From ebd396248ce5cf036d893753e1ed52fef8ba1e41 Mon Sep 17 00:00:00 2001
From: OksanaH <34384274+OksanaH@users.noreply.github.com>
Date: Fri, 7 May 2021 22:16:27 +0100
Subject: [PATCH] feat(cloudwatch): validate parameters for a metric dimensions
 (closes #3116) (#14365)

As per #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
---
 .../aws-cloudwatch/lib/metric-types.ts        |  6 +-
 .../@aws-cdk/aws-cloudwatch/lib/metric.ts     | 24 +++++-
 .../aws-cloudwatch/test/test.metrics.ts       | 73 +++++++++++++++++++
 3 files changed, 100 insertions(+), 3 deletions(-)

diff --git a/packages/@aws-cdk/aws-cloudwatch/lib/metric-types.ts b/packages/@aws-cdk/aws-cloudwatch/lib/metric-types.ts
index eaa48446672f9..296400ee7f910 100644
--- a/packages/@aws-cdk/aws-cloudwatch/lib/metric-types.ts
+++ b/packages/@aws-cdk/aws-cloudwatch/lib/metric-types.ts
@@ -12,14 +12,14 @@ 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;
 }
@@ -27,6 +27,8 @@ export interface IMetric {
 /**
  * Metric dimension
  *
+ * @see https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-cw-dimension.html
+ *
  */
 export interface Dimension {
   /**
diff --git a/packages/@aws-cdk/aws-cloudwatch/lib/metric.ts b/packages/@aws-cdk/aws-cloudwatch/lib/metric.ts
index 0590a592da502..3bb3d512c86d0 100644
--- a/packages/@aws-cdk/aws-cloudwatch/lib/metric.ts
+++ b/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 {
diff --git a/packages/@aws-cdk/aws-cloudwatch/test/test.metrics.ts b/packages/@aws-cdk/aws-cloudwatch/test/test.metrics.ts
index 18e1840e35cb6..e1dc9230e1404 100644
--- a/packages/@aws-cdk/aws-cloudwatch/test/test.metrics.ts
+++ b/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();
+  },
 };