data store: wipe workflow data on reload.

* When a workflow is reloaded or restarted (node restart infers reload),
  there may be objects left behind in the store which have been wiped
  out in the scheduler by the configuration change.
* To handle this, we must wipe all objects stored on the workflow
  (e.g. TaskProxies, TaskDefs, Jobs, etc), and rebuild from scratch.
* Note, we don't need to wipe the data on the Workflow object itself
  (e.g. port, stateTotals, etc), these things will be refreshed by
  this or subsequent deltas.

Author: oliver-sanders

src/graphql/queries.js

@@ -27,6 +27,7 @@ import gql from 'graphql-tag'
 const WORKFLOW_DATA_FRAGMENT = `
 fragment WorkflowData on Workflow {
   id
+  reloaded
   status
   statusMsg
   owner

src/services/treeCallback.js

@@ -25,8 +25,24 @@ class CylcTreeCallback extends DeltasCallback {
     }
   }
 
-  tearDown (store, errors) {
-    // never tear down, this callback lives for the live of the UI
+  before (deltas, store, errors) {
+    // Wipe all child nodes from a workflow in the data store if a reloaded
+    // delta is received. Reloaded deltas are sent whenever a workflow is
+    // restarted or reloaded (note, restarting a workflow implicitly reloads
+    // it).
+    //
+    // When a workflow reloads it is hard to generate the relevant pruned
+    // and updated deltas to remove any objects which have been wiped out by
+    // the configuration change, so the easiest solution is to wipe the
+    // entire tree under the workflow and rebuild from scratch. If we don't
+    // do this, we can end up with nodes in the store which aren't meant to be
+    // there and won't get pruned.
+    if (deltas.updated?.workflow?.reloaded) {
+      store.commit('workflows/remove_children', (deltas.updated.workflow.id))
+    }
+    if (deltas.added?.workflow?.reloaded) {
+      store.commit('workflows/remove_children', (deltas.added.workflow.id))
+    }
   }
 
   onAdded (added, store, errors) {
@@ -43,9 +59,9 @@ class CylcTreeCallback extends DeltasCallback {
     store.commit('workflows/REMOVE_DELTAS', pruned)
   }
 
-  // this callback does not need the before and commit methods
-  before (a, b, c) {}
+  // this callback does not need the tearDown and commit methods
   commit (a, b, c) {}
+  tearDown (store, errors) {}
 }
 
 export default CylcTreeCallback

src/services/workflow.service.js

@@ -321,6 +321,7 @@ class WorkflowService {
               const errors = []
 
               // run the global callback first
+              globalCallback.before(deltas, store, errors)
               globalCallback.onAdded(added, store, errors)
               globalCallback.onUpdated(updated, store, errors)
               globalCallback.onPruned(pruned, store, errors)

src/views/Graph.vue

@@ -127,6 +127,11 @@ subscription Workflow ($workflowId: ID) {
   }
 }
 
+fragment workflowdata on workflow {
+  id
+  reloaded
+}
+
 fragment EdgeData on Edge {
   id
   source
@@ -154,6 +159,9 @@ fragment JobData on Job {
 }
 
 fragment AddedDelta on Added {
+  workflows {
+    ...workflowdata
+  }
   edges {
     ...EdgeData
   }
@@ -166,6 +174,9 @@ fragment AddedDelta on Added {
 }
 
 fragment UpdatedDelta on Updated {
+  workflows {
+    ...workflowdata
+  }
   edges {
     ...EdgeData
   }

src/views/SimpleTree.vue

@@ -135,6 +135,9 @@ fragment Deltas on Deltas {
 }
 
 fragment AddedDelta on Added {
+  workflows {
+    ...WorkflowData
+  }
   taskProxies {
     ...TaskProxyData
   }
@@ -144,6 +147,9 @@ fragment AddedDelta on Added {
 }
 
 fragment UpdatedDelta on Updated {
+  workflows {
+    ...WorkflowData
+  }
   taskProxies {
     ...TaskProxyData
   }
@@ -160,6 +166,13 @@ fragment PrunedDelta on Pruned {
   jobs
 }
 
+# We must always request "id" and "reloaded" for the workflow.
+# These are required by the data store.
+fragment workflowData on Workflow {
+  id
+  reloaded
+}
+
 # We must always request the "id" for ALL types.
 # The only field this view requires beyond that is the status.
 fragment TaskProxyData on TaskProxy {