feat(cloudwatch): validate parameters for a metric dimensions (closes a…

…ws#3116) (aws#14365)

As per aws#3116, the changes in this PR validate metric dimension values (length, and checking if the value is null or undefined) and throw errors if the values are not valid. I've also corrected a comment in the metric-types.ts to use the correct method name

packages/@aws-cdk/aws-cloudwatch/lib/metric-types.ts

@@ -12,21 +12,23 @@ export interface IMetric {
   /**
    * Turn this metric object into an alarm configuration
    *
-   * @deprecated Use `toMetricsConfig()` instead.
+   * @deprecated Use `toMetricConfig()` instead.
    */
   toAlarmConfig(): MetricAlarmConfig;
 
   /**
    * Turn this metric object into a graph configuration
    *
-   * @deprecated Use `toMetricsConfig()` instead.
+   * @deprecated Use `toMetricConfig()` instead.
    */
   toGraphConfig(): MetricGraphConfig;
 }
 
 /**
  * Metric dimension
  *
+ * @see https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-cw-dimension.html
+ *
  */
 export interface Dimension {
   /**

packages/@aws-cdk/aws-cloudwatch/lib/metric.ts

@@ -216,7 +216,9 @@ export class Metric implements IMetric {
     if (periodSec !== 1 && periodSec !== 5 && periodSec !== 10 && periodSec !== 30 && periodSec % 60 !== 0) {
       throw new Error(`'period' must be 1, 5, 10, 30, or a multiple of 60 seconds, received ${periodSec}`);
     }
-
+    if (props.dimensions) {
+      this.validateDimensions(props.dimensions);
+    }
     this.dimensions = props.dimensions;
     this.namespace = props.namespace;
     this.metricName = props.metricName;
@@ -395,6 +397,26 @@ export class Metric implements IMetric {
 
     return list;
   }
+
+  private validateDimensions(dims: DimensionHash): void {
+    var dimsArray = Object.keys(dims);
+    if (dimsArray?.length > 10) {
+      throw new Error(`The maximum number of dimensions is 10, received ${dimsArray.length}`);
+    }
+
+    dimsArray.map(key => {
+      if (dims[key] === undefined || dims[key] === null) {
+        throw new Error(`Dimension value of '${dims[key]}' is invalid`);
+      };
+      if (key.length < 1 || key.length > 255) {
+        throw new Error(`Dimension name must be at least 1 and no more than 255 characters; received ${key}`);
+      };
+
+      if (dims[key].length < 1 || dims[key].length > 255) {
+        throw new Error(`Dimension value must be at least 1 and no more than 255 characters; received ${dims[key]}`);
+      };
+    });
+  }
 }
 
 function asString(x?: unknown): string | undefined {

packages/@aws-cdk/aws-cloudwatch/test/test.metrics.ts

@@ -51,4 +51,77 @@ export = {
 
     test.done();
   },
+
+  'cannot use null dimension value'(test: Test) {
+    test.throws(() => {
+      new Metric({
+        namespace: 'Test',
+        metricName: 'ACount',
+        period: cdk.Duration.minutes(10),
+        dimensions: {
+          DimensionWithNull: null,
+        },
+      });
+    }, /Dimension value of 'null' is invalid/);
+
+    test.done();
+  },
+
+  'cannot use undefined dimension value'(test: Test) {
+    test.throws(() => {
+      new Metric({
+        namespace: 'Test',
+        metricName: 'ACount',
+        period: cdk.Duration.minutes(10),
+        dimensions: {
+          DimensionWithUndefined: undefined,
+        },
+      });
+    }, /Dimension value of 'undefined' is invalid/);
+
+    test.done();
+  },
+
+  'cannot use long dimension values'(test: Test) {
+    const arr = new Array(256);
+    const invalidDimensionValue = arr.fill('A', 0).join('');
+
+    test.throws(() => {
+      new Metric({
+        namespace: 'Test',
+        metricName: 'ACount',
+        period: cdk.Duration.minutes(10),
+        dimensions: {
+          DimensionWithLongValue: invalidDimensionValue,
+        },
+      });
+    }, `Dimension value must be at least 1 and no more than 255 characters; received ${invalidDimensionValue}`);
+
+    test.done();
+  },
+
+  'throws error when there are more than 10 dimensions'(test: Test) {
+    test.throws(() => {
+      new Metric({
+        namespace: 'Test',
+        metricName: 'ACount',
+        period: cdk.Duration.minutes(10),
+        dimensions: {
+          dimensionA: 'value1',
+          dimensionB: 'value2',
+          dimensionC: 'value3',
+          dimensionD: 'value4',
+          dimensionE: 'value5',
+          dimensionF: 'value6',
+          dimensionG: 'value7',
+          dimensionH: 'value8',
+          dimensionI: 'value9',
+          dimensionJ: 'value10',
+          dimensionK: 'value11',
+        },
+      } );
+    }, /The maximum number of dimensions is 10, received 11/);
+
+    test.done();
+  },
 };