logan
b98840ee37
The v3 migration put application.Get() in backend/events and a ServiceStartup hook in backend/explore, both of which cmd/indexbuild reaches. v3's application package is GTK/WebKit bindings on Linux, so the index-artifact job — a plain golang container with CGO_ENABLED=0, on the stated grounds that neither command imports the app — stopped compiling with "undefined: pointer". That job owns the ~205 GB dump checkpoint, so it is the worst place to learn this. Both are behind the indexbuild tag now: the one app.Event.Emit lives in runtime_wails.go, runtime_indexbuild.go answers ErrNoRuntime (what the app itself returns before Run, so Deliver's callers need no second path), and explore's ServiceStartup moves to its own tagged file. TestIndexToolsDoNotImportWails walks `go list -deps -tags indexbuild` so the claim the workflow makes is checked rather than assumed.
87 lines
2.8 KiB
Go
87 lines
2.8 KiB
Go
package events
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import (
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"context"
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"errors"
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"log/slog"
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)
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// ErrNoRuntime is returned by Deliver when there is neither a test Sink
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// in the context nor a running application, so the event went nowhere.
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var ErrNoRuntime = errors.New(
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"no Wails runtime or event sink in context",
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)
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// Sink receives events in place of the Wails runtime.
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//
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// Installing one with WithSink is what makes a service that emits
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// events testable in-process: see Deliver for why the real runtime
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// cannot be used there.
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type Sink interface {
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Emit(name string, data ...any)
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}
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// sinkKey is the private context key an installed Sink is stored under.
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type sinkKey struct{}
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// WithSink returns a context whose events are recorded by sink rather
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// than pushed to the frontend.
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//
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// The sink travels in the context rather than in a package-level
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// variable so that parallel tests cannot observe each other's events
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// and so that production emits pay no synchronisation cost.
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func WithSink(ctx context.Context, sink Sink) context.Context {
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return context.WithValue(ctx, sinkKey{}, sink)
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}
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// sinkFrom returns the Sink installed in ctx, or nil.
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func sinkFrom(ctx context.Context) Sink {
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sink, _ := ctx.Value(sinkKey{}).(Sink)
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return sink
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}
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// Emit publishes a Wails event, tolerating any context.
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//
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// This is the only supported way to emit an event: nothing outside this
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// package may call app.Event.Emit, which TestNoDirectRuntimeEmits
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// enforces. That rule outlived its original reason — v2's
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// runtime.EventsEmit called log.Fatalf on a context that did not carry
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// the runtime, taking the process down from any background worker —
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// and is kept because one emit path is what keeps emitStatus-style
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// deduplication honest.
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//
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// The context is no longer a delivery mechanism: v3's emit takes none.
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// It stays because WithSink travels in it, which is what makes a
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// service that emits events testable in-process.
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func Emit(ctx context.Context, name string, data ...any) {
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if err := Deliver(ctx, name, data...); err != nil {
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slog.Default().Debug(
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"dropping event, no Wails runtime in context",
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"event", name,
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)
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}
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}
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// Deliver is Emit for the one caller that must know whether delivery
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// happened: the dev control surface (backend/testctl), whose whole
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// purpose is to impersonate a backend emit and which would otherwise
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// report success for an event that went nowhere.
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//
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// Ordinary emitters want Emit.
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func Deliver(ctx context.Context, name string, data ...any) error {
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// A nil context cannot carry a sink, but it is no longer a reason
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// not to deliver: v3 emits through the application, not the context.
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if ctx != nil {
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if sink := sinkFrom(ctx); sink != nil {
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sink.Emit(name, data...)
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return nil
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}
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}
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// emitRuntime is the only place the Wails application is touched,
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// and it is behind a build tag: see runtime_wails.go.
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return emitRuntime(name, data...)
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}
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