add ContextManager interface open-telemetry#46

packages/opentelemetry-context-base/src/index.ts

@@ -13,3 +13,5 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+export * from './types';

packages/opentelemetry-context-base/src/types.ts

@@ -0,0 +1,51 @@
+/**
+ * Copyright 2019, 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
+ *
+ *      http://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.
+ */
+
+export interface BaseContext {
+  /**
+   * Get the current state of the context propagation
+   */
+  active: boolean;
+
+  /**
+   * Wrap an object in the current context (or optionally in a specific context)
+   * @param object Object to which a context need to be set
+   * @param [context] Optionaly specify the context which you want to assign
+   */
+  wrap<T>(object: T, context?: unknown): T;
+
+  /**
+   * Get the current value of a given key from the current context.
+   * There are specific case where the context is not propagated by specific
+   * code (ex: user space queueing) so expect it to be undefined sometimes.
+   */
+  get(key: string): unknown;
+
+  /**
+   * Set the value of a given key in the current context.
+   */
+  set(key: string, value: unknown): void;
+
+  /**
+   * Enable context propagation
+   */
+  enable(): void;
+
+  /**
+   * Disable context propagation
+   */
+  disable(): void;
+}