Fetch Tools

This package contains the fetch utility to make development easier. For full details of command usage and arguments, run fetch -h and fetch COMMAND -h. It also adds useful aliases for connecting to robots. Below summarizes installation and common usage.

Intended Workflow

This tool was written to help make it easier to develop code and switch between robots with ease. It works by inferring what robot you’re working on from $ROS_MASTER_URI and automating common tasks such as account creation, code syncing, and running commands. It assumes that you always edit code in your ROS Workspace and then push a copy of the workspace to the robot afterwards, so that you can run it. This keeps all code that you are developing on your computer in case someone takes the robot.

Example Workflow

# Start working on freight 0 for the first time
ufr 0
fetch create-account --fullname "Not A. Robot"
fetch push --install-deps --build
fetch run "roslaunch my_awesome_package do_stuff.launch"
# Edit code to fix a bug
fetch push --build "--pkg my_awesome_package"
fetch run "roslaunch my_awesome_package do_stuff.launch"
# Switch over to freight 8, since someone kidnapped freight 0
ufr 8
fetch create-account --fullname "Not A. Robot"
fetch push --install-deps --build
fetch run "roslaunch my_awesome_package do_stuff.launch"

Installation

To install run, checkout the fetchrobotics/sandbox repo and run:

sudo apt-get install ros-noetic-fetch-tools

Afterwards, restart your terminal or run source $(rospack find fetch_tools)/setup.bash.

Common Arguments

Robot

Most operations interact with a robot, in this case they take an optional --robot argument. If the robot parameter is passed in using --robot, that is the value used. If not, the parameter defaults to the robot pointed at by $ROS_MASTER_URI. To set the default value, add the line export FETCH_ROBOT=myrobot to your .bashrc file.

If the robot is not on the DNS (i.e. pinging the robot name does not work), you can add .local to the parameter, e.g. fetch4.local, and communication with the robot will work via zeroconf (avahi).

Workspace

Some operations interact with a workspace, in this case take an optional --workspace argument. If the a parameter is passed in that value is used. If not, the parameter defaults to ~/$ROS_DISTRO. To set the default value, add the line export FETCH_WORKSPACE=/path/to/my/workspace to your .bashrc file. By default, the remote workspace is assumed to match your local workspace. If not, you can use either the --remote-workspace argument or the FETCH_REMOTE_WORKSPACE environment variable to change it.

User

Most operations interact with a robot, in this case they often effect a particular user on that robot, so they take an optional --user argument. If the robot parameter is passed in using --user, that is the value used. If not, the parameter defaults to $USER. To set the default value, add the line export FETCH_USER=myuser to your .bashrc file.

fetch Commands

fetch create-account

To create an account:

fetch create-account

To create an account with another username:

fetch create-account --robot freight0 --user test

Once it is done you can run ssh $USER@freight0 without entering your password. (If both users are the same you can just run ssh freight0)

Customizing Account Creation

If you are creating accounts on lots of robots, you can customize the install process. First, create a copy of the skeleton directory:

cp -r $(rospack find fetch_tools)/resources/robot_skeleton ~/.fetch/robot_skeleton

Next, customize all files to your desired value. initialize.sh is a special script that gets run during the account creation process. If you want to install software or run other commands every time you create an account, customize initialize.sh.

fetch push

WARNING: Synchronize in this context means make the remote workspace like the current workspace. This means new files will be added and old files will be deleted. It is strongly recommended that you never change files in the workspace on the robot directly.

To synchronize your $workspace/src directory with the matching directory on another robot:

fetch push

To synchronize another workspace with a robot:

fetch push --workspace ~/test_ws

To synchronize and then run catkin_make to build:

fetch push --build

To synchronize and install all dependencies with rosdep:

fetch push --install-deps

To synchronize and then run catkin_make --pkg follow_pick -DCMAKE_BUILD_TYPE=RELEASE instead of catkin_make --pkg follow_pick -DCMAKE_BUILD_TYPE=Debug to build:

fetch push --build "--pkg follow_pick -DCMAKE_BUILD_TYPE=RELEASE"

fetch pull

Is just fetch push in reverse, so it pulls code from the remote workspace into the local workspace. It supports the same arguments

fetch run

To run a command on the robot:

fetch run COMMAND

To run a command on the robot with arguments:

fetch run "COMMAND --flag1 --flag2 arg1"

fetch lint

Fetch lint runs pep8, roslint, and catkin_lint to make sure a package is compliant with all style guides. To lint a package:

fetch lint PACKAGE

To lint a folder:

fetch lint FOLDER

To lint a file:

fetch lint FILE

fetch workspace-status

This command produces a table of the current workspace, including the git information so that you can communicate what code is checked out easily. Running:

fetch workspace-status

Produces:

fetch debug-snapshot

This command takes a debug snapshot of running robot, gathering information that can be useful in diagnosing robot problems:

fetch debug-snapshot

NOTE: If this command is run on the robot itself, it may fail silently due to ssh prompts. You can fix this by manually doing ssh fetchXYZ (to add the robot’s own host key to its list of known hosts).

Useful Aliases

In addition to the fetch command, setup.bash loads some useful aliases for working with multiple Fetch and Freight robots.

Working with $ROS_MASTER_URI

There are three aliases for working with $ROS_MASTER_URI:

uf 5   # Set ROS_MASTER_URI="http://fetch5:11311"
ufr 0  # Set ROS_MASTER_URI="http://freight0:11311"
ul     # Set ROS_MASTER_URI="http://localhost:11311"

• uf is short for use fetch
• ufr is short for use freight
• ul is short for use localhost

Note also that ul supports setting a custom port

ul 11312  # Set ROS_MASTER_URI="http://localhost:11312"

SSH

There are two aliases for sshing into robots

sf 5   # SSH into fetch 5
sfr 0  # SSH into freight0

You can also use aliases to do ssh-copy-id for key setup with robots

kf 1104
kfr 1234

Using .local with uf/ufr and sf/sfr

If your network does not provide DNS for your robots, often the robot’s number can simply be appended with .local to take advantage of zeroconf (avahi) without needing any DNS configuration.

uf 5.local   # Set ROS_MASTER_URI="http://fetch5.local:11311"
sf 5.local   # SSH into fetch 5, without using DNS