feat(NODE-5159): add FaaS env information to client metadata

src/cmap/auth/auth_provider.ts

@@ -1,8 +1,9 @@
 import type { Document } from '../../bson';
 import { MongoRuntimeError } from '../../error';
-import type { Callback, ClientMetadataOptions } from '../../utils';
+import type { Callback } from '../../utils';
 import type { HandshakeDocument } from '../connect';
 import type { Connection, ConnectionOptions } from '../connection';
+import type { ClientMetadataOptions } from '../handshake/client_metadata';
 import type { MongoCredentials } from './mongo_credentials';
 
 export type AuthContextOptions = ConnectionOptions & ClientMetadataOptions;

src/cmap/connect.ts

@@ -18,7 +18,7 @@ import {
   MongoServerError,
   needsRetryableWriteLabel
 } from '../error';
-import { Callback, ClientMetadata, HostAddress, ns } from '../utils';
+import { Callback, HostAddress, ns } from '../utils';
 import { AuthContext, AuthProvider } from './auth/auth_provider';
 import { GSSAPI } from './auth/gssapi';
 import { MongoCR } from './auth/mongocr';
@@ -28,6 +28,7 @@ import { AuthMechanism } from './auth/providers';
 import { ScramSHA1, ScramSHA256 } from './auth/scram';
 import { X509 } from './auth/x509';
 import { Connection, ConnectionOptions, CryptoConnection } from './connection';
+import type { ClientMetadata } from './handshake/client_metadata';
 import {
   MAX_SUPPORTED_SERVER_VERSION,
   MAX_SUPPORTED_WIRE_VERSION,
@@ -347,7 +348,7 @@ function parseSslOptions(options: MakeConnectionOptions): TLSConnectionOpts {
 }
 
 const SOCKET_ERROR_EVENT_LIST = ['error', 'close', 'timeout', 'parseError'] as const;
-type ErrorHandlerEventName = typeof SOCKET_ERROR_EVENT_LIST[number] | 'cancel';
+type ErrorHandlerEventName = (typeof SOCKET_ERROR_EVENT_LIST)[number] | 'cancel';
 const SOCKET_ERROR_EVENTS = new Set(SOCKET_ERROR_EVENT_LIST);
 
 function makeConnection(options: MakeConnectionOptions, _callback: Callback<Stream>) {

src/cmap/connection.ts

@@ -28,7 +28,6 @@ import { applySession, ClientSession, updateSessionFromResponse } from '../sessi
 import {
   calculateDurationInMs,
   Callback,
-  ClientMetadata,
   HostAddress,
   maxWireVersion,
   MongoDBNamespace,
@@ -44,6 +43,7 @@ import {
 } from './command_monitoring_events';
 import { BinMsg, Msg, Query, Response, WriteProtocolMessageType } from './commands';
 import type { Stream } from './connect';
+import type { ClientMetadata } from './handshake/client_metadata';
 import { MessageStream, OperationDescription } from './message_stream';
 import { StreamDescription, StreamDescriptionOptions } from './stream_description';
 import { getReadPreference, isSharded } from './wire_protocol/shared';

src/cmap/handshake/client_metadata.ts

@@ -0,0 +1,236 @@
+import * as os from 'os';
+import * as process from 'process';
+
+import { BSON, Int32 } from '../../bson';
+import { MongoInvalidArgumentError } from '../../error';
+import type { MongoOptions } from '../../mongo_client';
+
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const NODE_DRIVER_VERSION = require('../../../package.json').version;
+
+/**
+ * @public
+ * @see https://github.com/mongodb/specifications/blob/master/source/mongodb-handshake/handshake.rst#hello-command
+ */
+export interface ClientMetadata {
+  driver: {
+    name: string;
+    version: string;
+  };
+  os: {
+    type: string;
+    name?: NodeJS.Platform;
+    architecture?: string;
+    version?: string;
+  };
+  platform: string;
+  application?: {
+    name: string;
+  };
+  /** FaaS environment information */
+  env?: {
+    name: 'aws.lambda' | 'gcp.func' | 'azure.func' | 'vercel';
+    timeout_sec?: Int32;
+    memory_mb?: Int32;
+    region?: string;
+    url?: string;
+  };
+}
+
+/** @public */
+export interface ClientMetadataOptions {
+  driverInfo?: {
+    name?: string;
+    version?: string;
+    platform?: string;
+  };
+  appName?: string;
+}
+
+/** @internal */
+export class LimitedSizeDocument {
+  private document = new Map();
+  /** BSON overhead: Int32 + Null byte */
+  private documentSize = 5;
+  constructor(private maxSize: number) {}
+
+  /** Only adds key/value if the bsonByteLength is less than MAX_SIZE */
+  public ifItFitsItSits(key: string, value: Record<string, any> | string): boolean {
+    // The BSON byteLength of the new element is the same as serializing it to its own document
+    // subtracting the document size int32 and the null terminator.
+    const newElementSize = BSON.serialize(new Map().set(key, value)).byteLength - 5;
+
+    if (newElementSize + this.documentSize > this.maxSize) {
+      return false;
+    }
+
+    this.documentSize += newElementSize;
+
+    this.document.set(key, value);
+
+    return true;
+  }
+
+  toObject(): ClientMetadata {
+    return BSON.deserialize(BSON.serialize(this.document), {
+      promoteLongs: false,
+      promoteBuffers: false,
+      promoteValues: false,
+      useBigInt64: false
+    }) as ClientMetadata;
+  }
+}
+
+type MakeClientMetadataOptions = Pick<MongoOptions, 'appName' | 'driverInfo'>;
+/**
+ * From the specs:
+ * Implementors SHOULD cumulatively update fields in the following order until the document is under the size limit:
+ * 1. Omit fields from `env` except `env.name`.
+ * 2. Omit fields from `os` except `os.type`.
+ * 3. Omit the `env` document entirely.
+ * 4. Truncate `platform`. -- special we do not truncate this field
+ */
+export function makeClientMetadata(options: MakeClientMetadataOptions): ClientMetadata {
+  const metadataDocument = new LimitedSizeDocument(512);
+
+  const { appName = '' } = options;
+  // Add app name first, it must be sent
+  if (appName.length > 0) {
+    const name =
+      Buffer.byteLength(appName, 'utf8') <= 128
+        ? options.appName
+        : Buffer.from(appName, 'utf8').subarray(0, 128).toString('utf8');
+    metadataDocument.ifItFitsItSits('application', { name });
+  }
+
+  const { name = '', version = '', platform = '' } = options.driverInfo;
+
+  const driverInfo = {
+    name: name.length > 0 ? `nodejs|${name}` : 'nodejs',
+    version: version.length > 0 ? `${NODE_DRIVER_VERSION}|${version}` : NODE_DRIVER_VERSION
+  };
+
+  if (!metadataDocument.ifItFitsItSits('driver', driverInfo)) {
+    throw new MongoInvalidArgumentError(
+      'Unable to include driverInfo name and version, metadata cannot exceed 512 bytes'
+    );
+  }
+
+  const platformInfo =
+    platform.length > 0
+      ? `Node.js ${process.version}, ${os.endianness()}|${platform}`
+      : `Node.js ${process.version}, ${os.endianness()}`;
+
+  if (!metadataDocument.ifItFitsItSits('platform', platformInfo)) {
+    throw new MongoInvalidArgumentError(
+      'Unable to include driverInfo platform, metadata cannot exceed 512 bytes'
+    );
+  }
+
+  // Note: order matters, os.type is last so it will be removed last if we're at maxSize
+  const osInfo = new Map()
+    .set('name', process.platform)
+    .set('architecture', process.arch)
+    .set('version', os.release())
+    .set('type', os.type());
+
+  if (!metadataDocument.ifItFitsItSits('os', osInfo)) {
+    for (const key of osInfo.keys()) {
+      osInfo.delete(key);
+      if (osInfo.size === 0) break;
+      if (metadataDocument.ifItFitsItSits('os', osInfo)) break;
+    }
+  }
+
+  const faasEnv = getFAASEnv();
+  if (faasEnv != null) {
+    if (!metadataDocument.ifItFitsItSits('env', faasEnv)) {
+      for (const key of faasEnv.keys()) {
+        faasEnv.delete(key);
+        if (faasEnv.size === 0) break;
+        if (metadataDocument.ifItFitsItSits('env', faasEnv)) break;
+      }
+    }
+  }
+
+  return metadataDocument.toObject();
+}
+
+/**
+ * Collects FaaS metadata.
+ * - `name` MUST be the last key in the Map returned.
+ */
+export function getFAASEnv(): Map<string, string | Int32> | null {
+  const {
+    AWS_EXECUTION_ENV = '',
+    AWS_LAMBDA_RUNTIME_API = '',
+    FUNCTIONS_WORKER_RUNTIME = '',
+    K_SERVICE = '',
+    FUNCTION_NAME = '',
+    VERCEL = '',
+    AWS_LAMBDA_FUNCTION_MEMORY_SIZE = '',
+    AWS_REGION = '',
+    FUNCTION_MEMORY_MB = '',
+    FUNCTION_REGION = '',
+    FUNCTION_TIMEOUT_SEC = '',
+    VERCEL_REGION = ''
+  } = process.env;
+
+  const isAWSFaaS = AWS_EXECUTION_ENV.length > 0 || AWS_LAMBDA_RUNTIME_API.length > 0;
+  const isAzureFaaS = FUNCTIONS_WORKER_RUNTIME.length > 0;
+  const isGCPFaaS = K_SERVICE.length > 0 || FUNCTION_NAME.length > 0;
+  const isVercelFaaS = VERCEL.length > 0;
+
+  // Note: order matters, name must always be the last key
+  const faasEnv = new Map();
+
+  // When isVercelFaaS is true so is isAWSFaaS; Vercel inherits the AWS env
+  if (isVercelFaaS && !(isAzureFaaS || isGCPFaaS)) {
+    if (VERCEL_REGION.length > 0) {
+      faasEnv.set('region', VERCEL_REGION);
+    }
+
+    faasEnv.set('name', 'vercel');
+    return faasEnv;
+  }
+
+  if (isAWSFaaS && !(isAzureFaaS || isGCPFaaS || isVercelFaaS)) {
+    if (AWS_REGION.length > 0) {
+      faasEnv.set('region', AWS_REGION);
+    }
+
+    if (
+      AWS_LAMBDA_FUNCTION_MEMORY_SIZE.length > 0 &&
+      Number.isInteger(+AWS_LAMBDA_FUNCTION_MEMORY_SIZE)
+    ) {
+      faasEnv.set('memory_mb', new Int32(AWS_LAMBDA_FUNCTION_MEMORY_SIZE));
+    }
+
+    faasEnv.set('name', 'aws.lambda');
+    return faasEnv;
+  }
+
+  if (isAzureFaaS && !(isGCPFaaS || isAWSFaaS || isVercelFaaS)) {
+    faasEnv.set('name', 'azure.func');
+    return faasEnv;
+  }
+
+  if (isGCPFaaS && !(isAzureFaaS || isAWSFaaS || isVercelFaaS)) {
+    if (FUNCTION_REGION.length > 0) {
+      faasEnv.set('region', FUNCTION_REGION);
+    }
+
+    if (FUNCTION_MEMORY_MB.length > 0 && Number.isInteger(+FUNCTION_MEMORY_MB)) {
+      faasEnv.set('memory_mb', new Int32(FUNCTION_MEMORY_MB));
+    }
+
+    if (FUNCTION_TIMEOUT_SEC.length > 0 && Number.isInteger(+FUNCTION_TIMEOUT_SEC)) {
+      faasEnv.set('timeout_sec', new Int32(FUNCTION_TIMEOUT_SEC));
+    }
+
+    faasEnv.set('name', 'gcp.func');
+    return faasEnv;
+  }
+
+  return null;
+}

src/connection_string.ts

@@ -6,6 +6,7 @@ import { URLSearchParams } from 'url';
 import type { Document } from './bson';
 import { MongoCredentials } from './cmap/auth/mongo_credentials';
 import { AUTH_MECHS_AUTH_SRC_EXTERNAL, AuthMechanism } from './cmap/auth/providers';
+import { makeClientMetadata } from './cmap/handshake/client_metadata';
 import { Compressor, CompressorName } from './cmap/wire_protocol/compression';
 import { Encrypter } from './encrypter';
 import {
@@ -34,7 +35,6 @@ import {
   emitWarningOnce,
   HostAddress,
   isRecord,
-  makeClientMetadata,
   parseInteger,
   setDifference
 } from './utils';

src/index.ts

@@ -248,6 +248,7 @@ export type {
   WaitQueueMember,
   WithConnectionCallback
 } from './cmap/connection_pool';
+export type { ClientMetadata, ClientMetadataOptions } from './cmap/handshake/client_metadata';
 export type {
   MessageStream,
   MessageStreamOptions,
@@ -480,8 +481,6 @@ export type { Transaction, TransactionOptions, TxnState } from './transactions';
 export type {
   BufferPool,
   Callback,
-  ClientMetadata,
-  ClientMetadataOptions,
   EventEmitterWithState,
   HostAddress,
   List,