Initial structure

internal/checks/probe.go

@@ -0,0 +1,65 @@
+// Package checks runs the configured HTTP/TCP/ICMP probes on every
+// node and aggregates per-check results on the master.
+//
+// Probers are the small "do one round of work" units. The Scheduler
+// drives them on a per-check timer and ships each result back to the
+// master via the inter-node transport. The Aggregator (master only)
+// folds incoming results into per-check sliding windows and decides
+// when a check has crossed UP↔DOWN.
+package checks
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/jasper/quptime/internal/config"
+)
+
+// Result is the outcome of a single probe.
+type Result struct {
+	CheckID   string
+	OK        bool
+	Detail    string
+	Latency   time.Duration
+	Timestamp time.Time
+}
+
+// Prober runs one probe of a configured check.
+type Prober interface {
+	Probe(ctx context.Context, c *config.Check) Result
+}
+
+// Run dispatches to the right Prober for the given check type. Returns
+// an error result instead of failing when a check has unknown type.
+func Run(ctx context.Context, c *config.Check) Result {
+	deadline := c.Timeout
+	if deadline <= 0 {
+		deadline = 10 * time.Second
+	}
+	pctx, cancel := context.WithTimeout(ctx, deadline)
+	defer cancel()
+
+	var p Prober
+	switch c.Type {
+	case config.CheckHTTP:
+		p = httpProber{}
+	case config.CheckTCP:
+		p = tcpProber{}
+	case config.CheckICMP:
+		p = icmpProber{}
+	default:
+		return Result{
+			CheckID:   c.ID,
+			OK:        false,
+			Detail:    fmt.Sprintf("unknown check type %q", c.Type),
+			Timestamp: time.Now().UTC(),
+		}
+	}
+	res := p.Probe(pctx, c)
+	res.CheckID = c.ID
+	if res.Timestamp.IsZero() {
+		res.Timestamp = time.Now().UTC()
+	}
+	return res
+}