From f0fea0dd3e86fde28ce8a75b30d7af7373716e46 Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Wed, 18 Feb 2026 10:34:36 -0600
Subject: [PATCH] fix: retry firmware fetch with exponential backoff on network
 errors
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Increase max_attempts from 3 to 10 and add custom backoff/1 that uses
quadratic growth (attempt² × 60s) capped at 2 hours, so transient
network failures retry over ~9 hours rather than being discarded after
3 quick attempts.
---
 .../firmware_version_fetcher_worker.ex        |  7 ++++++-
 .../firmware_version_fetcher_worker_test.exs  | 20 +++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/lib/towerops/workers/firmware_version_fetcher_worker.ex b/lib/towerops/workers/firmware_version_fetcher_worker.ex
index c47fe325..37ea048f 100644
--- a/lib/towerops/workers/firmware_version_fetcher_worker.ex
+++ b/lib/towerops/workers/firmware_version_fetcher_worker.ex
@@ -5,7 +5,7 @@ defmodule Towerops.Workers.FirmwareVersionFetcherWorker do
   Runs daily to check for new firmware releases and updates the firmware_releases table.
   """
 
-  use Oban.Worker, queue: :maintenance, max_attempts: 3
+  use Oban.Worker, queue: :maintenance, max_attempts: 10
 
   import SweetXml
 
@@ -13,6 +13,11 @@ defmodule Towerops.Workers.FirmwareVersionFetcherWorker do
 
   require Logger
 
+  @impl Oban.Worker
+  def backoff(%Oban.Job{attempt: attempt}) do
+    min(attempt * attempt * 60, 7_200)
+  end
+
   @rss_url "https://cdn.mikrotik.com/routeros/latest-stable.rss"
   @changelog_url "https://mikrotik.com/download/changelogs"
 
diff --git a/test/towerops/workers/firmware_version_fetcher_worker_test.exs b/test/towerops/workers/firmware_version_fetcher_worker_test.exs
index 6acc4eff..13e3387a 100644
--- a/test/towerops/workers/firmware_version_fetcher_worker_test.exs
+++ b/test/towerops/workers/firmware_version_fetcher_worker_test.exs
@@ -20,6 +20,26 @@ defmodule Towerops.Workers.FirmwareVersionFetcherWorkerTest do
     end
   end
 
+  describe "backoff/1" do
+    test "early attempts have shorter delays than later attempts" do
+      attempt_1 = FirmwareVersionFetcherWorker.backoff(%Oban.Job{attempt: 1})
+      attempt_5 = FirmwareVersionFetcherWorker.backoff(%Oban.Job{attempt: 5})
+      assert attempt_1 < attempt_5
+    end
+
+    test "backoff is capped at 2 hours" do
+      high_attempt = FirmwareVersionFetcherWorker.backoff(%Oban.Job{attempt: 100})
+      assert high_attempt <= 7_200
+    end
+
+    test "all attempts return positive values" do
+      for attempt <- 1..10 do
+        backoff = FirmwareVersionFetcherWorker.backoff(%Oban.Job{attempt: attempt})
+        assert backoff > 0, "attempt #{attempt} returned non-positive backoff"
+      end
+    end
+  end
+
   describe "parse_rss_feed/1" do
     test "parses valid RSS feed XML" do
       valid_rss = """