cf-node-debug - a node debugger for Cloud Foundry

The cf-node-debug package provides debugging capability for your node applications while running on Cloud Foundry. It launches two apps - node-inspector and your application, and acts as an HTTP proxy. It will proxy most of the requests to your application, and debugger-specific requests to node-inspector.

installation

npm install cf-node-debug

Make sure you add cf-node-debug to your package.json as well.

usage

cf-node-debug [options] -- program arg arg ...

program arg arg ... is what you would pass to node to start your program.

options:

-a --auth           authentication (see below)
-d --debug-prefix   URL prefix of requests sent to the debugger
-b --break          have the debugger pause at the beginning of the program
-v --verbose        generate diagnostic messages

The default debug-prefix is --debugger.

Note that the -- token is REQUIRED if your program or any arguments start with -. Otherwise it's optional.

This program does the following:

• starts the specified node application with arguments

  • it's PORT environment variable will be changed to port PORT+1
  • it will be launched with the appropriate node debug option

• starts node-inspector on PORT+2

• starts a proxy server on the PORT environment variable

• sends non-debug traffic (ie, not prefixed by --debug-prefix option) to the specified application

• sends debug traffic (ie, prefixed by --debug-prefix option) to node-inspector

example:

cf-node-debug -- server.js

authentication

When you use cf-node-debug, you need to specify authentication parameters to access the debugger. This is to keep random internet people from accessing your application's innards via the debugger.

You can specify the authentication parameters via the -a / --auth option, or via the CF_NODE_DEBUG_AUTH environment variable, or via a Cloud Foundry service. In all cases, the authentication parameters are specified as a string of the form:

scheme:parms

Currently the only scheme supported is local, and the parms for this scheme are the userid and password separated by a :. Thus, the authentication parameter of

local:joeuser:dumbsecret

indicates you should log in with the userid joeuser and password dumbsecret when prompted.

Cloud Foundry users should use a user-provided service to set the authentication parameters. To do this, you need to create a user-provided service whose name has cf-node-debug in it somewhere, and has one property auth, whose value will be the same as described above. You should then bind this service to all apps that you want to debug.

example:

Run this command to create a service named cf-node-debug:

cf cups cf-node-debug -p auth

You will be prompted for value of the auth property; enter something like

local:joeuser:dumbsecret

You should then see a message that service got created.

You can then bind the service to your app with the following command:

cf bind-service my-app cf-node-debug

assumptions

The main assumption is that your program is running on CloudFoundry, and thus determines the HTTP port it will be using based on the PORT environment variable.

In addition, it's assumed that you won't be using the path specified by the --debug-prefix option in your application, as these URLs will be redirected to the debugger.

quick start

Let's say you've developed a node application node-stuff, and you use the cf start command node node-stuff to start your app.

To debug this app:

• add a dependency of cf-node-debug to your package.json file

• change your start command to:

  node_modules/.bin/cf-node-debug node-stuff

• re-push your application

hacking

If you want to modify the source to play with it, you'll also want to have the jbuild program installed.

To install jbuild on Windows, use the command

npm -g install jbuild

To install jbuild on Mac or Linux, use the command

sudo npm -g install jbuild

The jbuild command runs tasks defined in the jbuild.coffee file. The task you will most likely use is watch, which you can run with the command:

jbuild watch

When you run this command, the application will be built from source, the server started, and tests run. When you subsequently edit and then save one of the source files, the application will be re-built, the server re-started, and the tests re-run. For ever. Use Ctrl-C to exit the jbuild watch loop.

You can run those build, server, and test tasks separately. Run jbuild with no arguments to see what tasks are available, along with a short description of them.

license

Apache License, Version 2.0

http://www.apache.org/licenses/LICENSE-2.0.html

icon composed from:

• https://github.com/voodootikigod/logo.js/
• http://commons.wikimedia.org/wiki/File:Bedbug_(PSF).png