fix: add Oban config to dev.exs and replace Exq telemetry with Oban

Changes:
- Add Oban configuration to config/dev.exs (was only in runtime.exs)
- Replace Exq telemetry metrics with Oban equivalents
- Update publish_exq_stats to publish_oban_stats using Oban.Job queries
- Track queue sizes, executing jobs, and available jobs

This fixes the startup error where Oban config was not available in dev.

config/dev.exs

@@ -25,6 +25,25 @@ config :phoenix_live_view,
 # Disable swoosh api client as it is only required for production adapters.
 config :swoosh, :api_client, false
 
+# Configure Oban for background jobs
+config :towerops, Oban,
+  repo: Towerops.Repo,
+  queues: [
+    default: 10,
+    discovery: 10,
+    # SNMP polling jobs - one per device
+    pollers: 50,
+    # Device monitoring jobs - health checks
+    monitors: 50,
+    maintenance: 5
+  ],
+  plugins: [
+    # Automatically delete completed jobs after 60 seconds
+    {Oban.Plugins.Pruner, max_age: 60},
+    # Rescue orphaned jobs (when node crashes)
+    {Oban.Plugins.Reindexer, schedule: "0 2 * * *"}
+  ]
+
 # Configure your database
 config :towerops, Towerops.Repo,
   username: "postgres",

lib/towerops_web/telemetry.ex

@@ -99,16 +99,16 @@ defmodule ToweropsWeb.Telemetry do
       summary("vm.total_run_queue_lengths.cpu"),
       summary("vm.total_run_queue_lengths.io"),
 
-      # Exq/Redis Metrics
-      last_value("towerops.exq.queue.size",
+      # Oban/Redis Metrics
+      last_value("towerops.oban.queue.size",
         tags: [:queue],
-        description: "Number of jobs in each Exq queue"
+        description: "Number of jobs in each Oban queue"
       ),
-      last_value("towerops.exq.processes.busy",
-        description: "Number of busy Exq worker processes"
+      last_value("towerops.oban.jobs.executing",
+        description: "Number of currently executing Oban jobs"
       ),
-      last_value("towerops.exq.processes.total",
-        description: "Total number of Exq worker processes"
+      last_value("towerops.oban.jobs.available",
+        description: "Number of available Oban jobs"
       ),
       last_value("towerops.redis.connected_clients",
         description: "Number of Redis/Valkey connected clients"
@@ -125,72 +125,84 @@ defmodule ToweropsWeb.Telemetry do
 
   defp periodic_measurements do
     [
-      # Measure Exq and Redis stats every 10 seconds
-      {__MODULE__, :publish_exq_stats, []},
+      # Measure Oban and Redis stats every 10 seconds
+      {__MODULE__, :publish_oban_stats, []},
       {__MODULE__, :publish_redis_stats, []}
     ]
   end
 
   @doc """
-  Publishes Exq queue and process statistics.
+  Publishes Oban queue and job statistics.
   """
-  def publish_exq_stats do
-    # Only run if Exq is available (not in test env) and the API process is running
-    # The Exq.Api.Server is registered as :"Exq.Api" when started with name: Exq
-    api_process = :"Exq.Api"
-
-    if Application.get_env(:towerops, :env) == :test or is_nil(Process.whereis(api_process)) do
+  def publish_oban_stats do
+    if Application.get_env(:towerops, :env) == :test do
       :ok
     else
       try do
-        queues = ["default", "discovery", "polling", "monitoring", "maintenance"]
+        import Ecto.Query
 
+        queues = ["default", "discovery", "pollers", "monitors", "maintenance"]
+
+        # Query queue sizes
         for queue <- queues do
           try do
-            case Exq.Api.queue_size(api_process, queue) do
-              {:ok, size} ->
-                :telemetry.execute(
-                  [:towerops, :exq, :queue, :size],
-                  %{value: size},
-                  %{queue: queue}
-                )
+            size =
+              Towerops.Repo.one(
+                from j in Oban.Job,
+                  where: j.queue == ^queue and j.state in ["available", "scheduled"],
+                  select: count(j.id)
+              )
 
-              _error ->
-                :ok
-            end
+            :telemetry.execute(
+              [:towerops, :oban, :queue, :size],
+              %{value: size},
+              %{queue: queue}
+            )
           rescue
             _ -> :ok
-          catch
-            :exit, _ -> :ok
           end
         end
 
+        # Query executing jobs count
         try do
-          with {:ok, processes} <- Exq.Api.processes(api_process),
-               {:ok, busy} <- Exq.Api.busy(api_process) do
-            :telemetry.execute(
-              [:towerops, :exq, :processes, :busy],
-              %{value: length(busy)},
-              %{}
+          executing_count =
+            Towerops.Repo.one(
+              from j in Oban.Job,
+                where: j.state == "executing",
+                select: count(j.id)
             )
 
-            :telemetry.execute(
-              [:towerops, :exq, :processes, :total],
-              %{value: length(processes)},
-              %{}
-            )
-          end
+          :telemetry.execute(
+            [:towerops, :oban, :jobs, :executing],
+            %{value: executing_count},
+            %{}
+          )
+        rescue
+          _ -> :ok
+        end
+
+        # Query available jobs count
+        try do
+          available_count =
+            Towerops.Repo.one(
+              from j in Oban.Job,
+                where: j.state == "available",
+                select: count(j.id)
+            )
+
+          :telemetry.execute(
+            [:towerops, :oban, :jobs, :available],
+            %{value: available_count},
+            %{}
+          )
         rescue
           _ -> :ok
-        catch
-          :exit, _ -> :ok
         end
 
         :ok
       rescue
         _ -> :ok
       catch
-        # Catch exits (like :noproc) and exceptions
         _, _ -> :ok
       end
     end