POLITE PREFIX MANAGER 2.5.1

The Polite Prefix Manager is a package manager for installing and managing software packages in isolated "prefixes". This utility is the main point of interaction with these prefixes.

Initial Installation Instructions

1. git clone ${REPOSITORY_URL}
   • Add this directory to the $PATH so that please can be executed anywhere. See Appendix B for instructions.
2. mkdir -p polite_prefix_manager/cookbooks
3. cd polite_prefix_manager/cookbooks
4. git clone ${COOKBOOK_URL}
5. please install build_essentials

Things PPM2 Can Do

The please command has brief help with please -h, and extensive help with please help. There are arguments to please which configure cache locations, build parameters, and output formatting. There are different verbs which perform different operations like building and installing binaries, construct dependency graphs, and remove installed binaries.

Notable Filesystem Details

There are two caches which are particularly relevant. ~/.cache/polite contains binary_cache and resource_cache. binary_cache contains cached binary artifacts to avoid compilation time in updating things. It is easily invalidated, but may save a lot of time. resource_cache contains cached downloaded artifacts. It provides resiliency to origin resources being unavailable, and avoids download time in updating the Prefix.

Testing Recipe Changes

please -p /tmp/Prefix_${CUSTOM_NAME} install ${PACKAGE_UNDER_TEST} will rebuild the Prefix in the new location, swapping in the components which you've already compiled from your binary and resource caches.

Clearing the resource cache (or using a different location) should only be necessary to verify that all resources still exist at their specified public locations. Since the payloads are bit-accurate to verified versions (via SHA sum) there is no worry about payload accuracy.

Clearing the binary cache (or using a different location) may be necessary if a build depends on environment variables or optional dependencies autodetected in the environment. Most of the time the binary cache is invalidated by changes to the install script or build tools, and are generally robust.

Appendices

Appendix A – The First Iteration of Polite Prefix Manager

The first generation of PolitePrefixManager has not been made open-source but is internally available within Akamai.

Appendix B – Adding please to the $PATH

The $PATH variable is generally tweaked in shell configuration files like .bashrc or .zshrc, or in .profile. Depending on how one has configured their dotfiles, there are many likely places to add it. Possibly the most appropriate place is .profile, as that is intended to be executed on any interactive shell on the system, where .bashrc or .zshrc are specifically for specific shells. Add lines like this:

# Add the Polite Prefix installer
export PATH="$HOME/git/ppm:$PATH"