grpc-js-core: implement setLogger() and setLogVerbosity()

These were missing from the pure JS implementation. This commit
adds them.

packages/grpc-js-core/src/constants.ts

@@ -17,3 +17,9 @@ export enum Status {
   DATA_LOSS,
   UNAUTHENTICATED
 }
+
+export enum LogVerbosity {
+  DEBUG = 0,
+  INFO,
+  ERROR
+}

packages/grpc-js-core/src/index.ts

@@ -4,10 +4,11 @@ import {IncomingHttpHeaders} from 'http';
 import {CallCredentials} from './call-credentials';
 import {ChannelCredentials} from './channel-credentials';
 import {Client} from './client';
-import {Status} from './constants';
+import {LogVerbosity, Status} from './constants';
 import {loadPackageDefinition, makeClientConstructor} from './make-client';
 import {Metadata} from './metadata';
 import { Channel } from './channel';
+import * as logging from './logging';
 
 interface IndexedObject {
   [key: string]: any;
@@ -96,6 +97,7 @@ export {Metadata};
 /**** Constants ****/
 
 export {
+  LogVerbosity as logVerbosity,
   Status as status
   // TODO: Other constants as well
 };
@@ -135,12 +137,12 @@ export const load = (filename: any, format: any, options: any) => {
       'Not available in this library. Use @grpc/proto-loader and loadPackageDefinition instead');
 };
 
-export const setLogger = (logger: any) => {
-  throw new Error('Not yet implemented');
+export const setLogger = (logger: Partial<Console>): void => {
+  logging.setLogger(logger);
 };
 
-export const setLogVerbosity = (verbosity: any) => {
-  throw new Error('Not yet implemented');
+export const setLogVerbosity = (verbosity: LogVerbosity): void => {
+  logging.setLoggerVerbosity(verbosity);
 };
 
 export const Server = (options: any) => {

packages/grpc-js-core/src/logging.ts

@@ -0,0 +1,22 @@
+import {LogVerbosity} from './constants';
+
+let _logger: Partial<Console> = console;
+let _logVerbosity: LogVerbosity = LogVerbosity.DEBUG;
+
+export const getLogger = (): Partial<Console> => {
+  return _logger;
+};
+
+export const setLogger = (logger: Partial<Console>): void => {
+  _logger = logger;
+};
+
+export const setLoggerVerbosity = (verbosity: LogVerbosity): void => {
+  _logVerbosity = verbosity;
+};
+
+export const log = (severity: LogVerbosity, ...args: any[]): void => {
+  if (severity >= _logVerbosity && typeof _logger.error === 'function') {
+    _logger.error(...args);
+  }
+};

packages/grpc-js-core/test/test-logging.ts

@@ -0,0 +1,60 @@
+import * as assert from 'assert';
+
+import * as grpc from '../src';
+import * as logging from '../src/logging';
+
+describe('Logging', () => {
+  afterEach(function() {
+    // Ensure that the logger is restored to its defaults after each test.
+    grpc.setLogger(console);
+    grpc.setLogVerbosity(grpc.logVerbosity.DEBUG);
+  });
+
+  it('logger defaults to console', () => {
+    assert.strictEqual(logging.getLogger(), console);
+  });
+
+  it('sets the logger to a new value', () => {
+    const logger: Partial<Console> = {};
+
+    logging.setLogger(logger);
+    assert.strictEqual(logging.getLogger(), logger);
+  });
+
+  it('gates logging based on severity', () => {
+    const output: any[] = [];
+    const logger: Partial<Console> = {
+      error(...args: any[]): void {
+        output.push(args);
+      }
+    };
+
+    logging.setLogger(logger);
+
+    // The default verbosity (DEBUG) should log everything.
+    logging.log(grpc.logVerbosity.DEBUG, 'a', 'b', 'c');
+    logging.log(grpc.logVerbosity.INFO, 'd', 'e');
+    logging.log(grpc.logVerbosity.ERROR, 'f');
+
+    // The INFO verbosity should not log DEBUG data.
+    logging.setLoggerVerbosity(grpc.logVerbosity.INFO);
+    logging.log(grpc.logVerbosity.DEBUG, 1, 2, 3);
+    logging.log(grpc.logVerbosity.INFO, 'g');
+    logging.log(grpc.logVerbosity.ERROR, 'h', 'i');
+
+    // The ERROR verbosity should not log DEBUG or INFO data.
+    logging.setLoggerVerbosity(grpc.logVerbosity.ERROR);
+    logging.log(grpc.logVerbosity.DEBUG, 4, 5, 6);
+    logging.log(grpc.logVerbosity.INFO, 7, 8);
+    logging.log(grpc.logVerbosity.ERROR, 'j', 'k');
+
+    assert.deepStrictEqual(output, [
+      ['a', 'b', 'c'],
+      ['d', 'e'],
+      ['f'],
+      ['g'],
+      ['h', 'i'],
+      ['j', 'k']
+    ]);
+  });
+});