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3.9 KiB
Go

// Package maintenance owns the server-side scheduler that fires
// forget/prune/check on the cadences operators set on
// host_repo_maintenance rows. Independent of the agent's local cron
// (which now only handles backup schedules).
//
// The ticker is intentionally side-effect-free at the package
// boundary: it asks an injected Backend for current state and emits
// a list of Decisions for the caller to act on. Easy to unit-test
// without a running server.
package maintenance
import (
"context"
"errors"
"time"
"github.com/robfig/cron/v3"
"gitea.dcglab.co.uk/steve/restic-manager/internal/store"
)
// Decision is one cadence-driven dispatch the ticker recommends.
// SubsetPct is populated only when Kind == "check"; ignored for
// "forget" and "prune".
type Decision struct {
HostID string
Kind string // "forget" | "prune" | "check"
SubsetPct int
}
// Backend is the subset of *store.Store the ticker depends on.
// Constrained interface so tests can pass a fake.
type Backend interface {
ListAllMaintenance(ctx context.Context) ([]store.HostRepoMaintenance, error)
LatestJobByKind(ctx context.Context, hostID, kind string) (*store.Job, error)
}
// Ticker decides which cadence-driven jobs are due to fire at a
// given instant. Stateless — the only state lives in the Backend.
type Ticker struct {
backend Backend
parser cron.Parser
}
// New builds a Ticker bound to the given Backend.
func New(b Backend) *Ticker {
return &Ticker{
backend: b,
parser: cron.NewParser(cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow),
}
}
// Decide returns the set of jobs the ticker would dispatch at `now`.
// The caller is responsible for: checking host online state,
// persisting the job row, and shipping command.run. Returns nil
// (not an error) when the maintenance table is empty — a fresh
// install is the most common case.
func (t *Ticker) Decide(ctx context.Context, now time.Time) ([]Decision, error) {
rows, err := t.backend.ListAllMaintenance(ctx)
if err != nil {
return nil, err
}
var out []Decision
for _, m := range rows {
if d, ok := t.dueFor(ctx, now, m.HostID, "forget", m.ForgetCron, m.ForgetEnabled, 0); ok {
out = append(out, d)
}
if d, ok := t.dueFor(ctx, now, m.HostID, "prune", m.PruneCron, m.PruneEnabled, 0); ok {
out = append(out, d)
}
if d, ok := t.dueFor(ctx, now, m.HostID, "check", m.CheckCron, m.CheckEnabled, m.CheckSubsetPct); ok {
out = append(out, d)
}
}
return out, nil
}
// dueFor returns true if the cron has a fire-instant strictly after
// the latest persisted job's created_at and at-or-before now.
//
// Anchor selection:
// - When LatestJobByKind returns a job: anchor = j.CreatedAt.
// - When LatestJobByKind returns ErrNotFound: anchor = now - 24h
// (first-run case — cap the lookback so a brand-new host doesn't
// fire 30 days of missed monthly-checks on first tick).
// - When LatestJobByKind returns a hard error: skip this kind for
// this host on this tick.
//
// Disabled (`enabled == false`) or empty cron skips silently.
// Cron parse failures skip silently — the schedule/maintenance
// routes already validate cron at write time, so this is defensive.
func (t *Ticker) dueFor(ctx context.Context, now time.Time, hostID, kind, expr string, enabled bool, subset int) (Decision, bool) {
if !enabled || expr == "" {
return Decision{}, false
}
sched, err := t.parser.Parse(expr)
if err != nil {
return Decision{}, false
}
j, err := t.backend.LatestJobByKind(ctx, hostID, kind)
var anchor time.Time
switch {
case err == nil && j != nil:
anchor = j.CreatedAt
case errors.Is(err, store.ErrNotFound):
anchor = now.Add(-24 * time.Hour)
default:
// Hard error — skip this kind on this tick.
return Decision{}, false
}
next := sched.Next(anchor)
if next.IsZero() || next.After(now) {
return Decision{}, false
}
return Decision{HostID: hostID, Kind: kind, SubsetPct: subset}, true
}