refactor: improved config initialization flow, add agent config

internal/config/config.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"context"
+	"errors"
 	"os"
 	"strconv"
 	"strings"
@@ -11,11 +12,11 @@ import (
 	"github.com/yusing/go-proxy/internal/api"
 	"github.com/yusing/go-proxy/internal/autocert"
 	"github.com/yusing/go-proxy/internal/common"
-	"github.com/yusing/go-proxy/internal/config/types"
+	config "github.com/yusing/go-proxy/internal/config/types"
 	"github.com/yusing/go-proxy/internal/entrypoint"
 	"github.com/yusing/go-proxy/internal/gperr"
 	"github.com/yusing/go-proxy/internal/logging"
-	"github.com/yusing/go-proxy/internal/net/http/server"
+	"github.com/yusing/go-proxy/internal/net/gphttp/server"
 	"github.com/yusing/go-proxy/internal/notif"
 	proxy "github.com/yusing/go-proxy/internal/route/provider"
 	"github.com/yusing/go-proxy/internal/task"
@@ -26,7 +27,7 @@ import (
 )
 
 type Config struct {
-	value            *types.Config
+	value            *config.Config
 	providers        F.Map[string, *proxy.Provider]
 	autocertProvider *autocert.Provider
 	entrypoint       *entrypoint.Entrypoint
@@ -35,7 +36,6 @@ type Config struct {
 }
 
 var (
-	instance   *Config
 	cfgWatcher watcher.Watcher
 	reloadMu   sync.Mutex
 )
@@ -49,15 +49,11 @@ Make sure you rename it back before next time you start.`
 You may run "ls-config" to show or dump the current config.`
 )
 
-var Validate = types.Validate
-
-func GetInstance() *Config {
-	return instance
-}
+var Validate = config.Validate
 
 func newConfig() *Config {
 	return &Config{
-		value:      types.DefaultConfig(),
+		value:      config.DefaultConfig(),
 		providers:  F.NewMapOf[string, *proxy.Provider](),
 		entrypoint: entrypoint.NewEntrypoint(),
 		task:       task.RootTask("config", false),
@@ -65,16 +61,17 @@ func newConfig() *Config {
 }
 
 func Load() (*Config, gperr.Error) {
-	if instance != nil {
-		return instance, nil
+	if config.HasInstance() {
+		panic(errors.New("config already loaded"))
 	}
-	instance = newConfig()
+	cfg := newConfig()
+	config.SetInstance(cfg)
 	cfgWatcher = watcher.NewConfigFileWatcher(common.ConfigFileName)
-	return instance, instance.load()
+	return cfg, cfg.load()
 }
 
 func MatchDomains() []string {
-	return instance.value.MatchDomains
+	return config.GetInstance().Value().MatchDomains
 }
 
 func WatchChanges() {
@@ -122,22 +119,25 @@ func Reload() gperr.Error {
 
 	// cancel all current subtasks -> wait
 	// -> replace config -> start new subtasks
-	instance.task.Finish("config changed")
-	instance = newCfg
-	instance.Start(StartAllServers)
+	config.GetInstance().(*Config).Task().Finish("config changed")
+	newCfg.Start(StartAllServers)
+	config.SetInstance(newCfg)
 	return nil
 }
 
-func (cfg *Config) Value() *types.Config {
-	return instance.value
+func (cfg *Config) Value() *config.Config {
+	return cfg.value
 }
 
 func (cfg *Config) Reload() gperr.Error {
 	return Reload()
 }
 
+// AutoCertProvider returns the autocert provider.
+//
+// If the autocert provider is not configured, it returns nil.
 func (cfg *Config) AutoCertProvider() *autocert.Provider {
-	return instance.autocertProvider
+	return cfg.autocertProvider
 }
 
 func (cfg *Config) Task() *task.Task {
@@ -217,7 +217,7 @@ func (cfg *Config) load() gperr.Error {
 		gperr.LogFatal(errMsg, err)
 	}
 
-	model := types.DefaultConfig()
+	model := config.DefaultConfig()
 	if err := utils.DeserializeYAML(data, model); err != nil {
 		gperr.LogFatal(errMsg, err)
 	}
@@ -260,31 +260,65 @@ func (cfg *Config) initAutoCert(autocertCfg *autocert.AutocertConfig) (err gperr
 	return
 }
 
-func (cfg *Config) loadRouteProviders(providers *config.Providers) gperr.Error {
+func (cfg *Config) errIfExists(p *proxy.Provider) gperr.Error {
+	if _, ok := cfg.providers.Load(p.String()); ok {
+		return gperr.Errorf("provider %s already exists", p.String())
+	}
+	return nil
+}
 
-	lenLongestName := 0
+func (cfg *Config) storeProvider(p *proxy.Provider) {
+	cfg.providers.Store(p.String(), p)
+}
+
+func (cfg *Config) loadRouteProviders(providers *config.Providers) gperr.Error {
+	errs := gperr.NewBuilder("route provider errors")
+	results := gperr.NewBuilder("loaded route providers")
+
+	removeAllAgents()
+
+	for _, agent := range providers.Agents {
+		if err := agent.Start(cfg.task); err != nil {
+			errs.Add(err.Subject(agent.String()))
+			continue
+		}
+		addAgent(agent)
+		p := proxy.NewAgentProvider(agent)
+		if err := cfg.errIfExists(p); err != nil {
+			errs.Add(err.Subject(p.String()))
+			continue
+		}
+		cfg.storeProvider(p)
+	}
 	for _, filename := range providers.Files {
 		p, err := proxy.NewFileProvider(filename)
+		if err == nil {
+			err = cfg.errIfExists(p)
+		}
 		if err != nil {
-			errs.Add(E.PrependSubject(filename, err))
+			errs.Add(gperr.PrependSubject(filename, err))
 			continue
 		}
-		cfg.providers.Store(p.String(), p)
-		if len(p.String()) > lenLongestName {
-			lenLongestName = len(p.String())
-		}
+		cfg.storeProvider(p)
 	}
 	for name, dockerHost := range providers.Docker {
-		p, err := proxy.NewDockerProvider(name, dockerHost)
-		if err != nil {
-			errs.Add(E.PrependSubject(name, err))
+		p := proxy.NewDockerProvider(name, dockerHost)
+		if err := cfg.errIfExists(p); err != nil {
+			errs.Add(err.Subject(p.String()))
 			continue
 		}
-		cfg.providers.Store(p.String(), p)
-		if len(p.String()) > lenLongestName {
-			lenLongestName = len(p.String())
-		}
+		cfg.storeProvider(p)
 	}
+	if cfg.providers.Size() == 0 {
+		return nil
+	}
+
+	lenLongestName := 0
+	cfg.providers.RangeAll(func(k string, _ *proxy.Provider) {
+		if len(k) > lenLongestName {
+			lenLongestName = len(k)
+		}
+	})
 	cfg.providers.RangeAllParallel(func(_ string, p *proxy.Provider) {
 		if err := p.LoadRoutes(); err != nil {
 			errs.Add(err.Subject(p.String()))