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

# Manage Python versions in non-Python containers

> See how to manage different Python versions in your Upsun Cloud containers.

> [!TIP]
>
> You can now use composable image to install runtimes and tools in your application container. To find out more, see the [Composable image](https://developer.upsun.com/docs/configure-apps/app-reference/composable-image.md) topic.

You may need to use a specific version of Python that isn't available in an app container for a different language.
For example, a container might have a long-term support version, while you want the latest version.

In such cases, use the [Pyenv version manager](https://github.com/pyenv/pyenv)
to install the specific version you want to use.

1. Add your target Python version as a [variable](https://developer.upsun.com/docs/development/variables):


    applications:
      \# The app's name, which must be unique within the project.
      myapp:
        type: 'php:\{\{version:php:latest}}'
        variables:
          env:
            \# Update for your desired Python version.
            PYTHON\_VERSION: "3.11.0"

2. Add Pyenv in a [`build` hook](https://developer.upsun.com/docs/configure-apps/hooks/hooks-comparison#build-hook):


    applications:
      \# The app's name, which must be unique within the project.
      myapp:
        type: 'php:\{\{version:php:latest}}'
        variables:
          env:
            \# Update for your desired Python version.
            PYTHON\_VERSION: "3.11.0"
        hooks:
          build: |
            \# Exit the hook on any failure
            set -e

            \# Clone Pyenv to the build cache if not present
            if \[ ! -d "\$PLATFORM\_CACHE\_DIR/.pyenv" ]; then
                mkdir -p \$PLATFORM\_CACHE\_DIR/.pyenv
                git clone https\://github.com/pyenv/pyenv.git \$PLATFORM\_CACHE\_DIR/.pyenv
            fi

            \# Pyenv environment variables
            export PYENV\_ROOT="\$PLATFORM\_CACHE\_DIR/.pyenv"
            export PATH="\$PYENV\_ROOT/bin:\$PATH"

            \# Initialize Pyenv
            if command -v pyenv 1>/dev/null 2>&1; then
                eval "\$(pyenv init --path)"
            fi

            \# Install desired Python version
            mkdir -p \$PLATFORM\_CACHE\_DIR/.pyenv/versions
            if \[ ! -d "\$PLATFORM\_CACHE\_DIR/.pyenv/versions/\$PYTHON\_VERSION" ]; then
                pyenv install \$PYTHON\_VERSION
            fi

            \# Set global Python version
            pyenv global \$PYTHON\_VERSION

Now your build hook can use the specified version of Python.
You can verify this by running `python --version`.

If you want this Python version to be available in the runtime environment, follow these steps:

1. Copy Pyenv to your runtime environment at the end of your build hook:


    applications:
      \# The app's name, which must be unique within the project.
      myapp:
        type: 'php:\{\{version:php:latest}}'
        hooks:
          build: |
            ...

            \# Copy Pyenv directory to runtime directory
            cp -R \$PLATFORM\_CACHE\_DIR/.pyenv \$PLATFORM\_APP\_DIR

            \# Rehash Pyenv for new (runtime) location
            PYENV\_ROOT="\$PLATFORM\_APP\_DIR/.pyenv" \$PLATFORM\_APP\_DIR/.pyenv/bin/pyenv rehash

2. Create an [`.environment` file](https://developer.upsun.com/docs/development/variables/set-variables#set-variables-via-script):

   ```bash theme={null}
   touch .environment
   ```

3. Update the PATH for the runtime environment:

   ```yaml .environment theme={null}
   export PATH=/app/.pyenv/bin:/app/.pyenv/shims:$PATH
   ```

Now the specified Python version is used in the runtime environment.


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