Add validation for dimension values

src/serializers/LogSerializer.ts

@@ -38,21 +38,21 @@ export class LogSerializer implements ISerializer {
     const dimensionKeys: string[][] = [];
     let dimensionProperties = {};
 
-    context.getDimensions().forEach(d => {
-      // we can only take the first 9 defined dimensions
-      // the reason we do this in the serializer is because
-      // it is possible that other sinks or formats can
-      // support more dimensions
-      // in the future it may make sense to introduce a higher-order
-      // representation for sink-specific validations
-      const keys = Object.keys(d);
+    context.getDimensions().forEach(dimensionSet => {
+      const keys = Object.keys(dimensionSet);
+
       if (keys.length > Constants.MAX_DIMENSION_SET_SIZE) {
-        const errMsg = `Maximum number of dimensions allowed are ${Constants.MAX_DIMENSION_SET_SIZE}.` +
-        `Account for default dimensions if not using set_dimensions.`;
-        throw new DimensionSetExceededError(errMsg)
+        const errMsg =
+          `Maximum number of dimensions allowed are ${Constants.MAX_DIMENSION_SET_SIZE}.` +
+          `Account for default dimensions if not using set_dimensions.`;
+        throw new DimensionSetExceededError(errMsg);
       }
+
+      // Stringify and remove non-ascii characeters (allow only 0x20-0x7E)
+      keys.forEach(key => (dimensionSet[key] = String(dimensionSet[key]).replace(/[^\x20-\x7F]/g, '')));
+
       dimensionKeys.push(keys);
-      dimensionProperties = { ...dimensionProperties, ...d };
+      dimensionProperties = { ...dimensionProperties, ...dimensionSet };
     });
 
     // eslint-disable-next-line @typescript-eslint/no-explicit-any

src/serializers/__tests__/LogSerializer.test.ts

@@ -180,7 +180,7 @@ test('cannot serialize more than 30 dimensions', () => {
 
   // assert
   expect(() => {
-    serializer.serialize(context)
+    serializer.serialize(context);
   }).toThrow(DimensionSetExceededError);
 });
 
@@ -189,6 +189,47 @@ const assertJsonEquality = (resultJson: string, expectedObj: any) => {
   expect(actual).toStrictEqual(expectedObj);
 };
 
+test('remove non-ascii characters from dimension values', () => {
+  // arrange
+  const key = faker.random.word();
+  const value = '¡é詵ascii🚀♞∑';
+  const expectedValue = 'ascii';
+  const dimensions: any = {};
+  const expectedDimensions: any = {};
+  expectedDimensions[key] = expectedValue;
+  dimensions[key] = value;
+
+  const expected: any = { ...getEmptyPayload(), ...expectedDimensions };
+  expected._aws.CloudWatchMetrics[0].Dimensions.push([key]);
+
+  const context = getContext();
+  context.putDimensions(dimensions);
+
+  // act
+  const resultJson = serializer.serialize(context)[0];
+
+  // assert
+  assertJsonEquality(resultJson, expected);
+});
+
+test('convert dimension values to strings', () => {
+  // arrange
+  const key = faker.random.word();
+  const value = faker.random.number();
+  const expectedValue = String(value);
+  const dimensions: any = {};
+  dimensions[key] = value;
+
+  const context = getContext();
+  context.putDimensions(dimensions);
+
+  // act
+  const resultJson = serializer.serialize(context)[0];
+
+  // assert
+  expect(JSON.parse(resultJson)[key]).toStrictEqual(expectedValue);
+});
+
 const getEmptyPayload = () => {
   return Object.assign(
     {},