feat: add scoped image sync endpoint

.env.example

@@ -14,3 +14,5 @@ IMAGE_PUBLIC_BASES=https://sam.hided.net/image,https://sam-image.hided.net
 
 GITEA_WEBHOOK_SECRET_FILE=./secrets/gitea_webhook_secret
 IMAGE_ADMIN_SECRET_FILE=./secrets/image_admin_secret
+IMAGE_SYNC_CORE_SECRET_FILE=./secrets/image_sync_core_secret
+IMAGE_SYNC_CORE2026_SECRET_FILE=./secrets/image_sync_core2026_secret

README.md

@@ -80,6 +80,30 @@ Use branch filter `master`. Disable the old PHP webhook before enabling the new
 writer. The legacy PHP files remain in `hook/` for an explicit rollback, but
 PHP and Node must never mutate the checkout concurrently.
 
+### Fallback sync callers
+
+If Gitea webhook delivery is missed, Core and Core2026 can request a restricted
+reconciliation through `POST /v1/sync`. This endpoint cannot select or change a
+branch: it only fetches the current active branch and applies the same clean
+worktree and fast-forward checks as a webhook deployment.
+
+Each caller has a separate secret:
+
+- `secrets/image_sync_core_secret` for legacy Core
+- `secrets/image_sync_core2026_secret` for Core2026
+
+The caller sends its name, a timestamp, a unique request ID, and an HMAC-SHA256
+signature over `timestamp.request-id.<exact JSON body>`. Requests expire after
+five minutes and successful request IDs are persisted for replay protection.
+The body is either `{}` or `{ "commit": "<full-image-commit-sha>" }`; all other
+fields are rejected. The optional commit asserts the expected remote tip and
+does not grant checkout selection.
+
+Distribute only the matching caller secret through an ignored secret file.
+Never give either caller `image_admin_secret`, which also authorizes explicit
+branch changes. This fallback handles webhook delivery outages; if the image
+service itself is stopped, restore it and run the caller command again.
+
 Legacy HTTP mutation is disabled by default. An emergency PHP rollback must
 first stop `image-hook`, then create the ignored `hook/legacy-enabled` sentinel
 in the legacy checkout before restoring its Caddy/Gitea route. Remove the

compose.yaml

@@ -4,7 +4,7 @@ services:
   image-hook:
     build:
       context: ./node-hook
-    image: sam-image-hook:1.0.0
+    image: sam-image-hook:1.1.0
     restart: unless-stopped
     user: "${IMAGE_UID:-1000}:${IMAGE_GID:-1000}"
     read_only: true
@@ -20,6 +20,7 @@ services:
       IMAGE_STATE_PATH: /var/lib/image-hook/state.json
       GITEA_WEBHOOK_SECRET_FILE: /run/secrets/gitea_webhook_secret
       IMAGE_ADMIN_SECRET_FILE: /run/secrets/image_admin_secret
+      IMAGE_SYNC_CLIENT_SECRET_FILES: core=/run/secrets/image_sync_core_secret,core2026=/run/secrets/image_sync_core2026_secret
     volumes:
       - type: bind
         source: ${IMAGE_REPOSITORY_PATH:-.}
@@ -28,6 +29,8 @@ services:
     secrets:
       - gitea_webhook_secret
       - image_admin_secret
+      - image_sync_core_secret
+      - image_sync_core2026_secret
     tmpfs:
       - /tmp:size=16m,mode=1777
     cap_drop: [ALL]
@@ -47,7 +50,7 @@ services:
   image-web:
     build:
       context: ./deploy/nginx
-    image: sam-image-web:1.0.0
+    image: sam-image-web:1.1.0
     restart: unless-stopped
     depends_on:
       image-hook:
@@ -88,3 +91,7 @@ secrets:
     file: ${GITEA_WEBHOOK_SECRET_FILE:-./secrets/gitea_webhook_secret}
   image_admin_secret:
     file: ${IMAGE_ADMIN_SECRET_FILE:-./secrets/image_admin_secret}
+  image_sync_core_secret:
+    file: ${IMAGE_SYNC_CORE_SECRET_FILE:-./secrets/image_sync_core_secret}
+  image_sync_core2026_secret:
+    file: ${IMAGE_SYNC_CORE2026_SECRET_FILE:-./secrets/image_sync_core2026_secret}

deploy/nginx/templates/default.conf.template

@@ -57,6 +57,18 @@ http {
         proxy_request_buffering on;
     }
 
+    location = /v1/sync {
+        limit_except POST { deny all; }
+        client_max_body_size 4k;
+        proxy_pass http://image-hook:8081/v1/sync;
+        proxy_set_header Host $host;
+        proxy_set_header X-Image-Client $http_x_image_client;
+        proxy_set_header X-Image-Timestamp $http_x_image_timestamp;
+        proxy_set_header X-Image-Request-Id $http_x_image_request_id;
+        proxy_set_header X-Image-Signature $http_x_image_signature;
+        proxy_request_buffering on;
+    }
+
     location ^~ /v1/admin/ { return 404; }
     location = /image { return 404; }
     location = /image/ { return 404; }

deploy/scripts/init-secrets.sh

@@ -9,7 +9,7 @@ state_dir="$repository_dir/runtime-data"
 umask 077
 mkdir -p "$secret_dir"
 mkdir -p "$state_dir"
-for name in gitea_webhook_secret image_admin_secret; do
+for name in gitea_webhook_secret image_admin_secret image_sync_core_secret image_sync_core2026_secret; do
     path="$secret_dir/$name"
     if [ ! -e "$path" ]; then
         openssl rand -hex 32 > "$path"

node-hook/package.json

@@ -1,6 +1,6 @@
 {
   "name": "sam-image-hook",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "private": true,
   "type": "module",
   "engines": {

node-hook/src/config.mjs

@@ -18,6 +18,35 @@ function secret(name, fileName) {
   return readFileSync(path, 'utf8').trim();
 }
 
+function syncClientSecrets() {
+  const entries = text('IMAGE_SYNC_CLIENT_SECRET_FILES', '')
+    .split(',')
+    .map((entry) => entry.trim())
+    .filter(Boolean);
+  if (entries.length === 0) {
+    throw new Error('IMAGE_SYNC_CLIENT_SECRET_FILES is required');
+  }
+
+  const result = Object.create(null);
+  for (const entry of entries) {
+    const separator = entry.indexOf('=');
+    const client = entry.slice(0, separator);
+    const path = entry.slice(separator + 1);
+    if (separator < 1 || !/^[a-z0-9][a-z0-9_-]{1,31}$/.test(client) || !path) {
+      throw new Error(`Invalid image sync client entry: ${entry}`);
+    }
+    const value = readFileSync(path, 'utf8').trim();
+    if (value.length < 32) {
+      throw new Error(`Image sync secret for ${client} must be at least 32 characters`);
+    }
+    if (result[client]) {
+      throw new Error(`Duplicate image sync client: ${client}`);
+    }
+    result[client] = value;
+  }
+  return result;
+}
+
 export function loadConfig() {
   const webhookSecret = secret('GITEA_WEBHOOK_SECRET', 'GITEA_WEBHOOK_SECRET_FILE');
   const adminSecret = secret('IMAGE_ADMIN_SECRET', 'IMAGE_ADMIN_SECRET_FILE');
@@ -44,6 +73,7 @@ export function loadConfig() {
       .filter(Boolean),
     webhookSecret,
     adminSecret,
+    syncClientSecrets: syncClientSecrets(),
     maxBodyBytes: Number(text('MAX_BODY_BYTES', '1048576')),
   };
 }

node-hook/src/git-service.mjs

@@ -77,6 +77,22 @@ export class GitService {
     });
   }
 
+  async deploySync({ requestKey, expectedCommit }) {
+    return this.enqueue(async () => {
+      if (this.state.syncRequests.includes(requestKey)) {
+        return { duplicate: true, ...this.publicStatus() };
+      }
+      const result = await this.#deploy({
+        branch: this.state.activeBranch,
+        expectedCommit,
+        allowUnrelated: false,
+      });
+      this.state.syncRequests = [...this.state.syncRequests.slice(-199), requestKey];
+      await this.#saveState();
+      return result;
+    });
+  }
+
   async #deploy({ branch, expectedCommit, allowUnrelated }) {
     this.#validateBranch(branch);
     await this.#assertClean();
@@ -163,6 +179,7 @@ export class GitService {
         activeBranch: saved.activeBranch ?? this.config.defaultBranch,
         deliveries: Array.isArray(saved.deliveries) ? saved.deliveries : [],
         adminRequests: Array.isArray(saved.adminRequests) ? saved.adminRequests : [],
+        syncRequests: Array.isArray(saved.syncRequests) ? saved.syncRequests : [],
         lastSuccess: saved.lastSuccess ?? null,
         lastError: saved.lastError ?? null,
       };
@@ -174,6 +191,7 @@ export class GitService {
         activeBranch: this.config.defaultBranch,
         deliveries: [],
         adminRequests: [],
+        syncRequests: [],
         lastSuccess: null,
         lastError: null,
       };

node-hook/src/server.mjs

@@ -35,8 +35,8 @@ function parseJson(body) {
   }
 }
 
-export async function createApp(config = loadConfig()) {
-  const service = new GitService(config);
+export async function createApp(config = loadConfig(), dependencies = {}) {
+  const service = dependencies.service ?? new GitService(config);
   await service.initialize();
 
   const server = createServer(async (request, response) => {
@@ -100,6 +100,41 @@ export async function createApp(config = loadConfig()) {
         const result = await service.deployAdmin({ requestId, branch: payload.branch, expectedCommit: payload.commit });
         return json(response, 200, { ok: true, ...result });
       }
+      if (request.method === 'POST' && url.pathname === '/v1/sync') {
+        if (!request.headers['content-type']?.toLowerCase().startsWith('application/json')) {
+          throw new DeploymentError('Content-Type must be application/json', 415);
+        }
+        const body = await readBody(request, config.maxBodyBytes);
+        const client = request.headers['x-image-client'];
+        const timestamp = request.headers['x-image-timestamp'];
+        const requestId = request.headers['x-image-request-id'];
+        const knownClient = typeof client === 'string'
+          && Object.hasOwn(config.syncClientSecrets, client);
+        const signatureValid = verifyAdminSignature({
+          secret: knownClient ? config.syncClientSecrets[client] : 'invalid-client-secret'.padEnd(32, '!'),
+          timestamp,
+          requestId,
+          body,
+          supplied: request.headers['x-image-signature'],
+        });
+        if (!knownClient || !signatureValid) {
+          return json(response, 401, { ok: false, reason: 'invalid sync signature' });
+        }
+        const payload = parseJson(body);
+        if (!payload || Array.isArray(payload) || typeof payload !== 'object'
+          || Object.keys(payload).some((key) => key !== 'commit')) {
+          throw new DeploymentError('Sync body may only contain commit', 400);
+        }
+        if (payload.commit !== undefined
+          && (typeof payload.commit !== 'string' || !/^[0-9a-f]{40,64}$/i.test(payload.commit))) {
+          throw new DeploymentError('Invalid target commit', 400);
+        }
+        const result = await service.deploySync({
+          requestKey: `${client}:${requestId}`,
+          expectedCommit: payload.commit,
+        });
+        return json(response, 200, { ok: true, ...result });
+      }
       return json(response, 404, { ok: false, reason: 'not found' });
     } catch (error) {
       await service.recordError(error).catch(() => undefined);

node-hook/test/git-service.test.mjs

@@ -124,3 +124,19 @@ test('same-branch force pushes and payload SHA mismatches are rejected', async (
     /Payload commit does not match remote branch tip/,
   );
 });
+
+test('signed sync callers can only fast-forward the active branch and requests are idempotent', async (t) => {
+  const f = await fixture();
+  t.after(() => rm(f.root, { recursive: true, force: true }));
+  await writeFile(join(f.seed, 'icons', 'sync.jpg'), 'sync');
+  await git(f.seed, 'add', '.');
+  await git(f.seed, 'commit', '-m', 'sync target');
+  await git(f.seed, 'push', 'origin', 'master');
+  const target = await git(f.seed, 'rev-parse', 'HEAD');
+
+  const result = await f.service.deploySync({ requestKey: 'core:sync-request-1', expectedCommit: target });
+  assert.equal(result.changed, true);
+  assert.equal(await git(f.deployed, 'rev-parse', 'HEAD'), target);
+  assert.equal((await f.service.deploySync({ requestKey: 'core:sync-request-1' })).duplicate, true);
+  assert.equal(f.service.publicStatus().activeBranch, 'master');
+});

node-hook/test/server.test.mjs

@@ -0,0 +1,79 @@
+import assert from 'node:assert/strict';
+import { once } from 'node:events';
+import test from 'node:test';
+import { adminSignature } from '../src/auth.mjs';
+import { createApp } from '../src/server.mjs';
+
+test('sync endpoint authenticates a scoped caller and passes only an optional commit', async (t) => {
+  const calls = [];
+  const service = {
+    async initialize() {},
+    async deploySync(value) {
+      calls.push(value);
+      return { changed: false };
+    },
+    async recordError() {},
+  };
+  const secret = 's'.repeat(32);
+  const { server } = await createApp({
+    maxBodyBytes: 4096,
+    syncClientSecrets: { core: secret },
+  }, { service });
+  server.listen(0, '127.0.0.1');
+  await once(server, 'listening');
+  t.after(() => server.close());
+  const address = server.address();
+  const body = Buffer.from(JSON.stringify({ commit: 'a'.repeat(40) }));
+  const timestamp = String(Date.now());
+  const requestId = 'sync-request-1234';
+  const response = await fetch(`http://127.0.0.1:${address.port}/v1/sync`, {
+    method: 'POST',
+    headers: {
+      'content-type': 'application/json',
+      'x-image-client': 'core',
+      'x-image-timestamp': timestamp,
+      'x-image-request-id': requestId,
+      'x-image-signature': adminSignature(secret, timestamp, requestId, body),
+    },
+    body,
+  });
+
+  assert.equal(response.status, 200);
+  assert.deepEqual(calls, [{ requestKey: `core:${requestId}`, expectedCommit: 'a'.repeat(40) }]);
+});
+
+test('sync endpoint rejects unknown callers and body fields outside the sync contract', async (t) => {
+  const service = {
+    async initialize() {},
+    async deploySync() { throw new Error('must not deploy'); },
+    async recordError() {},
+  };
+  const secret = 's'.repeat(32);
+  const { server } = await createApp({ maxBodyBytes: 4096, syncClientSecrets: { core: secret } }, { service });
+  server.listen(0, '127.0.0.1');
+  await once(server, 'listening');
+  t.after(() => server.close());
+  const address = server.address();
+  const body = Buffer.from(JSON.stringify({ branch: 'preview' }));
+  const timestamp = String(Date.now());
+  const requestId = 'sync-request-5678';
+  const signedHeaders = {
+    'content-type': 'application/json',
+    'x-image-timestamp': timestamp,
+    'x-image-request-id': requestId,
+    'x-image-signature': adminSignature(secret, timestamp, requestId, body),
+  };
+
+  const unknown = await fetch(`http://127.0.0.1:${address.port}/v1/sync`, {
+    method: 'POST', headers: { ...signedHeaders, 'x-image-client': 'unknown' }, body,
+  });
+  assert.equal(unknown.status, 401);
+  const prototypeName = await fetch(`http://127.0.0.1:${address.port}/v1/sync`, {
+    method: 'POST', headers: { ...signedHeaders, 'x-image-client': 'toString' }, body,
+  });
+  assert.equal(prototypeName.status, 401);
+  const extraField = await fetch(`http://127.0.0.1:${address.port}/v1/sync`, {
+    method: 'POST', headers: { ...signedHeaders, 'x-image-client': 'core' }, body,
+  });
+  assert.equal(extraField.status, 400);
+});