mgr: add doc to describe relationship to prometheus

The healthcheck for slow_ops is used by the mgr/prometheus
module so it's important the alert generated matches the
format expected in mgr/prometheus.

Signed-off-by: Paul Cuzner <pcuzner@redhat.com>
(cherry picked from commit fc1905b4a74aedc6bdbc928b6d6e514183bbf090)

Conflicts:
	src/mgr/DaemonHealthMetricCollector.cc

- docstring added to describe the link to mgr/prometheus conflicted with the
  const fmt definition for the message. resolved by adding doc under the const
  definition.

diff --git a/src/mgr/DaemonHealthMetricCollector.cc b/src/mgr/DaemonHealthMetricCollector.cc
index 09d98e51c484b3a91139ebc9b73bcac938756286..1c3dc431c40f3e9bd3c73925e4dfe4eb7f951c90 100644 (file)
--- a/src/mgr/DaemonHealthMetricCollector.cc
+++ b/src/mgr/DaemonHealthMetricCollector.cc
@@ -55,6 +55,8 @@ class SlowOps final : public DaemonHealthMetricCollector {
       return;
     }
     static const char* fmt = "%1% slow ops, oldest one blocked for %2% sec, %3%";
+    // Note this message format is used in mgr/prometheus, so any change in format
+    // requires a corresponding change in the mgr/prometheus module.
     ostringstream ss;
     if (daemons.size() > 1) {
       if (daemons.size() > 10) {