.dev/sdk";
import { python } from "@trigger.dev/python";

export const myStreamingScript = task({
  id: "my-streaming-python-script",
  run: async () => {
    // You don't need to await the result
    const result = python.stream.runScript("./python/my_script.py", ["hello", "world"]);

    // result is an async iterable/readable stream
    for await (const chunk of streamingResult) {
      console.log(chunk);
    }
  },
});
```

## Environment variables

We automatically inject the environment variables in the `process.env` object when running Python scripts. You can access these environment variables in your Python scripts using the `os.environ` dictionary. For example:

```python  theme={"theme":"css-variables"}
import os

print(os.environ["MY_ENV_VAR"])
```

You can also pass additional environment variables to the Python script using the `env` option in the `python.runScript` function. For example:

```ts  theme={"theme":"css-variables"}
import { task } from "@trigger.dev/sdk";
import { python } from "@trigger.dev/python";

export const myScript = task({
  id: "my-python-script",
  run: async () => {
    const result = await python.runScript("./python/my_script.py", ["hello", "world"], {
      env: {
        MY_ENV_VAR: "my value",
      },
    });
    return result.stdout;
  },
});
```