feat: add OTEL_LOG_LEVEL env var

User can now control the log level by means of env var.

Sets default log level to INFO as per open-telemetry#856

Also shares mock environment functions for tests to be used in
ConsoleLogger tests as well as environment tests.

Signed-off-by: Naseem <naseem@transit.app>

packages/opentelemetry-core/src/common/ConsoleLogger.ts

@@ -16,9 +16,10 @@
 
 import { Logger } from '@opentelemetry/api';
 import { LogLevel } from './types';
+import { getEnv } from '../platform';
 
 export class ConsoleLogger implements Logger {
-  constructor(level: LogLevel = LogLevel.INFO) {
+  constructor(level: LogLevel = getEnv().OTEL_LOG_LEVEL) {
     if (level >= LogLevel.DEBUG) {
       this.debug = (...args) => {
         console.debug(...args);

packages/opentelemetry-core/src/common/types.ts

@@ -20,6 +20,12 @@ export enum LogLevel {
   DEBUG,
 }
 
+/**
+ * This is equivalent to:
+ * type LogLevelString = 'ERROR' | 'WARN' | 'INFO' | 'DEBUG';
+ */
+export type LogLevelString = keyof typeof LogLevel;
+
 /**
  * This interface defines a fallback to read a timeOrigin when it is not available on performance.timeOrigin,
  * this happens for example on Safari Mac

packages/opentelemetry-core/src/utils/environment.ts

@@ -28,7 +28,6 @@ export interface ENVIRONMENT {
 }
 
 const ENVIRONMENT_NUMBERS: Partial<keyof ENVIRONMENT>[] = [
-  'OTEL_LOG_LEVEL',
   'OTEL_SAMPLING_PROBABILITY',
 ];
 
@@ -37,7 +36,7 @@ const ENVIRONMENT_NUMBERS: Partial<keyof ENVIRONMENT>[] = [
  */
 export const DEFAULT_ENVIRONMENT: Required<ENVIRONMENT> = {
   OTEL_NO_PATCH_MODULES: '',
-  OTEL_LOG_LEVEL: LogLevel.ERROR,
+  OTEL_LOG_LEVEL: LogLevel.INFO,
   OTEL_SAMPLING_PROBABILITY: 1,
 };
 
@@ -64,6 +63,41 @@ function parseNumber(
   }
 }
 
+/**
+ * Environmentally sets log level if valid log level string is provided
+ * @param key
+ * @param environment
+ * @param values
+ */
+function setLogLevelFromEnv(
+  key: keyof ENVIRONMENT,
+  environment: ENVIRONMENT_MAP | ENVIRONMENT,
+  values: ENVIRONMENT_MAP
+) {
+  const value = values[key];
+  switch (typeof value === 'string' ? value.toUpperCase() : value) {
+    case 'DEBUG':
+      environment[key] = LogLevel.DEBUG;
+      break;
+
+    case 'INFO':
+      environment[key] = LogLevel.INFO;
+      break;
+
+    case 'WARN':
+      environment[key] = LogLevel.WARN;
+      break;
+
+    case 'ERROR':
+      environment[key] = LogLevel.ERROR;
+      break;
+
+    default:
+      // do nothing
+      break;
+  }
+}
+
 /**
  * Parses environment values
  * @param values
@@ -79,7 +113,7 @@ export function parseEnvironment(values: ENVIRONMENT_MAP): ENVIRONMENT {
         break;
 
       case 'OTEL_LOG_LEVEL':
-        parseNumber(key, environment, values, LogLevel.ERROR, LogLevel.DEBUG);
+        setLogLevelFromEnv(key, environment, values);
         break;
 
       default:
@@ -95,3 +129,37 @@ export function parseEnvironment(values: ENVIRONMENT_MAP): ENVIRONMENT {
 
   return environment;
 }
+
+let lastMock: ENVIRONMENT_MAP = {};
+
+/**
+ * Mocks environment used for tests.
+ */
+export function mockEnvironment(values: ENVIRONMENT_MAP) {
+  lastMock = values;
+  if (typeof process !== 'undefined') {
+    Object.keys(values).forEach(key => {
+      process.env[key] = String(values[key]);
+    });
+  } else {
+    Object.keys(values).forEach(key => {
+      ((window as unknown) as ENVIRONMENT_MAP)[key] = String(values[key]);
+    });
+  }
+}
+
+/**
+ * Removes mocked environment ussed for tests.
+ */
+export function removeMockEnvironment() {
+  if (typeof process !== 'undefined') {
+    Object.keys(lastMock).forEach(key => {
+      delete process.env[key];
+    });
+  } else {
+    Object.keys(lastMock).forEach(key => {
+      delete ((window as unknown) as ENVIRONMENT_MAP)[key];
+    });
+  }
+  lastMock = {};
+}

packages/opentelemetry-core/test/common/ConsoleLogger.test.ts

@@ -17,6 +17,10 @@
 import * as assert from 'assert';
 import { ConsoleLogger } from '../../src/common/ConsoleLogger';
 import { LogLevel } from '../../src/common/types';
+import {
+  removeMockEnvironment,
+  mockEnvironment,
+} from '../../src/utils/environment';
 
 describe('ConsoleLogger', () => {
   const origDebug = console.debug;
@@ -54,6 +58,7 @@ describe('ConsoleLogger', () => {
     console.info = origInfo;
     console.warn = origWarn;
     console.error = origError;
+    removeMockEnvironment();
   });
 
   describe('constructor', () => {
@@ -65,6 +70,8 @@ describe('ConsoleLogger', () => {
       assert.deepStrictEqual(warnCalledArgs, ['warn called %s', 'param1']);
       consoleLogger.info('info called %s', 'param1');
       assert.deepStrictEqual(infoCalledArgs, ['info called %s', 'param1']);
+      consoleLogger.debug('debug called %s', 'param1');
+      assert.strictEqual(debugCalledArgs, undefined);
     });
 
     it('should log with debug', () => {
@@ -114,5 +121,35 @@ describe('ConsoleLogger', () => {
       consoleLogger.debug('debug called %s', 'param1');
       assert.strictEqual(debugCalledArgs, null);
     });
+
+    it('should log with environmentally set level ', () => {
+      mockEnvironment({
+        OTEL_LOG_LEVEL: 'WARN',
+      });
+      const consoleLogger = new ConsoleLogger();
+      consoleLogger.error('error called');
+      assert.deepStrictEqual(errorCalledArgs, ['error called']);
+      consoleLogger.warn('warn called %s', 'param1');
+      assert.deepStrictEqual(warnCalledArgs, ['warn called %s', 'param1']);
+      consoleLogger.info('info called %s', 'param1');
+      assert.deepStrictEqual(infoCalledArgs, null);
+      consoleLogger.debug('debug called %s', 'param1');
+      assert.deepStrictEqual(debugCalledArgs, null);
+    });
+
+    it('should log with default log level if environmentally set level is invalid', () => {
+      mockEnvironment({
+        OTEL_LOG_LEVEL: 'INVALID_VALUE',
+      });
+      const consoleLogger = new ConsoleLogger();
+      consoleLogger.error('error called');
+      assert.deepStrictEqual(errorCalledArgs, ['error called']);
+      consoleLogger.warn('warn called %s', 'param1');
+      assert.deepStrictEqual(warnCalledArgs, ['warn called %s', 'param1']);
+      consoleLogger.info('info called %s', 'param1');
+      assert.deepStrictEqual(infoCalledArgs, ['info called %s', 'param1']);
+      consoleLogger.debug('debug called %s', 'param1');
+      assert.deepStrictEqual(debugCalledArgs, null);
+    });
   });
 });

packages/opentelemetry-core/test/utils/environment.test.ts

@@ -18,38 +18,12 @@ import { getEnv } from '../../src/platform';
 import {
   DEFAULT_ENVIRONMENT,
   ENVIRONMENT,
-  ENVIRONMENT_MAP,
+  removeMockEnvironment,
+  mockEnvironment,
 } from '../../src/utils/environment';
 import * as assert from 'assert';
 import * as sinon from 'sinon';
-
-let lastMock: ENVIRONMENT_MAP = {};
-
-function mockEnvironment(values: ENVIRONMENT_MAP) {
-  lastMock = values;
-  if (typeof process !== 'undefined') {
-    Object.keys(values).forEach(key => {
-      process.env[key] = String(values[key]);
-    });
-  } else {
-    Object.keys(values).forEach(key => {
-      ((window as unknown) as ENVIRONMENT_MAP)[key] = String(values[key]);
-    });
-  }
-}
-
-function removeMockEnvironment() {
-  if (typeof process !== 'undefined') {
-    Object.keys(lastMock).forEach(key => {
-      delete process.env[key];
-    });
-  } else {
-    Object.keys(lastMock).forEach(key => {
-      delete ((window as unknown) as ENVIRONMENT_MAP)[key];
-    });
-  }
-  lastMock = {};
-}
+import { LogLevel } from '../../src';
 
 describe('environment', () => {
   let sandbox: sinon.SinonSandbox;
@@ -68,15 +42,23 @@ describe('environment', () => {
       mockEnvironment({
         FOO: '1',
         OTEL_NO_PATCH_MODULES: 'a,b,c',
-        OTEL_LOG_LEVEL: '1',
+        OTEL_LOG_LEVEL: 'WARN',
         OTEL_SAMPLING_PROBABILITY: '0.5',
       });
       const env = getEnv();
       assert.strictEqual(env.OTEL_NO_PATCH_MODULES, 'a,b,c');
-      assert.strictEqual(env.OTEL_LOG_LEVEL, 1);
+      assert.strictEqual(env.OTEL_LOG_LEVEL, LogLevel.WARN);
       assert.strictEqual(env.OTEL_SAMPLING_PROBABILITY, 0.5);
     });
 
+    it('should parse OTEL_LOG_LEVEL despite casing', () => {
+      mockEnvironment({
+        OTEL_LOG_LEVEL: 'waRn',
+      });
+      const env = getEnv();
+      assert.strictEqual(env.OTEL_LOG_LEVEL, LogLevel.WARN);
+    });
+
     it('should parse environment variables and use defaults', () => {
       const env = getEnv();
       Object.keys(DEFAULT_ENVIRONMENT).forEach(envKey => {

packages/opentelemetry-metrics/src/types.ts

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { LogLevel } from '@opentelemetry/core';
+import { LogLevel, getEnv } from '@opentelemetry/core';
 import * as api from '@opentelemetry/api';
 import { MetricExporter } from './export/types';
 import { Resource } from '@opentelemetry/resources';
@@ -43,7 +43,7 @@ export interface MeterConfig {
 
 /** Default Meter configuration. */
 export const DEFAULT_CONFIG = {
-  logLevel: LogLevel.INFO,
+  logLevel: getEnv().OTEL_LOG_LEVEL,
 };
 
 /** The default metric creation options value. */

packages/opentelemetry-tracing/src/config.ts

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import { AlwaysOnSampler, LogLevel } from '@opentelemetry/core';
+import { AlwaysOnSampler, getEnv } from '@opentelemetry/core';
 
 /** Default limit for Message events per span */
 export const DEFAULT_MAX_EVENTS_PER_SPAN = 128;
@@ -31,7 +31,7 @@ export const DEFAULT_MAX_LINKS_PER_SPAN = 32;
  */
 export const DEFAULT_CONFIG = {
   defaultAttributes: {},
-  logLevel: LogLevel.INFO,
+  logLevel: getEnv().OTEL_LOG_LEVEL,
   sampler: new AlwaysOnSampler(),
   traceParams: {
     numberOfAttributesPerSpan: DEFAULT_MAX_ATTRIBUTES_PER_SPAN,