Overview

The primary differences between this package and rosdistro_build_cache are:

• colcon-distro does not require package.xml files in order to locate packages in the distribution repos; instead it leverages colcon’s plugin-based package discovery and augmentation mechanisms.

• colcon-distro does not use the release attributes of the distribution.yaml, relying instead purely on the source attributes, making it suitable for building source workspaces during rolling development.

• colcon-distro remembers the state of the distribution.yaml when the version attributes have been frozen to hashes and the overall repo is tagged.

• colcon-distro is backed by a small SQLite database, and is an active server process rather than a script which generates one-off cache tarballs on each run.

In addition to the server process, two new verbs are added to colcon which provide the client interface to the distro server:

• colcon generate replaces rosinstall_generator, consuming the cached distro information and performing dependency resolution to assemble a list of repo/refs to clone. The output of this verb is compatible with vcstool.

• colcon download provides an alternative to wstool, vcs, and similar tools, with the primary difference that it always downloads git repos as tarballs, and does so asynchronously under colcon’s parallel execution framework.