From 995b59060c7c52b3f11b6ef8e1a8dca349599300 Mon Sep 17 00:00:00 2001
From: Alex Alaniz <Alex@AlexAlaniz.com>
Date: Thu, 26 Mar 2026 11:45:28 -0400
Subject: [PATCH] fix: handle expected fly exec 412s gracefully

---
 src/app/api/channels/route.ts                | 16 ++++++++-
 src/app/api/gateway/approve-pairing/route.ts |  3 ++
 src/lib/fly.ts                               | 36 ++++++++++++++++++--
 3 files changed, 52 insertions(+), 3 deletions(-)

diff --git a/src/app/api/channels/route.ts b/src/app/api/channels/route.ts
index a224055..7a8a8c9 100644
--- a/src/app/api/channels/route.ts
+++ b/src/app/api/channels/route.ts
@@ -4,7 +4,12 @@ import * as Sentry from '@sentry/nextjs';
 import { authOptions, getUserEmail } from '@/lib/auth';
 import { rateLimit, rateLimitResponse } from '@/lib/rate-limit';
 import { getInstanceByUserId } from '@/lib/supabase';
-import { getGatewayChannels, setGatewayChannel, removeGatewayChannel } from '@/lib/fly';
+import {
+  getGatewayChannels,
+  isFlyMachineNotRunningError,
+  removeGatewayChannel,
+  setGatewayChannel,
+} from '@/lib/fly';
 
 export const runtime = 'nodejs';
 export const dynamic = 'force-dynamic';
@@ -50,6 +55,9 @@ export async function GET() {
 
     return NextResponse.json({ channels: safe, available: Object.keys(CHANNEL_SCHEMA) });
   } catch (error) {
+    if (isFlyMachineNotRunningError(error)) {
+      return NextResponse.json({ channels: {}, available: Object.keys(CHANNEL_SCHEMA) });
+    }
     Sentry.captureException(error);
     return NextResponse.json({ error: 'Failed to fetch channels' }, { status: 500 });
   }
@@ -118,6 +126,9 @@ export async function POST(req: Request) {
 
     return NextResponse.json({ success: true, channel: channelName });
   } catch (error) {
+    if (isFlyMachineNotRunningError(error)) {
+      return NextResponse.json({ error: 'Gateway must be running to configure channels' }, { status: 409 });
+    }
     Sentry.captureException(error);
     return NextResponse.json({ error: 'Failed to configure channel' }, { status: 500 });
   }
@@ -157,6 +168,9 @@ export async function DELETE(req: Request) {
 
     return NextResponse.json({ success: true });
   } catch (error) {
+    if (isFlyMachineNotRunningError(error)) {
+      return NextResponse.json({ error: 'Gateway must be running to configure channels' }, { status: 409 });
+    }
     Sentry.captureException(error);
     return NextResponse.json({ error: 'Failed to remove channel' }, { status: 500 });
   }
diff --git a/src/app/api/gateway/approve-pairing/route.ts b/src/app/api/gateway/approve-pairing/route.ts
index e4483dd..deed870 100644
--- a/src/app/api/gateway/approve-pairing/route.ts
+++ b/src/app/api/gateway/approve-pairing/route.ts
@@ -56,6 +56,9 @@ export async function POST() {
 
     if (!execRes.ok) {
       const errText = await execRes.text().catch(() => '');
+      if (execRes.status === 412) {
+        return NextResponse.json({ error: 'Gateway is not running' }, { status: 409 });
+      }
       Sentry.captureMessage('Fly exec failed for approve-pairing', {
         level: 'warning',
         extra: { status: execRes.status, body: errText, app: instance.fly_app_name },
diff --git a/src/lib/fly.ts b/src/lib/fly.ts
index e951263..2e8f616 100644
--- a/src/lib/fly.ts
+++ b/src/lib/fly.ts
@@ -92,6 +92,32 @@ type FlyFetchOptions = RequestInit & {
   expectedStatuses?: number[];
 };
 
+export class FlyApiError extends Error {
+  status: number;
+  method: string;
+  path: string;
+  responseBody: string;
+  expected: boolean;
+
+  constructor(args: { status: number; method: string; path: string; responseBody: string; expected: boolean }) {
+    super(`Fly API ${args.status} on ${args.method} ${args.path}: ${args.responseBody}`);
+    this.name = 'FlyApiError';
+    this.status = args.status;
+    this.method = args.method;
+    this.path = args.path;
+    this.responseBody = args.responseBody;
+    this.expected = args.expected;
+  }
+}
+
+export function isFlyApiError(error: unknown, status?: number): error is FlyApiError {
+  return error instanceof FlyApiError && (status === undefined || error.status === status);
+}
+
+export function isFlyMachineNotRunningError(error: unknown): error is FlyApiError {
+  return isFlyApiError(error, 412) && error.path.includes('/exec');
+}
+
 async function flyFetch<T>(path: string, options: FlyFetchOptions = {}): Promise<T> {
   const { expectedStatuses, ...fetchOptions } = options;
   const token = getFlyToken();
@@ -109,9 +135,15 @@ async function flyFetch<T>(path: string, options: FlyFetchOptions = {}): Promise
 
   if (!res.ok) {
     const body = await res.text().catch(() => '');
-    const err = new Error(`Fly API ${res.status} on ${fetchOptions.method ?? 'GET'} ${path}: ${body}`);
+    const err = new FlyApiError({
+      status: res.status,
+      method: fetchOptions.method ?? 'GET',
+      path,
+      responseBody: body,
+      expected: expectedStatuses?.includes(res.status) ?? false,
+    });
     // Only report to Sentry if this status code is NOT expected
-    if (!expectedStatuses?.includes(res.status)) {
+    if (!err.expected) {
       Sentry.captureException(err, { extra: { responseBody: body, status: res.status } });
     }
     throw err;