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This post explains, at a high level, how Arch-style packages work, how pacman consumes repositories, and why I maintain both a binary mirror and a source repo for “Rostam‑exclusive” packages.

Links for reference:

• Binary mirror and automation: https://github.com/RostamOS/packages
• Rostam source PKGBUILDs: https://github.com/RostamOS/rostam-packages

Arch packaging model in brief

• PKGBUILD: a shell recipe describing how to fetch sources, apply patches, build, and package.
• makepkg: builds the package from a PKGBUILD, producing a .pkg.tar.zst (and optionally a .sig).
• repo-add/repo-remove: update the repository database files (e.g., repo.db, repo.files) to index available packages.
• Repository layout: typically per-arch subtree (e.g., x86_64/) containing packages and the repo database.

+------------------+     makepkg      +---------------------+
|   PKGBUILD (+)   | ---------------> | .pkg.tar.zst (+sig) |
|  sources/patches |                   +---------------------+
       |                                         |
       v                                  repo-add -> repo.db/.files
+------------------+        publish        +---------------------------+
|   build chroot   | --------------------> |  static repo (x86_64/)   |
+------------------+                       +---------------------------+

How pacman consumes repos

pacman uses libalpm to sync repository databases and resolve transactions.

• Configuration: /etc/pacman.conf lists repositories in priority order.
• Sync: pacman -Sy fetches repo.db(.tar*), optionally repo.files, and signatures if enabled.
• Resolve: pacman computes a transaction (add/remove/upgrade) with dependency solving and conflicts.
• Acquire: packages are downloaded (HTTP), signatures verified (if configured), and then extracted to the filesystem.

$ pacman -S foo
   |
   v
[mirrorlist] -> fetch repo.db[.sig]
   |
resolve dependencies -> build transaction
   |
download .pkg.tar.zst[.sig] -> verify -> extract to /

A minimal repository config (example; check the packages repo for the current URL):

# /etc/pacman.conf
[rostam]
SigLevel = Optional TrustAll
Server = <rostam_repo_url>/$arch

Why Rostam packages exist

• Velocity: prebuilt binaries remove local compile time for common and personal packages.
• Reproducibility: pinned PKGBUILD versions/patches yield predictable builds.
• Curation: slim defaults and opinionated variants aligned with my environment.
• Independence: external projects I rely on (and my own tools) are available even if AUR recipes drift.

RostamOS repositories

• Binary mirror automation - RostamOS/packages
  • Scripts/CI periodically rebuild a set of packages (including selected AUR) and run repo-add.
  • Artifacts are published in an x86_64/ directory with repo.db/.files for pacman.
• Rostam‑exclusive sources - RostamOS/rostam-packages
  • PKGBUILDs for my forks/patchsets and packages not present in official repos.
  • Built by the same pipeline to land in the binary mirror.

Build pipeline overview

RostamOS/rostam-packages (PKGBUILDs)
            |
            v
       makepkg in clean environment
            |
            v
 .pkg.tar.zst (+ .sig)  -- repo-add -->  repo.db / repo.files
            |                               |
            +----------- publish -----------+

For details and the current setup, see the READMEs in the two repositories linked above.