Switched to go-flagsfiller to enable env var config

cmd/mc-router/main.go

@@ -2,8 +2,8 @@ package main
 
 import (
 	"context"
-	"flag"
 	"fmt"
+	"github.com/itzg/go-flagsfiller"
 	"github.com/itzg/mc-router/server"
 	"github.com/sirupsen/logrus"
 	"net"
@@ -15,18 +15,18 @@ import (
 	"syscall"
 )
 
-var (
+type Config struct {
-	port           = flag.Int("port", 25565, "The port bound to listen for Minecraft client connections")
+	Port                int    `default:"25565" usage:"The [port] bound to listen for Minecraft client connections"`
-	apiBinding     = flag.String("api-binding", "", "The host:port bound for servicing API requests")
+	Mapping             string `usage:"Comma-separated mappings of externalHostname=host:port"`
-	mappings       = flag.String("mapping", "", "Comma-separated mappings of externalHostname=host:port")
+	ApiBinding          string `usage:"The [host:port] bound for servicing API requests"`
-	versionFlag    = flag.Bool("version", false, "Output version and exit")
+	Version             bool   `usage:"Output version and exit"`
-	kubeConfigFile = flag.String("kube-config", "", "The path to a kubernetes configuration file")
+	CpuProfile          string `usage:"Enables CPU profiling and writes to given path"`
-	inKubeCluster  = flag.Bool("in-kube-cluster", false, "Use in-cluster kubernetes config")
+	Debug               bool   `usage:"Enable debug logs"`
-	cpuProfile     = flag.String("cpu-profile", "", "Enables CPU profiling and writes to given path")
+	ConnectionRateLimit int    `default:"1" usage:"Max number of connections to allow per second"`
-	debug          = flag.Bool("debug", false, "Enable debug logs")
+	InKubeCluster       bool   `usage:"Use in-cluster kubernetes config"`
-	connRateLimit  = flag.Int("connection-rate-limit", 1, "Max number of connections to allow per second")
+	KubeConfig          string `usage:"The path to a kubernetes configuration file"`
-	metricsBackend = flag.String("metrics-backend", "discard", "Backend to use for metrics exposure/publishing: discard,expvar")
+	MetricsBackend      string `default:"discard" usage:"Backend to use for metrics exposure/publishing: discard,expvar"`
-)
+}
 
 var (
 	version = "dev"
@@ -39,26 +39,30 @@ func showVersion() {
 }
 
 func main() {
-	flag.Parse()
+	var config Config
+	err := flagsfiller.Parse(&config, flagsfiller.WithEnv(""))
+	if err != nil {
+		logrus.Fatal(err)
+	}
 
-	if *versionFlag {
+	if config.Version {
 		showVersion()
 		os.Exit(0)
 	}
 
-	if *debug {
+	if config.Debug {
 		logrus.SetLevel(logrus.DebugLevel)
 		logrus.Debug("Debug logs enabled")
 	}
 
-	if *cpuProfile != "" {
+	if config.CpuProfile != "" {
-		cpuProfileFile, err := os.Create(*cpuProfile)
+		cpuProfileFile, err := os.Create(config.CpuProfile)
 		if err != nil {
 			logrus.WithError(err).Fatal("trying to create cpu profile file")
 		}
 		defer cpuProfileFile.Close()
 
-		logrus.WithField("file", *cpuProfile).Info("Starting cpu profiling")
+		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")
@@ -68,33 +72,38 @@ func main() {
 
 	ctx, cancel := context.WithCancel(context.Background())
 
-	metricsBuilder := NewMetricsBuilder()
+	metricsBuilder := NewMetricsBuilder(config.MetricsBackend)
 
 	c := make(chan os.Signal, 1)
 	signal.Notify(c, syscall.SIGINT, syscall.SIGTERM)
 
-	server.Routes.RegisterAll(parseMappings(*mappings))
+	server.Routes.RegisterAll(parseMappings(config.Mapping))
 
-	if *connRateLimit < 1 {
+	if config.ConnectionRateLimit < 1 {
-		*connRateLimit = 1
+		config.ConnectionRateLimit = 1
 	}
 	connector := server.NewConnector(metricsBuilder.BuildConnectorMetrics())
-	connector.StartAcceptingConnections(ctx, net.JoinHostPort("", strconv.Itoa(*port)), *connRateLimit)
+	err = connector.StartAcceptingConnections(ctx,
-
+		net.JoinHostPort("", strconv.Itoa(config.Port)),
-	if *apiBinding != "" {
+		config.ConnectionRateLimit,
-		server.StartApiServer(*apiBinding)
+	)
+	if err != nil {
+		logrus.Fatal(err)
 	}
 
-	var err error
+	if config.ApiBinding != "" {
-	if *inKubeCluster {
+		server.StartApiServer(config.ApiBinding)
+	}
+
+	if config.InKubeCluster {
 		err = server.K8sWatcher.StartInCluster()
 		if err != nil {
 			logrus.WithError(err).Warn("Unable to start k8s integration")
 		} else {
 			defer server.K8sWatcher.Stop()
 		}
-	} else if *kubeConfigFile != "" {
+	} else if config.KubeConfig != "" {
-		err := server.K8sWatcher.StartWithConfig(*kubeConfigFile)
+		err := server.K8sWatcher.StartWithConfig(config.KubeConfig)
 		if err != nil {
 			logrus.WithError(err).Warn("Unable to start k8s integration")
 		} else {

cmd/mc-router/metrics.go

@@ -11,14 +11,14 @@ type MetricsBuilder interface {
 	BuildConnectorMetrics() *server.ConnectorMetrics
 }
 
-func NewMetricsBuilder() MetricsBuilder {
+func NewMetricsBuilder(backend string) MetricsBuilder {
-	switch *metricsBackend {
+	switch backend {
 	case "discard":
 		return &discardMetricsBuilder{}
 	case "expvar":
 		return &expvarMetricsBuilder{}
 	default:
-		logrus.Fatalf("Unsupported metrics backend: %s", *metricsBackend)
+		logrus.Fatalf("Unsupported metrics backend: %s", backend)
 		return nil
 	}
 }

go.mod

@@ -13,6 +13,7 @@ require (
 	github.com/gorilla/mux v1.7.1
 	github.com/hashicorp/golang-lru v0.5.1 // indirect
 	github.com/imdario/mergo v0.3.7 // indirect
+	github.com/itzg/go-flagsfiller v1.4.1
 	github.com/json-iterator/go v1.1.6 // indirect
 	github.com/juju/ratelimit v1.0.1
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
@@ -20,14 +21,13 @@ require (
 	github.com/pkg/errors v0.8.1
 	github.com/sirupsen/logrus v1.4.1
 	github.com/spf13/pflag v1.0.3 // indirect
-	github.com/stretchr/testify v1.2.2
+	github.com/stretchr/testify v1.4.0
 	golang.org/x/crypto v0.0.0-20190411191339-88737f569e3a // indirect
 	golang.org/x/net v0.0.0-20190415214537-1da14a5a36f2 // indirect
 	golang.org/x/oauth2 v0.0.0-20190402181905-9f3314589c9a // indirect
 	golang.org/x/text v0.3.0
 	golang.org/x/time v0.0.0-20190308202827-9d24e82272b4 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
-	gopkg.in/yaml.v2 v2.2.2 // indirect
 	k8s.io/api v0.0.0-20190313235455-40a48860b5ab
 	k8s.io/apimachinery v0.0.0-20190313205120-d7deff9243b1
 	k8s.io/client-go v11.0.0+incompatible

go.sum

@@ -1,6 +1,7 @@
 cloud.google.com/go v0.34.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
 github.com/VividCortex/gohistogram v1.0.0 h1:6+hBz+qvs0JOrrNhhmR7lFxo5sINxBCGXrdtl/UvroE=
 github.com/VividCortex/gohistogram v1.0.0/go.mod h1:Pf5mBqqDxYaXu3hDrrU+w6nw50o/4+TcAqDqk/vUH7g=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/go-kit/kit v0.9.0 h1:wDJmvq38kDhkVxi50ni9ykkdUr1PKgqKOoi01fa0Mdk=
@@ -20,8 +21,12 @@ github.com/gorilla/mux v1.7.1 h1:Dw4jY2nghMMRsh1ol8dv1axHkDwMQK2DHerMNJsIpJU=
 github.com/gorilla/mux v1.7.1/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
 github.com/hashicorp/golang-lru v0.5.1 h1:0hERBMJE1eitiLkihrMvRVBYAkpHzc/J3QdDN+dAcgU=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
+github.com/iancoleman/strcase v0.0.0-20191112232945-16388991a334 h1:VHgatEHNcBFEB7inlalqfNqw65aNkM1lGX2yt3NmbS8=
+github.com/iancoleman/strcase v0.0.0-20191112232945-16388991a334/go.mod h1:SK73tn/9oHe+/Y0h39VT4UCxmurVJkR5NA7kMEAOgSE=
 github.com/imdario/mergo v0.3.7 h1:Y+UAYTZ7gDEuOfhxKWy+dvb5dRQ6rJjFSdX2HZY1/gI=
 github.com/imdario/mergo v0.3.7/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
+github.com/itzg/go-flagsfiller v1.4.1 h1:h/t5g+WkvsOR449bz1ngU8UGosKNm4Sr3iMNNgOqHfo=
+github.com/itzg/go-flagsfiller v1.4.1/go.mod h1:mfQgTahSs4OHn8PYev2Wwi1LJXUiYiGuZVCpBLxzbYs=
 github.com/json-iterator/go v1.1.6 h1:MrUvLMLTMxbqFJ9kzlvat/rYZqZnW3u4wkLzWTaFwKs=
 github.com/json-iterator/go v1.1.6/go.mod h1:+SdeFBvtyEkXs7REEP0seUULqWtbJapLOCVDaaPEHmU=
 github.com/juju/ratelimit v1.0.1 h1:+7AIFJVQ0EQgq/K9+0Krm7m530Du7tIz0METWzN0RgY=
@@ -42,9 +47,12 @@ github.com/sirupsen/logrus v1.4.1 h1:GL2rEmy6nsikmW0r8opw9JIRScdMF5hA8cOYLH7In1k
 github.com/sirupsen/logrus v1.4.1/go.mod h1:ni0Sbl8bgC9z8RoU9G6nDWqqs/fq4eDPysMBDgk/93Q=
 github.com/spf13/pflag v1.0.3 h1:zPAT6CGy6wXeQ7NtTnaTerfKOsV6V6F8agHXFiazDkg=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190411191339-88737f569e3a h1:Igim7XhdOpBnWPuYJ70XcNpq8q3BCACtVgNfoJxOV7g=
 golang.org/x/crypto v0.0.0-20190411191339-88737f569e3a/go.mod h1:WFFai1msRO1wXaEeE5yQxYXgSfI8pQAWXbQop6sCtWE=