/
global-utils.ts
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/
global-utils.ts
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/*
* 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 { MeterProvider } from '../types/MeterProvider';
import { _globalThis } from '../platform';
export const GLOBAL_METRICS_API_KEY = Symbol.for(
'io.opentelemetry.js.api.metrics'
);
type Get<T> = (version: number) => T;
type OtelGlobal = Partial<{
[GLOBAL_METRICS_API_KEY]: Get<MeterProvider>;
}>;
export const _global = _globalThis as OtelGlobal;
/**
* Make a function which accepts a version integer and returns the instance of an API if the version
* is compatible, or a fallback version (usually NOOP) if it is not.
*
* @param requiredVersion Backwards compatibility version which is required to return the instance
* @param instance Instance which should be returned if the required version is compatible
* @param fallback Fallback instance, usually NOOP, which will be returned if the required version is not compatible
*/
export function makeGetter<T>(
requiredVersion: number,
instance: T,
fallback: T
): Get<T> {
return (version: number): T =>
version === requiredVersion ? instance : fallback;
}
/**
* A number which should be incremented each time a backwards incompatible
* change is made to the API. This number is used when an API package
* attempts to access the global API to ensure it is getting a compatible
* version. If the global API is not compatible with the API package
* attempting to get it, a NOOP API implementation will be returned.
*/
export const API_BACKWARDS_COMPATIBILITY_VERSION = 3;