@google-cloud/logging-winston
Version:
Cloud Logging transport for Winston
74 lines • 3.25 kB
JavaScript
;
// Copyright 2019 Google LLC
//
// 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.
Object.defineProperty(exports, "__esModule", { value: true });
exports.getDefaultMetadataForTracing = void 0;
const common_1 = require("./common");
/**
* Returns an object that can be passed to Winston.createLogger as defaultMeta
* to allow log-trace correlation with Winston 3. Log-trace correlation with
* Winston 3 is broken because the trace ID to be correlated with a log isn't
* evaluated when the log function is called, but rather when the log is
* written, which happens at some future point where the trace ID may no longer
* be accurate. To circumvent this, we take advantage of the fact that
* defaultMeta is copied when a log function is called, and use a dynamic
* property getter to evaluate the trace ID upon that copy.
*
* We apply the same principle for timestamps, which is not strictly necessary
* for tracing but allows for more accurate timestamps in general.
*
* If there are other default metadata fields with which the return value of
* this function must be merged, this object MUST be the base object. In other
* words, do not use the return value of this function as the non-first argument
* to Object.assign, or it will not work.
*
* See https://github.com/googleapis/nodejs-logging-winston/issues/287 for
* more information.
*/
function getDefaultMetadataForTracing() {
const agent = global._google_trace_agent;
// Enable log-trace correlation if the Trace Agent API is compatible.
const enableThunkAgent = !!(agent &&
agent.getCurrentContextId &&
agent.getWriterProjectId);
const defaultMeta = {};
// Make defaultMeta.timestamp return the current timestamp any time it's
// accessed.
Object.defineProperty(defaultMeta, 'timestamp', {
enumerable: true,
get: () => new Date(),
});
if (enableThunkAgent) {
// Make defaultMeta[LOGGING_TRACE_KEY] return the current trace ID any time
// it's accessed.
const loggingTraceKey = common_1.LOGGING_TRACE_KEY;
Object.defineProperty(defaultMeta, loggingTraceKey, {
enumerable: true,
get: () => {
const traceId = agent.getCurrentContextId();
if (!traceId) {
return null;
}
const traceProjectId = agent.getWriterProjectId();
if (!traceProjectId) {
return null;
}
return `projects/${traceProjectId}/traces/${traceId}`;
},
});
}
return defaultMeta;
}
exports.getDefaultMetadataForTracing = getDefaultMetadataForTracing;
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