open-telemetry · maryliag · Aug 20, 2025 · Aug 19, 2025 · Aug 19, 2025 · Aug 20, 2025
@@ -13,6 +13,7 @@ For notes on migrating to 2.x / 0.200.x see [the upgrade guide](doc/upgrade-to-2
 ### :rocket: Features
 
 *feat(opentelemetry-configuration): creation of basic ConfigProvider [#5809](https://github.com/open-telemetry/opentelemetry-js/pull/5809) @maryliag
+*feat(opentelemetry-configuration): creation of basic FileConfigProvider [#5863](https://github.com/open-telemetry/opentelemetry-js/pull/5863) @maryliag
 
 ### :bug: Bug Fixes
 

@@ -16,7 +16,11 @@
 
 import { ConfigProvider } from './IConfigProvider';
 import { EnvironmentConfigProvider } from './EnvironmentConfigProvider';
+import { FileConfigProvider, hasValidConfigFile } from './FileConfigProvider';
 
 export function createConfigProvider(): ConfigProvider {
+  if (hasValidConfigFile()) {
+    return new FileConfigProvider();
+  }
   return new EnvironmentConfigProvider();
 }
@@ -0,0 +1,48 @@
+/*
+ * 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 { getStringFromEnv } from '@opentelemetry/core';
+import {
+  ConfigurationModel,
+  initializeDefaultConfiguration,
+} from './configModel';
+import { ConfigProvider } from './IConfigProvider';
+import * as fs from 'fs';
+
+export class FileConfigProvider implements ConfigProvider {
+  private _config: ConfigurationModel;
+
+  constructor() {
+    this._config = initializeDefaultConfiguration();
+  }
+
+  getInstrumentationConfig(): ConfigurationModel {
+    return this._config;
+  }
+}
+
+export function hasValidConfigFile(): boolean {
+  const configFile = getStringFromEnv('OTEL_EXPERIMENTAL_CONFIG_FILE');
+  if (configFile) {
+    if (!configFile.endsWith('.yaml') || !fs.existsSync(configFile)) {
+      throw new Error(
+        `Config file ${configFile} set on OTEL_EXPERIMENTAL_CONFIG_FILE is not valid`
+      );
+    }
+    return true;
+  }
+  return false;
+}
@@ -99,4 +99,45 @@ describe('ConfigProvider', function () {
       );
     });
   });
+
+  describe('get values from config file', function () {
+    afterEach(function () {
+      delete process.env.OTEL_EXPERIMENTAL_CONFIG_FILE;
+    });
+
+    it('should initialize config with default values from valid config file', function () {
+      process.env.OTEL_EXPERIMENTAL_CONFIG_FILE =
+        'test/fixtures/kitchen-sink.yaml';
+      const configProvider = createConfigProvider();
+      assert.deepStrictEqual(
+        configProvider.getInstrumentationConfig(),
+        defaultConfig
+      );
+    });
+
+    it('should return error from invalid config file', function () {
+      process.env.OTEL_EXPERIMENTAL_CONFIG_FILE = './fixtures/kitchen-sink.txt';
+      assert.throws(() => {
+        createConfigProvider();
+      });
+    });
+
+    it('should initialize config with default values with empty string for config file', function () {
+      process.env.OTEL_EXPERIMENTAL_CONFIG_FILE = '';
+      const configProvider = createConfigProvider();
+      assert.deepStrictEqual(
+        configProvider.getInstrumentationConfig(),
+        defaultConfig
+      );
+    });
+
+    it('should initialize config with default values with all whitespace for config file', function () {
+      process.env.OTEL_EXPERIMENTAL_CONFIG_FILE = '  ';
+      const configProvider = createConfigProvider();
+      assert.deepStrictEqual(
+        configProvider.getInstrumentationConfig(),
+        defaultConfig
+      );
+    });
+  });
 });