Specify AWS region for metrics in cdk-monitoring-constructs

Question

I have 3 dyanmodb tables each in a different AWS region. I want to use cdk-monitoring-constructs to monitor them and have metrics for each dyanmodb table on the same dashboard. I create my monitoring facade and then iterate over my regions like so:

for (const region of regionsToMonitor) {

 const dyanmodbToMonitor = tableMap.get(region)
 monitoring.monitorDynamoTable(
     {
          table: dyanmodbToMonitor
      }
  )

however this only works for my table created in us-east-1. The other two tables, one in EU and the other in us-west-2 have missing metrics in the resulting dashboards. I can see in the cloudwatch metrics source for these two tables that they're empty because they're using the wrong region (i.e. using us-east-1 instead of us-west-2):

{
    "view": "timeSeries",
    "title": "Latency (Average)",
    "region": "us-east-1",

and when I manually change the region in their definitions the metrics appear.

How can I specify which region should be used when adding these tables to monitored?

Answer 1

TL;DR

Unfortunately, you can not create a graph with metrics from another region via cdk-monitoring-constructs. The current implementation doesn't support it.

---

I found this question interesting, so I traced the code and realised the current implementation doesn't pass the region to GraphWidget.

Here are the lines of code that show how aws-cdk defines the props of GraphWidget.

export interface MetricWidgetProps {
  ...
  /**
   * The region the metrics of this graph should be taken from
   *
   * @default Current region
   */
  readonly region?: string;
  ...
}

Here are the lines of code that show how cdk-monitoring-constructs generates graphs.

return new GraphWidget({
  width,
  height,
  title: "Read Usage",
  left: [this.consumedReadUnitsMetric, this.provisionedReadUnitsMetric],
  leftYAxis: CountAxisFromZero,
  leftAnnotations: this.dynamoReadCapacityAnnotations,
  right: [this.readCapacityUsageMetric],
  rightYAxis: PercentageAxisFromZeroToHundred,
  legendPosition: LegendPosition.RIGHT,
});

As you can see, it doesn't pass the region argument to GraphWidget, this result the graph is always created with the metrics in the current region (CloudFormation Stack region).