forked from open-telemetry/opentelemetry-js-contrib
/
instrumentation.ts
188 lines (177 loc) · 5.53 KB
/
instrumentation.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 { LookupAddress } from 'dns';
import { diag, Span, SpanKind } from '@opentelemetry/api';
import {
InstrumentationBase,
InstrumentationNodeModuleDefinition,
isWrapped,
safeExecuteInTheMiddle,
} from '@opentelemetry/instrumentation';
import * as semver from 'semver';
import { AddressFamily } from './enums/AddressFamily';
import {
Dns,
DnsInstrumentationConfig,
LookupCallbackSignature,
LookupPromiseSignature,
} from './types';
import * as utils from './utils';
import { VERSION } from './version';
/**
* Dns instrumentation for Opentelemetry
*/
export class DnsInstrumentation extends InstrumentationBase<Dns> {
constructor(protected override _config: DnsInstrumentationConfig = {}) {
super('@opentelemetry/instrumentation-dns', VERSION, _config);
}
init(): InstrumentationNodeModuleDefinition<Dns>[] {
return [
new InstrumentationNodeModuleDefinition<Dns>(
'dns',
['*'],
moduleExports => {
diag.debug('Applying patch for dns');
if (isWrapped(moduleExports.lookup)) {
this._unwrap(moduleExports, 'lookup');
}
// eslint-disable-next-line @typescript-eslint/no-explicit-any
this._wrap(moduleExports, 'lookup', this._getLookup() as any);
// new promise methods in node >= 10.6.0
// https://nodejs.org/docs/latest/api/dns.html#dns_dnspromises_lookup_hostname_options
if (semver.gte(process.version, '10.6.0')) {
this._wrap(
moduleExports.promises,
'lookup',
// eslint-disable-next-line @typescript-eslint/no-explicit-any
this._getLookup() as any
);
}
return moduleExports;
},
moduleExports => {
if (moduleExports === undefined) return;
diag.debug('Removing patch for dns');
this._unwrap(moduleExports, 'lookup');
if (semver.gte(process.version, '10.6.0')) {
this._unwrap(moduleExports.promises, 'lookup');
}
}
),
];
}
/**
* Get the patched lookup function
*/
private _getLookup() {
return (original: (hostname: string, ...args: unknown[]) => void) => {
return this._getPatchLookupFunction(original);
};
}
/**
* Creates spans for lookup operations, restoring spans' context if applied.
*/
private _getPatchLookupFunction(
original: (hostname: string, ...args: unknown[]) => void
) {
diag.debug('patch lookup function');
const plugin = this;
return function patchedLookup(
this: {},
hostname: string,
...args: unknown[]
) {
if (
utils.isIgnored(hostname, plugin._config.ignoreHostnames, (e: Error) =>
diag.error('caught ignoreHostname error: ', e)
)
) {
return original.apply(this, [hostname, ...args]);
}
const argsCount = args.length;
diag.debug('wrap lookup callback function and starts span');
const name = utils.getOperationName('lookup');
const span = plugin.tracer.startSpan(name, {
kind: SpanKind.CLIENT,
});
const originalCallback = args[argsCount - 1];
if (typeof originalCallback === 'function') {
args[argsCount - 1] = plugin._wrapLookupCallback(
originalCallback,
span
);
return safeExecuteInTheMiddle(
() => original.apply(this, [hostname, ...args]),
error => {
if (error != null) {
utils.setError(error, span, process.version);
span.end();
}
}
);
} else {
const promise = safeExecuteInTheMiddle(
() =>
(original as LookupPromiseSignature).apply(this, [
hostname,
...args,
]),
error => {
if (error != null) {
utils.setError(error, span, process.version);
span.end();
}
}
);
promise.then(
result => {
utils.setLookupAttributes(span, result as LookupAddress);
span.end();
},
(e: NodeJS.ErrnoException) => {
utils.setError(e, span, process.version);
span.end();
}
);
return promise;
}
};
}
/**
* Wrap lookup callback function
*/
private _wrapLookupCallback(
original: Function,
span: Span
): LookupCallbackSignature {
return function wrappedLookupCallback(
this: {},
err: NodeJS.ErrnoException | null,
address: string | LookupAddress[],
family?: AddressFamily
): void {
diag.debug('executing wrapped lookup callback function');
if (err !== null) {
utils.setError(err, span, process.version);
} else {
utils.setLookupAttributes(span, address, family);
}
span.end();
diag.debug('executing original lookup callback function');
return original.apply(this, arguments);
};
}
}