Implement target selection, autodiscovery via aggregator, implement listTargets

cmd/aggregator/registry.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"sort"
+	"sync"
+)
+
+// TargetInfo holds the display name and gRPC address of one collector target.
+type TargetInfo struct {
+	Name string // collector --source value, falls back to addr until first snapshot
+	Addr string // configured gRPC address
+}
+
+// TargetRegistry tracks addr → display name for all configured collectors.
+// Names default to the addr and are updated to the collector's --source value
+// when the first snapshot arrives.
+type TargetRegistry struct {
+	mu    sync.RWMutex
+	names map[string]string // addr → current name
+}
+
+func NewTargetRegistry(addrs []string) *TargetRegistry {
+	names := make(map[string]string, len(addrs))
+	for _, a := range addrs {
+		names[a] = a // default until first snapshot
+	}
+	return &TargetRegistry{names: names}
+}
+
+// SetName updates the display name for addr (called when a snapshot arrives).
+func (r *TargetRegistry) SetName(addr, name string) {
+	r.mu.Lock()
+	r.names[addr] = name
+	r.mu.Unlock()
+}
+
+// Targets returns all registered targets sorted by addr.
+func (r *TargetRegistry) Targets() []TargetInfo {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	out := make([]TargetInfo, 0, len(r.names))
+	for addr, name := range r.names {
+		out = append(out, TargetInfo{Name: name, Addr: addr})
+	}
+	sort.Slice(out, func(i, j int) bool { return out[i].Addr < out[j].Addr })
+	return out
+}