feat(front): add finite cache ttl for running pipelines (#515)

## 📝 Description
<!-- Describe your changes in detail -->

## ✅ Checklist
- [ ] I have tested this change
- [ ] This change requires documentation update

Author: skipi

front/lib/front/models/workflow.ex

@@ -115,7 +115,8 @@ defmodule Front.Models.Workflow do
           nil
 
         response ->
-          Cacheman.put(:front, cache_key, encode(response))
+          ttl = get_ttl_for_workflow(response)
+          Cacheman.put(:front, cache_key, encode(response), ttl: ttl)
           response
       end
     end
@@ -137,7 +138,8 @@ defmodule Front.Models.Workflow do
     non_cached_workflows = find_many(non_cached_ids, :from_api)
 
     Enum.each(non_cached_workflows, fn workflow ->
-      Cacheman.put(:front, workflow_cache_key(workflow.id), encode(workflow))
+      ttl = get_ttl_for_workflow(workflow)
+      Cacheman.put(:front, workflow_cache_key(workflow.id), encode(workflow), ttl: ttl)
     end)
 
     cached_workflows ++ non_cached_workflows
@@ -350,7 +352,8 @@ defmodule Front.Models.Workflow do
       requester_id: workflow.requester_id,
       created_at: DateTime.from_unix!(workflow.created_at.seconds),
       triggered_by: TriggeredBy.key(workflow.triggered_by),
-      rerun_of: workflow.rerun_of
+      rerun_of: workflow.rerun_of,
+      pipelines: []
     }
     |> then(fn
       workflow when preload? ->
@@ -526,4 +529,21 @@ defmodule Front.Models.Workflow do
 
     workflow
   end
+
+  defp has_active_pipelines?(workflow) do
+    workflow.pipelines
+    |> Enum.any?(fn pipeline ->
+      pipeline.state in [:RUNNING, :STOPPING, :PENDING, :QUEUING, :INITIALIZING]
+    end)
+  end
+
+  defp get_ttl_for_workflow(workflow) do
+    if has_active_pipelines?(workflow) do
+      # Finite cache for workflows with active pipelines
+      :timer.hours(2)
+    else
+      # Never expire for completed workflows
+      :infinity
+    end
+  end
 end

front/lib/front/workflow_page/pipeline_status/model.ex

@@ -11,7 +11,8 @@ defmodule Front.WorkflowPage.PipelineStatus.Model do
   def load(pipeline_id) do
     Cacheman.fetch(:front, cache_key(pipeline_id), fn ->
       pipeline_status = load_pipeline_status_from_api(pipeline_id)
-      Cacheman.put(:front, cache_key(pipeline_id), pipeline_status)
+      ttl = get_ttl_for_status(pipeline_status)
+      Cacheman.put(:front, cache_key(pipeline_id), pipeline_status, ttl: ttl)
       {:ok, pipeline_status}
     end)
   end
@@ -36,4 +37,11 @@ defmodule Front.WorkflowPage.PipelineStatus.Model do
   defp pipeline_favicon_status(:DONE, :STOPPED), do: "stopped"
   defp pipeline_favicon_status(:DONE, :CANCELED), do: "canceled"
   defp pipeline_favicon_status(_, _), do: "pending"
+
+  # Running pipelines should be cached for a limited time
+  defp get_ttl_for_status(status) when status in ["running", "stopping", "pending"],
+    do: :timer.minutes(15)
+
+  # Use default - infinite cache for completed pipelines
+  defp get_ttl_for_status(_status), do: :infinity
 end