mirror of
https://github.com/hanzoai/ha.git
synced 2026-09-30 22:38:49 +00:00
zeekay
f583260ce2
HRW (Rendezvous) single-writer election as its own coordination primitive — no coordinator, lock service, Postgres, or Redis. Answers "who is the single writer for key K" identically on every replica. Extracted from hanzoai/vfs/replica/owner.go (HIP-0107), which was storage-agnostic pure Go with no vfs-internal callers. Election (who writes) and replication (how state ships) are orthogonal; this is the cut. Generalizes orgID -> key (any ownership unit). API: Member, Owner, IsOwner, Replicas + the Membership seam + Static. Zero deps (stdlib crypto/sha256, encoding/binary, context).
40 lines
1.7 KiB
Go
40 lines
1.7 KiB
Go
// Copyright 2025 Hanzo AI Inc. All Rights Reserved.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
|
|
package ha
|
|
|
|
import "context"
|
|
|
|
// Membership is the seam election elects over: the live, writer-eligible replica
|
|
// set plus this replica's own stable ID. It is the ONE injectable source every
|
|
// consumer shares — production wires a cluster source (e.g. hanzoai/ha/k8s), tests
|
|
// and single-process mode wire Static.
|
|
//
|
|
// A consumer MUST fail CLOSED on a Members error or an empty set: election over an
|
|
// unknown or empty membership has no safe owner, so the caller skips rather than
|
|
// risk two writers. A nil error with a non-empty set is the only "proceed" signal.
|
|
type Membership interface {
|
|
// Self is this replica's stable ID — the value HRW weights derive from. It must
|
|
// be stable for the replica's life (e.g. its pod name / a persistent node id).
|
|
Self() string
|
|
// Members is the live writer-eligible set, or an error the caller fails closed
|
|
// on. A nil error with a non-empty set is the only signal safe to proceed on.
|
|
Members(ctx context.Context) ([]Member, error)
|
|
}
|
|
|
|
// Static is the single-process Membership: one member, itself, never an error — the
|
|
// sole process is the sole writer. It is the correct source for local dev, a
|
|
// standalone binary, and tests, and the safe default when no cluster source is
|
|
// wired (a single process is exactly-once by construction). id is this member's ID.
|
|
func Static(id string) Membership { return static(id) }
|
|
|
|
type static string
|
|
|
|
func (s static) Self() string { return string(s) }
|
|
|
|
func (s static) Members(context.Context) ([]Member, error) {
|
|
return []Member{{ID: string(s)}}, nil
|
|
}
|