From 82fcf3246f8aa09c3488bc35c2f554e239d24c0d Mon Sep 17 00:00:00 2001
From: David Buckley <isreal-github.com@bucko.me.uk>
Date: Wed, 21 Aug 2024 17:52:04 +0100
Subject: [PATCH] make metrics from carbon-cache go via relay config

---
 lib/carbon/instrumentation.py |  2 +-
 lib/carbon/routers.py         | 23 +++++++++++++++++++++++
 lib/carbon/service.py         |  1 +
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/lib/carbon/instrumentation.py b/lib/carbon/instrumentation.py
index 5e4f83e44..49c9abcfb 100644
--- a/lib/carbon/instrumentation.py
+++ b/lib/carbon/instrumentation.py
@@ -170,7 +170,7 @@ def cache_record(metric, value):
     else:
       fullMetric = '%s.agents.%s-%s.%s' % (prefix, HOSTNAME, settings.instance, metric)
     datapoint = (time.time(), value)
-    cache.MetricCache().store(fullMetric, datapoint)
+    state.client_manager.sendDatapoint(fullMetric, datapoint)
 
 
 def relay_record(metric, value):
diff --git a/lib/carbon/routers.py b/lib/carbon/routers.py
index 9b8d8ef1d..72d93cfa2 100644
--- a/lib/carbon/routers.py
+++ b/lib/carbon/routers.py
@@ -31,6 +31,29 @@ def getDestinations(self, key):
     raise NotImplementedError()
 
 
+class ConstantRouter(DatapointRouter):
+  plugin_name = 'constant'
+
+  def __init__(self, settings):
+    self.destinations = set()
+
+  def addDestination(self, destination):
+    self.destinations.add(destination)
+
+  def removeDestination(self, destination):
+    self.destinations.discard(destination)
+
+  def hasDestination(self, destination):
+    return destination in self.destinations
+
+  def countDestinations(self):
+    return len(self.destinations)
+
+  def getDestinations(self, key):
+    for destination in self.destinations:
+      yield destination
+
+
 class RelayRulesRouter(DatapointRouter):
   plugin_name = 'rules'
 
diff --git a/lib/carbon/service.py b/lib/carbon/service.py
index 0c0fb8948..5cd6bbb5d 100644
--- a/lib/carbon/service.py
+++ b/lib/carbon/service.py
@@ -87,6 +87,7 @@ def setupPipeline(pipeline, root_service, settings):
       setupRelayProcessor(root_service, settings)
     elif processor == 'write':
       setupWriterProcessor(root_service, settings)
+      setupRelayProcessor(root_service, settings)
     else:
       raise ValueError("Invalid pipeline processor '%s'" % processor)