wjwwood
commented
5 years ago There is a case you need to consider which is where something needs to be installed from apt, then from something else, like pip, and then yet another things from apt again. Specifically for apt, this is not a practical issue since apt never depends on other package managers, but this case exists (or existed in the past for Homebrew).
Secondly, I think there's some value in having repeatable, deterministic behavior from rosdep. If you coalesced apt installs to a single command, then it might be harder to determine which dependency failed to install in apt (it is more clear when you install them one at a time), and also if you try to install many things, some install and some fail, then you run rosdep again to reproduce you'll end up invoking a different command to apt, again making troubleshooting more difficult.
So, I think a script friendly output would be good to have, as long as it accounted for ordering between package manager calls.
And I think an option to have rosdep automatically coalesce apt calls into fewer apt calls would also be ok, though I'm not sure about it being the default.
tfoote
rotu
Right now rosdep executes apt-get once for every unmet dependency. Since these dependencies may depend on each other, some package installed by rosdep in a later step may be installed as dependency for an earlier package. Rosdep does not know that and tries to install that package again, apt-get does nothing but consumes time.
To accelerate some automated builds, I use
apt-get install -y $(rosdep check -i --from-paths /tmp | sed -n 's/^apt\s\+//p' | tr '\n' ' ')instead ofrosdep install -i -y --from-paths /tmp, since it calls apt-get once which eliminates duplicate depedencies.I would like to see this as a default behavior: Execute the install command (if the package manager supports it) once with a list of all packages instead once of for each package.
Alternatively, a script-friendly output for dumping all packages to stdout eliminating the use of sed (and tr) in the above command would satisfy the issue.