Request Lifecycle Plugin

This Go dynamic-library plugin demonstrates request admission, active termination, and exactly-once terminal lifecycle handling. It requires a host that supports plugin RPC schema version 2 or newer.

It declares two optional capabilities:

request_interceptor: acquires a concurrency slot in request.intercept_before and can terminate the request before any upstream executor runs.
request_lifecycle_plugin: releases the slot in request.complete for successful, failed, rejected, and canceled requests.

The host passes the same RequestID to request interception, response interception, stream interception, and the terminal RequestCompletion event.

Behavior

Allows at most max_concurrency requests in flight.
Returns a custom 429 JSON response with Retry-After: 1 when the limit is reached.
Returns a custom 403 JSON response when the raw request body contains reject_keyword.
Does not send terminated requests to an upstream model.
Releases only request IDs that were previously admitted, so rejected requests and duplicate terminal events do not underflow the counter.

Configuration

yaml

plugins:
  enabled: true
  configs:
    request-lifecycle:
      enabled: true
      priority: 100
      max_concurrency: 2
      reject_keyword: "blocked"

Set reject_keyword to an empty string to disable keyword rejection.

Build

From the repository root on macOS:

bash

mkdir -p plugins/darwin/$(go env GOARCH)
go build -buildmode=c-shared \
  -o plugins/darwin/$(go env GOARCH)/request-lifecycle.dylib \
  ./examples/plugin/request-lifecycle/go
rm -f plugins/darwin/$(go env GOARCH)/request-lifecycle.h

Use .so on Linux or FreeBSD and .dll on Windows.

The output filename is the plugin ID, so the example artifact must be named request-lifecycle for the configuration above.

Relevant RPC Methods

text

plugin.register
plugin.reconfigure
request.intercept_before
request.intercept_after
request.complete

request.complete is an observational callback. The host schedules it asynchronously so a blocked plugin cannot delay response delivery, logs callback errors, and uses a context detached from downstream cancellation so a canceled request can still release its slot.