feat: implement builder plugin

This plugin will allow users to override the builder used for their application, enabling users to use custom builders if desired.

plugins/builder/src/commands/commands.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/common"
+)
+
+const (
+	helpHeader = `Usage: dokku builder[:COMMAND]
+
+Manage builder settings for an app
+
+Additional commands:`
+
+	helpContent = `
+    builder:report [<app>] [<flag>], Displays a builder report for one or more apps
+    builder:set <app> <property> (<value>), Set or clear a builder property for an app
+`
+)
+
+func main() {
+	flag.Usage = usage
+	flag.Parse()
+
+	cmd := flag.Arg(0)
+	switch cmd {
+	case "builder", "builder: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    builder, Manage builder settings 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() {
+	common.CommandUsage(helpHeader, helpContent)
+}

plugins/builder/src/subcommands/subcommands.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/builder"
+	"github.com/dokku/dokku/plugins/common"
+
+	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("builder:report", flag.ExitOnError)
+		format := args.String("format", "stdout", "format: [ stdout | json ]")
+		osArgs, infoFlag, flagErr := common.ParseReportArgs("builder", os.Args[2:])
+		if flagErr == nil {
+			args.Parse(osArgs)
+			appName := args.Arg(0)
+			err = builder.CommandReport(appName, *format, infoFlag)
+		}
+	case "set":
+		args := flag.NewFlagSet("builder: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 = builder.CommandSet(appName, property, value)
+	default:
+		err = fmt.Errorf("Invalid plugin subcommand call: %s", subcommand)
+	}
+
+	if err != nil {
+		common.LogFailWithError(err)
+	}
+}

plugins/builder/src/triggers/triggers.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/builder"
+	"github.com/dokku/dokku/plugins/common"
+)
+
+// main entrypoint to all triggers
+func main() {
+	parts := strings.Split(os.Args[0], "/")
+	trigger := parts[len(parts)-1]
+	flag.Parse()
+
+	var err error
+	switch trigger {
+	case "builder-detect":
+		appName := flag.Arg(0)
+		err = builder.TriggerBuilderDetect(appName)
+	case "install":
+		err = builder.TriggerInstall()
+	case "post-delete":
+		appName := flag.Arg(0)
+		err = builder.TriggerPostDelete(appName)
+	case "report":
+		appName := flag.Arg(0)
+		err = builder.ReportSingleApp(appName, "", "")
+	default:
+		err = fmt.Errorf("Invalid plugin trigger call: %s", trigger)
+	}
+
+	if err != nil {
+		common.LogFailWithError(err)
+	}
+}