Struct EnvAllowlist 

pub struct EnvAllowlist { /* private fields */ }

The environment variables a deployed agent config is permitted to reference via ${VAR} — least privilege over the deploying process’s secrets.

Without this, any config the control plane accepts can name any variable the control-plane process holds (description = "${AWS_SECRET_ACCESS_KEY}") and have it expanded into the agent’s card, where anyone who can fetch the card reads it back. The allowlist is the operator’s explicit statement of which secrets the platform is willing to hand to agents.

Deny-by-default: deny_all is the Default, so a runtime built without an explicit allowlist rejects every config that references anything. Populate it at the composition edge (the --allow-env flag on a2a control-plane).

Implementations

impl EnvAllowlist

pub fn new(vars: impl IntoIterator<Item = impl Into<String>>) -> Self

Allow exactly these variable names.

pub fn deny_all() -> Self

Allow nothing — any ${VAR} reference in a deployed config is rejected.

pub fn is_empty(&self) -> bool

Whether any variable is permitted.

pub fn check(&self, raw_config: &str) -> Result<Vec<String>, RuntimeError>

Check a raw, unexpanded config against the allowlist, returning the variables it legitimately references (in sorted order) for a runtime to inject.

Call this before parsing the config. Expansion resolves ${VAR} against the host environment and errors differently for a set vs. unset variable, so parsing first would let a rejected config probe which secrets the control-plane process holds.

HOST is excluded from the result and exempt from the check: it is adapter-owned (the container runtime sets HOST=0.0.0.0 itself).

Trait Implementations

impl Clone for EnvAllowlist

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for EnvAllowlist

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for EnvAllowlist

fn default() -> Self

Returns the “default value” for a type.