Documentation
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Overview ¶
Package composition is the ADR-0019 S4 composition root (endgame P4): the ONE place tq's runtime meets go-cqrs-lite's system/ package. It builds system.New over a durable sqlite engine at the projection home (<db>.readmodel.db) with an EMPTY domain BY DESIGN — the queue engine's fact journal IS the journal since S2, so system's own event adapter stays unused (no second source of truth; the split-brain gate of the archived composition map §3).
What the System owns here (the map's sanctioned shape):
- the projection-home engine (deployment decision, one DeploymentConfig place: swap sqlite -> postgres by editing Engines, never domain code);
- close ordering for the surfaces that adopt it (GracefulClose after the runactor actors stop — serve today, per §4c "adopt per surface");
- the growth seam: timers (§4a ruled: sweeper ticking STAYS runactor until a genuinely timer-shaped feature lands), deciders, and system.Lookup/metaengine query declarations attach to THIS root.
What it deliberately does NOT own: the tq queue.Store (S1's thin-driver seam, injected as today), the worker claim loops, the sweepers, and the readmodel's fold projector (a tq-side projection over the QUEUE journal; its collections live on the same projection-home file through their own metaengine Plan).
Index ¶
Constants ¶
const DefaultEngineName = "projections"
DefaultEngineName is the projection-home engine's deployment name.
Variables ¶
This section is empty.
Functions ¶
Types ¶
type ProjectionRuntime ¶ added in v0.3.4
type ProjectionRuntime struct {
Model *readmodel.Model
Host *readmodel.ProjectionHost
// contains filtered or unexported fields
}
ProjectionRuntime bundles the ADR-0019 S3 fold surfaces one serve run owns: the model, the poison-fact sidecar (nil when it could not be opened — warn-and-continue), and the managed projection host. Close tears them down in LIFO order (host stop+close, sidecar, model), the ordering the serve wiring previously hand-rolled with stacked defers.
func NewProjectionRuntime ¶ added in v0.3.4
func NewProjectionRuntime(ctx context.Context, src queue.Store, modelPath string) (*ProjectionRuntime, error)
NewProjectionRuntime composes the projection runtime for the projection home at modelPath over the queue journal (src): open the model with a durable cursor, best-effort the DLQ sidecar beside it, and build the managed host wired with the sidecar. Starting stays the caller's job (Host.Start) so the runactor actor keeps its own lifecycle; on a build error nothing is left open.
func (*ProjectionRuntime) Close ¶ added in v0.3.4
func (r *ProjectionRuntime) Close() error
Close releases the runtime in reverse construction order: host stop and close, then the DLQ sidecar, then the model. Safe to call once; the serve wiring defers it exactly where its stacked defers used to live.
Source Files