# OxygenFlow

Hermetic pipelines for Oxygen repositories:

- a typed pipeline in `.flow/pipeline.kdl`
- jobs run in isolation tiers, Firecracker microVMs by default
- the host writes the receipts
- results go to OxygenHub as checks and appear on its Flow tab

The specification is [docs/spec.md](docs/spec.md). What works today is
[docs/m0.md](docs/m0.md).

## A pipeline

```kdl
schema-version 1

sandbox "alpine" {
    runtime "microvm"
    rootfs "cas://blob/…"      // printed by `flow rootfs import`
    memory-limit "256MiB"
    network "isolated"
}

job "build" {
    sandbox "alpine"
    exec "make"
}

job "test" {
    sandbox "alpine"
    depends-on "build"
    exec "sh" "-eu" "test.sh"   // argv, run as written: no shell unless you name one
}
```

Each job boots its own microVM:

- it has no network device
- the rootfs is read-only
- the workspace is the state being built, read-write at `/src`
- the job runs as a user that is not root

This repository's own pipeline is [.flow/pipeline.kdl](.flow/pipeline.kdl).

## Deploying the runner on Earth

`make deploy-runner` builds `flow` and the static `flow-init`, installs them
under `/home/claude/flow` (keeping the previous files as `.prev`), re-pins
`flow-init` in `flow.toml` and restarts the `flow-runner` service.

## Commands

    flow check                 # validate .flow/pipeline.kdl, print jobs and the pipeline hash
    flow run [JOB…]            # run the pipeline on this directory, locally, in microVMs
    flow rootfs import T.tgz --sha256 HEX   # make a rootfs image; prints the `rootfs` line to pin
    flow rootfs list
    flow hash FILE             # BLAKE3, for pinning in flow.toml
    flow runner                # claim and run jobs for the hub in flow.toml

## A Flow home

`$FLOW_HOME` (default `~/.local/share/flow`) holds:

- `flow.toml`
- the pinned Firecracker binary, guest kernel and `flow-init`
- rootfs images under `cas/`
- scratch space

Every pinned file is checked against its BLAKE3 before use.

```toml
[microvm]
firecracker = { path = "bin/firecracker", blake3 = "…" }
kernel = { path = "kernel/vmlinux", blake3 = "…" }
init = { path = "bin/flow-init", blake3 = "…" }

[runner]                     # only for `flow runner`
hub = "https://hub.example:7343"
token = "…"                  # listed in the hub's [flow] runner_tokens
ca = "/path/to/hub-ca.pem"   # when the hub's certificate is self-signed
name = "runner-1"
```

Setting one up needs Linux x86-64 with KVM and e2fsprogs 1.43 or later:

1. Build `flow` with `cargo build --release -p flow`. Build the guest init
   as a static binary:
   `RUSTFLAGS="-C target-feature=+crt-static" cargo build --release -p flow-init --target x86_64-unknown-linux-gnu`.
2. Download Firecracker v1.17.0 from its GitHub release, and check the
   published SHA-256. Download the guest kernel
   `firecracker-ci/v1.15/x86_64/vmlinux-6.1.155` from Firecracker's CI
   bucket.
3. Run `flow rootfs import alpine-minirootfs-3.24.2-x86_64.tar.gz --sha256 …`.
4. Write `flow.toml`, pinning each file by its `flow hash`.

On OxygenHub, `hub.toml` lists the runner token and the repositories whose
pushes run pipelines:

```toml
[flow]
runner_tokens = ["…"]
repos = ["owner/*"]
```

## Tests

`cargo test --workspace` runs every test that needs no VM. The microVM
conformance test also runs when `FLOW_TEST_HOME` names a Flow home and
`FLOW_TEST_ROOTFS` is the hash of an Alpine rootfs in it. The test checks
literal argv, network isolation, the read-only rootfs, and that dependents
are skipped after a failure.

## oxygen as a pinned subrepo

`flow` builds against `deps/oxygen`, a subrepo (`oxy submodule`) pinned to an exact state, so builds are reproducible and OxygenFlow can build this repository without network. `make pins` moves it to oxygen's `main` on Earth (push oxygen first); the next commit records the new pin. Format only this workspace, `cargo fmt -p flow -p flow-core -p flow-init`: `--all` also reaches `deps/`. After a fresh clone, `oxy submodule update --init` fetches it.