| 1 | package appconfig |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "crypto/ecdh" |
| 6 | "crypto/sha256" |
| 7 | "encoding/hex" |
| 8 | "errors" |
| 9 | "fmt" |
| 10 | "os" |
| 11 | "path/filepath" |
| 12 | "time" |
| 13 | |
| 14 | "github.com/carlosframework/platform/internal/hostwrite" |
| 15 | "github.com/carlosframework/platform/internal/registry" |
| 16 | "github.com/carlosframework/platform/internal/release" |
| 17 | ) |
| 18 | |
| 19 | // ErrNotHeld is RenderHeld refusing a route it does not own: a row SyncExec |
| 20 | // converges (status "" or "ready"), a row held by another operation, a row |
| 21 | // of a shape no move takes, or a call without the op and box the ack is |
| 22 | // bound to. |
| 23 | var ErrNotHeld = errors.New("config: not a held row of this move") |
| 24 | |
| 25 | // ErrHeldClaimWired is RenderHeld refusing to write while CARLOS_HOST_CLAIM |
| 26 | // is on (ruling F10): a held row's write has no claim selection until Plan |
| 27 | // 2 adds one under the landing op, and an unguarded write is not added. |
| 28 | var ErrHeldClaimWired = errors.New("config: held rows are not rendered while CARLOS_HOST_CLAIM is on") |
| 29 | |
| 30 | // HeldRender is what RenderHeld rendered: the file, the sha256 of its |
| 31 | // bytes, and the versions of the objects merged into it. BundleETags has |
| 32 | // the keys "default" and "environment". |
| 33 | type HeldRender struct { |
| 34 | Path string |
| 35 | SHA256 string |
| 36 | BundleETags map[string]string |
| 37 | OverlayETag string |
| 38 | } |
| 39 | |
| 40 | // RenderHeld renders the config file of a held row: one that a move holds |
| 41 | // on this box (status not "" or "ready", hold_op empty or op), which |
| 42 | // SyncExec therefore skips (execRouteBase), so the two never write one file. |
| 43 | // It merges through LoadMergedHostVersions, writes through the same writer |
| 44 | // SyncExec uses (renderExecConfig) when the bytes differ, and writes a |
| 45 | // move-bound ack through WriteConfigAck on every call, changed or not: the |
| 46 | // ack names op, the file's sha256 and the merged objects' etags, which T3 |
| 47 | // compares (moves design §9.1). |
| 48 | // |
| 49 | // It writes through legacyHostWork, so it refuses outright while |
| 50 | // CARLOS_HOST_CLAIM is on (ErrHeldClaimWired) and writes nothing. |
| 51 | func RenderHeld(ctx context.Context, s release.Store, priv *ecdh.PrivateKey, dataDir string, rt registry.Route, op string, box string) (HeldRender, error) { |
| 52 | if hostwrite.Enabled(os.Getenv) { |
| 53 | return HeldRender{}, ErrHeldClaimWired |
| 54 | } |
| 55 | return renderHeld(ctx, s, priv, dataDir, rt, op, box, func(HeldRender) (hostwrite.Work, error) { return legacyHostWork{}, nil }, nil) |
| 56 | } |
| 57 | |
| 58 | // RenderHeldBefore is RenderHeld with before called once the rendered bytes |
| 59 | // are known and before anything is written: before receives the hex sha256 |
| 60 | // of exactly the bytes the render then places (or finds already in place), |
| 61 | // so a caller can make its ownership of the file durable first (moves Plan 5 |
| 62 | // Task 9a, carry (c)). An error from before ends the render: nothing is |
| 63 | // written and no ack is sent. The write itself is RenderHeld's, unchanged. |
| 64 | func RenderHeldBefore(ctx context.Context, s release.Store, priv *ecdh.PrivateKey, dataDir string, rt registry.Route, op string, box string, before func(sha256hex string) error) (HeldRender, error) { |
| 65 | if before == nil { |
| 66 | return HeldRender{}, hostwrite.ErrUnavailable |
| 67 | } |
| 68 | if hostwrite.Enabled(os.Getenv) { |
| 69 | return HeldRender{}, ErrHeldClaimWired |
| 70 | } |
| 71 | return renderHeld(ctx, s, priv, dataDir, rt, op, box, func(HeldRender) (hostwrite.Work, error) { return legacyHostWork{}, nil }, before) |
| 72 | } |
| 73 | |
| 74 | // RenderHeldUnder is RenderHeld for a held row under the host claim (moves |
| 75 | // Phase 1 Plan 3 Task 5, ruling H13): the same ownership check, merge, |
| 76 | // renderer, writer and move-bound ack, with the file written through the |
| 77 | // claim selection work returns instead of legacyHostWork. work is called |
| 78 | // once the merged versions are known, with BundleETags and OverlayETag set |
| 79 | // (the rest of the HeldRender empty), so its caller can select a held-config |
| 80 | // work bound to exactly the etags this render writes; nothing is written |
| 81 | // before it returns. A nil work, or a work that is nil, is refused. It does |
| 82 | // not consult CARLOS_HOST_CLAIM: the selection is the authority. |
| 83 | func RenderHeldUnder(ctx context.Context, s release.Store, priv *ecdh.PrivateKey, dataDir string, rt registry.Route, op string, box string, work func(HeldRender) (hostwrite.Work, error)) (HeldRender, error) { |
| 84 | if work == nil { |
| 85 | return HeldRender{}, hostwrite.ErrUnavailable |
| 86 | } |
| 87 | return renderHeld(ctx, s, priv, dataDir, rt, op, box, work, nil) |
| 88 | } |
| 89 | |
| 90 | // RenderHeldUnderBefore is RenderHeldUnder with RenderHeldBefore's before |
| 91 | // (moves after claim Plan 12, Task 7; platform-1e's answer to Q2.2): the |
| 92 | // held render the landing's configured step runs under the claim, which |
| 93 | // keeps carry (c). The ownership checks, the merge, the renderer, the |
| 94 | // writer and the move-bound ack are RenderHeld's. work is called once the |
| 95 | // merged versions are known, as for RenderHeldUnder; before is then called |
| 96 | // with the hex sha256 of exactly the bytes the render places (or finds in |
| 97 | // place), and only after it returns is anything written, through the |
| 98 | // selection work returned. An error from before ends the render: nothing is |
| 99 | // written, the selection is never entered and no ack is sent. A nil work or |
| 100 | // a nil before is refused before anything is read. Like RenderHeldUnder it |
| 101 | // does not consult CARLOS_HOST_CLAIM: the selection is the authority. |
| 102 | func RenderHeldUnderBefore(ctx context.Context, s release.Store, priv *ecdh.PrivateKey, dataDir string, rt registry.Route, op string, box string, work func(HeldRender) (hostwrite.Work, error), before func(sha256hex string) error) (HeldRender, error) { |
| 103 | if work == nil || before == nil { |
| 104 | return HeldRender{}, hostwrite.ErrUnavailable |
| 105 | } |
| 106 | return renderHeld(ctx, s, priv, dataDir, rt, op, box, work, before) |
| 107 | } |
| 108 | |
| 109 | func renderHeld(ctx context.Context, s release.Store, priv *ecdh.PrivateKey, dataDir string, rt registry.Route, op string, box string, work func(HeldRender) (hostwrite.Work, error), before func(string) error) (HeldRender, error) { |
| 110 | if err := heldRenderable(rt, op, box); err != nil { |
| 111 | return HeldRender{}, err |
| 112 | } |
| 113 | acct := release.RouteAccount(rt) |
| 114 | m, v, err := LoadMergedHostVersions(ctx, s, acct, rt.App, rt.Environment, rt.Host) |
| 115 | if err != nil { |
| 116 | return HeldRender{}, err |
| 117 | } |
| 118 | w, err := work(HeldRender{BundleETags: map[string]string{"default": v.Default, "environment": v.Environment}, OverlayETag: v.Overlay}) |
| 119 | if err != nil { |
| 120 | return HeldRender{}, err |
| 121 | } |
| 122 | if w == nil { |
| 123 | return HeldRender{}, hostwrite.ErrUnavailable |
| 124 | } |
| 125 | r, err := renderExecConfigBefore(ctx, w, rt, m, priv, dataDir, "", v.Overlay, before, false) |
| 126 | if err != nil { |
| 127 | return HeldRender{}, err |
| 128 | } |
| 129 | sum := sha256.Sum256(r.rendered) |
| 130 | out := HeldRender{ |
| 131 | Path: r.path, |
| 132 | SHA256: hex.EncodeToString(sum[:]), |
| 133 | BundleETags: map[string]string{"default": v.Default, "environment": v.Environment}, |
| 134 | OverlayETag: v.Overlay, |
| 135 | } |
| 136 | a := ConfigAck{Schema: ConfigAckSchema, Box: box, Host: rt.Host, Shape: shapeOf(rt), At: time.Now(), |
| 137 | InstanceConfigETag: v.Overlay, MoveOp: op, FileSHA256: out.SHA256, |
| 138 | BundleETags: map[string]string{"default": v.Default, "environment": v.Environment}} |
| 139 | if suffixes, err := relaySuffixesFromRelayVar(m, priv, routeBinding(rt)); err != nil { |
| 140 | fmt.Printf(" %s: held config rendered, but CARLOS_RELAY could not be read for the config-ack: %v\n", rt.Host, err) |
| 141 | } else { |
| 142 | a.RelaySuffixes = suffixes |
| 143 | } |
| 144 | if err := WriteConfigAck(ctx, s, a); err != nil { |
| 145 | return out, fmt.Errorf("%s: held config ack: %w", rt.Host, err) |
| 146 | } |
| 147 | return out, nil |
| 148 | } |
| 149 | |
| 150 | // heldRenderable is RenderHeld's admission: the exec-instance shape a move |
| 151 | // takes (execSyncable without its status clause), a status SyncExec skips, |
| 152 | // no hold by another operation, a bare host name, and an op and box to bind |
| 153 | // the ack to. |
| 154 | func heldRenderable(rt registry.Route, op, box string) error { |
| 155 | switch { |
| 156 | case op == "" || box == "": |
| 157 | return fmt.Errorf("%w: a held render needs a move op and a box", ErrNotHeld) |
| 158 | case rt.Host == "" || rt.Host == "." || rt.Host == ".." || rt.Host != filepath.Base(rt.Host): |
| 159 | return fmt.Errorf("%w: %q is not a bare host name", ErrNotHeld, rt.Host) |
| 160 | case rt.Status == "" || rt.Status == "ready": |
| 161 | return fmt.Errorf("%w: %s is %q, which config sync owns", ErrNotHeld, rt.Host, rt.Status) |
| 162 | case rt.HoldOp != "" && rt.HoldOp != op: |
| 163 | return fmt.Errorf("%w: %s is held by %s", ErrNotHeld, rt.Host, rt.HoldOp) |
| 164 | case rt.Kind != "instance" || rt.App == "" || rt.Platform || rt.Backing == registry.BackingUnit || rt.Socket == "": |
| 165 | return fmt.Errorf("%w: %s is not an exec-backed instance", ErrNotHeld, rt.Host) |
| 166 | } |
| 167 | return nil |
| 168 | } |
| 169 | |
amadan