Installing from source

Install from source requires that you download and compile the source code on your own. ROS Melodic supports Ubuntu Artful and Bionic as well as Debian Stretch. Other platforms are possible to use but are not expected to work out of the box. Target platforms are defined in REP 3

Contents

Installing from source

Prerequisites

Installing bootstrap dependencies

Install bootstrap dependencies (Ubuntu):

These tools are used to facilitate the download and management of ROS packages and their dependencies, among other things.

Ubuntu or Debian:

```
$ sudo apt-get install python-rosdep python-rosinstall-generator python-vcstool python-rosinstall build-essential
```
If you have trouble installing the packages in the command above, make sure you have added the packages.ros.org debian repository to your apt source lists as described starting here: melodic/Installation/Ubuntu#Installation.2BAC8-Ubuntu.2BAC8-Sources.Setup_your_sources.list
If apt complains that the python-support package is not installable, make sure that you have the Ubuntu universe repositories enabled in your /etc/apt/sources.list

Fedora:

```
$ sudo dnf install gcc-c++ python-rosdep python3-rosinstall_generator python-vcstool python-rosinstall @buildsys-build
```
Some packages used in ROS are not currently available in the Fedora RPM repositories. Most of the other packages are available in RPM Fusion. See RPM Fusion Command Line Setup.

Generic (pip):

If you are using a non-Debian system you need to make sure that you have all build tools (compiler, CMake, etc.) installed. You can install all ROS Python tools via PIP:
```
$ sudo pip install -U rosdep rosinstall_generator vcstool rosinstall
```
If there are errors with this or the rosdep step below, your system's version of pip may be out-of-date. Use your system's package management to update it, or use it to update itself:
```
$ sudo pip install --upgrade setuptools
```
Note that on many platforms such as OSX you may want to install the above packages and use ROS inside a virtualenv so as to make sure not to collide with system dependencies.

Initializing rosdep

$ sudo rosdep init
$ rosdep update

Installation

Start by building the core ROS packages.

Create a catkin Workspace

In order to build the core packages, you will need a catkin workspace. Create one now:

$ mkdir ~/ros_catkin_ws
$ cd ~/ros_catkin_ws

Next we will want to fetch the core packages so we can build them. We will use vcstool for this. Select the vcstool command for the particular variant you want to install:

Desktop-Full Install: ROS, rqt, rviz, robot-generic libraries, 2D/3D simulators, navigation and 2D/3D perception

$ rosinstall_generator desktop_full --rosdistro melodic --deps --tar > melodic-desktop-full.rosinstall
$ vcs import src < melodic-desktop-full.rosinstall

Desktop Install (recommended): ROS, rqt, rviz, and robot-generic libraries

$ rosinstall_generator desktop --rosdistro melodic --deps --tar > melodic-desktop.rosinstall
$ mkdir src
$ vcs import src < melodic-desktop.rosinstall

ROS-Comm: (Bare Bones) ROS package, build, and communication libraries. No GUI tools.

$ rosinstall_generator ros_comm --rosdistro melodic --deps --tar > melodic-ros_comm.rosinstall
$ vcs import src < melodic-ros_comm.rosinstall

This will add all of the catkin packages in the given variant and then fetch the sources into the ~/ros_catkin_ws/src directory. The command will take a few minutes to download all of the core ROS packages into the src folder. The -j8 option downloads 8 packages in parallel.

In addition to the 3 variants above, more are defined in REP 131 such as robot, perception, etc. Just change the package path to the one you want, e.g., for robot do:

$ rosinstall_generator robot --rosdistro melodic --deps --tar > melodic-robot.rosinstall
$ vcs import src < melodic-robot.rosinstall

Resolving Dependencies

Before you can build your catkin workspace you need to make sure that you have all the required dependencies. We use the rosdep tool for this:

$ rosdep install --from-paths src --ignore-src --rosdistro melodic -y

This will look at all of the packages in the src directory and find all of the dependencies they have. Then it will recursively install the dependencies.

The --from-paths option indicates we want to install the dependencies for an entire directory of packages, in this case src. The --ignore-src option indicates to rosdep that it shouldn't try to install any ROS packages in the src folder from the package manager, we don't need it to since we are building them ourselves. The --rosdistro option is required because we don't have a ROS environment setup yet, so we have to indicate to rosdep what version of ROS we are building for. Finally, the -y option indicates to rosdep that we don't want to be bothered by too many prompts from the package manager.

After a while (and maybe some prompts for your password) rosdep will finish installing system dependencies and you can continue.

Building the catkin Workspace

Once it has completed downloading the packages and resolving the dependencies you are ready to build the catkin packages. We will use the catkin_make_isolated command because there are both catkin and plain cmake packages in the base install, when developing on your catkin only workspaces you may choose to use catkin/commands/catkin_make which only works with catkin packages.

Invoke catkin_make_isolated:

$ ./src/catkin/bin/catkin_make_isolated --install -DCMAKE_BUILD_TYPE=Release

Note: You might want to select a different CMake build type (e.g. RelWithDebInfo or Debug, see http://cmake.org/cmake/help/v2.8.12/cmake.html#variable:CMAKE_BUILD_TYPE).

Note: The default catkin installation location would be ~/ros_catkin_ws/install_isolated, if you would like to install somewhere else then you can do this by adding the --install-space /opt/ros/melodic argument to your catkin_make_isolated call.

For usage on a robot without Ubuntu, it is recommended to install compiled code into /opt/ros/melodic just as the Ubuntu packages would do. Don't do this in Ubuntu, as the packages would collide with apt-get packages. It is also possible to install elsewhere (e.g. /usr), but it is not recommended unless you really know what you are doing.

Please see REP 122: Filesystem Hierarchy Layout for more detailed documentation on how the installed files are placed.

Note: In the above command we are running the catkin_make_isolated command from the catkin source folder because it has not been installed yet, once installed it can be called directly.

Now the packages should have been installed to ~/ros_catkin_ws/install_isolated or to wherever you specified with the --install-space argument. If you look in that directory you will see that a setup.bash file have been generated. To utilize the things installed there simply source that file like so:

$ source ~/ros_catkin_ws/install_isolated/setup.bash

Maintaining a Source Checkout

If we want to keep our source checkout up to date, we will have to periodically update our rosinstall file, download the latest sources, and rebuild our workspace.

Update the workspace

To update your workspace, first move your existing rosinstall file so that it doesn't get overwritten, and generate an updated version. For simplicity, we will cover the *destop-full* variant. For other variants, update the filenames and rosinstall_generator arguments appropriately.

$ mv -i melodic-desktop-full.rosinstall melodic-desktop-full.rosinstall.old
$ rosinstall_generator desktop_full --rosdistro melodic --deps --tar > melodic-desktop-full.rosinstall

Then, compare the new rosinstall file to the old version to see which packages will be updated:

$ diff -u melodic-desktop-full.rosinstall melodic-desktop-full.rosinstall.old

If you're satisfied with these changes, incorporate the new rosinstall file into the workspace and update your workspace:

$ vcs import src < melodic-desktop-full.rosinstall

Rebuild your workspace

Now that the workspace is up to date with the latest sources, rebuild it:

$ ./src/catkin/bin/catkin_make_isolated --install

If you specified the --install-space option when your workspace initially, you should specify it again when rebuilding your workspace

Once your workspace has been rebuilt, you should source the setup files again:

$ source ~/ros_catkin_ws/install_isolated/setup.bash