fxstore

A content-addressed build store for fixpoint-linux.

fxstore reads a Dhall package set, computes the dependency closure as a least fixed point with datalog-dafsa, assigns every package a content-addressed store path, builds each package's typed recipe into the store, and garbage collects unreachable artifacts. It is the storage + build layer of a Nix-like, but-specified-in-Dhall system.

/fx/store/<sha256-of-input-closure>-<name>

Design

• Spec in Dhall — package-set.dhall defines Package = { name, version, src, deps, build { target, recipe } }, where recipe is the same typed List Action union that dhake executes.
• Closure as a fixed point — datalog-dafsa computes transitive reachability (closure(X) :- root(X). / closure(Y) :- closure(X), dep(X,Y).).
• Content addressing — a canonical, length-delimited serialization of the full input closure is sha256'd to form the store path; a change anywhere in a package's transitive dependency graph changes its path.
• Crash-consistent store — artifacts are built into a temp dir, atomically renamed to the final path, and then the metadata transaction commits (metadata-last: a crash leaves a reapable orphan dir, never dangling metadata).
• Time travel, native — datalog-dafsa versioned snapshots + as-of queries are available for timeline / rollback (future work).

See the fixpoint-linux design.

Dependencies

Git submodules, initialized via git submodule update --init --recursive:

• datalog-dafsa — the engine + vendored dafsa (under vendor/)
• dhall-c — the Dhall interpreter core (under vendor/)
• palisade — the stage3 inner sandbox binary (under vendor/)
• dhake — the build driver (Dhakefile.dhall, under dhake/)

Requires the cosmocc toolchain.

Build

./dhake/dhake.com            # builds ./fxstore (default target)
./dhake/dhake.com test       # runs every test suite
./dhake/dhake.com fxstore-golden
./dhake/dhake.com stage3     # build the palisade stage3 sandbox binary
./dhake/dhake.com clean      # remove the native binaries

The native build is driven entirely by ./Dhakefile.dhall (no Makefile); the docs-site build lives in the same buildfile (./dhake/dhake.com dist/index.html).

Usage

fxstore init [dir]                       # scaffold a project (worked-example package-set.dhall)
fxstore build [--store DIR] [<pkg>...]   # build the closure of <pkg>... (all when none),
                                         # print each store path
fxstore query <pkg> [--store DIR]        # print <pkg>'s closure names + store path
fxstore gc <root> [--store DIR]          # prune store dirs/facts unreachable from <root>

build/query load package-set.dhall from the current directory.

Security / sandbox

The two executing recipe actions (Shell, Run) run under bwrap (--unshare-all --die-with-parent, store + toolchain ro-bound, network off). If bwrap is absent, fxstore falls back to plain fork/exec with a loud non-hermetic warning. The pure-FS actions (Copy, Mkdir, …) run in-process under a trusted-author model in v1 (the package-set author is trusted).

License

MIT.