MM-11420: plugins: compute bundle hash on load (#9172)

* plugins: compute bundle hash on load

Use this hash to bust client caches whenever the plugin bundle changes.

* eliminate redundant pluginHandler

* switch to 64-bit FNV-1a

* Fix test

plugin/environment.go

@@ -5,6 +5,7 @@ package plugin
 
 import (
 	"fmt"
+	"hash/fnv"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -133,29 +134,27 @@ func (env *Environment) Statuses() (model.PluginStatuses, error) {
 	return pluginStatuses, nil
 }
 
-// Activate activates the plugin with the given id.
-func (env *Environment) Activate(id string) (reterr error) {
-
+func (env *Environment) Activate(id string) (manifest *model.Manifest, activated bool, reterr error) {
 	// Check if we are already active
 	if _, ok := env.activePlugins.Load(id); ok {
-		return nil
+		return nil, false, nil
 	}
 
 	plugins, err := env.Available()
 	if err != nil {
-		return err
+		return nil, false, err
 	}
 	var pluginInfo *model.BundleInfo
 	for _, p := range plugins {
 		if p.Manifest != nil && p.Manifest.Id == id {
 			if pluginInfo != nil {
-				return fmt.Errorf("multiple plugins found: %v", id)
+				return nil, false, fmt.Errorf("multiple plugins found: %v", id)
 			}
 			pluginInfo = p
 		}
 	}
 	if pluginInfo == nil {
-		return fmt.Errorf("plugin not found: %v", id)
+		return nil, false, fmt.Errorf("plugin not found: %v", id)
 	}
 
 	activePlugin := activePlugin{BundleInfo: pluginInfo}
@@ -171,43 +170,54 @@ func (env *Environment) Activate(id string) (reterr error) {
 	if pluginInfo.Manifest.Webapp != nil {
 		bundlePath := filepath.Clean(pluginInfo.Manifest.Webapp.BundlePath)
 		if bundlePath == "" || bundlePath[0] == '.' {
-			return fmt.Errorf("invalid webapp bundle path")
+			return nil, false, fmt.Errorf("invalid webapp bundle path")
 		}
 		bundlePath = filepath.Join(env.pluginDir, id, bundlePath)
 		destinationPath := filepath.Join(env.webappPluginDir, id)
 
 		if err := os.RemoveAll(destinationPath); err != nil {
-			return errors.Wrapf(err, "unable to remove old webapp bundle directory: %v", destinationPath)
+			return nil, false, errors.Wrapf(err, "unable to remove old webapp bundle directory: %v", destinationPath)
 		}
 
 		if err := utils.CopyDir(filepath.Dir(bundlePath), destinationPath); err != nil {
-			return errors.Wrapf(err, "unable to copy webapp bundle directory: %v", id)
+			return nil, false, errors.Wrapf(err, "unable to copy webapp bundle directory: %v", id)
 		}
 
+		sourceBundleFilepath := filepath.Join(destinationPath, filepath.Base(bundlePath))
+
+		sourceBundleFileContents, err := ioutil.ReadFile(sourceBundleFilepath)
+		if err != nil {
+			return nil, false, errors.Wrapf(err, "unable to read webapp bundle: %v", id)
+		}
+
+		hash := fnv.New64a()
+		hash.Write(sourceBundleFileContents)
+		pluginInfo.Manifest.Webapp.BundleHash = hash.Sum([]byte{})
+
 		if err := os.Rename(
-			filepath.Join(destinationPath, filepath.Base(bundlePath)),
-			filepath.Join(destinationPath, fmt.Sprintf("%s_bundle.js", id)),
+			sourceBundleFilepath,
+			filepath.Join(destinationPath, fmt.Sprintf("%s_%x_bundle.js", id, pluginInfo.Manifest.Webapp.BundleHash)),
 		); err != nil {
-			return errors.Wrapf(err, "unable to rename webapp bundle: %v", id)
+			return nil, false, errors.Wrapf(err, "unable to rename webapp bundle: %v", id)
 		}
 	}
 
 	if pluginInfo.Manifest.HasServer() {
 		supervisor, err := newSupervisor(pluginInfo, env.logger, env.newAPIImpl(pluginInfo.Manifest))
 		if err != nil {
-			return errors.Wrapf(err, "unable to start plugin: %v", id)
+			return nil, false, errors.Wrapf(err, "unable to start plugin: %v", id)
 		}
 		activePlugin.supervisor = supervisor
 	}
 
-	return nil
+	return pluginInfo.Manifest, true, nil
 }
 
 // Deactivates the plugin with the given id.
-func (env *Environment) Deactivate(id string) {
+func (env *Environment) Deactivate(id string) bool {
 	p, ok := env.activePlugins.Load(id)
 	if !ok {
-		return
+		return false
 	}
 
 	env.activePlugins.Delete(id)
@@ -219,6 +229,8 @@ func (env *Environment) Deactivate(id string) {
 		}
 		activePlugin.supervisor.Shutdown()
 	}
+
+	return true
 }
 
 // Shutdown deactivates all plugins and gracefully shuts down the environment.