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GazeboJs installation on Mac

Overview

GazeboJs provides a scripting interface to the Gazebo simulator. Specifically, it provides a javascript client for the simulator, using Node.js and built on Google's V8 script engine.

GazeboJs is a C++ addon to Node.js that is loaded inside node process at runtime (using the require javascript function). Once loaded, it provides javascript functions that communicate with the Gazebo simultation server (the gzserver process) over the network, using the Gazebo transport library. This is the same mechanism that the Gazebo simulation client (the gzclient process) uses to communicate with the simulation server. The source code for this project can be found here: https://bitbucket.org/osrf/gazebojs

This page explains how to install the GazeboJs Node bindings to Gazebo.

Mac OSX (using homebrew)

This tutorial shows how to download, install and compile Gazebojs on a computer where Gazebo and its development libraries are installed. Please refer to the Install Gazebo on Mac (using homebrew).

Setup

The homebrew install of Gazebo also install the corresponding development libraries (for example, libgazebo6-dev for Gazebo 6). The dev libraries also contain the Gazebo header files that are necessary for the gazebojs installation. This is because the Node.js Gazebo modules are automatically compiled on your machine when the npm install gazebojs is invoked (see below). Like Gazebo, gazebojs module uses semantic versioning, so the major version of gazebojs should be the same as the major version of Gazebo you are using. You can specify rules about the version of gazebojs you want to use in the package.json file (see https://www.npmjs.org/doc/files/package.json.html).

Install Node.js and npm

brew search node

This might give you the following results

homebrew/versions/node012
homebrew/versions/node010
homebrew/versions/node08
homebrew/versions/node06
homebrew/versions/node04
node nodebrew leafnode nodenv

Gazebo 6 is compatible with node 0.10 (which is the version of node that is bundled with Ubuntu 14.04). The following versions have been found to work well together: node v0.10.40, npm 2.14.4 (node package manager), and Gazebo 6.4.

To install node:

brew install homebrew/versions/node010

The above command also installs npm. To check your installed version:

npm --version
node --version
gazebo --version

Install the required libraries

brew install jpeg
brew install pkg-config
brew install jansson

Make sure that these packages can be found in your pkg-config path. This is because gazebojs uses pkg-config. You can check this by executing this command without any error:

pkg-config --cflags gazebo jansson protobuf || echo "error :-("

If error :-( is printed at the end then one or more of the packages can not be found.

Running

Now that everything is installed, here are the steps to test it:

Create a Node.js project directory

mkdir gz_node_inst
cd gz_node_inst
npm init

Npm will prompt you for details about your project. You can add information or press ENTER a few times. This step creates a package.json directory. Having a package.json file in your local directory will also ensure that npm will install all its packages in your local directory.

Install Gazebojs

 npm install gazebojs --save

This operation should download and compile the latest gazebojs. There is a C++ compilation phase where a Node.js module is created. There should now be a node_modules directory created in your project directory.

Test your installation:

Launch Gazebo in a separate terminal and verify that the simulation is running (when simulation is running, the Sim Time increases in the status bar in the bottom of the screen):

gazebo

Use the 'node' command (from the same directory where you invoked the npm command) to invoke the Node.js REPL console

node

Type in the following commands to load the gazebojs module, create a simulation client and pause the running simulation. Note that the undefined messages are Node.js console valid responses to your command.

> var gazebojs = require('gazebojs')
undefined
> var sim = new gazebojs.Gazebo()
undefined
> sim.pause()
undefined

You should see the simulation become paused in Gazebo.

Troubleshooting

Problem: Npm error about incompatible version

npm http 304 https://registry.npmjs.org/which
npm ERR! Error: No compatible version found: mkdirp@'^0.5.0'
npm ERR! Valid install targets:
npm ERR! ["0.0.1","0.0.2","0.0.3","0.0.4","0.0.5","0.0.6","0.0.7","0.1.0","0.2.0","0.2.1","0.2.2","0.3.0","0.3.1","0.3.2","0.3.3","0.3.4","0.3.5","0.4.0","0.4.1","0.4.2","0.5.0","0.5.1"]
npm ERR!     at installTargetsError (/usr/local/lib/node_modules/npm/lib/cache.js:685:10)
npm ERR!     at /usr/local/lib/node_modules/npm/lib/cache.js:607:10
npm ERR!     at saved (/usr/local/lib/node_modules/npm/node_modules/npm-registry-client/lib/get.js:138:7)
npm ERR!     at FSReqWrap.oncomplete (fs.js:82:15)

Solution: check that your npm version is above 1.4.3

http://apple.stackexchange.com/questions/171530/how-do-i-downgrade-node-or-install-a-specific-previous-version-using-homebrew

Problem: missing jpeg

> node-gyp rebuild

  CXX(target) Release/obj.target/canvas/src/Canvas.o
In file included from ../src/Canvas.cc:19:
../src/JPEGStream.h:11:10: fatal error: 'jpeglib.h' file not found
#include <jpeglib.h>
         ^
1 error generated.
make: *** [Release/obj.target/canvas/src/Canvas.o] Error 1
gyp ERR! build error
gyp ERR! stack Error: `make` failed with exit code: 2
gyp ERR! stack     at ChildProcess.onExit (/usr/local/lib/node_modules/npm/node_modules/node-gyp/lib/build.js:267:23)
gyp ERR! stack     at ChildProcess.EventEmitter.emit (events.js:98:17)
gyp ERR! stack     at Process.ChildProcess._handle.onexit (child_process.js:789:12)
gyp ERR! System Darwin 13.0.0

Solution:

brew uninstall jpeg && brew install jpeg

Jpeg is also part of the xcode command line tools. You can try:

xcode-select --install

It is good to try to use a new bash terminal after jpeg installation, in case the path to the library has not been set for the compiler/linker.

https://github.com/Automattic/node-canvas/issues/348

Problem: linker error, ld: library not found for -lgcc_s.10.5

> bcrypt@0.8.5 install /Users/Kyle/Documents/Software/mean/mean_scotch/node_modules/bcrypt
> node-gyp rebuild

  CXX(target) Release/obj.target/bcrypt_lib/src/blowfish.o
  CXX(target) Release/obj.target/bcrypt_lib/src/bcrypt.o
  CXX(target) Release/obj.target/bcrypt_lib/src/bcrypt_node.o
  SOLINK_MODULE(target) Release/bcrypt_lib.node
ld: library not found for -lgcc_s.10.5
collect2: error: ld returned 1 exit status
make: *** [Release/bcrypt_lib.node] Error 1
gyp ERR! build error
gyp ERR! stack Error: `make` failed with exit code: 2

Solution: add the missing libraries in your '/usr/local/lib' directory

cd /usr/lib sudo ln -s ../lib/libSystem.B.dylib libgcc_s.10.5.dylib

Another (better) solution is to (re) install Xcode 7.