Make sure you have activated the mongodb instrument in your CodSpeed GitHub workflow.

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In-depth guides

To see complete guides of the different integrations, check out the pages below:

Benchmarking a MongoDB based NestJS API with vitest

Setup and run MongoDB performance tests in a Node.js API using vitest, leveraging Docker.

Benchmarking a MongoDB based NestJS API with tinybench

Setup and run MongoDB performance tests in a Node.js API using tinybench, leveraging Docker.

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Dynamically providing the connection string

Each integration exports a setupInstruments function that can be used to dynamically setup the instruments. This function takes the actual connection string as an argument and returns the patched connection string that should be used to connect to the database. 
type SetupInstrumentsRequestBody = {
  /**
   * The full `MONGO_URL` that is usually used to connect to the database.
   */
  mongoUrl: string;
};

type SetupInstrumentsResponse = {
  /**
   * The patched `MONGO_URL` that should be used to connect to the database.
   */
  remoteAddr: string;
};

/**
 * Dynamically setup the CodSpeed instruments.
 */
declare function setupInstruments(
  body: SetupInstrumentsRequestBody
): Promise<SetupInstrumentsResponse>;
You can use this function to set up the instruments in your application:
src/bench.ts
import { setupInstruments, withCodSpeed } from "@codspeed/tinybench-plugin";
import { MongoDBContainer } from "@testcontainers/mongodb";
import { registerCatControllerBenches } from "cats/cats.controller.tinybench";
import { Bench } from "tinybench";

async function setupDatabase() {
  const mongodbContainer = await new MongoDBContainer("mongo:7.0.5").start();
  const mongoUrl =
    mongodbContainer.getConnectionString() +
    "/test?replicaSet=rs0&directConnection=true";

  const { remoteAddr } = await setupInstruments({ mongoUrl });
  process.env.MONGO_URL = remoteAddr;
}

const bench = withCodSpeed(new Bench());

(async () => {
  await setupDatabase();

  registerCatControllerBenches(bench);

  await bench.run();
  console.table(bench.table());
})();
The example above uses the testcontainers library to start a MongoDB container and get the connection string. Then, the setupInstruments function is used to patch the connection string and set it as the MONGO_URL environment variable. Finally, the bench is run as usual.
The setupInstruments function should be called only once during the whole benchmark run, and before any connection to the database is established. Otherwise, the CodSpeed MongoDB instrument will not be able to collect the metrics.