refactor: rewrite proxy plugin in golang

plugins/proxy/src/commands/commands.go

@@ -0,0 +1,70 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/common"
+	columnize "github.com/ryanuber/columnize"
+)
+
+const (
+	helpHeader = `Usage: dokku proxy[:COMMAND]
+
+Manage the proxy integration for an app
+
+Additional commands:`
+
+	helpContent = `
+    proxy:disable <app>, Disable proxy for app
+    proxy:enable <app>, Enable proxy for app
+    proxy:ports <app>, List proxy port mappings for app
+    proxy:ports-add <app> [<scheme>:<host-port>:<container-port>...], Add proxy port mappings to an app
+    proxy:ports-clear <app>, Clear all proxy port mappings for an app
+    proxy:ports-remove <app> [<host-port>|<scheme>:<host-port>:<container-port>...], Remove specific proxy port mappings from an app
+    proxy:ports-set <app> [<scheme>:<host-port>:<container-port>...], Set proxy port mappings for an app
+    proxy:report [<app>] [<flag>], Displays a proxy report for one or more apps
+    proxy:set <app> <proxy-type>, Set proxy type for app
+`
+)
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+
+	cmd := flag.Arg(0)
+	switch cmd {
+	case "proxy", "proxy:help":
+		usage()
+	case "help":
+		command := common.NewShellCmd(fmt.Sprintf("ps -o command= %d", os.Getppid()))
+		command.ShowOutput = false
+		output, err := command.Output()
+
+		if err == nil && strings.Contains(string(output), "--all") {
+			fmt.Println(helpContent)
+		} else {
+			fmt.Print("\n    proxy, Manage the proxy integration for an app\n")
+		}
+	default:
+		dokkuNotImplementExitCode, err := strconv.Atoi(os.Getenv("DOKKU_NOT_IMPLEMENTED_EXIT"))
+		if err != nil {
+			fmt.Println("failed to retrieve DOKKU_NOT_IMPLEMENTED_EXIT environment variable")
+			dokkuNotImplementExitCode = 10
+		}
+		os.Exit(dokkuNotImplementExitCode)
+	}
+}
+
+func usage() {
+	config := columnize.DefaultConfig()
+	config.Delim = ","
+	config.Prefix = "    "
+	config.Empty = ""
+	content := strings.Split(helpContent, "\n")[1:]
+	fmt.Println(helpHeader)
+	fmt.Println(columnize.Format(content, config))
+}