Method fillDynamicHost

modules/caddyhttp/reverseproxy/hosts.go:143–172

fillDynamicHost is like fillHost, but stores the host in the separate dynamicHosts map rather than the reference-counted UsagePool. Dynamic hosts are not reference-counted; instead, they are retained as long as they are actively seen and are evicted by a background cleanup goroutine after dynamicHos

()

// after dynamicHostIdleExpiry of inactivity. This preserves health state
// (e.g. passive fail counts) across sequential requests.
func (u *Upstream) fillDynamicHost() {
	dynamicHostsMu.Lock()
	entry, ok := dynamicHosts[u.String()]
	if ok {
		entry.lastSeen = time.Now()
		dynamicHosts[u.String()] = entry
		u.Host = entry.host
	} else {
		h := new(Host)
		dynamicHosts[u.String()] = dynamicHostEntry{host: h, lastSeen: time.Now()}
		u.Host = h
	}
	dynamicHostsMu.Unlock()

	// ensure the cleanup goroutine is running
	dynamicHostsCleanerOnce.Do(func() {
		go func() {
			for {
				time.Sleep(dynamicHostCleanupInterval)
				dynamicHostsMu.Lock()
				for addr, entry := range dynamicHosts {
					if time.Since(entry.lastSeen) > dynamicHostIdleExpiry {
						delete(dynamicHosts, addr)
					}
				}
				dynamicHostsMu.Unlock()
			}
		}()
	})
}

// Host is the basic, in-memory representation of the state of a remote host.
// Its fields are accessed atomically and Host values must not be copied.