refactor: decrease compile time for golang plugins

This change refactors the compiled golang plugins into 3 distinct binaries:

- commands: already existing
- subcommands/subcommands: entrypoint into all subcommands
- triggers: entrypoint into all triggers

It then further symlinks triggers and subcommands to the built binaries. This results in both a much faster build process as well as smaller package size.

plugins/repo/.gitignore

@@ -1,2 +1,4 @@
 /commands
 /subcommands/*
+/triggers/*
+/triggers

plugins/repo/Makefile

@@ -1,37 +1,6 @@
-include ../../common.mk
-
-GO_ARGS ?= -a
-
 SUBCOMMANDS = subcommands/gc subcommands/purge-cache
 TRIGGERS = triggers/pre-delete
-build-in-docker: clean
-	docker run --rm \
-		-v $$PWD/../..:$(GO_REPO_ROOT) \
-		-w $(GO_REPO_ROOT)/plugins/repo \
-		$(BUILD_IMAGE) \
-		bash -c "GO_ARGS='$(GO_ARGS)' make -j4 build" || exit $$?
+BUILD = commands subcommands triggers
+PLUGIN_NAME = repo
 
-build: commands subcommands triggers
-	$(MAKE) triggers-copy
-
-commands: **/**/commands.go
-	go build $(GO_ARGS) -o commands src/commands/commands.go
-
-subcommands: $(SUBCOMMANDS)
-
-subcommands/%: src/subcommands/*/%.go
-	go build $(GO_ARGS) -o $@ $<
-
-clean:
-	rm -rf commands subcommands triggers pre-delete
-
-src-clean:
-	rm -rf .gitignore src triggers vendor Makefile *.go glide.*
-
-triggers: $(TRIGGERS)
-
-triggers/%: src/triggers/*/%.go
-	go build $(GO_ARGS) -o $@ $<
-
-triggers-copy:
-	cp triggers/* .
+include ../../common.mk

plugins/repo/pre-delete

@@ -0,0 +1 @@
+triggers

plugins/repo/src/subcommands/purge-cache/purge-cache.go

@@ -1,22 +0,0 @@
-package main
-
-import (
-	"flag"
-
-	"github.com/dokku/dokku/plugins/common"
-	"github.com/dokku/dokku/plugins/repo"
-)
-
-// deletes the contents of the build cache stored in the repository
-func main() {
-	flag.Parse()
-	appName := flag.Arg(1)
-	if appName == "" {
-		common.LogFail("Please specify an app to run the command on")
-	}
-
-	err := repo.PurgeCache(appName)
-	if err != nil {
-		common.LogWarn(err.Error())
-	}
-}

plugins/repo/src/subcommands/subcommands.go

@@ -0,0 +1,35 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/common"
+	"github.com/dokku/dokku/plugins/repo"
+)
+
+// main entrypoint to all subcommands
+func main() {
+	parts := strings.Split(os.Args[0], "/")
+	subcommand := parts[len(parts)-1]
+	flag.Parse()
+
+	var err error
+	switch subcommand {
+	case "gc":
+		flag.Parse()
+		appName := flag.Arg(1)
+		err = repo.CommandGc(appName)
+	case "purge-cache":
+		appName := flag.Arg(1)
+		err = repo.CommandPurgeCache(appName)
+	default:
+		common.LogFail(fmt.Sprintf("Invalid plugin subcommand call: %s", subcommand))
+	}
+
+	if err != nil {
+		common.LogFail(err.Error())
+	}
+}

plugins/repo/src/triggers/pre-delete/pre-delete.go

@@ -1,19 +0,0 @@
-package main
-
-import (
-	"flag"
-
-	"github.com/dokku/dokku/plugins/common"
-	"github.com/dokku/dokku/plugins/repo"
-)
-
-// destroys the buildpacks property for a given app container
-func main() {
-	flag.Parse()
-	appName := flag.Arg(0)
-
-	err := repo.PurgeCache(appName)
-	if err != nil {
-		common.LogFail(err.Error())
-	}
-}

plugins/repo/src/triggers/triggers.go

@@ -0,0 +1,31 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/dokku/dokku/plugins/common"
+	"github.com/dokku/dokku/plugins/repo"
+)
+
+// 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 "pre-delete":
+		appName := flag.Arg(0)
+		err = repo.PurgeCache(appName)
+	default:
+		common.LogFail(fmt.Sprintf("Invalid plugin trigger call: %s", trigger))
+	}
+
+	if err != nil {
+		common.LogFail(err.Error())
+	}
+}

plugins/repo/subcommands.go

@@ -1,22 +1,20 @@
-package main
+package repo
 
 import (
-	"flag"
+	"errors"
 	"strings"
 
 	"github.com/dokku/dokku/plugins/common"
 )
 
-// runs 'git gc --aggressive' against the application's repo
-func main() {
-	flag.Parse()
-	appName := flag.Arg(1)
+// CommandGc runs 'git gc --aggressive' against the application's repo
+func CommandGc(appName string) error {
 	if appName == "" {
-		common.LogFail("Please specify an app to run the command on")
+		return errors.New("Please specify an app to run the command on")
 	}
 	err := common.VerifyAppName(appName)
 	if err != nil {
-		common.LogFail(err.Error())
+		return err
 	}
 
 	appRoot := strings.Join([]string{common.MustGetEnv("DOKKU_ROOT"), appName}, "/")
@@ -26,4 +24,14 @@ func main() {
 	gitGcCmd := common.NewShellCmd("git gc --aggressive")
 	gitGcCmd.Env = cmdEnv
 	gitGcCmd.Execute()
+	return nil
+}
+
+// CommandPurgeCache deletes the contents of the build cache stored in the repository
+func CommandPurgeCache(appName string) error {
+	if appName == "" {
+		common.LogFail("Please specify an app to run the command on")
+	}
+
+	return PurgeCache(appName)
 }