# Application settings

This page lists environment variables that tune application behavior for each module. Infrastructure settings (ports, database hosts, credentials) are covered in the [Docker Compose](/deploy-syntho/deploy-syntho-using-docker.md) and [Kubernetes](/deploy-syntho/deploy-syntho-using-kubernetes.md) deployment guides.

## How to configure

### Docker Compose

Add variables to the `.env` file at the root of your deployment directory. Docker Compose picks them up automatically.

```bash
# .env
DATABRICKS_READ_STMT_MAX_ATTEMPTS=15
LOG_LEVEL=WARNING
```

### Kubernetes (Helm)

The Helm chart uses different schemas depending on the service.

**Core API and Backend** — set variables under the service's `env:` map in `values.yaml`:

```yaml
# values.yaml
core:
  env:
    MAX_RUNNING_JOBS: "8"
    CANCEL_TIMEOUT: "120"

backend:
  env:
    SESSION_AGE: "1800"
    DATA_ACCESS: "False"
```

**Core (Ray)** — Ray uses the KubeRay chart with a standard Kubernetes env list under `head.containerEnv:` and `worker.containerEnv:`:

```yaml
# ray values.yaml
head:
  containerEnv:
    - name: DATABRICKS_READ_STMT_MAX_ATTEMPTS
      value: "15"
    - name: LOG_LEVEL
      value: "WARNING"

worker:
  containerEnv:
    - name: DATABRICKS_READ_STMT_MAX_ATTEMPTS
      value: "15"
    - name: LOG_LEVEL
      value: "WARNING"
```

***

## Core

| Name                                | Default | Description                                                                                                                                                                                                                  |
| ----------------------------------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `LOG_LEVEL`                         | `INFO`  | Log verbosity. Accepted values: `DEBUG`, `INFO`, `WARNING`, `ERROR`, `CRITICAL`. Falls back to `INFO` if the value is invalid.                                                                                               |
| `DATABRICKS_READ_STMT_MAX_ATTEMPTS` | `10`    | Maximum number of polling attempts when waiting for a Databricks SQL statement to finish executing. If the statement has not succeeded after this many attempts, the read fails with an error. Must be a positive integer.   |
| `DATABRICKS_READ_STMT_INITIAL_WAIT` | `2`     | Base wait time in seconds used for the exponential backoff between polling attempts. The wait after attempt *n* is `initial_wait ** n` seconds (e.g. with the default of `2`: 2 s, 4 s, 8 s, …). Must be a positive integer. |

***

## Core API

| Name                        | Default     | Description                                                                                                                                                                              |
| --------------------------- | ----------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `MAX_RUNNING_JOBS`          | `6`         | Maximum number of data generation jobs that can run in parallel.                                                                                                                         |
| `CANCEL_TIMEOUT`            | `60`        | Default timeout in seconds for cancellable blocking operations (used as the fallback for `run_cancellable`). Affects any operation that wraps a blocking call with a cancellation guard. |
| `FILE_SYSTEM_MAX_SIZE`      | `104857600` | Maximum allowed size in bytes for a single file upload when using the filesystem connector (default: 100 MB).                                                                            |
| `FILE_SYSTEM_MAX_FILES`     | `2`         | Maximum number of files allowed per filesystem connector upload.                                                                                                                         |
| `STREAMING_MAX_BYTES`       | `524288`    | Maximum bytes per chunk when streaming data (default: \~512 KB).                                                                                                                         |
| `STREAMING_MAX_ROWS`        | `2000`      | Maximum rows per chunk when streaming data. Also controls database `yield_per` batch size.                                                                                               |
| `STREAMING_MAX_INTERVAL_MS` | `400`       | Flush cadence in milliseconds for streaming responses.                                                                                                                                   |
| `FEATURE_CHAT_ASSISTANT`    | `False`     | Enable the AI chat assistant feature.                                                                                                                                                    |

***

## Backend

| Name                              | Default             | Description                                                                     |
| --------------------------------- | ------------------- | ------------------------------------------------------------------------------- |
| `SESSION_AGE`                     | `900`               | Session lifetime in seconds (default: 15 minutes).                              |
| `SESSION_EXPIRE_AT_BROWSER_CLOSE` | `FALSE`             | When `TRUE`, the session ends when the browser is closed.                       |
| `DATA_ACCESS`                     | `TRUE`              | When `TRUE`, users have access to source data by default.                       |
| `EMAIL_LOGIN_ENABLED`             | `FALSE`             | Allow users to log in with email and password when SSO is also enabled.         |
| `EXTRA_ALLOWED_HOSTS`             | `backend localhost` | Space-separated list of additional hostnames the service accepts requests from. |


---

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