CLI Flag --bind (#77)

* CLI Flag for Bind Address

Signed-off-by: Bhargav Ravuri <bhargav.ravuri@infracloud.io>

* Update Documentation for --bind

Signed-off-by: Bhargav Ravuri <bhargav.ravuri@infracloud.io>

Signed-off-by: Bhargav Ravuri <bhargav.ravuri@infracloud.io>

README.md

@@ -61,6 +61,8 @@ You can see the list of available command-line flags by running `helm dashboard
 
 By default, the web server is only available locally. You can change that by specifying `HD_BIND` environment variable
 to the desired value. For example, `0.0.0.0` would bind to all IPv4 addresses or `[::0]` would be all IPv6 addresses.
+This can also be specified using flag `--bind <host>`, for example `--bind=0.0.0.0` or `--bind 0.0.0.0`.
+> Precedence order: flag `--bind=<host>` > env `HD_BIND=<host>` > default value `localhost`
 
 If your port 8080 is busy, you can specify a different port to use via `--port <number>` command-line flag.
 

go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/hashicorp/go-version v1.6.0
 	github.com/hexops/gotextdiff v1.0.3
 	github.com/jessevdk/go-flags v1.5.0
+	github.com/olekukonko/tablewriter v0.0.5
 	github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8
 	github.com/sirupsen/logrus v1.9.0
 	gopkg.in/yaml.v3 v3.0.1
@@ -31,7 +32,6 @@ require (
 	github.com/mattn/go-runewidth v0.0.9 // indirect
 	github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
 	github.com/modern-go/reflect2 v1.0.2 // indirect
-	github.com/olekukonko/tablewriter v0.0.5 // indirect
 	github.com/pelletier/go-toml/v2 v2.0.3 // indirect
 	github.com/ugorji/go/codec v1.2.7 // indirect
 	golang.org/x/crypto v0.0.0-20220817201139-bc19a97f63c8 // indirect

main.go

@@ -2,12 +2,13 @@ package main
 
 import (
 	"fmt"
+	"os"
+
 	"github.com/gin-gonic/gin"
 	"github.com/jessevdk/go-flags"
 	"github.com/komodorio/helm-dashboard/pkg/dashboard"
 	"github.com/pkg/browser"
 	log "github.com/sirupsen/logrus"
-	"os"
 )
 
 var (
@@ -21,18 +22,31 @@ type options struct {
 	Verbose    bool   `short:"v" long:"verbose" description:"Show verbose debug information"`
 	NoBrowser  bool   `short:"b" long:"no-browser" description:"Do not attempt to open Web browser upon start"`
 	NoTracking bool   `long:"no-analytics" description:"Disable user analytics (GA, DataDog etc.)"`
-
+	BindHost   string `long:"bind" description:"Host binding to start server (default: localhost)"` // default should be printed but not assigned as the precedence: flag > env > default
 	Port       uint   `short:"p" long:"port" description:"Port to start server on" default:"8080"`  // TODO: better default port to clash less?
-
 	Namespace  string `short:"n" long:"namespace" description:"Limit operations to a specific namespace"`
 }
 
 func main() {
 	opts := parseFlags()
+	if opts.BindHost == "" {
+		host := os.Getenv("HD_BIND")
+		if host == "" {
+			host = "localhost"
+		}
+		opts.BindHost = host
+	}
 
 	setupLogging(opts.Verbose)
 
-	address, webServerDone := dashboard.StartServer(version, int(opts.Port), opts.Namespace, opts.Verbose, opts.NoTracking)
+	server := dashboard.Server{
+		Version:    version,
+		Namespace:  opts.Namespace,
+		Address:    fmt.Sprintf("%s:%d", opts.BindHost, opts.Port),
+		Debug:      opts.Verbose,
+		NoTracking: opts.NoTracking,
+	}
+	address, webServerDone := server.StartServer()
 
 	if !opts.NoTracking {
 		log.Infof("User analytics is collected to improve the quality, disable it with --no-analytics")

pkg/dashboard/server.go

@@ -3,22 +3,31 @@ package dashboard
 import (
 	"context"
 	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
 	"github.com/gin-gonic/gin"
 	"github.com/hashicorp/go-version"
 	"github.com/komodorio/helm-dashboard/pkg/dashboard/scanners"
 	"github.com/komodorio/helm-dashboard/pkg/dashboard/subproc"
 	"github.com/komodorio/helm-dashboard/pkg/dashboard/utils"
 	log "github.com/sirupsen/logrus"
-	"net/http"
-	"os"
-	"strconv"
-	"strings"
-	"time"
 )
 
-func StartServer(version string, port int, ns string, debug bool, noTracking bool) (string, utils.ControlChan) {
+type Server struct {
+	Version    string
+	Namespace  string
+	Address    string
+	Debug      bool
+	NoTracking bool
+}
+
+func (s Server) StartServer() (string, utils.ControlChan) {
 	data := subproc.DataLayer{
-		Namespace: ns,
+		Namespace: s.Namespace,
 	}
 	err := data.CheckConnectivity()
 	if err != nil {
@@ -27,37 +36,33 @@ func StartServer(version string, port int, ns string, debug bool, noTracking boo
 	}
 
 	data.StatusInfo = &subproc.StatusInfo{
-		CurVer:             version,
+		CurVer:             s.Version,
-		Analytics:          !noTracking,
+		Analytics:          !s.NoTracking,
-		LimitedToNamespace: ns,
+		LimitedToNamespace: s.Namespace,
 	}
 	go checkUpgrade(data.StatusInfo)
 
 	discoverScanners(&data)
 
-	address := os.Getenv("HD_BIND")
-	if address == "" {
-		address = "localhost"
-	}
-
-	address += ":" + strconv.Itoa(port)
-
 	abort := make(utils.ControlChan)
-	api := NewRouter(abort, &data, debug)
+	api := NewRouter(abort, &data, s.Debug)
-	done := startBackgroundServer(address, api, abort)
+	done := s.startBackgroundServer(api, abort)
 
-	return "http://" + address, done
+	return "http://" + s.Address, done
 }
 
-func startBackgroundServer(addr string, routes *gin.Engine, abort utils.ControlChan) utils.ControlChan {
+func (s Server) startBackgroundServer(routes *gin.Engine, abort utils.ControlChan) utils.ControlChan {
 	done := make(utils.ControlChan)
-	server := &http.Server{Addr: addr, Handler: routes}
+	server := &http.Server{
+		Addr:    s.Address,
+		Handler: routes,
+	}
 
 	go func() {
 		err := server.ListenAndServe()
 		if err != nil && err != http.ErrServerClosed {
-			log.Warnf("Looks like port is busy for %s, checking if it's us...", addr)
+			log.Warnf("Looks like port is busy for %s, checking if it's us...", s.Address)
-			if itIsUs(addr) {
+			if s.itIsUs() {
 				log.Infof("Yes, it's another instance of us. Just reuse it.")
 			} else {
 				panic(err)
@@ -77,11 +82,14 @@ func startBackgroundServer(addr string, routes *gin.Engine, abort utils.ControlC
 	return done
 }
 
-func itIsUs(addr string) bool {
+func (s Server) itIsUs() bool {
-	var myClient = &http.Client{Timeout: 5 * time.Second}
+	url := fmt.Sprintf("http://%s/status", s.Address)
-	r, err := myClient.Get("http://" + addr + "/status")
+	var myClient = &http.Client{
+		Timeout: 5 * time.Second,
+	}
+	r, err := myClient.Get(url)
 	if err != nil {
-		log.Debugf("It's not us on %s: %s", addr, err)
+		log.Debugf("It's not us on %s: %s", s.Address, err)
 		return false
 	}
 	defer r.Body.Close()