Set custom environment variables

Applications commonly use environment variables, especially for sensitive information like API keys. This guide shows how to set environment variables for use in Deephaven via Docker.

docker-compose.yml

Environment variables must be set in the deephaven service of the docker-compose.yml file. The default Deephaven docker-compose.yml file already has an environment section, so you'll need to expand on this.

services:
  deephaven:
    image: ghcr.io/deephaven/server:${VERSION:-latest}
    ports:
      - "${DEEPHAVEN_PORT:-10000}:10000"
    volumes:
      - ./data:/data
    environment:
      - START_OPTS=-Xmx4g
      - MY_VALUE=test

You can access your environment variables in Deephaven using os.getenv:

import os

my_value = os.getenv("MY_VALUE")
print(my_value)

Warning

Avoid printing os.environ in full. It dumps all environment variables, including sensitive values like API keys and passwords, which can expose secrets in logs or shared notebooks.

Parameterizing the environment variables

The above example hardcodes the value of MY_VALUE in the docker-compose.yml file. This may not be ideal for sensitive information, or for easily doing deployments in different environments.

Instead, you can use the variable substitution syntax ${MY_VALUE} within your docker-compose.yml file. Docker Compose fills in the value with the matching environment variable from the host system.

- MY_VALUE=${MY_VALUE}

Now the value of MY_VALUE in the Deephaven server matches the value of MY_VALUE on the local machine.

Setting environment variables locally

There are many ways to set environment variables locally. Covering all of them is beyond the scope of this documentation, but many guides are available for that information. Here we show two primary ways to set environment variables for use within Deephaven.

.env file

In the same directory as your docker-compose.yml file, you can create a .env that contains key-value pairs to assign your environment variables.

.env

MY_VALUE=test

These environment variables are set when you run docker compose up.

CLI parameters

You can also include environment variables when calling docker compose up. Simply assign the key-value pairs before the docker compose up command.

MY_VALUE=test docker compose up