From d537bf1f23038b9e202312e2cf6ede2d36ad978d Mon Sep 17 00:00:00 2001
From: Meena Alfons <meena.alfons@messagebird.com>
Date: Sat, 15 Apr 2023 15:41:58 +0200
Subject: [PATCH 1/2] Filter old metrics using maxMetricAgeMs

---
 lib/gateway.js | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/lib/gateway.js b/lib/gateway.js
index 435331b..df41a29 100644
--- a/lib/gateway.js
+++ b/lib/gateway.js
@@ -210,10 +210,22 @@ Gateway.prototype.reportMetrics = function reportMetrics( ) {
 
     for (i=0; i<averages.length; i++) averages[i].value /= averages[i].count;
 
-    // never omit any known metrics, report the previous value if no change
+    // Don't omit any known metrics, report the previous value if no change
+    // except for metrics older than the configured cutoff.
     // This allows /metrics to be called more frequently than the /push interval.
     var allValues = {};
-    for (id in this.previousValues) allValues[id] = this.previousValues[id];
+    const now = this.getTimestamp();
+    const oldestKeepTs = this.maxMetricAgeMs >= 0 ? (now - this.maxMetricAgeMs) : 0;
+    const filterOldMetrics = this.maxMetricAgeMs >= 0;
+    for (id in this.previousValues) {
+        if (!filterOldMetrics || this.previousValues[id].ts >= oldestKeepTs) {
+            allValues[id] = this.previousValues[id];
+        }
+    }
+    const discardedMetrics = Object.keys(this.previousValues).length - Object.keys(allValues).length;
+    if (discardedMetrics > 0) {
+        Gateway.trace("discarding %d metrics older than %d ms", discardedMetrics, this.maxMetricAgeMs);
+    }
     for (id in map) allValues[id] = map[id];
     this.previousValues = allValues;
 

From 4be9aa61d7643555c1d56c4ae2b894570ed68fcb Mon Sep 17 00:00:00 2001
From: Meena Alfons <meena.alfons@messagebird.com>
Date: Sat, 15 Apr 2023 15:45:14 +0200
Subject: [PATCH 2/2] Filter old metrics using maxMetricAgeMs

---
 .gitignore     |  1 +
 lib/gateway.js | 10 ++++------
 2 files changed, 5 insertions(+), 6 deletions(-)
 create mode 100644 .gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3c3629e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+node_modules
diff --git a/lib/gateway.js b/lib/gateway.js
index df41a29..9b2b851 100644
--- a/lib/gateway.js
+++ b/lib/gateway.js
@@ -184,9 +184,10 @@ Gateway.prototype.reportMetrics = function reportMetrics( ) {
     samples = samples.splice(0);
 
     // discard samples older than the configured cutoff
-    if (this.maxMetricAgeMs >= 0) {
-        var now = this.getTimestamp();
-        var oldestKeepTs = now - this.maxMetricAgeMs;
+    const now = this.getTimestamp();
+    const oldestKeepTs = this.maxMetricAgeMs >= 0 ? (now - this.maxMetricAgeMs) : 0;
+    const filterOldMetrics = this.maxMetricAgeMs >= 0;
+    if (filterOldMetrics) {
         for (i=0; i<samples.length && samples[i].ts < oldestKeepTs; i++) ;
         if (i > 0) {
             Gateway.trace("discarding %d samples older than %d ms, from %d to %d",
@@ -214,9 +215,6 @@ Gateway.prototype.reportMetrics = function reportMetrics( ) {
     // except for metrics older than the configured cutoff.
     // This allows /metrics to be called more frequently than the /push interval.
     var allValues = {};
-    const now = this.getTimestamp();
-    const oldestKeepTs = this.maxMetricAgeMs >= 0 ? (now - this.maxMetricAgeMs) : 0;
-    const filterOldMetrics = this.maxMetricAgeMs >= 0;
     for (id in this.previousValues) {
         if (!filterOldMetrics || this.previousValues[id].ts >= oldestKeepTs) {
             allValues[id] = this.previousValues[id];