How the OpenBSD -stable packages are built

Author: Solène

Date: 29 October 2020

Tags: openbsd

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In this long blog post, I will write about the technical details

of the OpenBSD stable packages building infrastructure. I have setup

the infrastructure with the help of Theo De Raadt who provided me

the hardware in summer 2019, since then, OpenBSD users can upgrade

their packages using `pkg_add -u` for critical updates that has

been backported by the contributors. Many thanks to them, without

their work there would be no packages to build. Thanks to pea@ who

is my backup for operating this infrastructure in case something

happens to me.

**The total lines of code used is around 110 lines of shell.**

Original design

In the original design, the process was the following. It was done

separately on each machine (amd64, arm64, i386, sparc64).

Updating ports

First step is to update the ports tree using `cvs up` from a cron

job and capture its output. **If** there is a result, the process

continues into the next steps and we discard the result.

With CVS being per-directory and not using a database like git or

svn, it is not possible to "poll" for an update except by verifying

every directory if a new version of files is available. This check

is done three time a day.

Make a list of ports to compile

This step is the most complicated of the process and weights for a

third of the total lines of code.

The script uses `cvs rdiff` between the cvs release and stable

branches to show what changed since release, and its output is

passed through a few grep and awk scripts to only retrieve the

"pkgpaths" (the pkgpath of curl is **net/curl**) of the packages

that were updated since the last release.

From this raw output of cvs rdiff:

File ports/net/dhcpcd/Makefile changed from revision 1.80 to 1.80.2.1

File ports/net/dhcpcd/distinfo changed from revision 1.48 to 1.48.2.1

File ports/net/dnsdist/Makefile changed from revision 1.19 to 1.19.2.1

File ports/net/dnsdist/distinfo changed from revision 1.7 to 1.7.2.1

File ports/net/icinga/core2/Makefile changed from revision 1.104 to 1.104.2.1

File ports/net/icinga/core2/distinfo changed from revision 1.40 to 1.40.2.1

File ports/net/synapse/Makefile changed from revision 1.13 to 1.13.2.1

File ports/net/synapse/distinfo changed from revision 1.11 to 1.11.2.1

File ports/net/synapse/pkg/PLIST changed from revision 1.10 to 1.10.2.1

The script will produce:

net/dhcpcd

net/dnsdist

net/icinga/core2

net/synapse

From here, for each pkgpath we have sorted out, the sqlports database

is queried to get the full list of pkgpaths of each packages, this

will include all packages like flavors, subpackages and multipackages.

This is important because an update in `editors/vim` pkgpath will

trigger this long list of packages:

editors/vim,-lang

editors/vim,-main

editors/vim,gtk2

editors/vim,gtk2,-lang

[...40 results hidden for readability...]

editors/vim,no_x11,ruby

editors/vim,no_x11,ruby,-lang

editors/vim,no_x11,ruby,-main

Once we gathered all the pkgpaths to build and stored them in a

file, next step can start.

Preparing the environment

As the compilation is done on the real system (using PORTS_PRIVSEP

though) and not in a chroot we need to clean all packages installed

except the minimum required for the build infrastructure, which are

rsync and sqlports.

`dpb(1)` can't be used because it didn't gave good results for

building the delta of the packages between release and stable.

The various temporary directories used by the ports infrastructure

are cleaned to be sure the build starts in a clean environment.

Compiling and creating the packages

This step is really simple. The ports infrastructure is used

to build the packages list we produced at step 2.

env SUBDIRLIST=package_list BULK=yes make package

In the script there is some code to manage the logs of the previous

batch but there is nothing more.

Every new run of the process will pass over all the packages which

received a commit, but the ports infrastructure is smart enough to

avoid rebuilding ports which already have a package with the correct

version.

Transfer the package to the signing team

Once the packages are built, we need to pass only the built

packages to the person who will manually sign the packages before

publishing them and have the mirrors to sync.

From the package list, the package file lists are generated and

reused by rsync to only copy the packages generated.

env SUBDIRLIST=package_list show=PKGNAMES make | grep -v "^=" | \

grep ^. | tr ' ' '\n' | sed 's,$,\.tgz,' | sort -u

**The system has all the -release packages in

`${PACKAGE_REPOSITORY}/${MACHINE_ARCH}/all/` (like

`/usr/ports/packages/amd64/all`) to avoid rebuilding all dependencies

required for building a package update, thus we can't copy all the

packages from the directory where the packages are moved after

compilation.**

Send a notification

Last step is to send an email with the output of rsync to send an

email telling which machine built which package to tell the people

signing the packages that some packages are available.

As this process is done on each machine and that they

don't necessarily build the same packages (no firefox on sparc64)

and they don't build at the same speed (arm64 is slower), mails

from the four machines could arrive at very different time, which

led to a small design change.

The whole process is automatic from building to delivering the

packages for signature. The signature step requires a human to be

done though, but this is the price for security and privilege

separation.

Current design

In the original design, all the servers were running their separate

cron job, updating their own cvs ports tree and doing a very long

cvs diff. The result was working but not very practical for the

people signing who were receiving mails from each machine for each

batch.

The new design only changed one thing: One machine was chosen to

run the cron job, produce the package list and then will copy that

list to the other machines which update their ports tree and run

the build. Once all machines finished to build, the initiator machine

will gather outputs and send an unique mail with a summary of each

machine. This became easier to compare the output of each architecture

and once you receive the email this means every machine finished

their job and the signing can be done.

Having the summary of all the building machines resulted in another

improvement: In the logic of the script, it is possible to send an

email telling absolutely no package has been built while the process

was triggered, which means, something went wrong. From here, I

need to check the logs to understand why the last commit didn't

produce a package. This can be failures like a **distinfo** file

update forgotten in the commit.

Also, this permitted fixing one issue: As the distfiles are shared

through a common NFS mount point, if multiples machines try to fetch

a distfile at the same time, both will fail to build. Now, the

initiator machine will download all the required distfiles before

starting the build on every node.

All of the previous scripts were reused, except the one

sending the email which had to be rewritten.