1import * as Lambda from "@/AWS/Lambda";
2import { Bucket } from "@/AWS/S3";
3import * as Synthetics from "@/AWS/Synthetics";
4import * as Output from "@/Output";
5import * as Duration from "effect/Duration";
6import * as Effect from "effect/Effect";
7import * as Layer from "effect/Layer";
8import * as Stream from "effect/Stream";
9import { HttpServerRequest } from "effect/http/HttpServerRequest";
10import * as HttpServerResponse from "effect/http/HttpServerResponse";
11import path from "pathe";
12
13const main = path.resolve(import.meta.dirname, "handler.ts");
14
15// Trivial heartbeat script — a single successful step, no page load.
16const HEARTBEAT_SCRIPT = `
17const synthetics = require("Synthetics");
18exports.handler = async function () {
19 return await synthetics.executeStep("heartbeat", async function () {});
20};
21`;
22
23export class SyntheticsBindingsFunction extends Lambda.Function<Lambda.Function>()(
24 "SyntheticsBindingsFunction",
25) {}
26
27export default SyntheticsBindingsFunction.make(
28 {
29 main,
30 functionUrl: true,
31 timeout: Duration.seconds(120),
32 },
33 Effect.gen(function* () {
34 const bucket = yield* Bucket("SynthBindingsArtifacts", {
35 forceDestroy: true,
36 });
37 // `rate(0 minute)` = run exactly once when started, so /start does not
38 // leave a continuously-running canary behind.
39 const canary = yield* Synthetics.Canary("BindingsCanary", {
40 script: HEARTBEAT_SCRIPT,
41 artifactS3Location: Output.interpolate`s3://${bucket.bucketName}/bindings`,
42 schedule: { expression: "rate(0 minute)" },
43 runConfig: { timeout: "60 seconds" },
44 successRetentionPeriod: "1 day",
45 failureRetentionPeriod: "1 day",
46 });
47
48 // Event source: subscribe the host to this canary's status/run events.
49 // The deploy proves the EventBridge rule + invoke permission wiring.
50 yield* Synthetics.consumeCanaryEvents(
51 { canaryNames: [canary.canaryName] },
52 (events) =>
53 Stream.runForEach(events, (event) =>
54 Effect.log(
55 `synthetics event: ${event["detail-type"]} for ${event.detail["canary-name"]}`,
56 ),
57 ),
58 );
59
60 const bound = {
61 getCanary: yield* Synthetics.GetCanary(canary),
62 getCanaryRuns: yield* Synthetics.GetCanaryRuns(canary),
63 startCanary: yield* Synthetics.StartCanary(canary),
64 stopCanary: yield* Synthetics.StopCanary(canary),
65 describeCanariesLastRun: yield* Synthetics.DescribeCanariesLastRun(),
66 };
67
68 return {
69 fetch: Effect.gen(function* () {
70 const request = yield* HttpServerRequest;
71 const url = new URL(request.originalUrl);
72 const pathname = url.pathname;
73
74 if (request.method === "GET" && pathname === "/bindings") {
75 return yield* HttpServerResponse.json({
76 bound: Object.keys(bound),
77 });
78 }
79
80 // Canary-scoped read — the canary name is injected.
81 if (request.method === "GET" && pathname === "/canary") {
82 const result = yield* bound.getCanary().pipe(
83 Effect.map((r) => ({
84 tag: "ok",
85 state: r.Canary?.Status?.State,
86 })),
87 Effect.catch((e) =>
88 Effect.succeed({ tag: e._tag, state: undefined }),
89 ),
90 );
91 return yield* HttpServerResponse.json(result);
92 }
93
94 if (request.method === "GET" && pathname === "/runs") {
95 const result = yield* bound.getCanaryRuns({ MaxResults: 10 }).pipe(
96 Effect.map((r) => ({
97 tag: "ok",
98 count: (r.CanaryRuns ?? []).length,
99 })),
100 Effect.catch((e) =>
101 Effect.succeed({ tag: e._tag, count: undefined }),
102 ),
103 );
104 return yield* HttpServerResponse.json(result);
105 }
106
107 // Account-level read across every canary.
108 if (request.method === "GET" && pathname === "/last-run") {
109 const result = yield* bound.describeCanariesLastRun().pipe(
110 Effect.map((r) => ({
111 tag: "ok",
112 count: (r.CanariesLastRun ?? []).length,
113 })),
114 Effect.catch((e) =>
115 Effect.succeed({ tag: e._tag, count: undefined }),
116 ),
117 );
118 return yield* HttpServerResponse.json(result);
119 }
120
121 // Control plane: start the (READY) canary / stop it. A typed
122 // ConflictException still proves the grant round-tripped.
123 if (request.method === "GET" && pathname === "/start") {
124 const tag = yield* bound.startCanary().pipe(
125 Effect.map(() => "ok"),
126 Effect.catch((e) => Effect.succeed(e._tag)),
127 );
128 return yield* HttpServerResponse.json({ tag });
129 }
130
131 if (request.method === "GET" && pathname === "/stop") {
132 const tag = yield* bound.stopCanary().pipe(
133 Effect.map(() => "ok"),
134 Effect.catch((e) => Effect.succeed(e._tag)),
135 );
136 return yield* HttpServerResponse.json({ tag });
137 }
138
139 return yield* HttpServerResponse.json(
140 { error: "Not found", method: request.method, pathname },
141 { status: 404 },
142 );
143 }).pipe(Effect.orDie),
144 };
145 }).pipe(
146 Effect.provide(
147 Layer.mergeAll(
148 Lambda.EventSource,
149 Synthetics.GetCanaryHttp,
150 Synthetics.GetCanaryRunsHttp,
151 Synthetics.StartCanaryHttp,
152 Synthetics.StopCanaryHttp,
153 Synthetics.DescribeCanariesLastRunHttp,
154 ),
155 ),
156 ),
157);