sails-hook-dev

A Sails hook that provides diagnostic / debugging information during development.

Check the memory usage or environent variables of the currently-running Sails/Node.js process. Or check how it's configured, or the installed versions of its dependencies. You can also fetch session data for the currently logged in user, or force Node's garbage collector to run.

Note

The diagnostic routes exposed by this hook will work when your app is in development mode (i.e. NODE_ENV !== "production")

If you want to enable this hook in a production-like environment where NODE_ENV is set to production (such as your staging environment), then use the dev.enableInProduction setting.

For security reasons, this hook should never be used in a true production environment that touches real users.

Install

In your Sails project:

npm install sails-hook-dev --save-dev

^^ That will install this hook as a dev dependency, for local development only. If you also want to use sails-hook-dev somewhere else (like in your staging environment), then instead use:

npm install sails-hook-dev

Usage

To see all available development routes, visit http://localhost:1337/dev:

See all available routes

http://localhost:1337/dev/routes

See session of currently logged-in user

http://localhost:1337/dev/session

See actual versions of dependencies in node_modules

http://localhost:1337/dev/dependencies

See current memory usage

http://localhost:1337/dev/memory

Debugging

Deliberately crash the process

http://localhost:1337/dev/throw-uncaught

Simulate endpoint that never sends a response

http://localhost:1337/dev/dont-respond

Simulate locking up the process by overwhelming its CPU

http://localhost:1337/dev/peg

Simulate runaway recursion that overflows the call stack

http://localhost:1337/dev/overflow-stack

Simulate exceeding the process's available memory

http://localhost:1337/dev/overflow-memory

Simulate an endpoint that consumes memory, but does not leak

http://localhost:1337/dev/consume-memory

Simulate an endpoint with an actual memory leak

http://localhost:1337/dev/leak-memory

Run the garbage collector

http://localhost:1337/dev/gc

Note that you must lift your app with node --expose-gc app.js in order for the garbage collector to be accessible from userland.

Setting this up on your staging server

Want to use this hook in your staging environment? Since the NODE_ENV environment variable will be set to production, the hook will be disabled by default. But never fear: there is a simple, recommended solution.

At the bottom of your staging configuration (config/env/staging.js), set:

  dev: Object.assign({}, PRODUCTION_CONFIG.dev||{}, {
    enableInProduction: true
  }),

Note that you could hypothetically specify this in your environment variables, by setting sails_dev__enableInProduction=true. But as of Sails 1.1.0 the behavior of rc when merging this particular config key gets a little bit wonky, so it's best to stick with the solution above.

Help

If you have further questions or are having trouble, click here.

Bugs  

To report a bug, click here.

Contributing

Please observe the guidelines and conventions laid out in the Sails project contribution guide when opening issues or submitting pull requests.

License

MIT © 2015, 2016, 2018-present Mike McNeil

As for the Sails framework, it's free and open-source under the MIT License too.