Crate unitbus 

unitbus is a Rust SDK for Linux systemd: control units/jobs via the system D-Bus (systemctl-like), run one-shot transient tasks, and query journald logs (default: pure Rust backend).

It is designed as a control-plane foundation for traditional deployments (non-Kubernetes) and CD/agent tooling.

Runtime is Linux-only (systemd + system bus required). The public API is designed to compile on other platforms but will return Error::BackendUnavailable where appropriate.

Quick start

use unitbus::{UnitBus, UnitStartMode};

async fn restart_nginx() -> Result<(), unitbus::Error> {
    let bus = UnitBus::connect_system().await?;
    let job = bus.units().restart("nginx", UnitStartMode::Replace).await?;
    let outcome = job.wait(std::time::Duration::from_secs(30)).await?;
    println!("{outcome:?}");
    Ok(())
}

Unit name rules

• You can pass either a full unit name (e.g. "nginx.service") or a shorthand (e.g. "nginx").
• Shorthand names are canonicalized to "<name>.service".
• Names containing path separators or control characters are rejected as Error::InvalidInput.

Journald limits

The journald backend enforces bounded results:

• limit (default: 200)
• max_bytes (default: 1 MiB)
• max_message_bytes (default: 16 KiB)

Default backend: pure Rust journal reader (feature=journal-sdjournal). Alternative backend: journalctl --output=json (feature=journal-cli).

When limits are exceeded, the returned JournalResult.truncated is set to true.

Structs

Capabilities

Runtime capabilities derived from conservative probing.

Diagnosis

DiagnosisOptions

Options for diagnose_unit_failure.

JobHandle

Handle for a systemd job.

Journal

JournalEntry

One log entry from journald.

JournalFilter

Query filter for journald.

JournalResult

JournalStats

Manager

systemd Manager APIs.

ManagerInfo

A small snapshot of org.freedesktop.systemd1.Manager global information.

Properties

A GetAll property bag (values are stored internally as D-Bus variants).

ServiceUnitSpec

Specification for generating a systemd service unit file.

UnitBus

Primary entrypoint for interacting with systemd and journald.

UnitBusOptions

Configuration options for UnitBus.

UnitListEntry

A single row returned by org.freedesktop.systemd1.Manager.ListUnits*.

UnitStatus

Snapshot of relevant systemd unit/service properties.

Units

Unit/job control APIs.

Enums

ActiveState

systemd Unit.ActiveState.

Error

Error returned by unitbus APIs.

FailureHint

A best-effort classification of why a job failed.

JobOutcome

Normalized outcome for a job wait.

LoadState

systemd Unit.LoadState.

ParseErrorMode

How to handle malformed journal entries from the configured backend.

ServiceType

systemd service Type=....

UnitStartMode

systemd StartUnit/StopUnit mode.

Type Aliases

JournalCursor

Result

Crate-wide result type.