From be1ebdc035ab1a39b3d64ca2f4dea20d084f87dc Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Fri, 8 May 2026 10:40:45 -0500
Subject: [PATCH] test: gate Oban queue-depth poller on :start_telemetry_poller
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MicrowavepropWeb.Telemetry's :telemetry_poller fires
dispatch_oban_queue_depth/0 every 30 s. In test env it runs outside
any Ecto sandbox owner, so its `Repo.all` against oban_jobs holds a
pool connection long enough to starve LiveView `render_async` tests
with 100 ms async windows — repro'd as flaky SkewtLive failures.

Same shape as the PromEx Oban plugin we already disable in test via
:prom_ex_include_oban_plugin. Add :start_telemetry_poller (defaults
to true) and toggle it off in config/test.exs. Production keeps the
30-second per-(queue,state) gauge.
---
 config/test.exs                    |  7 +++++++
 lib/microwaveprop_web/telemetry.ex | 22 +++++++++++++---------
 2 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/config/test.exs b/config/test.exs
index 36cd48fc..8aad59e8 100644
--- a/config/test.exs
+++ b/config/test.exs
@@ -113,6 +113,13 @@ config :microwaveprop, nexrad_req_options: [plug: {Req.Test, Microwaveprop.Weath
 config :microwaveprop, solar_req_options: [plug: {Req.Test, Microwaveprop.Weather.SolarClient}]
 config :microwaveprop, srtm_req_options: [plug: {Req.Test, Microwaveprop.Terrain.Srtm}, retry: false]
 config :microwaveprop, start_freshness_monitor: false
+
+# The Oban queue-depth poller (`MicrowavepropWeb.Telemetry`) runs every
+# 30 s outside any sandbox owner. Its query against `oban_jobs` holds a
+# pool connection long enough to race LiveView `start_async` tests with
+# 100 ms async windows (e.g. SkewtLive). Off in tests; the same
+# poll-once-per-pod metric is irrelevant inside a single-process suite.
+config :microwaveprop, start_telemetry_poller: false
 config :microwaveprop, swpc_req_options: [plug: {Req.Test, Microwaveprop.SpaceWeather.SwpcClient}, retry: false]
 config :microwaveprop, uwyo_req_options: [plug: {Req.Test, Microwaveprop.Weather.UwyoSoundingClient}, retry: false]
 
diff --git a/lib/microwaveprop_web/telemetry.ex b/lib/microwaveprop_web/telemetry.ex
index f53615bb..38493f05 100644
--- a/lib/microwaveprop_web/telemetry.ex
+++ b/lib/microwaveprop_web/telemetry.ex
@@ -10,15 +10,19 @@ defmodule MicrowavepropWeb.Telemetry do
 
   @impl true
   def init(_arg) do
-    children = [
-      # Oban queue-depth is the only poller measurement and each replica
-      # issues the same GROUP-BY over oban_jobs. 30s gives enough fidelity
-      # for dashboard trends without burning ~3/min of identical queries
-      # per extra replica.
-      {:telemetry_poller, measurements: periodic_measurements(), period: 30_000}
-      # Add reporters as children of your supervision tree.
-      # {Telemetry.Metrics.ConsoleReporter, metrics: metrics()}
-    ]
+    # Oban queue-depth is the only poller measurement and each replica
+    # issues the same GROUP-BY over oban_jobs. 30s gives enough fidelity
+    # for dashboard trends without burning ~3/min of identical queries
+    # per extra replica. Skipped in test (no sandbox owner → connection
+    # contention with LiveView async tests; identical pattern to the
+    # PromEx Oban plugin we already disable via
+    # `:prom_ex_include_oban_plugin`).
+    children =
+      if Application.get_env(:microwaveprop, :start_telemetry_poller, true) do
+        [{:telemetry_poller, measurements: periodic_measurements(), period: 30_000}]
+      else
+        []
+      end
 
     Supervisor.init(children, strategy: :one_for_one)
   end