get-sandbox-id

A UUID generated by Fastly for each sandbox.

This is often a useful value to include in log messages, and also to send to upstream servers as an additional custom HTTP header, allowing for straightforward correlation of which sandbox processed a request to requests later processed by an origin server.

By default, each sandbox handles exactly one downstream request, in which case this sandbox UUID is unique for each request. However, by using http-downstream.next-request, a single sandbox can accept multiple downstream requests. For a UUID that reliably identifies a request, you may wish to use http-downstream.downstream-client-request-id.

Equivalent to the "FASTLY_TRACE_ID" environment variable.