feat: add failed jobs and recent completions queries

Add list_failed_jobs/0 to return retryable and cancelled jobs
and list_recent_completions/1 to return completed, cancelled,
or discarded jobs with configurable limit.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

lib/towerops/job_monitoring.ex

@@ -7,8 +7,8 @@ defmodule Towerops.JobMonitoring do
   """
 
   import Ecto.Query
-  alias Towerops.Repo
   alias Oban.Job
+  alias Towerops.Repo
 
   @worker_names [
     "Towerops.Workers.DevicePollerWorker",
@@ -53,4 +53,37 @@ defmodule Towerops.JobMonitoring do
     )
     |> Repo.all()
   end
+
+  @doc """
+  Lists jobs that have failed and are retrying or have been cancelled.
+
+  Limited to last 100 jobs.
+  """
+  @spec list_failed_jobs() :: [Job.t()]
+  def list_failed_jobs do
+    from(j in Job,
+      where: j.state in ["retryable", "cancelled"],
+      where: j.worker in ^@worker_names,
+      order_by: [desc: j.inserted_at],
+      limit: 100
+    )
+    |> Repo.all()
+  end
+
+  @doc """
+  Lists recently completed jobs (completed, cancelled, or discarded).
+
+  ## Options
+  - `:limit` - Maximum number of jobs to return (default: 100)
+  """
+  @spec list_recent_completions(integer()) :: [Job.t()]
+  def list_recent_completions(limit \\ 100) do
+    from(j in Job,
+      where: j.state in ["completed", "cancelled", "discarded"],
+      where: j.worker in ^@worker_names,
+      order_by: [desc: j.completed_at],
+      limit: ^limit
+    )
+    |> Repo.all()
+  end
 end

test/towerops/job_monitoring_test.exs

@@ -202,4 +202,62 @@ defmodule Towerops.JobMonitoringTest do
       assert stuck |> Enum.map(& &1.id) |> Enum.sort() == [stuck_discovery.id, stuck_poller.id] |> Enum.sort()
     end
   end
+
+  describe "list_failed_jobs/0" do
+    test "returns retryable and cancelled jobs" do
+      device = device_fixture()
+
+      oban_job_fixture(%{
+        worker: "Towerops.Workers.DevicePollerWorker",
+        state: "retryable",
+        args: %{"device_id" => device.id}
+      })
+
+      oban_job_fixture(%{
+        worker: "Towerops.Workers.DiscoveryWorker",
+        state: "cancelled",
+        args: %{"device_id" => device.id}
+      })
+
+      # Should not include completed
+      oban_job_fixture(%{
+        worker: "Towerops.Workers.DevicePollerWorker",
+        state: "completed",
+        args: %{"device_id" => device.id}
+      })
+
+      failed = JobMonitoring.list_failed_jobs()
+
+      assert length(failed) == 2
+      assert Enum.all?(failed, fn j -> j.state in ["retryable", "cancelled"] end)
+    end
+  end
+
+  describe "list_recent_completions/1" do
+    test "returns completed, cancelled, and discarded jobs up to limit" do
+      device = device_fixture()
+
+      # Create 5 completed jobs
+      for _ <- 1..5 do
+        oban_job_fixture(%{
+          worker: "Towerops.Workers.DevicePollerWorker",
+          state: "completed",
+          args: %{"device_id" => device.id},
+          completed_at: DateTime.utc_now()
+        })
+      end
+
+      # Should not include executing
+      oban_job_fixture(%{
+        worker: "Towerops.Workers.DevicePollerWorker",
+        state: "executing",
+        args: %{"device_id" => device.id}
+      })
+
+      recent = JobMonitoring.list_recent_completions(3)
+
+      assert length(recent) == 3
+      assert Enum.all?(recent, fn j -> j.state == "completed" end)
+    end
+  end
 end