feat: implement the scheduler plugin

This also performs a one-time migration of the DOKKU_SCHEDULER values the scheduler plugin properties.

Closes #4739

plugins/scheduler/src/subcommands/subcommands.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/common"
+	"github.com/dokku/dokku/plugins/scheduler"
+
+	flag "github.com/spf13/pflag"
+)
+
+// main entrypoint to all subcommands
+func main() {
+	parts := strings.Split(os.Args[0], "/")
+	subcommand := parts[len(parts)-1]
+
+	var err error
+	switch subcommand {
+	case "report":
+		args := flag.NewFlagSet("scheduler:report", flag.ExitOnError)
+		format := args.String("format", "stdout", "format: [ stdout | json ]")
+		osArgs, infoFlag, flagErr := common.ParseReportArgs("scheduler", os.Args[2:])
+		if flagErr == nil {
+			args.Parse(osArgs)
+			appName := args.Arg(0)
+			err = scheduler.CommandReport(appName, *format, infoFlag)
+		}
+	case "set":
+		args := flag.NewFlagSet("scheduler:set", flag.ExitOnError)
+		global := args.Bool("global", false, "--global: set a global property")
+		args.Parse(os.Args[2:])
+		appName := args.Arg(0)
+		property := args.Arg(1)
+		value := args.Arg(2)
+		if *global {
+			appName = "--global"
+			property = args.Arg(0)
+			value = args.Arg(1)
+		}
+		err = scheduler.CommandSet(appName, property, value)
+	default:
+		err = fmt.Errorf("Invalid plugin subcommand call: %s", subcommand)
+	}
+
+	if err != nil {
+		common.LogFailWithError(err)
+	}
+}