fix: log to console using structured logging (#780)

Replaces 'console-log-level' with '@google-cloud/logging-min' to write logs to stdout.
Replaces new line with its escape notation '\\n'.
Refactors single location that prints array to print a single string.

package.json

@@ -29,6 +29,7 @@
   "license": "Apache-2.0",
   "dependencies": {
     "@google-cloud/common": "^3.0.0",
+    "@google-cloud/logging-min": "^9.6.3",
     "@types/console-log-level": "^1.4.0",
     "@types/semver": "^7.0.0",
     "console-log-level": "^1.4.0",

src/index.ts

@@ -236,7 +236,7 @@ export async function startLocal(config: Config = {}): Promise<void> {
   setInterval(() => {
     const curTime = Date.now();
     const {rss, heapTotal, heapUsed} = process.memoryUsage();
-    logger.debug(
+    const debugInfo = [
       new Date().toISOString(),
       'rss',
       (rss / (1024 * 1024)).toFixed(3),
@@ -252,8 +252,9 @@ export async function startLocal(config: Config = {}): Promise<void> {
       'profiles/s,',
       'time profile collection rate',
       ((timeProfileCount * 1000) / (curTime - prevLogTime)).toFixed(3),
-      'profiles/s'
-    );
+      'profiles/s',
+    ].map(v => v + '');
+    logger.debug(debugInfo.join(' '));
 
     heapProfileCount = 0;
     timeProfileCount = 0;

src/logger.ts

@@ -12,36 +12,74 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-import * as consoleLogLevel from 'console-log-level';
+/* eslint-disable @typescript-eslint/no-explicit-any */
+
 import {defaultConfig} from './config';
+import {LogSync, Logging} from '@google-cloud/logging-min';
+
+const logging = new Logging();
+
+// migrating from 'console-log-level' package we keep
+// min and max log levels numeric interface used there
+const [MIN_LEVEL, MAX_LEVEL] = [0, 4];
+
+logging.setProjectId().catch(err => {
+  console.error(`failed to set logging project id ${err}`);
+});
+logging.setDetectedResource().catch(err => {
+  console.error(`failed to discover resource metadata ${err}`);
+});
 
 // eslint-disable-next-line @typescript-eslint/no-var-requires
 const pjson = require('../../package.json');
 
-const LEVEL_NAMES: consoleLogLevel.LogLevelNames[] = [
-  'fatal',
-  'error',
-  'warn',
-  'info',
-  'debug',
-  'trace',
-];
-
-function logLevelToName(level?: number): consoleLogLevel.LogLevelNames {
-  if (level === undefined) {
-    level = defaultConfig.logLevel;
-  } else if (level < 0) {
-    level = 0;
-  } else if (level > 4) {
-    level = 4;
+export class Logger {
+  private log: LogSync;
+  private severityThreshold: number;
+
+  constructor(readonly level?: number) {
+    if (level === undefined) {
+      level = defaultConfig.logLevel;
+    }
+    if (level < MIN_LEVEL) {
+      level = MIN_LEVEL;
+    } else if (level > MAX_LEVEL) {
+      level = MAX_LEVEL;
+    }
+    this.severityThreshold = level;
+    this.log = logging.logSync(pjson.name);
+  }
+
+  debug(msg: string) {
+    if (this.severityThreshold > 3) {
+      this.log.debug(this.log.entry(this.toOneLine(msg)));
+    }
+  }
+
+  info(msg: string) {
+    if (this.severityThreshold > 2) {
+      this.log.info(this.log.entry(this.toOneLine(msg)));
+    }
+  }
+
+  warn(msg: string) {
+    if (this.severityThreshold > 1) {
+      this.log.warning(this.log.entry(this.toOneLine(msg)));
+    }
+  }
+
+  error(msg: string) {
+    if (this.severityThreshold > 0) {
+      this.log.error(this.log.entry(this.toOneLine(msg)));
+    }
+  }
+
+  private toOneLine(msg: string): string {
+    const temp = msg.replace('\r\n', '\\r\\n');
+    return temp.replace('\n', '\\n');
   }
-  return LEVEL_NAMES[level];
 }
 
-export function createLogger(level?: number) {
-  return consoleLogLevel({
-    stderr: true,
-    prefix: pjson.name,
-    level: logLevelToName(level),
-  });
+export function createLogger(level?: number): Logger {
+  return new Logger(level);
 }