Peren documentation
Worker isolation
Limits on a Worker isolate, and which calls leave the isolate through a binding.
Worker code runs inside a V8 isolate. It can reach the node only through bindings you configured. Signing keys and client certificate PEM stay in the node process.
Isolate and resource limits
What it covers: the Worker isolate, its heap, and the wall-clock duration of one invocation.
What Peren does: Worker execution inside a V8 isolate, with heap and wall-clock ceilings taken from fleet [limits] (and per-service overrides where configured). Defaults on the live HTTP path:
| Field | Default |
|---|---|
max_request_body_bytes |
32 MiB |
max_heap_bytes |
128 MiB |
max_execution_time_ms |
30000 |
max_subrequests_per_invocation |
10000 |
max_isolates |
256 |
Crossing max_heap_bytes terminates the isolate. max_execution_time_ms ends a long invocation. max_isolates caps how many isolates the process admits at once.
max_cpu_time_ms exists in config and defaults to 30000. Peren does not apply it to live HTTP requests. max_execution_time_ms is the limit that stops a long request.
What you configure: which [limits] and per-service override values the fleet file declares, and that those values match the workload the node must serve.
What you can check: a Worker that allocates past max_heap_bytes stops. A request longer than max_execution_time_ms stops. See Limits and Workers.
Host-mediated bindings
What it covers: every host capability the Worker can call: storage, queues, outbound HTTP, SigV4, client mTLS, and other bindings.
What Peren does: the node places bindings on env and performs the calls. The Worker receives those bindings and the secret strings you declared. It does not receive the process environment, the filesystem, or open network access.
AWS SigV4 keys are read by the host from environment variables named in the binding. Client mTLS PEM is read by the host from cert_pem_env and key_pem_env. The Worker cannot read those keys or PEM values. SigV4 signing runs in the node process. The node attaches the mTLS identity when the Worker passes that binding into fetch for an allowed host.
What you configure: which bindings appear on each service, which environment variables supply provider material, and which names are Worker-readable secrets.
What you can check: the Worker can use the binding and cannot read the SigV4 keys or the mTLS PEM. See Credentials and secrets.