Environment variables

Wasm Workers Server allows you to configure environment variables so a worker can read them. This configuration is done through the TOML file associated to a worker (a TOML file with the same filename as the worker). This means every worker has its own set of environment variables.

The following TOML config file adds a new JSON_MESSAGE environment variable:

name = "json"
version = "1"

[vars]
JSON_MESSAGE = "Hello 👋! This message comes from an environment variable"

Then, you can read them in your worker:

• Read environment variables in JavaScript
• Read environment variables in Rust
• Read environment variables in Python
• Read environment variables in Ruby
• Read environment variables in Go
• Read environment variables in Zig

Inject existing environment variables

You can inject existing environment variables from your current context. In this case, the value of the configured variable will be the name of the existing one with the $ prefix.

For example, let's configure the TOKEN variable for the previous worker. This variable will get its value from the TOKEN environment variable in the current context:

name = "json"
version = "1"

[vars]
JSON_MESSAGE = "Hello 👋! This message comes from an environment variable"
TOKEN = "$TOKEN"

This feature allows you to configure environment variables dynamically.

Language compatibility

Language	Environment variables
JavaScript	✅
Rust	✅
Go	✅
Ruby	✅
Python	✅
Zig	✅