feat(opentelemetry-js): add content size attributes to HTTP spans (#1625)

* feat(opentelemetry-js): extract content-length header for span attrs

Signed-off-by: Carlo Pearson <cpearson@newrelic.com>

* feat(opentelemetry-js): add content-length attributes to HTTP spans

Signed-off-by: Carlo Pearson <cpearson@newrelic.com>

* feat(opentelemetry-js): linting

* feat(opentelemetry-js): verify content length attributes are a number

* feat(opentelemetry-js): refactor setting content-length attributes

* feat(opentelemetry-js): lint fixes

* feat(opentelemetry-js): lint fixes

* fix: incorrect docs

Co-authored-by: Carlo Pearson <cpearson@newrelic.com>
Co-authored-by: Daniel Dyla <dyladan@users.noreply.github.com>
Co-authored-by: Bartlomiej Obecny <bobecny@gmail.com>

packages/opentelemetry-plugin-http/src/utils.ts

@@ -177,6 +177,66 @@ export const setSpanWithError = (
   span.setStatus(status);
 };
 
+/**
+ * Adds attributes for request content-length and content-encoding HTTP headers
+ * @param { IncomingMessage } Request object whose headers will be analyzed
+ * @param { Attributes } Attributes object to be modified
+ */
+export const setRequestContentLengthAttribute = (
+  request: IncomingMessage,
+  attributes: Attributes
+) => {
+  const length = getContentLength(request.headers);
+  if (length === null) return;
+
+  if (isCompressed(request.headers)) {
+    attributes[HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH] = length;
+  } else {
+    attributes[HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH_UNCOMPRESSED] = length;
+  }
+};
+
+/**
+ * Adds attributes for response content-length and content-encoding HTTP headers
+ * @param { IncomingMessage } Response object whose headers will be analyzed
+ * @param { Attributes } Attributes object to be modified
+ */
+export const setResponseContentLengthAttribute = (
+  response: IncomingMessage,
+  attributes: Attributes
+) => {
+  const length = getContentLength(response.headers);
+  if (length === null) return;
+
+  if (isCompressed(response.headers)) {
+    attributes[HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH] = length;
+  } else {
+    attributes[
+      HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH_UNCOMPRESSED
+    ] = length;
+  }
+};
+
+function getContentLength(
+  headers: OutgoingHttpHeaders | IncomingHttpHeaders
+): number | null {
+  const contentLengthHeader = headers['content-length'];
+  if (contentLengthHeader === undefined) return null;
+
+  const contentLength = parseInt(contentLengthHeader as string, 10);
+  if (isNaN(contentLength)) return null;
+
+  return contentLength;
+}
+
+export const isCompressed = (
+  headers: OutgoingHttpHeaders | IncomingHttpHeaders
+): boolean => {
+  const encoding = headers['content-encoding'];
+
+  return !!encoding && encoding !== 'identity';
+};
+
 /**
  * Makes sure options is an url object
  * return an object with default value and parsed options
@@ -318,12 +378,15 @@ export const getOutgoingRequestAttributesOnResponse = (
 ): Attributes => {
   const { statusCode, statusMessage, httpVersion, socket } = response;
   const { remoteAddress, remotePort } = socket;
+
   const attributes: Attributes = {
     [GeneralAttribute.NET_PEER_IP]: remoteAddress,
     [GeneralAttribute.NET_PEER_PORT]: remotePort,
     [HttpAttribute.HTTP_HOST]: `${options.hostname}:${remotePort}`,
   };
 
+  setResponseContentLengthAttribute(response, attributes);
+
   if (statusCode) {
     attributes[HttpAttribute.HTTP_STATUS_CODE] = statusCode;
     attributes[HttpAttribute.HTTP_STATUS_TEXT] = (
@@ -384,6 +447,8 @@ export const getIncomingRequestAttributes = (
     attributes[HttpAttribute.HTTP_USER_AGENT] = userAgent;
   }
 
+  setRequestContentLengthAttribute(request, attributes);
+
   const httpKindAttributes = getAttributesFromHttpKind(httpVersion);
   return Object.assign(attributes, httpKindAttributes);
 };

packages/opentelemetry-plugin-http/test/functionals/utils.test.ts

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 import {
+  Attributes,
   StatusCode,
   ROOT_CONTEXT,
   SpanKind,
@@ -308,4 +309,146 @@ describe('Utility', () => {
       assert.deepEqual(attributes[HttpAttribute.HTTP_ROUTE], undefined);
     });
   });
+
+  // Verify the key in the given attributes is set to the given value,
+  // and that no other HTTP Content Length attributes are set.
+  function verifyValueInAttributes(
+    attributes: Attributes,
+    key: string | undefined,
+    value: number
+  ) {
+    const httpAttributes = [
+      HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH_UNCOMPRESSED,
+      HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH,
+      HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH_UNCOMPRESSED,
+      HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH,
+    ];
+
+    for (const attr of httpAttributes) {
+      if (attr === key) {
+        assert.strictEqual(attributes[attr], value);
+      } else {
+        assert.strictEqual(attributes[attr], undefined);
+      }
+    }
+  }
+
+  describe('setRequestContentLengthAttributes()', () => {
+    it('should set request content-length uncompressed attribute with no content-encoding header', () => {
+      const attributes: Attributes = {};
+      const request = {} as IncomingMessage;
+
+      request.headers = {
+        'content-length': '1200',
+      };
+      utils.setRequestContentLengthAttribute(request, attributes);
+
+      verifyValueInAttributes(
+        attributes,
+        HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH_UNCOMPRESSED,
+        1200
+      );
+    });
+
+    it('should set request content-length uncompressed attribute with "identity" content-encoding header', () => {
+      const attributes: Attributes = {};
+      const request = {} as IncomingMessage;
+      request.headers = {
+        'content-length': '1200',
+        'content-encoding': 'identity',
+      };
+      utils.setRequestContentLengthAttribute(request, attributes);
+
+      verifyValueInAttributes(
+        attributes,
+        HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH_UNCOMPRESSED,
+        1200
+      );
+    });
+
+    it('should set request content-length compressed attribute with "gzip" content-encoding header', () => {
+      const attributes: Attributes = {};
+      const request = {} as IncomingMessage;
+      request.headers = {
+        'content-length': '1200',
+        'content-encoding': 'gzip',
+      };
+      utils.setRequestContentLengthAttribute(request, attributes);
+
+      verifyValueInAttributes(
+        attributes,
+        HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH,
+        1200
+      );
+    });
+  });
+
+  describe('setResponseContentLengthAttributes()', () => {
+    it('should set response content-length uncompressed attribute with no content-encoding header', () => {
+      const attributes: Attributes = {};
+
+      const response = {} as IncomingMessage;
+
+      response.headers = {
+        'content-length': '1200',
+      };
+      utils.setResponseContentLengthAttribute(response, attributes);
+
+      verifyValueInAttributes(
+        attributes,
+        HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH_UNCOMPRESSED,
+        1200
+      );
+    });
+
+    it('should set response content-length uncompressed attribute with "identity" content-encoding header', () => {
+      const attributes: Attributes = {};
+
+      const response = {} as IncomingMessage;
+
+      response.headers = {
+        'content-length': '1200',
+        'content-encoding': 'identity',
+      };
+
+      utils.setResponseContentLengthAttribute(response, attributes);
+
+      verifyValueInAttributes(
+        attributes,
+        HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH_UNCOMPRESSED,
+        1200
+      );
+    });
+
+    it('should set response content-length compressed attribute with "gzip" content-encoding header', () => {
+      const attributes: Attributes = {};
+
+      const response = {} as IncomingMessage;
+
+      response.headers = {
+        'content-length': '1200',
+        'content-encoding': 'gzip',
+      };
+
+      utils.setResponseContentLengthAttribute(response, attributes);
+
+      verifyValueInAttributes(
+        attributes,
+        HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH,
+        1200
+      );
+    });
+
+    it('should set no attributes with no content-length header', () => {
+      const attributes: Attributes = {};
+      const message = {} as IncomingMessage;
+
+      message.headers = {
+        'content-encoding': 'gzip',
+      };
+      utils.setResponseContentLengthAttribute(message, attributes);
+
+      verifyValueInAttributes(attributes, undefined, 1200);
+    });
+  });
 });

packages/opentelemetry-plugin-http/test/utils/assertSpan.ts

@@ -83,7 +83,29 @@ export const assertSpan = (
       );
     }
   }
+
   if (span.kind === SpanKind.CLIENT) {
+    if (validations.resHeaders['content-length']) {
+      const contentLength = Number(validations.resHeaders['content-length']);
+
+      if (
+        validations.resHeaders['content-encoding'] &&
+        validations.resHeaders['content-encoding'] !== 'identity'
+      ) {
+        assert.strictEqual(
+          span.attributes[HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH],
+          contentLength
+        );
+      } else {
+        assert.strictEqual(
+          span.attributes[
+            HttpAttribute.HTTP_RESPONSE_CONTENT_LENGTH_UNCOMPRESSED
+          ],
+          contentLength
+        );
+      }
+    }
+
     assert.strictEqual(
       span.attributes[GeneralAttribute.NET_PEER_NAME],
       validations.hostname,
@@ -105,6 +127,27 @@ export const assertSpan = (
     );
   }
   if (span.kind === SpanKind.SERVER) {
+    if (validations.reqHeaders && validations.reqHeaders['content-length']) {
+      const contentLength = validations.reqHeaders['content-length'];
+
+      if (
+        validations.reqHeaders['content-encoding'] &&
+        validations.reqHeaders['content-encoding'] !== 'identity'
+      ) {
+        assert.strictEqual(
+          span.attributes[HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH],
+          contentLength
+        );
+      } else {
+        assert.strictEqual(
+          span.attributes[
+            HttpAttribute.HTTP_REQUEST_CONTENT_LENGTH_UNCOMPRESSED
+          ],
+          contentLength
+        );
+      }
+    }
+
     if (validations.serverName) {
       assert.strictEqual(
         span.attributes[HttpAttribute.HTTP_SERVER_NAME],

packages/opentelemetry-semantic-conventions/src/trace/http.ts

@@ -26,6 +26,11 @@ export const HttpAttribute = {
   HTTP_CLIENT_IP: 'http.client_ip',
   HTTP_SCHEME: 'http.scheme',
   HTTP_RESPONSE_CONTENT_LENGTH: 'http.response_content_length',
+  HTTP_RESPONSE_CONTENT_LENGTH_UNCOMPRESSED:
+    'http.response_content_length_uncompressed',
+  HTTP_REQUEST_CONTENT_LENGTH: 'http.request_content_length',
+  HTTP_REQUEST_CONTENT_LENGTH_UNCOMPRESSED:
+    'http.request_content_length_uncompressed',
 
   // NOT ON OFFICIAL SPEC
   HTTP_ERROR_NAME: 'http.error_name',