ThundraSampler.js

let spanCounter = -1;
const HTTP_FILTER_RATIO = 2;

const thundra = require("@thundra/core")({
    traceConfig: {
        disableRequest: true,
        disableResponse: true,
        runCustomSamplerOnEachSpan: true,
        sampler: {   
            isSampled(span) {
                spanCounter++;
                
                if (spanCounter === 0) {
                    return true;
                }

                if (span.className === 'HTTP' && spanCounter % HTTP_FILTER_RATIO !== 0) {
                    return true;
                } 

                return false;
            }
        }
    } 
});

exports.handler = thundra((event, context, callback) => {  
    // Do not forget this line.
    spanCounter = -1;
    /// User code
});