better logs for discovery and polling

lib/towerops/workers/discovery_worker.ex

@@ -32,8 +32,6 @@ defmodule Towerops.Workers.DiscoveryWorker do
 
   @impl Oban.Worker
   def perform(%Oban.Job{args: %{"device_id" => device_id}}) do
-    Logger.info("Starting SNMP discovery for device #{device_id}")
-
     case Devices.get_device_with_details(device_id) do
       nil ->
         Logger.error("Device #{device_id} not found")
@@ -42,10 +40,15 @@ defmodule Towerops.Workers.DiscoveryWorker do
       device ->
         case get_assigned_agent(device) do
           {agent_token_id, source} when not is_nil(agent_token_id) ->
+            agent = Agents.get_agent_token!(agent_token_id)
+            poller_type = if agent.cloud_poller, do: "cloud poller", else: "user's poller"
+
             Logger.info(
-              "Device has assigned agent, delegating discovery",
+              "Starting SNMP discovery for device #{device_id} using #{poller_type} '#{agent.name}' (#{source} assignment)",
               device_id: device_id,
               agent_token_id: agent_token_id,
+              agent_name: agent.name,
+              cloud_poller: agent.cloud_poller,
               source: source
             )
 
@@ -53,7 +56,7 @@ defmodule Towerops.Workers.DiscoveryWorker do
 
           {nil, :none} ->
             Logger.info(
-              "No agent assigned, attempting cloud poller fallback",
+              "Starting SNMP discovery for device #{device_id} with no assigned agent, will try cloud pollers then cluster fallback",
               device_id: device_id
             )
 
@@ -124,17 +127,20 @@ defmodule Towerops.Workers.DiscoveryWorker do
     case get_next_cloud_poller(tried_agents) do
       nil ->
         Logger.info(
-          "No more cloud pollers available, falling back to direct SNMP from cluster",
+          "No more cloud pollers available, falling back to direct SNMP from Phoenix cluster",
           device_id: device.id
         )
 
         perform_direct_discovery(device)
 
       next_agent_id ->
+        agent = Agents.get_agent_token!(next_agent_id)
+
         Logger.info(
-          "Trying next cloud poller",
+          "Trying cloud poller '#{agent.name}' for device #{device.id}",
           device_id: device.id,
-          cloud_poller_id: next_agent_id
+          cloud_poller_id: next_agent_id,
+          agent_name: agent.name
         )
 
         attempt_agent_discovery(device, next_agent_id, [next_agent_id | tried_agents])
@@ -228,13 +234,27 @@ defmodule Towerops.Workers.DiscoveryWorker do
   end
 
   defp perform_direct_discovery(device) do
+    Logger.info(
+      "Performing SNMP discovery from Phoenix cluster for device #{device.id}",
+      device_id: device.id
+    )
+
     case Snmp.discover_device(device) do
       {:ok, _snmp_device} ->
-        Logger.info("SNMP discovery completed successfully for device #{device.id}")
+        Logger.info(
+          "SNMP discovery completed successfully from Phoenix cluster for device #{device.id}",
+          device_id: device.id
+        )
+
         :ok
 
       {:error, reason} ->
-        Logger.error("SNMP discovery failed for device #{device.id}: #{inspect(reason)}")
+        Logger.error(
+          "SNMP discovery failed from Phoenix cluster for device #{device.id}: #{inspect(reason)}",
+          device_id: device.id,
+          reason: reason
+        )
+
         {:error, reason}
     end
   end