| 1 | import * as AWS from "@/AWS/index.ts"; |
| 2 | import * as Context from "effect/Context"; |
| 3 | import * as Effect from "effect/Effect"; |
| 4 | import * as Layer from "effect/Layer"; |
| 5 | import * as HttpClient from "effect/http/HttpClient"; |
| 6 | import * as HttpServerResponse from "effect/http/HttpServerResponse"; |
| 7 | |
| 8 | /** |
| 9 | * A service whose Layer performs real async I/O during the sandbox's init |
| 10 | * (cold start) — the "fetch a value once and cache it for every |
| 11 | * invocation" pattern. |
| 12 | */ |
| 13 | class TraceConfig extends Context.Service< |
| 14 | TraceConfig, |
| 15 | { trace: string; nonce: string } |
| 16 | >()("InitIO.TraceConfig") {} |
| 17 | |
| 18 | const TraceConfigLive = Layer.effect( |
| 19 | TraceConfig, |
| 20 | Effect.gen(function* () { |
| 21 | // Counted per sandbox so every response can assert the layer's I/O ran |
| 22 | // exactly once no matter how many invocations the sandbox has served. |
| 23 | yield* Effect.sync(() => { |
| 24 | (globalThis as any).__initFetches = |
| 25 | ((globalThis as any).__initFetches ?? 0) + 1; |
| 26 | }); |
| 27 | const client = yield* HttpClient.HttpClient; |
| 28 | const response = yield* client.get( |
| 29 | "https://www.cloudflare.com/cdn-cgi/trace", |
| 30 | ); |
| 31 | const trace = yield* response.text; |
| 32 | return { trace, nonce: crypto.randomUUID() }; |
| 33 | }).pipe( |
| 34 | // A failed init fetch is a defect: the sandbox is useless without its |
| 35 | // config, and init's typed error channel is reserved for ConfigError. |
| 36 | Effect.orDie, |
| 37 | ), |
| 38 | ); |
| 39 | |
| 40 | /** |
| 41 | * Pins that one-shot async I/O during init / layer build works on Lambda: |
| 42 | * the layer's fetch runs exactly once per sandbox (at cold start, under the |
| 43 | * instance scope) and the cached plain value serves every invocation. |
| 44 | */ |
| 45 | export default class InitIOProbe extends AWS.Lambda.Function<InitIOProbe>()( |
| 46 | "InitIOProbe", |
| 47 | { |
| 48 | main: import.meta.url, |
| 49 | functionUrl: true, |
| 50 | }, |
| 51 | Effect.gen(function* () { |
| 52 | const config = yield* TraceConfig; |
| 53 | |
| 54 | return { |
| 55 | fetch: Effect.gen(function* () { |
| 56 | return yield* HttpServerResponse.json({ |
| 57 | nonce: config.nonce, |
| 58 | traceLength: config.trace.length, |
| 59 | hasUag: config.trace.includes("uag="), |
| 60 | initFetches: (globalThis as any).__initFetches ?? 0, |
| 61 | }); |
| 62 | }), |
| 63 | }; |
| 64 | }).pipe(Effect.provide(TraceConfigLive)), |
| 65 | ) {} |