Bosn

Bosn is a Rust daemon for safely managing Docker development applications. It keeps ownership, generation, volume, lease, execution-session, and event state in a durable SQLite registry. The daemon is the only component that mutates Docker or that writes that registry.

The distribution includes three intentionally thin front ends:

• bosn, a bundled native CLI;
• import bosn, a PyO3 client binding; and
• bosn mcp, a stdio MCP server for Hermes and other MCP clients.

The former Python daemon, Docker front doors, manifest parser, and SQLite registry are deliberately not packaged. Python callers use bosn.Client; they cannot import or invoke a second lifecycle implementation.

Install

pip install bosn
bosn --version

Platform wheels contain the native bosn CLI and the bosn._native Python extension. Installing the wheel puts the bosn binary itself into the environment's scripts directory, so the bosn on PATH is the native CLI, with no Python wrapper in between. The extension uses PyO3's abi3-py310 ABI, so Bosn supports CPython 3.10 and newer with one platform wheel rather than publishing cp311-only artifacts.

One-file setup

Bosn accepts a local file or HTTPS URL for a versioned setup document. The document declares a digest-pinned image or inline Dockerfile, optional inline files, environment, bind mounts, named volumes, tmpfs mounts, and named tasks. Planning is inert; ensure and task submission are daemon-owned jobs.

version = 1

[app]
image = "registry.example/team/app@sha256:REPLACE_WITH_64_LOWERCASE_HEX_DIGEST"
command = "exec sleep 120"

[task.check]
command = "cargo check"

bosn setup plan --state-dir "$HOME/.local/state/bosn" \
  --workspace "$PWD" --config https://example.invalid/bosn-setup.toml \
  --refresh
bosn setup ensure --state-dir "$HOME/.local/state/bosn" \
  --workspace "$PWD" --config https://example.invalid/bosn-setup.toml \
  --refresh --deadline-ms 300000 --output-limit 8388608

online_refresh is explicit; offline_cache_only uses only a previously validated local cache record. URLs with credentials, unsupported schemes, path traversal, unpinned images, and oversized documents are refused.

Python

from pathlib import Path
import bosn

client = bosn.Client(Path.home() / ".local/state/bosn")
plan = client.plan_setup(
    Path.cwd(), "https://example.invalid/bosn-setup.toml", policy="online_refresh"
)
job_id = client.submit_setup_ensure(
    Path.cwd(),
    "https://example.invalid/bosn-setup.toml",
    policy="online_refresh",
    deadline_ms=300_000,
    output_limit=8 * 1024 * 1024,
)

The binding exposes typed request and observation operations only. It does not accept Docker command arguments, container identifiers, mounts, or arbitrary commands from callers.

MCP / Hermes

Run bosn mcp over stdio. A typical Hermes registration is:

mcp_servers:
  bosn:
    command: bosn
    args: [mcp]

Set BOSN_STATE_DIR if the default state directory is not appropriate. MCP tools use the same typed daemon operations as the CLI and Python client; long operations return durable job IDs.

Development

./install
./lint
./test

The Rust migration status, native manifest lifecycle boundary, and registry details are documented in docs/migration-rust.md, docs/rust-manifest-runtime.md, and docs/rust-registry.md. Daemon-owned task secrets (an opt-in GITHUB_TOKEN for act runs) are in docs/task-secrets.md; the read-only GitHub API proxy that keeps the token out of containers is in docs/github-api-proxy.md.