Improve performance of job status updates through caching hashes

lib/server/job_server.py

@@ -55,6 +55,22 @@ def index():
                            render_clients=render_clients(), preset_list=presets)
 
 
+@server.get('/api/jobs')
+def jobs_json():
+    try:
+        hash_token = request.args.get('token', None)
+        all_jobs = [x.json() for x in RenderQueue.all_jobs()]
+        job_cache_token = str(json.dumps(all_jobs).__hash__())
+
+        if hash_token and hash_token == job_cache_token:
+            return [], 204  # no need to update
+        else:
+            return {'jobs': all_jobs, 'token': job_cache_token}
+    except Exception as e:
+        logger.exception(f"Exception fetching all_jobs_cached: {e}")
+    return [], 500
+
+
 @server.route('/ui/job/<job_id>/full_details')
 def job_detail(job_id):
     found_job = RenderQueue.job_with_id(job_id)
@@ -131,15 +147,6 @@ def get_job_file(job_id, filename):
         abort(404)
 
 
-@server.get('/api/jobs')
-def jobs_json():
-    try:
-        return [x.json() for x in RenderQueue.all_jobs()]
-    except Exception as e:
-        logger.exception(f"Exception fetching all_jobs: {e}")
-    return [], 500
-
-
 @server.get('/api/jobs/<status_val>')
 def filtered_jobs_json(status_val):
     state = string_to_status(status_val)

lib/server/server_proxy.py

@@ -1,3 +1,4 @@
+import logging
 import os
 import json
 import requests
@@ -10,13 +11,25 @@ status_colors = {RenderStatus.ERROR: "red", RenderStatus.CANCELLED: 'orange1', R
 categories = [RenderStatus.RUNNING, RenderStatus.ERROR, RenderStatus.NOT_STARTED, RenderStatus.SCHEDULED,
               RenderStatus.COMPLETED, RenderStatus.CANCELLED, RenderStatus.UNDEFINED]
 
+logger = logging.getLogger()
+
 
 class RenderServerProxy:
 
     def __init__(self, hostname=None, server_port="8080"):
-        self.hostname = hostname
+        self._hostname = hostname
         self.port = server_port
         self.fetched_status_data = None
+        self.__jobs_cache_token = None
+
+    @property
+    def hostname(self):
+        return self._hostname
+
+    @hostname.setter
+    def hostname(self, value):
+        self._hostname = value
+        self.__jobs_cache_token = None
 
     def connect(self):
         status = self.request_data('status')
@@ -25,24 +38,29 @@ class RenderServerProxy:
     def request_data(self, payload, timeout=5):
         try:
             req = self.request(payload, timeout)
-            if req.ok:
+            if req.ok and req.status_code == 200:
                 return req.json()
+        except requests.ConnectionError as e:
+            logger.error(f"Connection error: {e}")
         except Exception as e:
-            pass
+            logger.exception(f"Uncaught exception: {e}")
         return None
 
     def request(self, payload, timeout=5):
         return requests.get(f'http://{self.hostname}:{self.port}/api/{payload}', timeout=timeout)
 
     def get_jobs(self, timeout=5):
-        all_jobs = self.request_data('jobs', timeout=timeout)
-        if all_jobs is not None:
+        url = f'jobs?token={self.__jobs_cache_token}' if self.__jobs_cache_token else 'jobs'
+        status_result = self.request_data(url, timeout=timeout)
+        all_jobs = None
+        if status_result is not None:
             sorted_jobs = []
             for status_category in categories:
-                found_jobs = [x for x in all_jobs if x['status'] == status_category.value]
+                found_jobs = [x for x in status_result['jobs'] if x['status'] == status_category.value]
                 if found_jobs:
                     sorted_jobs.extend(found_jobs)
             all_jobs = sorted_jobs
+            self.__jobs_cache_token = status_result['token']
         return all_jobs
 
     def get_data(self, timeout=5):

lib/server/static/js/job_table.js

@@ -58,7 +58,7 @@ columns: [
 autoWidth: true,
 server: {
   url: '/api/jobs',
-  then: results => results,
+  then: results => results['jobs'],
 },
 sort: true,
 }).render(document.getElementById('table'));