SpEL Environment variables

The tsmRuntimeConfig provides a safe way to read configuration parameters at runtime. It offers a mechanism for accessing values defined in the application (e.g., in application.yaml) with an emphasis on security when used in dynamic scripts (SpEL).

Key Features

• Priority Search: First, it searches in the "safe" tsm.runtime map, then in the Spring Environment.
• Security (Whitelist): Access to the Environment is restricted to keys with allowed prefixes.

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Configuration

Properties are configured using the tsm prefix.

tsm:
  # Definition of safe parameters directly in the configuration
  runtime:
    prefix: "TSM-DEV-"
    timeoutMs: "5000"
    apiBaseUrl: "https://api.example.com"
  
  # Environment access settings (optional)
  spel-access:
    allowed-prefixes:
      - "tsm.runtime"
      - "app.custom"

Property	Description	Default Value
tsm.runtime	A key-value map accessible without restrictions.	empty map
tsm.spel-access.allowed-prefixes	A list of prefixes allowed to be read from the Environment.	["tsm.runtime"]

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Usage in SpEL (Scripts, Camunda)

The component is available in the Spring context under the name tsmRuntimeConfig. The most common use is in dynamic expressions.

Get value:

@tsmRuntimeConfig.get("tsm.runtime.prefix")

Note: If the key does not exist and the prefix is not allowed, an AccessDeniedException may be thrown.

Get value with a default:

@tsmRuntimeConfig.getOrDefault("timeoutMs", "1000")

Require a value (throws an error if missing):

@tsmRuntimeConfig.require("apiBaseUrl")

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The default allowed prefix is tsm.runtime. Therefore, if you want to access any system property (e.g., java.version), you must explicitly allow it in allowed-prefixes or use * (not recommended).