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Version: Python

Environmental variables

Environmental variables are commonly found amongst applications, especially when dealing with sensitive information like API keys. This guide shows how to set environmental variables for use in Deephaven via Docker.

docker-compose.yml​

Environmental variables must be set in the server 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:
  server:
    image: ghcr.io/deephaven/server:${VERSION:-latest}
    expose:
      - '8080'
    volumes:
      - ./data:/data
      - api-cache:/cache
    environment:
      - START_OPTS=-Xmx4g -Ddeephaven.console.type=python
      - MY_VALUE=test

You can now see your environmental variables in Deephaven on launch:

import os

print(os.environ)

Parameterizing the environmental 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, we can use the bracket syntax ${MY_VALUE} within our docker-compose.yml file. The value in the bracket will be filled in by the current environmental variable on the system.

    - MY_VALUE=${MY_VALUE}

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

Settings environmental variables locally​

There are many ways to set environmental variables locally. Covering all of them is beyond the scope of this documentation, but there are many guides out there for that information. Here we will show two primary ways to set environmental 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 environmental variables.

.env

MY_VALUE=test

These environmental variables will be set when using docker compose up.

CLI parameters​

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

MY_VALUE=test docker compose up