refactor(agent): extract agent pool and HTTP utilities to dedicated package

Moved non-agent-specific logic from agent/pkg/agent/ to internal/agentpool/:
- pool.go: Agent pool management (Get, Add, Remove, List, Iter, etc.)
- http_requests.go: HTTP utilities (health checks, forwarding, websockets, reverse proxy)
- agent.go: Agent struct with HTTP client management

This separates general-purpose pool management from agent-specific configuration,
improving code organization and making the agent package focused on agent config only.

internal/agentpool/agent.go

@@ -0,0 +1,54 @@
+package agentpool
+
+import (
+	"net"
+	"net/http"
+	"time"
+
+	"github.com/valyala/fasthttp"
+	"github.com/yusing/godoxy/agent/pkg/agent"
+)
+
+type Agent struct {
+	*agent.AgentConfig
+
+	httpClient       *http.Client
+	fasthttpHcClient *fasthttp.Client
+}
+
+func newAgent(cfg *agent.AgentConfig) *Agent {
+	transport := cfg.Transport()
+	transport.MaxIdleConns = 100
+	transport.MaxIdleConnsPerHost = 100
+	transport.ReadBufferSize = 16384
+	transport.WriteBufferSize = 16384
+
+	return &Agent{
+		AgentConfig: cfg,
+		httpClient: &http.Client{
+			Transport: transport,
+		},
+		fasthttpHcClient: &fasthttp.Client{
+			DialTimeout: func(addr string, timeout time.Duration) (net.Conn, error) {
+				if addr != agent.AgentHost+":443" {
+					return nil, &net.AddrError{Err: "invalid address", Addr: addr}
+				}
+				return net.DialTimeout("tcp", cfg.Addr, timeout)
+			},
+			TLSConfig:                     cfg.TLSConfig(),
+			ReadTimeout:                   5 * time.Second,
+			WriteTimeout:                  3 * time.Second,
+			DisableHeaderNamesNormalizing: true,
+			DisablePathNormalizing:        true,
+			NoDefaultUserAgentHeader:      true,
+			ReadBufferSize:                1024,
+			WriteBufferSize:               1024,
+		},
+	}
+}
+
+func (agent *Agent) HTTPClient() *http.Client {
+	return &http.Client{
+		Transport: agent.Transport(),
+	}
+}

internal/agentpool/http_requests.go

@@ -0,0 +1,96 @@
+package agentpool
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"github.com/bytedance/sonic"
+	"github.com/gorilla/websocket"
+	"github.com/valyala/fasthttp"
+	"github.com/yusing/godoxy/agent/pkg/agent"
+	"github.com/yusing/goutils/http/reverseproxy"
+)
+
+func (cfg *Agent) Do(ctx context.Context, method, endpoint string, body io.Reader) (*http.Response, error) {
+	req, err := http.NewRequestWithContext(ctx, method, agent.APIBaseURL+endpoint, body)
+	if err != nil {
+		return nil, err
+	}
+	return cfg.httpClient.Do(req)
+}
+
+func (cfg *Agent) Forward(req *http.Request, endpoint string) (*http.Response, error) {
+	req.URL.Host = agent.AgentHost
+	req.URL.Scheme = "https"
+	req.URL.Path = agent.APIEndpointBase + endpoint
+	req.RequestURI = ""
+	resp, err := cfg.httpClient.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	return resp, nil
+}
+
+type HealthCheckResponse struct {
+	Healthy bool          `json:"healthy"`
+	Detail  string        `json:"detail"`
+	Latency time.Duration `json:"latency"`
+}
+
+func (cfg *Agent) DoHealthCheck(timeout time.Duration, query string) (ret HealthCheckResponse, err error) {
+	req := fasthttp.AcquireRequest()
+	defer fasthttp.ReleaseRequest(req)
+
+	resp := fasthttp.AcquireResponse()
+	defer fasthttp.ReleaseResponse(resp)
+
+	req.SetRequestURI(agent.APIBaseURL + agent.EndpointHealth + "?" + query)
+	req.Header.SetMethod(fasthttp.MethodGet)
+	req.Header.Set("Accept-Encoding", "identity")
+	req.SetConnectionClose()
+
+	start := time.Now()
+	err = cfg.fasthttpHcClient.DoTimeout(req, resp, timeout)
+	ret.Latency = time.Since(start)
+	if err != nil {
+		return ret, err
+	}
+
+	if status := resp.StatusCode(); status != http.StatusOK {
+		ret.Detail = fmt.Sprintf("HTTP %d %s", status, resp.Body())
+		return ret, nil
+	} else {
+		err = sonic.Unmarshal(resp.Body(), &ret)
+		if err != nil {
+			return ret, err
+		}
+	}
+	return ret, nil
+}
+
+func (cfg *Agent) Websocket(ctx context.Context, endpoint string) (*websocket.Conn, *http.Response, error) {
+	transport := cfg.Transport()
+	dialer := websocket.Dialer{
+		NetDialContext:    transport.DialContext,
+		NetDialTLSContext: transport.DialTLSContext,
+	}
+	return dialer.DialContext(ctx, agent.APIBaseURL+endpoint, http.Header{
+		"Host": {agent.AgentHost},
+	})
+}
+
+// ReverseProxy reverse proxies the request to the agent
+//
+// It will create a new request with the same context, method, and body, but with the agent host and scheme, and the endpoint
+// If the request has a query, it will be added to the proxy request's URL
+func (cfg *Agent) ReverseProxy(w http.ResponseWriter, req *http.Request, endpoint string) {
+	rp := reverseproxy.NewReverseProxy("agent", agent.AgentURL, cfg.Transport())
+	req.URL.Host = agent.AgentHost
+	req.URL.Scheme = "https"
+	req.URL.Path = endpoint
+	req.RequestURI = ""
+	rp.ServeHTTP(w, req)
+}

internal/agentpool/pool.go

@@ -0,0 +1,79 @@
+package agentpool
+
+import (
+	"iter"
+	"os"
+	"strings"
+
+	"github.com/puzpuzpuz/xsync/v4"
+	"github.com/yusing/godoxy/agent/pkg/agent"
+)
+
+var agentPool = xsync.NewMap[string, *Agent](xsync.WithPresize(10))
+
+func init() {
+	if strings.HasSuffix(os.Args[0], ".test") {
+		agentPool.Store("test-agent", &Agent{
+			AgentConfig: &agent.AgentConfig{
+				Addr: "test-agent",
+			},
+		})
+	}
+}
+
+func Get(agentAddrOrDockerHost string) (*Agent, bool) {
+	if !agent.IsDockerHostAgent(agentAddrOrDockerHost) {
+		return getAgentByAddr(agentAddrOrDockerHost)
+	}
+	return getAgentByAddr(agent.GetAgentAddrFromDockerHost(agentAddrOrDockerHost))
+}
+
+func GetAgent(name string) (*Agent, bool) {
+	for _, agent := range agentPool.Range {
+		if agent.Name == name {
+			return agent, true
+		}
+	}
+	return nil, false
+}
+
+func Add(cfg *agent.AgentConfig) (added bool) {
+	_, loaded := agentPool.LoadOrCompute(cfg.Addr, func() (*Agent, bool) {
+		return newAgent(cfg), false
+	})
+	return !loaded
+}
+
+func Has(cfg *agent.AgentConfig) bool {
+	_, ok := agentPool.Load(cfg.Addr)
+	return ok
+}
+
+func Remove(cfg *agent.AgentConfig) {
+	agentPool.Delete(cfg.Addr)
+}
+
+func RemoveAll() {
+	agentPool.Clear()
+}
+
+func List() []*Agent {
+	agents := make([]*Agent, 0, agentPool.Size())
+	for _, agent := range agentPool.Range {
+		agents = append(agents, agent)
+	}
+	return agents
+}
+
+func Iter() iter.Seq2[string, *Agent] {
+	return agentPool.Range
+}
+
+func Num() int {
+	return agentPool.Size()
+}
+
+func getAgentByAddr(addr string) (agent *Agent, ok bool) {
+	agent, ok = agentPool.Load(addr)
+	return agent, ok
+}