| 1 | package hostbox |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "sort" |
| 7 | |
| 8 | "github.com/carlosframework/platform/internal/park" |
| 9 | ) |
| 10 | |
| 11 | // LeaseSet names locks in the engine's data bucket. A moves/<host>[/<op>] |
| 12 | // scope needs its own lock; staging writers are bounded by Park.EvidenceAt. |
| 13 | // An instances/<host>[/<inc>] scope needs its replica lease and scope lock |
| 14 | // (the same location, deduplicated). Deployment-bucket staging leases must |
| 15 | // never be expressed as data-bucket names. An empty set refuses. |
| 16 | type LeaseSet func(context.Context, string, string) ([]string, error) |
| 17 | |
| 18 | // AggregateLeases adapts a renewing lease implementation to park.Leases. |
| 19 | // Constituents are acquired in lexical order so competing workers cannot |
| 20 | // deadlock by discovering the same set in a different order. |
| 21 | type AggregateLeases struct { |
| 22 | Leases park.Leases |
| 23 | Resolve LeaseSet |
| 24 | } |
| 25 | |
| 26 | func (a AggregateLeases) Acquire(ctx context.Context, bucket, scope string) (park.HeldLease, error) { |
| 27 | return a.acquire(ctx, bucket, scope, nil) |
| 28 | } |
| 29 | func (a AggregateLeases) AcquireHeld(ctx context.Context, bucket, scope string, own park.HeldLease) (park.HeldLease, error) { |
| 30 | bound, ok := own.(interface{ LeaseScope() (string, string) }) |
| 31 | if !ok || own == nil { |
| 32 | return nil, ErrUnsupported |
| 33 | } |
| 34 | b, s := bound.LeaseScope() |
| 35 | if b != bucket || s != scope { |
| 36 | return nil, ErrChanged |
| 37 | } |
| 38 | if err := own.Check(ctx); err != nil { |
| 39 | return nil, err |
| 40 | } |
| 41 | return a.acquire(ctx, bucket, scope, own) |
| 42 | } |
| 43 | func (a AggregateLeases) acquire(ctx context.Context, bucket, scope string, own park.HeldLease) (park.HeldLease, error) { |
| 44 | if ctx == nil || a.Leases == nil || a.Resolve == nil || bucket == "" || scope == "" { |
| 45 | return nil, ErrUnsupported |
| 46 | } |
| 47 | names, err := a.Resolve(ctx, bucket, scope) |
| 48 | if err != nil { |
| 49 | return nil, err |
| 50 | } |
| 51 | names = append([]string(nil), names...) |
| 52 | sort.Strings(names) |
| 53 | uniq := names[:0] |
| 54 | hasScope := false |
| 55 | for _, name := range names { |
| 56 | if name == "" { |
| 57 | return nil, ErrUnsupported |
| 58 | } |
| 59 | if len(uniq) == 0 || uniq[len(uniq)-1] != name { |
| 60 | uniq = append(uniq, name) |
| 61 | } |
| 62 | if name == scope { |
| 63 | hasScope = true |
| 64 | } |
| 65 | } |
| 66 | if len(uniq) == 0 || !hasScope { |
| 67 | return nil, ErrUnsupported |
| 68 | } |
| 69 | held := &aggregateHeld{bucket: bucket, scope: scope} |
| 70 | for _, name := range uniq { |
| 71 | var h park.HeldLease |
| 72 | var acquireErr error |
| 73 | if own != nil && name == scope { |
| 74 | h = borrowedLease{own} |
| 75 | } else { |
| 76 | h, acquireErr = a.Leases.Acquire(ctx, bucket, name) |
| 77 | } |
| 78 | if acquireErr != nil { |
| 79 | return nil, errors.Join(acquireErr, held.releaseAndClose(ctx)) |
| 80 | } |
| 81 | if h == nil { |
| 82 | return nil, errors.Join(ErrUnsupported, held.releaseAndClose(ctx)) |
| 83 | } |
| 84 | held.leases = append(held.leases, h) |
| 85 | } |
| 86 | return held, nil |
| 87 | } |
| 88 | |
| 89 | type aggregateHeld struct { |
| 90 | bucket, scope string |
| 91 | leases []park.HeldLease |
| 92 | closed bool |
| 93 | } |
| 94 | |
| 95 | func (h *aggregateHeld) Check(ctx context.Context) error { |
| 96 | if h == nil || h.closed || len(h.leases) == 0 { |
| 97 | return ErrChanged |
| 98 | } |
| 99 | var errs []error |
| 100 | for _, lease := range h.leases { |
| 101 | errs = append(errs, lease.Check(ctx)) |
| 102 | } |
| 103 | return errors.Join(errs...) |
| 104 | } |
| 105 | |
| 106 | func (h *aggregateHeld) Release(ctx context.Context) error { |
| 107 | if h == nil || h.closed || len(h.leases) == 0 { |
| 108 | return ErrChanged |
| 109 | } |
| 110 | var errs []error |
| 111 | for i := len(h.leases) - 1; i >= 0; i-- { |
| 112 | errs = append(errs, h.leases[i].Release(ctx)) |
| 113 | } |
| 114 | return errors.Join(errs...) |
| 115 | } |
| 116 | |
| 117 | func (h *aggregateHeld) Close() { |
| 118 | if h == nil || h.closed { |
| 119 | return |
| 120 | } |
| 121 | h.closed = true |
| 122 | for i := len(h.leases) - 1; i >= 0; i-- { |
| 123 | h.leases[i].Close() |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | func (h *aggregateHeld) releaseAndClose(ctx context.Context) error { |
| 128 | var errs []error |
| 129 | for i := len(h.leases) - 1; i >= 0; i-- { |
| 130 | errs = append(errs, h.leases[i].Release(ctx)) |
| 131 | h.leases[i].Close() |
| 132 | } |
| 133 | h.closed = true |
| 134 | return errors.Join(errs...) |
| 135 | } |
| 136 | |
| 137 | func (h *aggregateHeld) LeaseScope() (string, string) { return h.bucket, h.scope } |
| 138 | |
| 139 | type borrowedLease struct{ park.HeldLease } |
| 140 | |
| 141 | func (b borrowedLease) Release(ctx context.Context) error { return b.Check(ctx) } |
| 142 | func (b borrowedLease) Close() {} |
| 143 | func (b borrowedLease) Context(ctx context.Context) context.Context { |
| 144 | if bound, ok := b.HeldLease.(interface { |
| 145 | Context(context.Context) context.Context |
| 146 | }); ok { |
| 147 | return bound.Context(ctx) |
| 148 | } |
| 149 | return ctx |
| 150 | } |
| 151 | |
amadan