Module protocol 

The client<->daemon wire protocol (version 3)

Typed request/response enums + bus events. Framing lives in wire; every type here is snapshot-pinned — changing any serialized shape is a protocol version bump recorded in the CHANGELOG.

What version 2 added: the instance slot on ProcessInfo. A sheep that is one of several instances of an app reports which slot it is, so every listing can group an app’s instances and roll their numbers up rather than showing several rows that share a name and explain nothing. A sheep reports its own slot, counting from 0, so a single-instance app reports Some(0). None means the peer daemon predates the field, and a reader that finds it should render exactly what it rendered before this field existed.

What version 3 changed: ResetDepth::Settings was renamed to ResetDepth::Policy (and gained File/Env siblings). Unlike every bump before it except SelectorSpec::Instance’s, this one is not an addition: "settings" was the wire spelling of a Request::ApplyConfig already shipping, and a rename removes a string an older daemon already decoded rather than adding one it never saw. Without the bump, a CLI built after this change sends "policy" for what used to be --reset, and a daemon that has not restarted since the upgrade cannot decode it: the connection ends on an envelope it cannot read instead of a named refusal at the handshake. Restart the shepherd after upgrading to this version, the same as the last bump asked.

Two sets of tests carry a version in their name and they assert opposite things. The *_wire_v3 snapshots pin the shape this crate serializes TODAY, so they follow PROTOCOL_VERSION and get renamed whenever it moves. The v1_*_fixture_still_deserializes tests pin a literal payload captured from a version 1 peer and assert it STILL decodes, so their name records where the bytes came from and never moves; renaming one would erase the compatibility claim it exists to make.

Re-exports

pub use channel::CHANNEL_VERSION;

pub use channel::ChildMessage;

pub use channel::ShepherdMessage;

pub use events::BusEvent;

pub use events::ProcessEventKind;

pub use frame::ServerFrame;

pub use request::ActionOutcome;

pub use request::ActionReply;

pub use request::DogSectionToml;

pub use request::DogSource;

pub use request::Envelope;

pub use request::ExitInfo;

pub use request::Hello;

pub use request::HelloAck;

pub use request::HelloReply;

pub use request::Lamb;

pub use request::LineOutcome;

pub use request::LineReply;

pub use request::ProcessInfo;

pub use request::ProcessInfoBuilder;

pub use request::Reply;

pub use request::Request;

pub use request::Response;

pub use request::RpcError;

pub use request::RpcErrorCode;

pub use request::SelectorSpec;

pub use request::SheepApplied;

pub use request::SheepDrift;

pub use request::SignalOutcome;

pub use request::SignalReply;

pub use request::Smit;

pub use request::SmitError;

pub use request::sort_flock;

pub use wire::MAX_FRAME_BYTES;

pub use wire::WireError;

pub use wire::codec;

pub use wire::decode_frame;

pub use wire::encode_frame;

Modules

channel

The shepherd channel: the newline-JSON wire carried on fd 3 between the shepherd and each spawned child.

events

Bus events broadcast to subscribed clients

frame

Anything the daemon writes to a connected client

request

RPC frames: requests, responses, envelopes, and structured errors

wire

Frame encoding shared by daemon and client Frame encoding: u32 length prefix + JSON payload

Constants

PROTOCOL_VERSION

Wire protocol version.