Add optional Discord webhook notifications

README.md

@@ -18,8 +18,14 @@ PORT=3000
 DATA_DIR=/app/data
 JOJO_WEBHOOK_SECRET=...
 GITHUB_WEBHOOK_SECRET=...
+DISCORD_WEBHOOK_URL=
+DISCORD_NOTIFY_EVENTS=push,pull_request,release
 ```
 
+Discord notifications are optional. When `DISCORD_WEBHOOK_URL` is unset, the
+service skips Discord output. `DISCORD_NOTIFY_EVENTS` is a comma-separated
+allow list and defaults to `push,pull_request,release`.
+
 ## Development
 
 ```bash

src/discord.ts

@@ -0,0 +1,159 @@
+import type { GitWebhookEvent, QueuedJob } from "./types";
+
+type DiscordEmbedField = {
+  name: string;
+  value: string;
+  inline?: boolean;
+};
+
+type DiscordEmbed = {
+  title: string;
+  description?: string;
+  url?: string;
+  color: number;
+  fields: DiscordEmbedField[];
+  timestamp: string;
+  footer: {
+    text: string;
+  };
+};
+
+type DiscordPayload = {
+  username: string;
+  embeds: DiscordEmbed[];
+};
+
+type FetchLike = (url: string, init: RequestInit) => Promise<Response>;
+
+export type DiscordConfig = {
+  webhookUrl?: string;
+  notifyEvents: Set<string>;
+};
+
+export type DiscordNotification = {
+  event: GitWebhookEvent;
+  job?: QueuedJob | null;
+};
+
+const defaultNotifyEvents = ["push", "pull_request", "release"];
+
+export function parseDiscordConfig(input: {
+  webhookUrl?: string;
+  notifyEvents?: string;
+}): DiscordConfig {
+  const notifyEvents = new Set(
+    (input.notifyEvents?.trim() ? input.notifyEvents : defaultNotifyEvents.join(","))
+      .split(",")
+      .map((event) => event.trim())
+      .filter(Boolean),
+  );
+
+  return {
+    webhookUrl: input.webhookUrl?.trim() || undefined,
+    notifyEvents,
+  };
+}
+
+function branchName(ref?: string): string | undefined {
+  return ref?.startsWith("refs/heads/") ? ref.slice("refs/heads/".length) : ref;
+}
+
+function shortSha(sha?: string): string | undefined {
+  return sha ? sha.slice(0, 12) : undefined;
+}
+
+function eventTitle(event: GitWebhookEvent): string {
+  const repo = event.repo?.fullName ?? "unknown repo";
+  if (event.event === "push") {
+    return `[${event.provider}] ${repo} push${branchName(event.ref) ? ` to ${branchName(event.ref)}` : ""}`;
+  }
+  if (event.event === "pull_request") {
+    return `[${event.provider}] ${repo} pull_request${event.action ? ` ${event.action}` : ""}`;
+  }
+  if (event.event === "release") {
+    return `[${event.provider}] ${repo} release${event.action ? ` ${event.action}` : ""}`;
+  }
+  return `[${event.provider}] ${repo} ${event.event}`;
+}
+
+function rawRecord(event: GitWebhookEvent): Record<string, unknown> {
+  return typeof event.raw === "object" && event.raw !== null ? event.raw as Record<string, unknown> : {};
+}
+
+function objectRecord(value: unknown): Record<string, unknown> | undefined {
+  return typeof value === "object" && value !== null ? value as Record<string, unknown> : undefined;
+}
+
+function stringValue(value: unknown): string | undefined {
+  return typeof value === "string" && value.trim() ? value : undefined;
+}
+
+function eventUrl(event: GitWebhookEvent): string | undefined {
+  const raw = rawRecord(event);
+  if (event.event === "push") {
+    const headCommit = objectRecord(raw.head_commit);
+    return stringValue(headCommit?.url) ?? stringValue(raw.compare_url);
+  }
+  if (event.event === "pull_request") {
+    return stringValue(objectRecord(raw.pull_request)?.html_url);
+  }
+  if (event.event === "release") {
+    return stringValue(objectRecord(raw.release)?.html_url);
+  }
+  return undefined;
+}
+
+function field(name: string, value?: string, inline = true): DiscordEmbedField | null {
+  if (!value) return null;
+  return { name, value: value.slice(0, 1024), inline };
+}
+
+export function buildDiscordPayload(input: DiscordNotification): DiscordPayload {
+  const { event, job } = input;
+  const fields = [
+    field("Provider", event.provider),
+    field("Repo", event.repo?.fullName),
+    field("Event", event.action ? `${event.event}:${event.action}` : event.event),
+    field("Branch", branchName(event.ref)),
+    field("Sender", event.sender?.username),
+    field("SHA", shortSha(event.after)),
+    field("Queued", job ? job.kind : undefined),
+    field("Delivery", event.deliveryId, false),
+  ].filter((item): item is DiscordEmbedField => item !== null);
+
+  return {
+    username: "git-webhooks",
+    embeds: [
+      {
+        title: eventTitle(event).slice(0, 256),
+        url: eventUrl(event),
+        color: event.provider === "github" ? 0x24292f : 0xf97316,
+        fields,
+        timestamp: event.receivedAt,
+        footer: {
+          text: "git-webhooks",
+        },
+      },
+    ],
+  };
+}
+
+export async function notifyDiscord(
+  config: DiscordConfig,
+  notification: DiscordNotification,
+  fetchImpl: FetchLike = fetch,
+): Promise<void> {
+  if (!config.webhookUrl || !config.notifyEvents.has(notification.event.event)) {
+    return;
+  }
+
+  const response = await fetchImpl(config.webhookUrl, {
+    method: "POST",
+    headers: { "content-type": "application/json" },
+    body: JSON.stringify(buildDiscordPayload(notification)),
+  });
+
+  if (!response.ok) {
+    throw new Error(`Discord webhook returned ${response.status}`);
+  }
+}

src/server.ts

@@ -1,4 +1,5 @@
 import { randomUUID } from "node:crypto";
+import { notifyDiscord, parseDiscordConfig, type DiscordConfig } from "./discord";
 import { jsonResponse, methodNotAllowed, textResponse } from "./http";
 import { normalizeGithubEvent } from "./providers/github";
 import { normalizeJojoEvent } from "./providers/jojo";
@@ -12,6 +13,7 @@ export type ServerConfig = {
   githubSecret: string;
   jojoSecret: string;
   dataDir: string;
+  discord?: DiscordConfig;
 };
 
 function getHeader(headers: Headers, name: string, fallback: string): string {
@@ -31,12 +33,25 @@ async function parseJsonBody(request: Request): Promise<{ body: string; payload:
   }
 }
 
-async function persistAcceptedEvent(store: EventStore, event: GitWebhookEvent): Promise<Response> {
+async function persistAcceptedEvent(store: EventStore, event: GitWebhookEvent, discord?: DiscordConfig): Promise<Response> {
   await store.appendEvent(event);
   const job = jobForEvent(event);
   if (job) {
     await store.appendJob(job);
   }
+
+  try {
+    await notifyDiscord(discord ?? parseDiscordConfig({}), { event, job });
+  } catch (error) {
+    console.error(JSON.stringify({
+      type: "discord.notify_failed",
+      provider: event.provider,
+      event: event.event,
+      deliveryId: event.deliveryId,
+      error: error instanceof Error ? error.message : String(error),
+    }));
+  }
+
   console.log(JSON.stringify({ type: "webhook.accepted", provider: event.provider, event: event.event, deliveryId: event.deliveryId, job: job?.id }));
   return jsonResponse({ status: event.event === "ping" ? "ok" : "accepted", event: event.event, deliveryId: event.deliveryId }, {
     status: event.event === "ping" ? 200 : 202,
@@ -57,7 +72,7 @@ async function handleGithub(request: Request, config: ServerConfig, store: Event
     receivedAt: new Date().toISOString(),
     payload: parsed.payload as never,
   });
-  return persistAcceptedEvent(store, event);
+  return persistAcceptedEvent(store, event, config.discord);
 }
 
 async function handleJojo(request: Request, config: ServerConfig, store: EventStore): Promise<Response> {
@@ -74,7 +89,7 @@ async function handleJojo(request: Request, config: ServerConfig, store: EventSt
     receivedAt: new Date().toISOString(),
     payload: parsed.payload as never,
   });
-  return persistAcceptedEvent(store, event);
+  return persistAcceptedEvent(store, event, config.discord);
 }
 
 export function createHandler(config: ServerConfig): (request: Request) => Promise<Response> | Response {
@@ -102,6 +117,10 @@ if (import.meta.main) {
     githubSecret: process.env.GITHUB_WEBHOOK_SECRET ?? "",
     jojoSecret: process.env.JOJO_WEBHOOK_SECRET ?? "",
     dataDir: process.env.DATA_DIR ?? "./data",
+    discord: parseDiscordConfig({
+      webhookUrl: process.env.DISCORD_WEBHOOK_URL,
+      notifyEvents: process.env.DISCORD_NOTIFY_EVENTS,
+    }),
   };
 
   Bun.serve({

test/discord.test.ts

@@ -0,0 +1,91 @@
+import { describe, expect, test } from "bun:test";
+import { buildDiscordPayload, notifyDiscord, parseDiscordConfig } from "../src/discord";
+import type { GitWebhookEvent } from "../src/types";
+
+const pushEvent: GitWebhookEvent = {
+  provider: "jojo",
+  event: "push",
+  providerEvent: "push",
+  deliveryId: "delivery-1",
+  receivedAt: "2026-05-12T21:00:00.000Z",
+  repo: {
+    owner: "peezy-tech",
+    name: "git-webhooks",
+    fullName: "peezy-tech/git-webhooks",
+  },
+  sender: {
+    username: "matamune",
+  },
+  ref: "refs/heads/main",
+  after: "0123456789abcdef",
+  raw: {
+    head_commit: {
+      url: "https://jojo.build/peezy-tech/git-webhooks/commit/0123456789abcdef",
+    },
+  },
+};
+
+describe("discord notifications", () => {
+  test("parses default notify events", () => {
+    const config = parseDiscordConfig({});
+    expect(config.notifyEvents.has("push")).toBe(true);
+    expect(config.notifyEvents.has("pull_request")).toBe(true);
+    expect(config.notifyEvents.has("release")).toBe(true);
+    expect(config.notifyEvents.has("ping")).toBe(false);
+  });
+
+  test("builds readable push embeds", () => {
+    const payload = buildDiscordPayload({
+      event: pushEvent,
+      job: {
+        id: "jojo:delivery-1:main_push",
+        kind: "main_push",
+        provider: "jojo",
+        repoFullName: "peezy-tech/git-webhooks",
+        ref: "refs/heads/main",
+        sha: "0123456789abcdef",
+        deliveryId: "delivery-1",
+        createdAt: "2026-05-12T21:00:00.000Z",
+      },
+    });
+
+    expect(payload.username).toBe("git-webhooks");
+    expect(payload.embeds[0].title).toBe("[jojo] peezy-tech/git-webhooks push to main");
+    expect(payload.embeds[0].url).toBe("https://jojo.build/peezy-tech/git-webhooks/commit/0123456789abcdef");
+    expect(payload.embeds[0].fields).toContainEqual({ name: "Queued", value: "main_push", inline: true });
+  });
+
+  test("does nothing without a webhook URL", async () => {
+    let calls = 0;
+    await notifyDiscord(parseDiscordConfig({}), { event: pushEvent }, async () => {
+      calls += 1;
+      return new Response(null, { status: 204 });
+    });
+    expect(calls).toBe(0);
+  });
+
+  test("skips unconfigured events", async () => {
+    let calls = 0;
+    await notifyDiscord(parseDiscordConfig({ webhookUrl: "https://discord.example/webhook", notifyEvents: "release" }), { event: pushEvent }, async () => {
+      calls += 1;
+      return new Response(null, { status: 204 });
+    });
+    expect(calls).toBe(0);
+  });
+
+  test("posts configured events", async () => {
+    let body = "";
+    await notifyDiscord(parseDiscordConfig({ webhookUrl: "https://discord.example/webhook", notifyEvents: "push" }), { event: pushEvent }, async (_url, init) => {
+      body = String(init?.body);
+      return new Response(null, { status: 204 });
+    });
+
+    expect(JSON.parse(body).embeds[0].title).toBe("[jojo] peezy-tech/git-webhooks push to main");
+  });
+
+  test("throws on Discord failure", async () => {
+    await expect(notifyDiscord(parseDiscordConfig({ webhookUrl: "https://discord.example/webhook" }), { event: pushEvent }, async () => {
+      return new Response("bad", { status: 500 });
+    })).rejects.toThrow("Discord webhook returned 500");
+  });
+});

test/server.test.ts

@@ -57,4 +57,38 @@ describe("server", () => {
     expect(await readFile(join(dataDir, "events.jsonl"), "utf8")).toContain("\"provider\":\"jojo\"");
     expect(await readFile(join(dataDir, "jobs.jsonl"), "utf8")).toContain("\"kind\":\"main_push\"");
   });
+
+  test("continues accepting webhooks when Discord returns an error", async () => {
+    const originalFetch = globalThis.fetch;
+    globalThis.fetch = (async () => new Response("bad", { status: 500 })) as unknown as typeof fetch;
+
+    try {
+      const dataDir = await mkdtemp(join(tmpdir(), "git-webhooks-"));
+      const handler = createHandler({
+        githubSecret: "gh",
+        jojoSecret: "jojo",
+        dataDir,
+        discord: {
+          webhookUrl: "https://discord.example/webhook",
+          notifyEvents: new Set(["push"]),
+        },
+      });
+      const request = await signedRequest("/git-webhooks/jojo", "jojo", "jojo", {
+        ref: "refs/heads/main",
+        after: "abc123",
+        repository: {
+          name: "git-webhooks",
+          full_name: "peezy-tech/git-webhooks",
+          owner: { username: "peezy-tech" },
+        },
+      });
+
+      const response = await handler(request);
+      expect(response.status).toBe(202);
+      expect(await readFile(join(dataDir, "events.jsonl"), "utf8")).toContain("\"provider\":\"jojo\"");
+      expect(await readFile(join(dataDir, "jobs.jsonl"), "utf8")).toContain("\"kind\":\"main_push\"");
+    } finally {
+      globalThis.fetch = originalFetch;
+    }
+  });
 });