Add a gauge for the events channel state id

1 files changed, 13 insertions, 4 deletions

diff --git a/bffe/server.scm b/bffe/server.scm
index 2cc6322..8157843 100644
--- a/bffe/server.scm
+++ b/bffe/server.scm
@@ -121,7 +121,8 @@
        (raise-exception exn))
       (result result))))
 
-(define (make-events-channel event-source initial-state-id)
+(define* (make-events-channel event-source initial-state-id
+                              #:key metrics-registry)
   (let* ((submission-channel (make-channel))
          (listener-channels-box (make-atomic-box vlist-null))
 
@@ -129,7 +130,11 @@
          (event-buffer (make-vector buffer-size))
 
          (current-state-id-and-event-buffer-index-box
-          (make-atomic-box (cons 0 -1))))
+          (make-atomic-box (cons 0 -1)))
+
+         (events-channel-state-id-gauge
+          (make-gauge-metric metrics-registry
+                             "events_channel_state_id")))
 
     (define (get-state-id)
       (match (atomic-box-ref
@@ -214,7 +219,10 @@
 
            (vector-set! event-buffer
                         new-event-index
-                        (list id event-name data))))))
+                        (list id event-name data))
+
+           (metric-set events-channel-state-id-gauge
+                       id)))))
 
     (spawn-fiber
      (lambda ()
@@ -492,7 +500,8 @@
                        get-state-id
                        (make-events-channel
                         event-source
-                        initial-state-id))
+                        initial-state-id
+                        #:metrics-registry metrics-registry))
                       (controller
                        (apply make-controller assets-directory
                               metrics-registry