Let a seat receive blocks as data its holder renders, placed where the machine has the hardware (hq ADR 0255)
A module adding a battery to the bar had to write i3status-rust's TOML, so a second bar could not take its place. node-bar now receives a bar-neutral block: the contributor says what it shows, the holder renders it with its own template, places every bar and place once, and a contribution may name a capability the machine must report. The block is offered: the power module runs on servers without a bar.
This commit is contained in:
jochen
@@ -0,0 +1,370 @@
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package catalogue
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"math"
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"regexp"
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"sort"
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"strings"
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"text/template"
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)
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// A kind a seat receives as data, rendered by its holder (novox/hq ADR 0255).
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//
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// ADR 0212 made a contribution text in the tool's own grammar, which the controller places and never
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// reads. That is right where the tool is the seat's for good — a hotkey daemon's trigger lines — and
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// wrong where the seat's whole point is that its tool can be replaced: a module adding a battery to the
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// bar would write i3status-rust's TOML, and a second bar would have to read it. So a seat may define a
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// kind as data instead. The seat says the data's shape; a contributor gives data in that shape; the
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// holder gives a template that renders one piece of it into its tool's grammar, as a module's facts
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// template renders the roster (`facts`): the data is the mesh's, the format is the holder's.
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//
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// What the holder places is narrowed by the shape's placing fields — the bar's `bar` and `place` — in
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// the placeholder, `${contribution:<seat>:<kind>:<field>=<value>,…}`, and every combination of them is
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// placed by the holder exactly once, so nothing a module contributes is dropped by a holder that forgot
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// a corner of the shape.
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// Shape is what a kind received as data looks like.
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type Shape struct {
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// Places are the fields a holder narrows its placeholders by, each with every value it takes.
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Places []PlaceField
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// Order is the whole-number field that orders the pieces within one placeholder (lowest first,
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// then module order); absent in a piece means OrderDefault.
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Order string
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// Check is what else is wrong with one piece's data, beyond its placing fields and its order.
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Check func(data map[string]any) []string `json:"-"`
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// Examples are pieces every holder's template must render, one for each variant the shape has,
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// so a holder that cannot render one is refused at registration and not found on a machine.
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Examples []map[string]any
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}
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// PlaceField is one field a holder places by, and the values it takes.
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type PlaceField struct {
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Field string
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Values []string
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}
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// OrderDefault is a piece's order when it gives none: the middle of 0–99.
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const OrderDefault = 50
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// capabilityName is what an `if-capability` may name: a capability as a node's profile reports it.
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var capabilityName = regexp.MustCompile(`^[a-z0-9][a-z0-9-]*$`)
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// renderFuncs are the functions a holder's template may call. `quote` writes a value as a JSON
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// string — a valid basic string in TOML and in most tools' grammars — so a contributed command
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// with quotes in it cannot break out of the holder's line.
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var renderFuncs = template.FuncMap{
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"quote": func(v any) (string, error) {
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b, err := json.Marshal(fmt.Sprint(v))
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return string(b), err
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},
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}
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// shapedProblems is what is wrong with one contribution of a kind received as data.
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func shapedProblems(module string, i int, r Receivable, c SeatContribution) []string {
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var problems []string
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at := fmt.Sprintf("%s's contribution %d to %s (%s)", module, i+1, c.Seat, c.Kind)
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if strings.TrimSpace(c.Content) != "" {
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problems = append(problems, at+" has content; this kind is data, given as `data` (novox/hq ADR 0255)")
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}
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if len(c.Data) == 0 {
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return append(problems, at+" has no data")
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}
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for _, p := range r.Shape.Places {
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v, _ := c.Data[p.Field].(string)
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if !oneOf(p.Values, v) {
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problems = append(problems, fmt.Sprintf("%s says %s %q; it is one of %s",
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at, p.Field, fmt.Sprint(c.Data[p.Field]), strings.Join(p.Values, ", ")))
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}
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}
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if r.Shape.Order != "" {
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if v, has := c.Data[r.Shape.Order]; has {
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if _, ok := wholeIn(v, 0, 99); !ok {
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problems = append(problems, fmt.Sprintf("%s says %s %v; it is a whole number from 0 to 99",
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at, r.Shape.Order, v))
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}
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}
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}
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if r.Shape.Check != nil {
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for _, p := range r.Shape.Check(c.Data) {
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problems = append(problems, at+": "+p)
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}
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}
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return problems
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}
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// wholeIn is v as a whole number within [lo, hi]; JSON gives every number as a float.
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func wholeIn(v any, lo, hi int) (int, bool) {
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f, ok := v.(float64)
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if !ok {
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if i, isInt := v.(int); isInt {
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f, ok = float64(i), true
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}
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}
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if !ok || f != math.Trunc(f) || f < float64(lo) || f > float64(hi) {
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return 0, false
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}
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return int(f), true
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}
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// placeholderWhere parses the narrowing part of a placeholder, `bar=bottom,place=status`, against the
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// kind's shape. Empty narrows nothing.
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func placeholderWhere(r Receivable, where string) (map[string]string, error) {
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out := map[string]string{}
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if where == "" {
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return out, nil
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}
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if r.Shape == nil {
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return nil, fmt.Errorf("%s is text, which a placeholder does not narrow", r.Kind)
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}
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for _, pair := range strings.Split(where, ",") {
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field, value, ok := strings.Cut(pair, "=")
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var p *PlaceField
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for i := range r.Shape.Places {
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if r.Shape.Places[i].Field == field {
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p = &r.Shape.Places[i]
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}
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}
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switch {
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case !ok || p == nil:
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return nil, fmt.Errorf("%q narrows by %s, and %s is placed by %s", where, field, r.Kind, placeFields(r))
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case !oneOf(p.Values, value):
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return nil, fmt.Errorf("%q says %s=%s; %s is one of %s", where, field, value, field, strings.Join(p.Values, ", "))
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case out[field] != "":
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return nil, fmt.Errorf("%q names %s twice", where, field)
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}
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out[field] = value
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}
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return out, nil
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}
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func placeFields(r Receivable) string {
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var names []string
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for _, p := range r.Shape.Places {
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names = append(names, p.Field)
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}
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return strings.Join(names, ", ")
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}
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// holderTemplate is the holder's template for a kind, parsed.
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func holderTemplate(holder Manifest, seat Seat, kind string) (*template.Template, error) {
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for _, c := range holder.Claims {
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if s, known := SeatNamed(c.Name); !known || s.Name != seat.Name {
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continue
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}
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text, has := c.Renders[kind]
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if !has || strings.TrimSpace(text) == "" {
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break
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}
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t, err := template.New(seat.Name + ":" + kind).Funcs(renderFuncs).Parse(text)
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if err != nil {
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return nil, fmt.Errorf("%s's template for %s:%s does not parse: %v", holder.Module, seat.Name, kind, err)
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}
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return t, nil
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}
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return nil, fmt.Errorf("%s places %s:%s, which is data, and its claim gives no template for it in `renders` "+
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"(novox/hq ADR 0255)", holder.Module, seat.Name, kind)
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}
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// renderPiece is one piece of data in the holder's grammar. The template sees the piece's fields and
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// `module`, the contributor. A value the piece does not have reads as nothing in a `with` or an `if`;
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// printed bare it would write `<no value>` into the tool's file, which is refused here instead.
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func renderPiece(t *template.Template, module string, data map[string]any) (string, error) {
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view := map[string]any{"module": module}
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for k, v := range data {
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view[k] = v
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}
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var b bytes.Buffer
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if err := t.Execute(&b, view); err != nil {
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return "", fmt.Errorf("rendering %s's piece: %v", module, err)
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}
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out := b.String()
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if strings.Contains(out, "<no value>") {
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return "", fmt.Errorf("rendering %s's piece printed a value it does not have: %q", module, out)
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}
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return out, nil
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}
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// placedPiece is one contributed piece on its way into a holder's file.
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type placedPiece struct {
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module string
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data map[string]any
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order int
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}
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// shapedContributions is every module's data of one kind to one seat, narrowed by where and by the
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// machine's capabilities, ordered, and rendered through the holder's template — each piece under a
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// comment line naming its module.
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func shapedContributions(modules []Manifest, holder Manifest, s Seat, r Receivable, where map[string]string, caps map[string]bool) (string, error) {
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var pieces []placedPiece
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for _, m := range inModuleOrder(modules) {
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for _, c := range m.allContributions() {
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if c.Kind != r.Kind || !capable(c, caps) {
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continue
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}
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if cs, known := SeatNamed(c.Seat); !known || cs.Name != s.Name {
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continue
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}
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match := true
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for field, value := range where {
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if v, _ := c.Data[field].(string); v != value {
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match = false
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}
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}
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if !match {
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continue
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}
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order := OrderDefault
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if v, ok := wholeIn(c.Data[r.Shape.Order], 0, 99); ok {
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order = v
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}
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pieces = append(pieces, placedPiece{module: m.Module, data: c.Data, order: order})
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}
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}
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if len(pieces) == 0 {
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return "", nil
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}
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t, err := holderTemplate(holder, s, r.Kind)
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if err != nil {
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return "", err
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}
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sort.SliceStable(pieces, func(a, b int) bool { return pieces[a].order < pieces[b].order })
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var b strings.Builder
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for _, p := range pieces {
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out, err := renderPiece(t, p.module, p.data)
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if err != nil {
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return "", err
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}
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fmt.Fprintf(&b, "%s %s\n", r.Comment, p.module)
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b.WriteString(out)
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if !strings.HasSuffix(out, "\n") {
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b.WriteString("\n")
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}
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}
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return b.String(), nil
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}
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// capable is whether a contribution applies on a machine with these capabilities: always, unless it
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// names one with `if-capability` the machine did not report (novox/hq ADR 0255). A machine whose
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// capabilities are not known has none, so a conditional piece is left out rather than guessed in.
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func capable(c SeatContribution, caps map[string]bool) bool {
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return c.IfCapability == "" || caps[c.IfCapability]
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}
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// placementProblems is what is wrong with how a holder places the kinds its seats receive as data:
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// once it places one at all, it needs a template that renders every example of the shape, and every combination of the placing
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// fields placed exactly once across its files — or something contributed would be dropped, or written
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// twice (novox/hq ADR 0255).
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func (m Manifest) placementProblems() []string {
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var problems []string
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for _, c := range m.Claims {
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s, known := SeatNamed(c.Name)
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if !known {
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continue
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}
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for _, r := range s.Receives {
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// A holder that places none of the kind is older than it (novox/hq ADR 0255): refusing it
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// would refuse every bar registered before the kind existed, and the controller that
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// defines the kind ships first. Its contributions wait, unplaced, until it places them.
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if r.Shape == nil || !placesKind(m, s, r.Kind) {
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continue
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}
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t, err := holderTemplate(m, s, r.Kind)
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if err != nil {
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problems = append(problems, err.Error())
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continue
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}
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for _, ex := range r.Shape.Examples {
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if out, err := renderPiece(t, "example", ex); err != nil || strings.TrimSpace(out) == "" {
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problems = append(problems, fmt.Sprintf("%s's template for %s:%s renders nothing for %v: %v",
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m.Module, s.Name, r.Kind, ex, err))
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}
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}
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placed := map[string]int{}
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for _, res := range m.Resources {
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content, _ := res["content"].(string)
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for _, f := range ofContribution.FindAllStringSubmatch(content, -1) {
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seat, rest, _ := strings.Cut(f[1], ":")
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kind, whereText, _ := strings.Cut(rest, ":")
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if cs, ok := SeatNamed(seat); !ok || cs.Name != s.Name || kind != r.Kind {
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continue
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}
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where, err := placeholderWhere(r, whereText)
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if err != nil {
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continue // said by seatPlaceholderProblems
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}
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for _, combo := range combinations(r.Shape.Places) {
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if covers(where, combo) {
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placed[comboKey(combo)]++
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}
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}
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}
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}
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for _, combo := range combinations(r.Shape.Places) {
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switch n := placed[comboKey(combo)]; {
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case n == 0:
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problems = append(problems, fmt.Sprintf("%s never places %s:%s for %s; every combination of %s is "+
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"placed once, or a contribution to it is lost (novox/hq ADR 0255)",
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m.Module, s.Name, r.Kind, comboKey(combo), placeFields(r)))
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case n > 1:
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problems = append(problems, fmt.Sprintf("%s places %s:%s for %s %d times; once, or a contribution "+
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"is written twice (novox/hq ADR 0255)", m.Module, s.Name, r.Kind, comboKey(combo), n))
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}
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}
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}
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}
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return problems
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}
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// placesKind is whether any of a holder's files names the kind's placeholder.
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func placesKind(m Manifest, s Seat, kind string) bool {
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for _, res := range m.Resources {
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content, _ := res["content"].(string)
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for _, f := range ofContribution.FindAllStringSubmatch(content, -1) {
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seat, rest, _ := strings.Cut(f[1], ":")
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k, _, _ := strings.Cut(rest, ":")
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if cs, ok := SeatNamed(seat); ok && cs.Name == s.Name && k == kind {
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return true
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}
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}
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}
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return false
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}
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// combinations is every assignment of a value to each placing field.
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func combinations(places []PlaceField) []map[string]string {
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out := []map[string]string{{}}
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for _, p := range places {
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var next []map[string]string
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for _, partial := range out {
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for _, v := range p.Values {
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c := map[string]string{p.Field: v}
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for k, w := range partial {
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c[k] = w
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}
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next = append(next, c)
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}
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}
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out = next
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}
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return out
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}
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func covers(where, combo map[string]string) bool {
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for field, value := range where {
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if combo[field] != value {
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return false
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}
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}
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return true
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}
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func comboKey(combo map[string]string) string {
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var parts []string
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for _, k := range sortedKeys(combo) {
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parts = append(parts, k+"="+combo[k])
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}
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return strings.Join(parts, ",")
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}
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Reference in New Issue
Block a user