From 683b47d0f1f20219558f008657f11be707fc863d Mon Sep 17 00:00:00 2001
From: Haibo Lin <hlin@redhat.com>
Date: Jun 17 2021 03:13:34 +0000
Subject: Add expected number of hosts to metrics


JIRA: RHELCMP-5494
Signed-off-by: Haibo Lin <hlin@redhat.com>

---

diff --git a/server/conf/config.py b/server/conf/config.py
index 7419101..af07400 100644
--- a/server/conf/config.py
+++ b/server/conf/config.py
@@ -157,6 +157,9 @@ class BaseConfiguration(object):
     #     'another_raw_config': ['arg1', ...],
     # }
 
+    # Expected number of celery backends
+    EXPECTED_BACKEND_NUMBER = 1
+
 
 class DevConfiguration(BaseConfiguration):
     DEBUG = True
diff --git a/server/odcs/server/metrics.py b/server/odcs/server/metrics.py
index d3fc49b..97ea1de 100644
--- a/server/odcs/server/metrics.py
+++ b/server/odcs/server/metrics.py
@@ -114,6 +114,7 @@ class WorkerCountThread(threading.Thread):
     """
     Thread providing and updating following metrics:
 
+    - celery_workers_expected - Number of expected workers.
     - celery_workers_totals - Number of alive workers.
     - celery_workers[worker_name] - 1 if worker is online, 0 if offline.
     """
@@ -121,10 +122,16 @@ class WorkerCountThread(threading.Thread):
     def __init__(self, registry=None):
         super(WorkerCountThread, self).__init__()
         self.daemon = True
+        self.workers_expected = Gauge(
+            "celery_workers_expected", "Number of expected workers", registry=registry
+        )
+        self.workers_expected.set(conf.expected_backend_number)
+
         self.workers_total = Gauge(
             "celery_workers_totals", "Number of alive workers", registry=registry
         )
         self.workers_total.set(0)
+
         self.workers = Gauge(
             "celery_workers",
             "Number of alive workers",