Enhance blocking workers flow

* Old messages become immutable
* The message is required thus explaining more the reason why would an approver/the same user unblock/block.
* Full history of the blocking notes
* automatic inclusion for timestamp and blocker name

server/fishtest/rundb.py

@@ -1033,7 +1033,7 @@ def sync_request_task(self, worker_info):
         if w["blocked"]:
             # updates last_updated
             self.workerdb.update_worker(
-                my_name, blocked=w["blocked"], message=w["message"]
+                my_name, blocked=w["blocked"], message=w["message"], username=None
             )
             error = self.blocked_worker_message(my_name, w["message"], host_url)
             return {"task_waiting": False, "error": error}

server/fishtest/templates/workers.mak

@@ -66,12 +66,24 @@
   <form method="POST">
     <div class="mb-3">Last changed: ${delta_date(diff_date(last_updated)) if last_updated is not None else "Never"}</div>
     <div class="mb-3">
-      <label for="messageInput" class="form-label">Issue</label>
+      % if message:
+        <label for="messageView" class="form-label">Issues</label>
+        <textarea
+          id="messageView"
+          rows="6"
+          class="form-control mb-4"
+          readonly
+          >${message}</textarea>
+      % endif
+
+      <label for="messageInput" class="form-label">New Notes</label>
       <textarea
         id="messageInput"
+        name="message"
         rows="4" class="form-control"
         placeholder="Describe the issue here" name="message"
-      >${message}</textarea>
+        required
+      ></textarea>
     </div>
     <div class="mb-3 form-check">
       <label class="form-check-label" for="blockWorker">Blocked</label>
@@ -148,3 +160,15 @@
     % endif
   </tbody>
 </table>
+
+
+<script>
+  async function handleScrollTextArea () {
+    await DOMContentLoaded();
+    const messageView = document.getElementById('messageView');
+    if (messageView) {
+      messageView.scrollTop = messageView.scrollHeight;
+    }
+  }
+  handleScrollTextArea();
+</script>

server/fishtest/views.py

@@ -247,9 +247,12 @@ def workers(request):
                 )
                 message = message[:max_chars]
             message = normalize_lf(message)
+            if message.strip() == "":
+                request.session.flash("A new message is required for unblocking/blocking workers", "error")
+                return home(request)
             was_blocked = request.workerdb.get_worker(worker_name)["blocked"]
             request.rundb.workerdb.update_worker(
-                worker_name, blocked=blocked, message=message
+                worker_name, blocked=blocked, message=message, username=blocker_name,
             )
             if blocked != was_blocked:
                 request.session.flash(

server/fishtest/workerdb.py

@@ -27,13 +27,23 @@ def get_worker(
         else:
             return r
 
-    def update_worker(self, worker_name, blocked=None, message=None):
+    def update_worker(self, worker_name, blocked=None, message=None, username=None):
+        current_worker = self.get_worker(worker_name)
+
+        new_message = message
+        if message and current_worker and current_worker.get("message") != message:
+            timestamp = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S %Z")
+            new_message = (
+                f"{current_worker['message']}\n{username} {timestamp}\n{message}\n"
+            )
+
         r = {
             "worker_name": worker_name,
             "blocked": blocked,
-            "message": message,
+            "message": new_message,
             "last_updated": datetime.now(timezone.utc),
         }
+
         validate(worker_schema, r, "worker")  # may throw exception
         self.workers.replace_one({"worker_name": worker_name}, r, upsert=True)