---
asIndexPage: true
---

# Overview

Cube is configured via [environment variables][link-env-vars] and
[configuration options][link-config] in a configuration file. Usually,
both would be used to configure a Cube deployment in production.

## Environment variables

Environment variables are mostly used for configuration that is defined
statically and is not supposed to change while a Cube deployment is running.

<InfoBox>

For example, <EnvVar>CUBEJS_DATASOURCES</EnvVar> defines a list of data sources to connect
to; changing that list would require the deployment to restart.

</InfoBox>

<ReferenceBox>

See the [environment variables reference][link-env-vars] for all supported options.

</ReferenceBox>

<ReferenceBox>

See [this recipe][ref-env-var-recipe] if you'd like to reference environment variables
in code.

</ReferenceBox>

### Cube Core

You can set environment variables in any way [supported by
Docker][link-docker-env-vars], e.g., a `.env` file or the `environment`
option in the `docker-compose.yml` file.

### Cube Cloud

You can set environment variables in <Btn>Settings → Configuration</Btn>:

<Screenshot
  alt="Cube Cloud Environment Variables Screen"
  src="https://ucarecdn.com/b47693b9-f770-4e01-a0d1-60e3fcf19e23/"
/>

## Configuration options

Configuration options are mostly used for configuration that is defined
programmatically and applied dynamically while a Cube deployment is running.

<InfoBox>

For example, [`query_rewrite`](/product/configuration/reference/config#query_rewrite)
provides a way to inspect, modify, or restrict every query that is being
processed by Cube.

</InfoBox>

Configuration options take precedence over environment variables.

<ReferenceBox>

See the [configuration options reference][link-config] for all supported options.

</ReferenceBox>

### `cube.py` and `cube.js` files

Configuration options can be defined either using Python, in a `cube.py` file,
or using JavaScript, in a `cube.js` file in the root folder of a Cube project.

<CodeTabs>

```python
from cube import config

# Base path for the REST API
config.base_path = '/cube-api'

# Inspect, modify, or restrict every query
@config('query_rewrite')
def query_rewrite(query: dict, ctx: dict) -> dict:
  if 'order_id' in ctx['securityContext']:
    query['filters'].append({
      'member': 'orders_view.id',
      'operator': 'equals',
      'values': [ctx['securityContext']['order_id']]
    })
  return query

```

```javascript
module.exports = {
  // Base path for the REST API
  basePath: '/cube-api',

  // Inspect, modify, or restrict every query
  queryRewrite: (query, { securityContext }) => {
    if (securityContext.order_id) {
      query.filters.push({
        member: 'orders_view.id',
        operator: 'equals',
        values: [securityContext.order_id]
      })
    }
    return query
  }
}
```

</CodeTabs>

Both ways are equivalent; when in doubt, use Python.

Here is a minimal correct `cube.py` file. Note that the [`config`
object][ref-cube-package-config] must be imported:

```python
from cube import config

# Configuration goes here...
```

Here is a minimal correct `cube.js` file. Note that the `module.exports` object must be defined:

```javascript
module.exports = {
  // Configuration goes here...
}
```

You can read more about [Python][ref-python] and [JavaScript][ref-javascript] support
in the dynamic data modeling section of the documentation.

### Cube Core

When using Docker, ensure that the configuration file and your [data model
folder][ref-folder-structure] are mounted to `/cube/conf` within the
Docker container.

### Cube Cloud

You can edit the configuration file by going into <Btn>Development Mode</Btn>
and navigating to <Btn>[Data Model][ref-data-model]</Btn> or <Btn>[Visual
Modeler][ref-visual-model]</Btn> pages.

## Runtimes and dependencies

Cube uses Python and Node.js as runtime environments for the code of
configuration and [dynamic data models][ref-dynamic-data-models]. You can look
current versions up on GitHub: [Python][link-current-python-version],
[Node.js][link-current-nodejs-version].

It's recommended to use `requirements.txt` and `package.json` files to
specify dependencies for your Python and JavaScript code, respectively.

### Cube Core

If you have specified Python packages in the `requirements.txt` file,
make sure to install them by running `pip install -r requirements.txt`
inside the Docker container.

If you have specified npm packages in the `package.json` file, make sure
to install them by running `npm install` inside the Docker container.
Alternatively, you can run `npm install` on your local machine and mount
the `node_modules` folder under `/cube/conf` in the Docker container;
however, if your dependencies contain native extensions, they might not work
when provided this way.

To automate the installation of dependencies, build and use a [custom
Docker image][ref-custom-docker-image].

### Cube Cloud

Cube Cloud automatically installs dependencies from `requirements.txt` and
`package.json` files.

## Development mode

Cube can be run in an insecure, development mode by setting the
<EnvVar>CUBEJS_DEV_MODE</EnvVar> environment variable to `true`. Putting Cube in development
mode does the following:

- Disables authentication checks.
- Disables [member-level access control][ref-mls].
- Enables Cube Store in single instance mode.
- Enables background refresh for in-memory cache and [scheduled
  pre-aggregations][link-scheduled-refresh].
- Allows another log level to be set (`trace`).
- Enables [Playground][link-dev-playground] on `http://localhost:4000`.
- Uses `memory` instead of `cubestore` as the default cache/queue engine.
- Logs incorrect/invalid configuration for `externalRefresh` /`waitForRenew`
  instead of throwing errors.

[ref-folder-structure]:
  /product/data-modeling/syntax#folder-structure
[link-config]: /product/configuration/reference/config
[link-dev-playground]: /product/workspace/playground
[link-env-vars]: /product/configuration/reference/environment-variables
[link-scheduled-refresh]:
  /product/data-modeling/reference/pre-aggregations#scheduled_refresh
[ref-dynamic-data-models]: /product/data-modeling/dynamic
[ref-custom-docker-image]: /product/deployment/core#extend-the-docker-image
[link-docker-env-vars]: https://docs.docker.com/compose/environment-variables/set-environment-variables/
[ref-mls]: /product/auth/member-level-security
[link-current-python-version]: https://github.com/cube-js/cube/blob/master/packages/cubejs-docker/latest.Dockerfile#L13
[link-current-nodejs-version]: https://github.com/cube-js/cube/blob/master/packages/cubejs-docker/latest.Dockerfile#L1
[ref-data-model]: /product/data-modeling/data-model-ide
[ref-visual-model]: /product/data-modeling/visual-modeler
[ref-python]: /product/data-modeling/dynamic/jinja#python
[ref-javascript]: /product/data-modeling/dynamic/javascript
[ref-cube-package-config]: /product/data-modeling/reference/cube-package#config-object
[ref-env-var-recipe]: /product/configuration/recipes/environment-variables