# Changelog

OxygenFlow has no release yet: the runner on Earth runs `main`. This file starts on 2026-10-01; earlier history is in `oxy log`.

## Unreleased

- **The syscall tier (#36, docs/m0.md §3).** `runtime "syscall"` jobs run without KVM, so boards such as the OrangePi RV2 can take them. The sandbox uses user, mount, PID, network, IPC and UTS namespaces on the image's unpacked tree, read-only. Landlock limits writes to `/src` and `/tmp`, and a seccomp filter refuses network sockets, tracing, mounts, BPF, keys, modules and io_uring. A delegated cgroup v2 group enforces the CPU and memory limits, and a job killed for memory is told so. A runner offers the tier only where all of this works. `flow tiers` shows which tiers a machine can run and why the others cannot, and `flow run` runs syscall jobs too.

- **A runner offers only the tiers it can run (#36).** It checks that `/dev/kvm` opens before offering the MicroVM tier, says which tiers it serves when it starts, and refuses to start with none, naming why, rather than claiming jobs it would fail.

- **A runner tries a fetch again after a network hiccup (oxygenhub#111).** Fetching or cloning the job's repository or a subrepo is retried on DNS, connection, timeout and 502/503/504 errors, waiting 2, 4, 8, 16 and 30 seconds; any other error still ends the job at once.

- **Architecture awareness (#36, spec §11.2).** `flow rootfs import` records an image's architecture from its shell's ELF header and refuses an image for another architecture; a claim reports each image's architecture, and a sandbox may say `arch "riscv64"`.

- **A job's identity (oxygenhub#103).** `identity "AUDIENCE" { mount-path "/run/secrets/…" }` asks the hub for an OIDC token for that audience, mounted as a file like a secret.

- **Secrets as files (oxygenhub#107).** A job's `secret "name" { mount-path "/run/secrets/…" }` names a secret the hub holds; it comes with the claim and `flow-init` writes it at that path, 0400, on a tmpfs, before the job starts. Never in the environment, the receipt or an artifact (spec §9). `flow run --secret NAME=VALUE` locally.

- **Variables from the hub (oxygenhub#102).** A claim carries `env`, the variables the hub holds for the repository; they join the job's environment under `FLOW_*` and the pipeline's own `env`. `flow run --var NAME=VALUE` does the same locally.

- **A job says how long it may run (#23).** `timeout "90m"` on a job, or on a sandbox for its jobs (hours, minutes, seconds; a minute to a day). The hub caps it at the site's maximum.

- **A pinned file is re-read from the disk before its hash is called wrong (#22).**

- **A runner says which jobs it holds (oxygenhub#71).** Each claim lists the jobs the runner is running or still has a result for, so the hub ends at once any job it lost by restarting, instead of an hour later at the time limit.

- **A runner says which images it holds (oxygenhub#73).** Each claim lists the rootfs images in the runner's `cas/` (read each time, so an image imported while it runs counts), and the hub offers only jobs whose image is among them. plex-1 had failed metalgear's jobs for want of one.

- **A job's result is kept until the hub has it (oxygenhub#71).** The runner offered a finished job's result three times over seven seconds and then dropped it, so a hub that was briefly down (Earth's reset) left the job running forever. The result is now kept on disk (`pending/` in the Flow home) and offered again, every 5 s doubling to a minute, for up to two hours, through any server error or lost connection; a runner that restarts sends what it kept. A refusal (the hub ended the job already) is final.

- **The Rust build image vendors mimalloc (#20).** Oxygen's new allocator was missing from the image, so oxygen's runs #150 to #153 failed. The image was rebuilt with `images/rust/build.sh`, imported on Earth and pinned in the oxygen, oxygenhub and oxygenflow pipelines. Rebuild it whenever a `Cargo.lock` of those projects changes.

- **A hint for shell escapes in a pipeline.** KDL 2.0 strings have no `\033`, `\e` or `\x` escapes; a pipeline that uses one (for ANSI colours, say) is still invalid, but `flow check` and the hub now name the line and say to write ESC as `\u{1b}`.