Add platform agnostic way to read environment variables (open-telemet…

…ry#1191)

Co-authored-by: Mayur Kale <mayurkale@google.com>

packages/opentelemetry-core/src/platform/browser/environment.ts

@@ -0,0 +1,31 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  DEFAULT_ENVIRONMENT,
+  ENVIRONMENT,
+  ENVIRONMENT_MAP,
+  parseEnvironment,
+} from '../../utils/environment';
+
+/**
+ * Gets the environment variables
+ */
+export function getEnv(): ENVIRONMENT {
+  const _window = window as typeof window & ENVIRONMENT_MAP;
+  const globalEnv = parseEnvironment(_window);
+  return Object.assign({}, DEFAULT_ENVIRONMENT, globalEnv);
+}

packages/opentelemetry-core/src/platform/browser/index.ts

@@ -15,6 +15,7 @@
  */
 
 export * from './BasePlugin';
+export * from './environment';
 export * from './hex-to-base64';
 export * from './id';
 export * from './performance';

packages/opentelemetry-core/src/platform/node/environment.ts

@@ -0,0 +1,30 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  DEFAULT_ENVIRONMENT,
+  ENVIRONMENT,
+  ENVIRONMENT_MAP,
+  parseEnvironment,
+} from '../../utils/environment';
+
+/**
+ * Gets the environment variables
+ */
+export function getEnv(): ENVIRONMENT {
+  const processEnv = parseEnvironment(process.env as ENVIRONMENT_MAP);
+  return Object.assign({}, DEFAULT_ENVIRONMENT, processEnv);
+}

packages/opentelemetry-core/src/platform/node/index.ts

@@ -15,8 +15,9 @@
  */
 
 export * from './BasePlugin';
+export * from './environment';
+export * from './hex-to-base64';
 export * from './id';
 export * from './performance';
 export * from './sdk-info';
 export * from './timer-util';
-export * from './hex-to-base64';

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

@@ -0,0 +1,97 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { LogLevel } from '../common/types';
+
+export type ENVIRONMENT_MAP = { [key: string]: string | number };
+
+/**
+ * Environment interface to define all names
+ */
+export interface ENVIRONMENT {
+  OTEL_LOG_LEVEL?: LogLevel;
+  OTEL_NO_PATCH_MODULES?: string;
+  OTEL_SAMPLING_PROBABILITY?: number;
+}
+
+const ENVIRONMENT_NUMBERS: Partial<keyof ENVIRONMENT>[] = [
+  'OTEL_LOG_LEVEL',
+  'OTEL_SAMPLING_PROBABILITY',
+];
+
+/**
+ * Default environment variables
+ */
+export const DEFAULT_ENVIRONMENT: ENVIRONMENT = {
+  OTEL_NO_PATCH_MODULES: '',
+  OTEL_LOG_LEVEL: LogLevel.ERROR,
+  OTEL_SAMPLING_PROBABILITY: 1,
+};
+
+/**
+ * Parses a variable as number with number validation
+ * @param name
+ * @param environment
+ * @param values
+ * @param min
+ * @param max
+ */
+function parseNumber(
+  name: keyof ENVIRONMENT,
+  environment: ENVIRONMENT_MAP | ENVIRONMENT,
+  values: ENVIRONMENT_MAP,
+  min = -Infinity,
+  max = Infinity
+) {
+  if (typeof values[name] !== 'undefined') {
+    const value = Number(values[name] as string);
+    if (!isNaN(value) && value >= min && value <= max) {
+      environment[name] = value;
+    }
+  }
+}
+
+/**
+ * Parses environment values
+ * @param values
+ */
+export function parseEnvironment(values: ENVIRONMENT_MAP): ENVIRONMENT {
+  const environment: ENVIRONMENT_MAP = {};
+
+  for (const env in DEFAULT_ENVIRONMENT) {
+    const key = env as keyof ENVIRONMENT;
+    switch (key) {
+      case 'OTEL_SAMPLING_PROBABILITY':
+        parseNumber(key, environment, values, 0, 1);
+        break;
+
+      case 'OTEL_LOG_LEVEL':
+        parseNumber(key, environment, values, LogLevel.ERROR, LogLevel.DEBUG);
+        break;
+
+      default:
+        if (ENVIRONMENT_NUMBERS.indexOf(key) >= 0) {
+          parseNumber(key, environment, values);
+        } else {
+          if (typeof values[key] !== 'undefined') {
+            environment[key] = values[key];
+          }
+        }
+    }
+  }
+
+  return environment;
+}

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

@@ -0,0 +1,92 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { getEnv } from '../../src/platform';
+import {
+  DEFAULT_ENVIRONMENT,
+  ENVIRONMENT,
+  ENVIRONMENT_MAP,
+} 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 = {};
+}
+
+describe('environment', () => {
+  let sandbox: sinon.SinonSandbox;
+
+  beforeEach(() => {
+    sandbox = sinon.createSandbox();
+  });
+
+  afterEach(() => {
+    removeMockEnvironment();
+    sandbox.restore();
+  });
+
+  describe('parseEnvironment', () => {
+    it('should parse environment variables', () => {
+      mockEnvironment({
+        FOO: '1',
+        OTEL_NO_PATCH_MODULES: 'a,b,c',
+        OTEL_LOG_LEVEL: '1',
+        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_SAMPLING_PROBABILITY, 0.5);
+    });
+
+    it('should parse environment variables and use defaults', () => {
+      const env = getEnv();
+      Object.keys(DEFAULT_ENVIRONMENT).forEach(envKey => {
+        const key = envKey as keyof ENVIRONMENT;
+        assert.strictEqual(
+          env[key as keyof ENVIRONMENT],
+          DEFAULT_ENVIRONMENT[key],
+          `Variable '${key}' doesn't match`
+        );
+      });
+    });
+  });
+});