fix: monitorEc2Instances for instanceId list failing (#663)

Fixes #
In the previous PR where I added monitoring for network egress ingress I
started setting color to 'Total Network In" unfortunately this is not
caught during test or synthesis but only during deployment, and I only
did e2e testing for ASG monitoring.


<img width="1795" height="672" alt="per-instance-network"
src="https://github.com/user-attachments/assets/3d73854b-ccac-47db-ab8e-7b3eb09b7714"
/>
<img width="1895" height="233" alt="per-instance"
src="https://github.com/user-attachments/assets/6db15921-2a4f-48ba-9d8d-c144efce6e56"
/>
<img width="1801" height="670" alt="per-instance-network-multiple"
src="https://github.com/user-attachments/assets/c9d21efa-a9de-439a-bc35-452d64349bd7"
/>

<img width="1117" height="493" alt="network-monitoring-multiple"
src="https://github.com/user-attachments/assets/ecd08a54-3fd4-40bd-b0c7-9da2971441f7"
/>



---

_By submitting this pull request, I confirm that my contribution is made
under the terms of the Apache-2.0 license_

---------

Co-authored-by: Jerzy 'Cedric' Zagorski <[email protected]>

Author: xendo

lib/monitoring/aws-ec2/EC2MetricFactory.ts

@@ -80,9 +80,9 @@ class SelectedInstancesStrategy implements IEC2MetricFactoryStrategy {
       return metricFactory.createMetric(
         metricName,
         statistic,
-        `${metricName} (${instanceId})`,
+        `${label ?? metricName} (${instanceId})`,
         resolveDimensions(this.autoScalingGroup, instanceId),
-        label,
+        undefined,
         EC2Namespace,
         undefined,
         region,

lib/monitoring/aws-ec2/EC2Monitoring.ts

@@ -115,11 +115,13 @@ export class EC2Monitoring extends Monitoring {
       const alarmProps =
         props.addNetworkInTotalBytesExceedThresholdAlarm[disambiguator];
 
-      const createdAlarms = this.networkInMetrics.map((metric) => {
+      const createdAlarms = this.networkInSumMetrics.map((metric, idx) => {
+        const indexedDisambiguator =
+          idx > 0 ? `${disambiguator}-${idx}` : disambiguator;
         const createdAlarm = this.ec2AlarmFactory.addNetworkInAlarm(
           metric,
           alarmProps,
-          disambiguator,
+          indexedDisambiguator,
         );
         this.addAlarm(createdAlarm);
         return createdAlarm;
@@ -133,11 +135,13 @@ export class EC2Monitoring extends Monitoring {
     for (const disambiguator in props.addNetworkOutTotalBytesExceedThresholdAlarm) {
       const alarmProps =
         props.addNetworkOutTotalBytesExceedThresholdAlarm[disambiguator];
-      const createdAlarms = this.networkOutSumMetrics.map((metric) => {
+      const createdAlarms = this.networkOutSumMetrics.map((metric, idx) => {
+        const indexedDisambiguator =
+          idx > 0 ? `${disambiguator}-${idx}` : disambiguator;
         const createdAlarm = this.ec2AlarmFactory.addNetworkOutAlarm(
           metric,
           alarmProps,
-          disambiguator,
+          indexedDisambiguator,
         );
         this.addAlarm(createdAlarm);
         return createdAlarm;

test/monitoring/aws-ec2/EC2Monitoring.test.ts

@@ -102,3 +102,114 @@ test("snapshot test: all instances, network alarms", () => {
   expect(numAlarmsCreated).toBe(2);
   expect(Template.fromStack(stack)).toMatchSnapshot();
 });
+
+test("snapshot test: ASG, network alarms", () => {
+  const stack = new Stack();
+
+  const scope = new TestMonitoringScope(stack, "Scope");
+
+  let numAlarmsCreated = 0;
+
+  const monitoring = new EC2Monitoring(scope, {
+    alarmFriendlyName: "EC2",
+    autoScalingGroup: AutoScalingGroup.fromAutoScalingGroupName(
+      stack,
+      "DummyASG",
+      "DummyASG",
+    ),
+    addNetworkInTotalBytesExceedThresholdAlarm: {
+      WARNING: {
+        maxNetworkInBytes: 100,
+        period: Duration.days(1),
+      },
+    },
+    addNetworkOutTotalBytesExceedThresholdAlarm: {
+      ERROR: {
+        maxNetworkOutBytes: 200,
+        period: Duration.days(4),
+      },
+    },
+    useCreatedAlarms: {
+      consume(alarms: AlarmWithAnnotation[]) {
+        numAlarmsCreated = alarms.length;
+      },
+    },
+  });
+
+  addMonitoringDashboardsToStack(stack, monitoring);
+  expect(numAlarmsCreated).toBe(2);
+  expect(Template.fromStack(stack)).toMatchSnapshot();
+});
+
+test("snapshot test: instance filter, network alarms", () => {
+  const stack = new Stack();
+
+  const scope = new TestMonitoringScope(stack, "Scope");
+
+  let numAlarmsCreated = 0;
+
+  const monitoring = new EC2Monitoring(scope, {
+    alarmFriendlyName: "EC2",
+    instanceIds: ["instanceId1", "instanceId2"],
+    addNetworkInTotalBytesExceedThresholdAlarm: {
+      WARNING: {
+        maxNetworkInBytes: 100,
+        period: Duration.days(1),
+      },
+    },
+    addNetworkOutTotalBytesExceedThresholdAlarm: {
+      ERROR: {
+        maxNetworkOutBytes: 200,
+        period: Duration.days(4),
+      },
+    },
+    useCreatedAlarms: {
+      consume(alarms: AlarmWithAnnotation[]) {
+        numAlarmsCreated = alarms.length;
+      },
+    },
+  });
+
+  addMonitoringDashboardsToStack(stack, monitoring);
+  expect(numAlarmsCreated).toBe(4);
+  expect(Template.fromStack(stack)).toMatchSnapshot();
+});
+
+test("snapshot test: instance filter + ASG, network alarms", () => {
+  const stack = new Stack();
+
+  const scope = new TestMonitoringScope(stack, "Scope");
+
+  let numAlarmsCreated = 0;
+
+  const monitoring = new EC2Monitoring(scope, {
+    alarmFriendlyName: "EC2",
+    instanceIds: ["instanceId1", "instanceId2"],
+    autoScalingGroup: AutoScalingGroup.fromAutoScalingGroupName(
+      stack,
+      "DummyASG",
+      "DummyASG",
+    ),
+    addNetworkInTotalBytesExceedThresholdAlarm: {
+      WARNING: {
+        maxNetworkInBytes: 100,
+        period: Duration.days(1),
+      },
+    },
+    addNetworkOutTotalBytesExceedThresholdAlarm: {
+      ERROR: {
+        maxNetworkOutBytes: 200,
+        period: Duration.days(4),
+      },
+    },
+    useCreatedAlarms: {
+      consume(alarms: AlarmWithAnnotation[]) {
+        numAlarmsCreated = alarms.length;
+      },
+    },
+  });
+
+  addMonitoringDashboardsToStack(stack, monitoring);
+  expect(numAlarmsCreated).toBe(4);
+  expect(Template.fromStack(stack)).toMatchSnapshot();
+});