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Edit File: b3-format.js

"use strict";
/**
 * Copyright 2018, OpenCensus 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.
 */
Object.defineProperty(exports, "__esModule", { value: true });
const crypto = require("crypto");
const uuid = require("uuid");
const X_B3_TRACE_ID = 'x-b3-traceid';
const X_B3_SPAN_ID = 'x-b3-spanid';
const X_B3_PARENT_SPAN_ID = 'x-x3-parentspanid';
const X_B3_SAMPLED = 'x-b3-sampled';
const SAMPLED_VALUE = 0x1;
const NOT_SAMPLED_VALUE = 0x0;
/** Propagates span context through B3 Format propagation. */
class B3Format {
    /**
     * Gets the trace context from a request headers. If there is no trace context
     * in the headers, null is returned.
     * @param getter
     */
    extract(getter) {
        if (getter) {
            let opt = getter.getHeader(X_B3_SAMPLED);
            if (opt instanceof Array) {
                opt = opt[0];
            }
            const spanContext = {
                traceId: getter.getHeader(X_B3_TRACE_ID),
                spanId: getter.getHeader(X_B3_SPAN_ID),
                options: isNaN(Number(opt)) ? undefined : Number(opt)
            };
            return spanContext;
        }
        return null;
    }
    /**
     * Adds a trace context in a request headers.
     * @param setter
     * @param spanContext
     */
    inject(setter, spanContext) {
        if (setter) {
            setter.setHeader(X_B3_TRACE_ID, spanContext.traceId || 'undefined');
            setter.setHeader(X_B3_SPAN_ID, spanContext.spanId || 'undefined');
            if (spanContext && (spanContext.options & SAMPLED_VALUE) !== 0) {
                setter.setHeader(X_B3_SAMPLED, `${SAMPLED_VALUE}`);
            }
            else {
                setter.setHeader(X_B3_SAMPLED, `${NOT_SAMPLED_VALUE}`);
            }
        }
    }
    /**
     * Generate SpanContexts
     */
    generate() {
        return {
            traceId: uuid.v4().split('-').join(''),
            spanId: crypto.randomBytes(8).toString('hex'),
            options: SAMPLED_VALUE
        };
    }
}
exports.B3Format = B3Format;
//# sourceMappingURL=b3-format.js.map

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