Refactored server setup and run out of main (#425)

cmd/mc-router/main.go

@@ -3,70 +3,14 @@ package main
 import (
 	"context"
 	"fmt"
-	"net"
-	"os"
-	"os/signal"
-	"runtime/pprof"
-	"strconv"
-	"syscall"
-	"time"
-
 	"github.com/itzg/go-flagsfiller"
 	"github.com/itzg/mc-router/server"
 	"github.com/sirupsen/logrus"
+	"os"
+	"os/signal"
+	"syscall"
 )
 
-type WebhookConfig struct {
-	Url         string `usage:"If set, a POST request that contains connection status notifications will be sent to this HTTP address"`
-	RequireUser bool   `default:"false" usage:"Indicates if the webhook will only be called if a user is connecting rather than just server list/ping"`
-}
-
-type AutoScale struct {
-	Up        bool   `usage:"Increase Kubernetes StatefulSet Replicas (only) from 0 to 1 on respective backend servers when accessed"`
-	Down      bool   `default:"false" usage:"Decrease Kubernetes StatefulSet Replicas (only) from 1 to 0 on respective backend servers after there are no connections"`
-	DownAfter string `default:"10m" usage:"Server scale down delay after there are no connections"`
-	AllowDeny string `usage:"Path to config for server allowlists and denylists. If a global/server entry is specified, only players allowed to connect to the server will be able to trigger a scale up when -auto-scale-up is enabled or cancel active down scalers when -auto-scale-down is enabled"`
-}
-
-type RoutesConfig struct {
-	Config      string `usage:"Name or full [path] to routes config file"`
-	ConfigWatch bool   `usage:"Watch for config file changes"`
-}
-
-type Config struct {
-	Port                  int               `default:"25565" usage:"The [port] bound to listen for Minecraft client connections"`
-	Default               string            `usage:"host:port of a default Minecraft server to use when mapping not found"`
-	Mapping               map[string]string `usage:"Comma or newline delimited or repeated mappings of externalHostname=host:port"`
-	ApiBinding            string            `usage:"The [host:port] bound for servicing API requests"`
-	Version               bool              `usage:"Output version and exit"`
-	CpuProfile            string            `usage:"Enables CPU profiling and writes to given path"`
-	Debug                 bool              `usage:"Enable debug logs"`
-	ConnectionRateLimit   int               `default:"1" usage:"Max number of connections to allow per second"`
-	InKubeCluster         bool              `usage:"Use in-cluster Kubernetes config"`
-	KubeConfig            string            `usage:"The path to a Kubernetes configuration file"`
-	InDocker              bool              `usage:"Use Docker service discovery"`
-	InDockerSwarm         bool              `usage:"Use Docker Swarm service discovery"`
-	DockerSocket          string            `default:"unix:///var/run/docker.sock" usage:"Path to Docker socket to use"`
-	DockerTimeout         int               `default:"0" usage:"Timeout configuration in seconds for the Docker integrations"`
-	DockerRefreshInterval int               `default:"15" usage:"Refresh interval in seconds for the Docker integrations"`
-	MetricsBackend        string            `default:"discard" usage:"Backend to use for metrics exposure/publishing: discard,expvar,influxdb,prometheus"`
-	MetricsBackendConfig  server.MetricsBackendConfig
-	UseProxyProtocol      bool     `default:"false" usage:"Send PROXY protocol to backend servers"`
-	ReceiveProxyProtocol  bool     `default:"false" usage:"Receive PROXY protocol from backend servers, by default trusts every proxy header that it receives, combine with -trusted-proxies to specify a list of trusted proxies"`
-	TrustedProxies        []string `usage:"Comma delimited list of CIDR notation IP blocks to trust when receiving PROXY protocol"`
-	RecordLogins          bool     `default:"false" usage:"Log and generate metrics on player logins. Metrics only supported with influxdb or prometheus backend"`
-	Routes                RoutesConfig
-	NgrokToken            string `usage:"If set, an ngrok tunnel will be established. It is HIGHLY recommended to pass as an environment variable."`
-	AutoScale             AutoScale
-
-	ClientsToAllow []string `usage:"Zero or more client IP addresses or CIDRs to allow. Takes precedence over deny."`
-	ClientsToDeny  []string `usage:"Zero or more client IP addresses or CIDRs to deny. Ignored if any configured to allow"`
-
-	SimplifySRV bool `default:"false" usage:"Simplify fully qualified SRV records for mapping"`
-
-	Webhook WebhookConfig `usage:"Webhook configuration"`
-}
-
 var (
 	version = "dev"
 	commit  = "none"
@@ -77,190 +21,60 @@ func showVersion() {
 	fmt.Printf("%v, commit %v, built at %v", version, commit, date)
 }
 
+type CliConfig struct {
+	Version bool `usage:"Output version and exit"`
+	Debug   bool `usage:"Enable debug logs"`
+
+	ServerConfig server.Config `flatten:"true"`
+}
+
 func main() {
-	var config Config
+	var cliConfig CliConfig
-	err := flagsfiller.Parse(&config, flagsfiller.WithEnv(""))
+	err := flagsfiller.Parse(&cliConfig, flagsfiller.WithEnv(""))
 	if err != nil {
 		logrus.Fatal(err)
 	}
 
-	if config.Version {
+	if cliConfig.Version {
 		showVersion()
 		os.Exit(0)
 	}
 
-	if config.Debug {
+	if cliConfig.Debug {
 		logrus.SetLevel(logrus.DebugLevel)
 		logrus.Debug("Debug logs enabled")
 	}
 
-	if config.CpuProfile != "" {
-		cpuProfileFile, err := os.Create(config.CpuProfile)
-		if err != nil {
-			logrus.WithError(err).Fatal("trying to create cpu profile file")
-		}
-		//goland:noinspection GoUnhandledErrorResult
-		defer cpuProfileFile.Close()
-
-		logrus.WithField("file", config.CpuProfile).Info("Starting cpu profiling")
-		err = pprof.StartCPUProfile(cpuProfileFile)
-		if err != nil {
-			logrus.WithError(err).Fatal("trying to start cpu profile")
-		}
-		defer pprof.StopCPUProfile()
-	}
-
-	var autoScaleAllowDenyConfig *server.AllowDenyConfig = nil
-	if config.AutoScale.AllowDeny != "" {
-		autoScaleAllowDenyConfig, err = server.ParseAllowDenyConfig(config.AutoScale.AllowDeny)
-		if err != nil {
-			logrus.WithError(err).Fatal("trying to parse autoscale up allow-deny-list file")
-		}
-	}
-
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	metricsBuilder := server.NewMetricsBuilder(config.MetricsBackend, &config.MetricsBackendConfig)
+	signals := make(chan os.Signal, 1)
+	signal.Notify(signals, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
 
-	downScalerEnabled := config.AutoScale.Down && (config.InKubeCluster || config.KubeConfig != "")
+	s, err := server.NewServer(ctx, &cliConfig.ServerConfig)
-	downScalerDelay, err := time.ParseDuration(config.AutoScale.DownAfter)
 	if err != nil {
-		logrus.WithError(err).Fatal("Unable to parse auto scale down after duration")
+		logrus.WithError(err).Fatal("Could not setup server")
-	}
-	// Only one instance should be created
-	server.DownScaler = server.NewDownScaler(ctx, downScalerEnabled, downScalerDelay)
-
-	c := make(chan os.Signal, 1)
-	signal.Notify(c, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
-
-	if config.Routes.Config != "" {
-		err := server.RoutesConfigLoader.Load(config.Routes.Config)
-		if err != nil {
-			logrus.WithError(err).Fatal("Unable to load routes from config file")
-		}
-
-		if config.Routes.ConfigWatch {
-			err := server.RoutesConfigLoader.WatchForChanges(ctx)
-			if err != nil {
-				logrus.WithError(err).Fatal("Unable to watch for changes")
-			}
-		}
 	}
 
-	server.Routes.RegisterAll(config.Mapping)
+	go s.Run()
-	if config.Default != "" {
-		server.Routes.SetDefaultRoute(config.Default)
-	}
 
-	if config.ConnectionRateLimit < 1 {
-		config.ConnectionRateLimit = 1
-	}
-
-	trustedIpNets := make([]*net.IPNet, 0)
-	for _, ip := range config.TrustedProxies {
-		_, ipNet, err := net.ParseCIDR(ip)
-		if err != nil {
-			logrus.WithError(err).Fatal("Unable to parse trusted proxy CIDR block")
-		}
-		trustedIpNets = append(trustedIpNets, ipNet)
-	}
-
-	connector := server.NewConnector(metricsBuilder.BuildConnectorMetrics(), config.UseProxyProtocol, config.ReceiveProxyProtocol, trustedIpNets, config.RecordLogins, autoScaleAllowDenyConfig)
-
-	clientFilter, err := server.NewClientFilter(config.ClientsToAllow, config.ClientsToDeny)
-	if err != nil {
-		logrus.WithError(err).Fatal("Unable to create client filter")
-	}
-	connector.SetClientFilter(clientFilter)
-
-	if config.Webhook.Url != "" {
-		logrus.
-			WithField("url", config.Webhook.Url).
-			WithField("require-user", config.Webhook.RequireUser).
-			Info("Using webhook for connection status notifications")
-		connector.SetConnectionNotifier(
-			server.NewWebhookNotifier(config.Webhook.Url, config.Webhook.RequireUser))
-	}
-
-	if config.NgrokToken != "" {
-		connector.UseNgrok(config.NgrokToken)
-	}
-	err = connector.StartAcceptingConnections(ctx,
-		net.JoinHostPort("", strconv.Itoa(config.Port)),
-		config.ConnectionRateLimit,
-	)
-	if err != nil {
-		logrus.Fatal(err)
-	}
-
-	if config.ApiBinding != "" {
-		server.StartApiServer(config.ApiBinding)
-	}
-
-	if config.InKubeCluster {
-		err = server.K8sWatcher.StartInCluster(config.AutoScale.Up, config.AutoScale.Down)
-		if err != nil {
-			logrus.WithError(err).Fatal("Unable to start k8s integration")
-		} else {
-			defer server.K8sWatcher.Stop()
-		}
-	} else if config.KubeConfig != "" {
-		err := server.K8sWatcher.StartWithConfig(config.KubeConfig, config.AutoScale.Up, config.AutoScale.Down)
-		if err != nil {
-			logrus.WithError(err).Fatal("Unable to start k8s integration")
-		} else {
-			defer server.K8sWatcher.Stop()
-		}
-	}
-
-	if config.InDocker {
-		err = server.DockerWatcher.Start(config.DockerSocket, config.DockerTimeout, config.DockerRefreshInterval, config.AutoScale.Up, config.AutoScale.Down)
-		if err != nil {
-			logrus.WithError(err).Fatal("Unable to start docker integration")
-		} else {
-			defer server.DockerWatcher.Stop()
-		}
-	}
-
-	if config.InDockerSwarm {
-		err = server.DockerSwarmWatcher.Start(config.DockerSocket, config.DockerTimeout, config.DockerRefreshInterval, config.AutoScale.Up, config.AutoScale.Down)
-		if err != nil {
-			logrus.WithError(err).Fatal("Unable to start docker swarm integration")
-		} else {
-			defer server.DockerSwarmWatcher.Stop()
-		}
-	}
-
-	server.Routes.SimplifySRV(config.SimplifySRV)
-
-	err = metricsBuilder.Start(ctx)
-	if err != nil {
-		logrus.WithError(err).Fatal("Unable to start metrics reporter")
-	}
-
-	// handle signals
 	for {
-		sig := <-c
+		select {
-		switch sig {
+		case <-s.Done():
-		case syscall.SIGHUP:
-			if config.Routes.Config != "" {
-				logrus.Info("Received SIGHUP, reloading routes config...")
-				if err := server.RoutesConfigLoader.Reload(); err != nil {
-					logrus.
-						WithError(err).
-						WithField("routesConfig", config.Routes.Config).
-						Error("Could not re-read the routes config file")
-				}
-			}
-		case syscall.SIGINT, syscall.SIGTERM:
-			logrus.WithField("signal", sig).Info("Stopping. Waiting for connections to complete...")
-			signal.Stop(c)
-			connector.WaitForConnections()
-			logrus.Info("Stopped")
 			return
-		default:
+
-			logrus.WithField("signal", sig).Warn("Received unexpected signal")
+		case sig := <-signals:
+			switch sig {
+			case syscall.SIGHUP:
+				s.ReloadConfig()
+
+			case syscall.SIGINT, syscall.SIGTERM:
+				cancel()
+				// but wait for the server to be done
+
+			default:
+				logrus.WithField("signal", sig).Warn("Received unexpected signal")
+			}
 		}
 	}
 }

go.mod

@@ -7,7 +7,7 @@ require (
 	github.com/go-kit/kit v0.13.0
 	github.com/gorilla/mux v1.8.1
 	github.com/influxdata/influxdb1-client v0.0.0-20220302092344-a9ab5670611c
-	github.com/itzg/go-flagsfiller v1.15.2
+	github.com/itzg/go-flagsfiller v1.16.0
 	github.com/juju/ratelimit v1.0.2
 	github.com/pires/go-proxyproto v0.8.1
 	github.com/pkg/errors v0.9.1
@@ -80,7 +80,7 @@ require (
 	github.com/Microsoft/go-winio v0.6.2 // indirect
 	github.com/VividCortex/gohistogram v1.0.0 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
-	github.com/docker/docker v28.3.0+incompatible
+	github.com/docker/docker v28.3.1+incompatible
 	github.com/docker/go-connections v0.5.0 // indirect
 	github.com/docker/go-units v0.5.0 // indirect
 	github.com/go-kit/log v0.2.1 // indirect
@@ -98,7 +98,7 @@ require (
 	github.com/opencontainers/image-spec v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
 	github.com/spf13/pflag v1.0.6 // indirect
-	golang.org/x/net v0.40.0 // indirect
+	golang.org/x/net v0.41.0 // indirect
 	golang.org/x/oauth2 v0.30.0 // indirect
 	golang.org/x/sys v0.33.0 // indirect
 	golang.org/x/term v0.32.0 // indirect

go.sum

@@ -25,6 +25,8 @@ github.com/distribution/reference v0.6.0 h1:0IXCQ5g4/QMHHkarYzh5l+u8T3t73zM5Qvfr
 github.com/distribution/reference v0.6.0/go.mod h1:BbU0aIcezP1/5jX/8MP0YiH4SdvB5Y4f/wlDRiLyi3E=
 github.com/docker/docker v28.3.0+incompatible h1:ffS62aKWupCWdvcee7nBU9fhnmknOqDPaJAMtfK0ImQ=
 github.com/docker/docker v28.3.0+incompatible/go.mod h1:eEKB0N0r5NX/I1kEveEz05bcu8tLC/8azJZsviup8Sk=
+github.com/docker/docker v28.3.1+incompatible h1:20+BmuA9FXlCX4ByQ0vYJcUEnOmRM6XljDnFWR+jCyY=
+github.com/docker/docker v28.3.1+incompatible/go.mod h1:eEKB0N0r5NX/I1kEveEz05bcu8tLC/8azJZsviup8Sk=
 github.com/docker/go-connections v0.5.0 h1:USnMq7hx7gwdVZq1L49hLXaFtUdTADjXGp+uj1Br63c=
 github.com/docker/go-connections v0.5.0/go.mod h1:ov60Kzw0kKElRwhNs9UlUHAE/F9Fe6GLaXnqyDdmEXc=
 github.com/docker/go-units v0.5.0 h1:69rxXcBk27SvSaaxTtLh/8llcHD8vYHT7WSdRZ/jvr4=
@@ -89,6 +91,8 @@ github.com/influxdata/influxdb1-client v0.0.0-20220302092344-a9ab5670611c h1:qSH
 github.com/influxdata/influxdb1-client v0.0.0-20220302092344-a9ab5670611c/go.mod h1:qj24IKcXYK6Iy9ceXlo3Tc+vtHo9lIhSX5JddghvEPo=
 github.com/itzg/go-flagsfiller v1.15.2 h1:DvhhOKuqzawoa6C/3Q/y8pFbdO5PBdgnIvz84ZGkY0g=
 github.com/itzg/go-flagsfiller v1.15.2/go.mod h1:XmllPPi99O7vXTG9wa/Hzmhnkv6BXBF1W57ifbQTVs4=
+github.com/itzg/go-flagsfiller v1.16.0 h1:YNwjLzFIeFzZpctT2RiN8T5qxiGrCX33bGSwtN6OSAA=
+github.com/itzg/go-flagsfiller v1.16.0/go.mod h1:XmllPPi99O7vXTG9wa/Hzmhnkv6BXBF1W57ifbQTVs4=
 github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
 github.com/jpillora/backoff v1.0.0 h1:uvFg412JmmHBHw7iwprIxkPMI+sGQ4kzOWsMeHnm2EA=
@@ -205,6 +209,7 @@ golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.38.0 h1:jt+WWG8IZlBnVbomuhg2Mdq0+BBQaHbtqHEFEigjUV8=
 golang.org/x/crypto v0.38.0/go.mod h1:MvrbAqul58NNYPKnOra203SB9vpuZW0e+RRZV+Ggqjw=
+golang.org/x/crypto v0.39.0 h1:SHs+kF4LP+f+p14esP5jAoDpHU8Gu/v9lFRK6IT5imM=
 golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
 golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
@@ -214,6 +219,8 @@ golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLL
 golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
 golang.org/x/net v0.40.0 h1:79Xs7wF06Gbdcg4kdCCIQArK11Z1hr5POQ6+fIYHNuY=
 golang.org/x/net v0.40.0/go.mod h1:y0hY0exeL2Pku80/zKK7tpntoX23cqL3Oa6njdgRtds=
+golang.org/x/net v0.41.0 h1:vBTly1HeNPEn3wtREYfy4GZ/NECgw2Cnl+nK6Nz3uvw=
+golang.org/x/net v0.41.0/go.mod h1:B/K4NNqkfmg07DQYrbwvSluqCJOOXwUjeb/5lOisjbA=
 golang.org/x/oauth2 v0.30.0 h1:dnDm7JmhM45NNpd8FDDeLhK6FwqbOf4MLCM9zb1BOHI=
 golang.org/x/oauth2 v0.30.0/go.mod h1:B++QgG3ZKulg6sRPGD/mqlHQs5rB3Ml9erfeDY7xKlU=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=

server/configs.go

@@ -0,0 +1,50 @@
+package server
+
+type WebhookConfig struct {
+	Url         string `usage:"If set, a POST request that contains connection status notifications will be sent to this HTTP address"`
+	RequireUser bool   `default:"false" usage:"Indicates if the webhook will only be called if a user is connecting rather than just server list/ping"`
+}
+
+type AutoScale struct {
+	Up        bool   `usage:"Increase Kubernetes StatefulSet Replicas (only) from 0 to 1 on respective backend servers when accessed"`
+	Down      bool   `default:"false" usage:"Decrease Kubernetes StatefulSet Replicas (only) from 1 to 0 on respective backend servers after there are no connections"`
+	DownAfter string `default:"10m" usage:"Server scale down delay after there are no connections"`
+	AllowDeny string `usage:"Path to config for server allowlists and denylists. If a global/server entry is specified, only players allowed to connect to the server will be able to trigger a scale up when -auto-scale-up is enabled or cancel active down scalers when -auto-scale-down is enabled"`
+}
+
+type RoutesConfig struct {
+	Config      string `usage:"Name or full [path] to routes config file"`
+	ConfigWatch bool   `usage:"Watch for config file changes"`
+}
+
+type Config struct {
+	Port                  int               `default:"25565" usage:"The [port] bound to listen for Minecraft client connections"`
+	Default               string            `usage:"host:port of a default Minecraft server to use when mapping not found"`
+	Mapping               map[string]string `usage:"Comma or newline delimited or repeated mappings of externalHostname=host:port"`
+	ApiBinding            string            `usage:"The [host:port] bound for servicing API requests"`
+	CpuProfile            string            `usage:"Enables CPU profiling and writes to given path"`
+	ConnectionRateLimit   int               `default:"1" usage:"Max number of connections to allow per second"`
+	InKubeCluster         bool              `usage:"Use in-cluster Kubernetes config"`
+	KubeConfig            string            `usage:"The path to a Kubernetes configuration file"`
+	InDocker              bool              `usage:"Use Docker service discovery"`
+	InDockerSwarm         bool              `usage:"Use Docker Swarm service discovery"`
+	DockerSocket          string            `default:"unix:///var/run/docker.sock" usage:"Path to Docker socket to use"`
+	DockerTimeout         int               `default:"0" usage:"Timeout configuration in seconds for the Docker integrations"`
+	DockerRefreshInterval int               `default:"15" usage:"Refresh interval in seconds for the Docker integrations"`
+	MetricsBackend        string            `default:"discard" usage:"Backend to use for metrics exposure/publishing: discard,expvar,influxdb,prometheus"`
+	MetricsBackendConfig  MetricsBackendConfig
+	UseProxyProtocol      bool     `default:"false" usage:"Send PROXY protocol to backend servers"`
+	ReceiveProxyProtocol  bool     `default:"false" usage:"Receive PROXY protocol from backend servers, by default trusts every proxy header that it receives, combine with -trusted-proxies to specify a list of trusted proxies"`
+	TrustedProxies        []string `usage:"Comma delimited list of CIDR notation IP blocks to trust when receiving PROXY protocol"`
+	RecordLogins          bool     `default:"false" usage:"Log and generate metrics on player logins. Metrics only supported with influxdb or prometheus backend"`
+	Routes                RoutesConfig
+	NgrokToken            string `usage:"If set, an ngrok tunnel will be established. It is HIGHLY recommended to pass as an environment variable."`
+	AutoScale             AutoScale
+
+	ClientsToAllow []string `usage:"Zero or more client IP addresses or CIDRs to allow. Takes precedence over deny."`
+	ClientsToDeny  []string `usage:"Zero or more client IP addresses or CIDRs to deny. Ignored if any configured to allow"`
+
+	SimplifySRV bool `default:"false" usage:"Simplify fully qualified SRV records for mapping"`
+
+	Webhook WebhookConfig `usage:"Webhook configuration"`
+}

server/routes_config_loader.go

@@ -49,6 +49,10 @@ func (r *routesConfigLoader) Load(routesConfigFileName string) error {
 }
 
 func (r *routesConfigLoader) Reload() error {
+	if !r.isEnabled() {
+		return nil
+	}
+
 	config, readErr := r.readFile()
 
 	if readErr != nil {

server/server.go

@@ -0,0 +1,210 @@
+package server
+
+import (
+	"context"
+	"fmt"
+	"github.com/sirupsen/logrus"
+	"net"
+	"os"
+	"runtime/pprof"
+	"strconv"
+	"time"
+)
+
+type Server struct {
+	ctx              context.Context
+	config           *Config
+	connector        *Connector
+	reloadConfigChan chan struct{}
+	doneChan         chan struct{}
+}
+
+func NewServer(ctx context.Context, config *Config) (*Server, error) {
+	if config.CpuProfile != "" {
+		cpuProfileFile, err := os.Create(config.CpuProfile)
+		if err != nil {
+			return nil, fmt.Errorf("could not create cpu profile file: %w", err)
+		}
+		//goland:noinspection GoUnhandledErrorResult
+		defer cpuProfileFile.Close()
+
+		logrus.WithField("file", config.CpuProfile).Info("Starting cpu profiling")
+		err = pprof.StartCPUProfile(cpuProfileFile)
+		if err != nil {
+			return nil, fmt.Errorf("could not start cpu profile: %w", err)
+		}
+		defer pprof.StopCPUProfile()
+	}
+
+	var err error
+
+	var autoScaleAllowDenyConfig *AllowDenyConfig = nil
+	if config.AutoScale.AllowDeny != "" {
+		autoScaleAllowDenyConfig, err = ParseAllowDenyConfig(config.AutoScale.AllowDeny)
+		if err != nil {
+			return nil, fmt.Errorf("could not parse autoscale allow-deny-list: %w", err)
+		}
+	}
+
+	metricsBuilder := NewMetricsBuilder(config.MetricsBackend, &config.MetricsBackendConfig)
+
+	downScalerEnabled := config.AutoScale.Down && (config.InKubeCluster || config.KubeConfig != "")
+	downScalerDelay, err := time.ParseDuration(config.AutoScale.DownAfter)
+	if err != nil {
+		return nil, fmt.Errorf("could not parse auto-scale-down-after duration: %w", err)
+	}
+	// Only one instance should be created
+	DownScaler = NewDownScaler(ctx, downScalerEnabled, downScalerDelay)
+
+	if config.Routes.Config != "" {
+		err := RoutesConfigLoader.Load(config.Routes.Config)
+		if err != nil {
+			return nil, fmt.Errorf("could not load routes config file: %w", err)
+		}
+
+		if config.Routes.ConfigWatch {
+			err := RoutesConfigLoader.WatchForChanges(ctx)
+			if err != nil {
+				return nil, fmt.Errorf("could not watch for changes to routes config file: %w", err)
+			}
+		}
+	}
+
+	Routes.RegisterAll(config.Mapping)
+	if config.Default != "" {
+		Routes.SetDefaultRoute(config.Default)
+	}
+
+	if config.ConnectionRateLimit < 1 {
+		config.ConnectionRateLimit = 1
+	}
+
+	trustedIpNets := make([]*net.IPNet, 0)
+	for _, ip := range config.TrustedProxies {
+		_, ipNet, err := net.ParseCIDR(ip)
+		if err != nil {
+			return nil, fmt.Errorf("could not parse trusted proxy CIDR block: %w", err)
+		}
+		trustedIpNets = append(trustedIpNets, ipNet)
+	}
+
+	connector := NewConnector(metricsBuilder.BuildConnectorMetrics(), config.UseProxyProtocol, config.ReceiveProxyProtocol, trustedIpNets, config.RecordLogins, autoScaleAllowDenyConfig)
+
+	clientFilter, err := NewClientFilter(config.ClientsToAllow, config.ClientsToDeny)
+	if err != nil {
+		return nil, fmt.Errorf("could not create client filter: %w", err)
+	}
+	connector.SetClientFilter(clientFilter)
+
+	if config.Webhook.Url != "" {
+		logrus.WithField("url", config.Webhook.Url).
+			WithField("require-user", config.Webhook.RequireUser).
+			Info("Using webhook for connection status notifications")
+		connector.SetConnectionNotifier(
+			NewWebhookNotifier(config.Webhook.Url, config.Webhook.RequireUser))
+	}
+
+	if config.NgrokToken != "" {
+		connector.UseNgrok(config.NgrokToken)
+	}
+
+	if config.ApiBinding != "" {
+		StartApiServer(config.ApiBinding)
+	}
+
+	if config.InKubeCluster {
+		err = K8sWatcher.StartInCluster(config.AutoScale.Up, config.AutoScale.Down)
+		if err != nil {
+			return nil, fmt.Errorf("could not start in-cluster k8s integration: %w", err)
+		} else {
+			defer K8sWatcher.Stop()
+		}
+	} else if config.KubeConfig != "" {
+		err := K8sWatcher.StartWithConfig(config.KubeConfig, config.AutoScale.Up, config.AutoScale.Down)
+		if err != nil {
+			return nil, fmt.Errorf("could not start k8s integration with kube config: %w", err)
+		} else {
+			defer K8sWatcher.Stop()
+		}
+	}
+
+	if config.InDocker {
+		err = DockerWatcher.Start(config.DockerSocket, config.DockerTimeout, config.DockerRefreshInterval, config.AutoScale.Up, config.AutoScale.Down)
+		if err != nil {
+			return nil, fmt.Errorf("could not start docker integration: %w", err)
+		} else {
+			defer DockerWatcher.Stop()
+		}
+	}
+
+	if config.InDockerSwarm {
+		err = DockerSwarmWatcher.Start(config.DockerSocket, config.DockerTimeout, config.DockerRefreshInterval, config.AutoScale.Up, config.AutoScale.Down)
+		if err != nil {
+			return nil, fmt.Errorf("could not start docker swarm integration: %w", err)
+		} else {
+			defer DockerSwarmWatcher.Stop()
+		}
+	}
+
+	Routes.SimplifySRV(config.SimplifySRV)
+
+	err = metricsBuilder.Start(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("could not start metrics reporter: %w", err)
+	}
+
+	return &Server{
+		ctx:              ctx,
+		config:           config,
+		connector:        connector,
+		reloadConfigChan: make(chan struct{}),
+		doneChan:         make(chan struct{}),
+	}, nil
+}
+
+// Done provides a channel notified when the server has closed all connections, etc
+func (s *Server) Done() <-chan struct{} {
+	return s.doneChan
+}
+
+func (s *Server) notifyDone() {
+	s.doneChan <- struct{}{}
+}
+
+// ReloadConfig indicates that an external request, such as a SIGHUP,
+// is requesting the routes config file to be reloaded, if enabled
+func (s *Server) ReloadConfig() {
+	s.reloadConfigChan <- struct{}{}
+}
+
+// Run will run the server until the context is done or a fatal error occurs, so this should be
+// in a go routine.
+func (s *Server) Run() {
+	err := s.connector.StartAcceptingConnections(s.ctx,
+		net.JoinHostPort("", strconv.Itoa(s.config.Port)),
+		s.config.ConnectionRateLimit,
+	)
+	if err != nil {
+		logrus.WithError(err).Error("Could not start accepting connections")
+		s.notifyDone()
+		return
+	}
+
+	for {
+		select {
+		case <-s.reloadConfigChan:
+			if err := RoutesConfigLoader.Reload(); err != nil {
+				logrus.WithError(err).
+					Error("Could not re-read the routes config file")
+			}
+
+		case <-s.ctx.Done():
+			logrus.Info("Stopping. Waiting for connections to complete...")
+			s.connector.WaitForConnections()
+			logrus.Info("Stopped")
+			s.notifyDone()
+			return
+		}
+	}
+
+}