Set up Continuous Test

Setting up a continuous testing service to find memory leaks with memlab involves three steps:

1. Prepare test scenarios that cover the key interactions of the web app under test.
2. Trigger test runs through the memlab command line interface or through the memlab API.
3. Collect the memory leak results saved to disk.

Write Test Scenarios

Follow the instructions in this tutorial.

Run Tests

Run in CLI: Your test job can run the test scenarios via the memlab command line interface, for example:

memlab run --scenario /path/to/test/scenario/file.js \
  --work-dir /path/to/save/memlab/run/results/

Use the --work-dir option to specify a directory where you want memlab to save browser interaction metadata (e.g., screenshots and heap snapshots).

Run in Node.js: Alternatively, if your test job is written in node.js, you can invoke memlab APIs:

const {run} = require('@memlab/api');
const scenario = require('/path/to/test/scenario/file.js');
const fs = require('fs-extra');

(async function () {
  const workDir = '/path/to/save/memlab/run/results/';
  // make sure the working directory exists
  fs.mkdirsSync(workDir);
  const result = await run({scenario, workDir});
})();

Collect Results

After the memlab run completes, all results and metadata are saved in the specified working directory, with the following directory structure:

/path/to/save/memlab/run/results/
├── data
│   ├── cur
│   │   ├── browser-info.txt    # browser web console output
│   │   ├── console-log.txt     # memlab terminal logging
│   │   ├── leaks.txt           # text summary of clustered memory leaks
│   │   ├── run-meta.json       # metadata for the memlab run and browser configuration
│   │   ├── s1.heapsnapshot     # heap snapshot after the url callback (initial page load)
│   │   ├── s2.heapsnapshot     # heap snapshot after the action callback (after target interaction)
│   │   ├── s3.heapsnapshot     # heap snapshot after the back callback (after reverting target interaction)
│   │   ├── screenshot-1.png    # web page screenshot after the url callback (initial page load)
│   │   ├── screenshot-2.png    # web page screenshot after the action callback (after target interaction)
│   │   ├── screenshot-3.png    # web page screenshot after the back callback (after reverting target interaction)
│   │   └── snap-seq.json       # metadata about each browser interaction step
│   ├── logger
│   │   ├── trace-clusters
│   │   │   ├── @1846905.json   # metadata for a memory leak trace cluster
│   │   │   ...
│   │   └── trace-jsons
│   │       ├── @1846905.json   # detailed JSON trace of a representative leak in a cluster;
│   │       ...                 # can be used for trace visualization
...

To read results, use the built-in result reader or write your own script or library if the test job is running on a different runtime.

const {BrowserInteractionResultReader} = require('@memlab/api');

const workDir = '/path/to/save/memlab/run/results/';
const result = BrowserInteractionResultReader.from(workDir);

// get absolute paths of all snapshot files
const files = result.getSnapshotFiles();

// print all browser web console output
const metaInfo = result.getRunMetaInfo();
console.log(metaInfo.browserInfo._consoleMessages.join('\n'));

// clean up the results
result.cleanup();

For more APIs on the built-in result reader, click here.