This part of the code-base is Meteor's CLI tool that reads commands from the user, builds the application, adds runtime code, provides an interface to Meteor Services (Accounts, Packages, Build Farms, deployments, etc).

The Meteor Tool is designed to be the "minimal kernel" as most of the functionality that goes into a typical Meteor app can pulled from core and 3rd-party packages.

Getting set up

Using Meteor in development is very simple. If Meteor spots that it is running from a Git checkout folder (having a .git directory), it will run in dev mode, download npm dependencies dynamically and pull the latest dev_bundle on the first run.

dev_bundle is a tarball with prebuilt binaries (node, npm, mongod, etc) and npm modules necessary for the Meteor tool. dev_bundles are versioned and are built with a script in the admin directory. It is commonly built on Jenkins.

Usually it doesn't take long to get a new dev_bundle but if you are on a spotty network or switching between branches referencing different versions often, you can set the environment variable that will cache all downloaded versions indefinitely:

set SAVE_DEV_BUNDLE_TARBALL=t

You can also run ./meteor --get-ready to install all npm dependencies for the tool.

Testing

Since the tool is a node app, it is not testable with general Meteor testing tools such as Tinytest or Velocity. Instead the home-grown system "self test" is used.

"Self test" is a testing library that is focused on testing the CLI interactions and is rather an end-to-end testing tool (not a unit-testing tool). Albeit, it is often used for testing individual functions.

Besides monitoring the process output, "self test" is capable of moching the package catalog, running from template apps.

The asserting syntax of "self test" is rather unusual since it operates on the process's stdout/stderr output after the process has run (not in real-time). A lot of assertions depend on timeouts and waits.

To run all tests, run the following:

# download all npm dependencies, etc
./meteor --get-ready

# set the multiplier for time-outs
SET TIMEOUT_SCALE_FACTOR=3

# run the tests
./meteor self-test

Note, the scale factor for time-outs might be different depending on the hardware, but 3 is a safe choice for automation.

To quickly run an individual test or a group, pass a regular expression as an argument, it will be matched against test names:

./meteor self-test "login.*"

You can also run a particular file, or list all tests matching certain pattern, run with phantom or browserstack. See more at ./meteor help self-test.

Profiling

Profiling is done in an ad-hoc way but it works well enough to spot obvious differences in things like build performance.

To enable profiling, set the environment variable to a "cut off" point, which is 100ms by default.

set METEOR_PROFILE=200

In this case, the reporter will only print calls that took more than 200ms to complete.

Internally, every profiled function should be wrapped into a Profile(fn) call. The entry point should be started explicitly with the Profile.run() call. Otherwise, it won't start measuring anything.

Debugging

Currently, debugging the tool with node-inspector is only possible if you edit the meteor bash/batch script and add the --debug or --debug-brk flag to the node call. Note that node-inspector should be compatible with the node version in the dev_bundle.