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/api/v1/agent/create.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/gin-gonic/gin"
 	"github.com/yusing/godoxy/agent/pkg/agent"
+	"github.com/yusing/godoxy/internal/agentpool"
 	apitypes "github.com/yusing/goutils/apitypes"
 )
 
@@ -50,7 +51,7 @@ func Create(c *gin.Context) {
 	}
 
 	hostport := net.JoinHostPort(request.Host, strconv.Itoa(request.Port))
-	if _, ok := agent.GetAgent(hostport); ok {
+	if _, ok := agentpool.Get(hostport); ok {
 		c.JSON(http.StatusConflict, apitypes.Error("agent already exists"))
 		return
 	}

internal/api/v1/agent/list.go

@@ -5,7 +5,7 @@ import (
 	"time"
 
 	"github.com/gin-gonic/gin"
-	"github.com/yusing/godoxy/agent/pkg/agent"
+	"github.com/yusing/godoxy/internal/agentpool"
 	"github.com/yusing/goutils/http/httpheaders"
 	"github.com/yusing/goutils/http/websocket"
 
@@ -19,15 +19,15 @@ import (
 // @Tags			agent,websocket
 // @Accept			json
 // @Produce		json
-// @Success		200	{array}		Agent
+// @Success		200	{array}		agent.AgentConfig
 // @Failure		403	{object}	apitypes.ErrorResponse
 // @Router			/agent/list [get]
 func List(c *gin.Context) {
 	if httpheaders.IsWebsocket(c.Request.Header) {
 		websocket.PeriodicWrite(c, 10*time.Second, func() (any, error) {
-			return agent.ListAgents(), nil
+			return agentpool.List(), nil
 		})
 	} else {
-		c.JSON(http.StatusOK, agent.ListAgents())
+		c.JSON(http.StatusOK, agentpool.List())
 	}
 }

internal/api/v1/agent/verify.go

@@ -8,6 +8,7 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/yusing/godoxy/agent/pkg/agent"
 	"github.com/yusing/godoxy/agent/pkg/certs"
+	"github.com/yusing/godoxy/internal/agentpool"
 	config "github.com/yusing/godoxy/internal/config/types"
 	"github.com/yusing/godoxy/internal/route/provider"
 	apitypes "github.com/yusing/goutils/apitypes"
@@ -79,21 +80,28 @@ func Verify(c *gin.Context) {
 	c.JSON(http.StatusOK, apitypes.Success(fmt.Sprintf("Added %d routes", nRoutesAdded)))
 }
 
-func verifyNewAgent(host string, ca agent.PEMPair, client agent.PEMPair, containerRuntime agent.ContainerRuntime) (int, gperr.Error) {
-	cfgState := config.ActiveState.Load()
-	for _, a := range cfgState.Value().Providers.Agents {
-		if a.Addr == host {
-			return 0, gperr.New("agent already exists")
-		}
-	}
+var errAgentAlreadyExists = gperr.New("agent already exists")
 
+func verifyNewAgent(host string, ca agent.PEMPair, client agent.PEMPair, containerRuntime agent.ContainerRuntime) (int, gperr.Error) {
 	var agentCfg agent.AgentConfig
 	agentCfg.Addr = host
 	agentCfg.Runtime = containerRuntime
 
-	err := agentCfg.StartWithCerts(cfgState.Context(), ca.Cert, client.Cert, client.Key)
+	// check if agent host exists in the config
+	cfgState := config.ActiveState.Load()
+	for _, a := range cfgState.Value().Providers.Agents {
+		if a.Addr == host {
+			return 0, errAgentAlreadyExists
+		}
+	}
+	// check if agent host exists in the agent pool
+	if agentpool.Has(&agentCfg) {
+		return 0, errAgentAlreadyExists
+	}
+
+	err := agentCfg.InitWithCerts(cfgState.Context(), ca.Cert, client.Cert, client.Key)
 	if err != nil {
-		return 0, gperr.Wrap(err, "failed to start agent")
+		return 0, gperr.Wrap(err, "failed to initialize agent config")
 	}
 
 	provider := provider.NewAgentProvider(&agentCfg)
@@ -102,11 +110,14 @@ func verifyNewAgent(host string, ca agent.PEMPair, client agent.PEMPair, contain
 	}
 
 	// agent must be added before loading routes
-	agent.AddAgent(&agentCfg)
+	added := agentpool.Add(&agentCfg)
+	if !added {
+		return 0, errAgentAlreadyExists
+	}
 	err = provider.LoadRoutes()
 	if err != nil {
 		cfgState.DeleteProvider(provider.String())
-		agent.RemoveAgent(&agentCfg)
+		agentpool.Remove(&agentCfg)
 		return 0, gperr.Wrap(err, "failed to load routes")
 	}
 

internal/api/v1/metrics/all_system_info.go

@@ -11,6 +11,7 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/rs/zerolog/log"
 	"github.com/yusing/godoxy/agent/pkg/agent"
+	"github.com/yusing/godoxy/internal/agentpool"
 	"github.com/yusing/godoxy/internal/metrics/period"
 	"github.com/yusing/godoxy/internal/metrics/systeminfo"
 	apitypes "github.com/yusing/goutils/apitypes"
@@ -79,7 +80,7 @@ func AllSystemInfo(c *gin.Context) {
 	}
 
 	// leave 5 extra slots for buffering in case new agents are added.
-	dataCh := make(chan SystemInfoData, 1+agent.NumAgents()+5)
+	dataCh := make(chan SystemInfoData, 1+agentpool.Num()+5)
 	defer close(dataCh)
 
 	ticker := time.NewTicker(req.Interval)
@@ -125,7 +126,7 @@ func AllSystemInfo(c *gin.Context) {
 			return nil
 		})
 
-		for _, a := range agent.IterAgents() {
+		for _, a := range agentpool.Iter() {
 			totalAgents++
 
 			errs.Go(func() error {
@@ -175,7 +176,7 @@ func AllSystemInfo(c *gin.Context) {
 	}
 }
 
-func getAgentSystemInfo(ctx context.Context, a *agent.AgentConfig, query string) (bytesFromPool, error) {
+func getAgentSystemInfo(ctx context.Context, a *agentpool.Agent, query string) (bytesFromPool, error) {
 	ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
 	defer cancel()
 
@@ -194,7 +195,7 @@ func getAgentSystemInfo(ctx context.Context, a *agent.AgentConfig, query string)
 	return bytesFromPool{json.RawMessage(bytesBuf), release}, nil
 }
 
-func getAgentSystemInfoWithRetry(ctx context.Context, a *agent.AgentConfig, query string) (bytesFromPool, error) {
+func getAgentSystemInfoWithRetry(ctx context.Context, a *agentpool.Agent, query string) (bytesFromPool, error) {
 	const maxRetries = 3
 	var lastErr error
 

internal/api/v1/metrics/system_info.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/gin-gonic/gin"
 	agentPkg "github.com/yusing/godoxy/agent/pkg/agent"
+	"github.com/yusing/godoxy/internal/agentpool"
 	"github.com/yusing/godoxy/internal/metrics/period"
 	"github.com/yusing/godoxy/internal/metrics/systeminfo"
 	apitypes "github.com/yusing/goutils/apitypes"
@@ -49,9 +50,9 @@ func SystemInfo(c *gin.Context) {
 	}
 	c.Request.URL.RawQuery = query.Encode()
 
-	agent, ok := agentPkg.GetAgent(agentAddr)
+	agent, ok := agentpool.Get(agentAddr)
 	if !ok {
-		agent, ok = agentPkg.GetAgentByName(agentName)
+		agent, ok = agentpool.GetAgent(agentName)
 	}
 	if !ok {
 		c.JSON(http.StatusNotFound, apitypes.Error("agent_addr or agent_name not found"))