switch to iterators and client polling

pkg/client/poll.go

@@ -0,0 +1,73 @@
+package client
+
+import (
+	"context"
+	"iter"
+	"time"
+
+	"gitea.libretechconsulting.com/rmcguire/wingbits/pkg/types/readsb"
+	"gitea.libretechconsulting.com/rmcguire/wingbits/pkg/types/wingbits"
+)
+
+// Poll turns any fetch into a pull-based stream: an iter.Seq2[R, error] that
+// yields a fresh result immediately, then once per interval, until ctx is
+// cancelled or the consumer breaks out of the range. Each step yields exactly
+// one of a value or the error from that poll.
+//
+// It is the engine behind every Poll* method, exported so the same cadence can
+// be applied to a custom or composed fetch without re-implementing the loop.
+// Because the iterator runs in the consumer's goroutine, breaking the range
+// stops polling immediately — there is no background goroutine to leak.
+func Poll[R any](ctx context.Context, interval time.Duration, fetch func(context.Context) (R, error)) iter.Seq2[R, error] {
+	return func(yield func(R, error) bool) {
+		tick := time.NewTicker(interval)
+		defer tick.Stop()
+		for {
+			if !yield(fetch(ctx)) {
+				return
+			}
+			select {
+			case <-ctx.Done():
+				return
+			case <-tick.C:
+			}
+		}
+	}
+}
+
+// PollAircraft polls aircraft.json every interval, applying the given filters.
+func (c *Client) PollAircraft(ctx context.Context, interval time.Duration, filters ...readsb.AircraftFilter) iter.Seq2[*readsb.AircraftReport, error] {
+	return Poll(ctx, interval, func(ctx context.Context) (*readsb.AircraftReport, error) {
+		return c.Aircraft(ctx, filters...)
+	})
+}
+
+// PollStats polls stats.json every interval.
+func (c *Client) PollStats(ctx context.Context, interval time.Duration) iter.Seq2[*readsb.Stats, error] {
+	return Poll(ctx, interval, c.Stats)
+}
+
+// PollReceiver polls receiver.json every interval.
+func (c *Client) PollReceiver(ctx context.Context, interval time.Duration) iter.Seq2[*readsb.Receiver, error] {
+	return Poll(ctx, interval, c.Receiver)
+}
+
+// PollOutline polls outline.json every interval.
+func (c *Client) PollOutline(ctx context.Context, interval time.Duration) iter.Seq2[*readsb.Outline, error] {
+	return Poll(ctx, interval, c.Outline)
+}
+
+// PollDiagnostics polls /network/diagnostics every interval.
+func (c *Client) PollDiagnostics(ctx context.Context, interval time.Duration) iter.Seq2[*wingbits.Diagnostics, error] {
+	return Poll(ctx, interval, c.Diagnostics)
+}
+
+// PollMetrics polls /metrics every interval.
+func (c *Client) PollMetrics(ctx context.Context, interval time.Duration) iter.Seq2[*wingbits.Metrics, error] {
+	return Poll(ctx, interval, c.Metrics)
+}
+
+// PollStatus polls the Tailscale status every interval.
+func (c *Client) PollStatus(ctx context.Context, interval time.Duration) iter.Seq2[*wingbits.TailscaleStatus, error] {
+	return Poll(ctx, interval, c.Status)
+}