Plugins: Add Plugin FS abstraction (#63734)

* unexport pluginDir from dto

* first pass

* tidy

* naming + add mutex

* add dupe checking

* fix func typo

* interface + move logic from renderer

* remote finder

* remote signing

* fix tests

* tidy up

* tidy markdown logic

* split changes

* fix tests

* slim interface down

* fix status code

* tidy exec path func

* fixup

* undo changes

* remove unused func

* remove unused func

* fix goimports

* fetch remotely

* simultaneous support

* fix linter

* use var

* add exception for gosec warning

* fixup

* fix tests

* tidy

* rework cfg pattern

* simplify

* PR feedback

* fix dupe field

* remove g304 nolint

* apply PR feedback

* remove unnecessary gosec nolint

* fix finder loop and update comment

* fix map alloc

* fix test

* remove commented code

pkg/plugins/plugins.go

@@ -6,8 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"io/fs"
-	"os"
-	"path/filepath"
+	"path"
 	"runtime"
 	"strings"
 
@@ -26,8 +25,8 @@ var ErrFileNotExist = errors.New("file does not exist")
 type Plugin struct {
 	JSONData
 
-	PluginDir string
-	Class     Class
+	FS    FS
+	Class Class
 
 	// App fields
 	IncludedInAppID string
@@ -55,8 +54,8 @@ type Plugin struct {
 type PluginDTO struct {
 	JSONData
 
+	fs                FS
 	logger            log.Logger
-	pluginDir         string
 	supportsStreaming bool
 
 	Class Class
@@ -81,6 +80,10 @@ func (p PluginDTO) SupportsStreaming() bool {
 	return p.supportsStreaming
 }
 
+func (p PluginDTO) Base() string {
+	return p.fs.Base()
+}
+
 func (p PluginDTO) IsApp() bool {
 	return p.Type == App
 }
@@ -96,21 +99,15 @@ func (p PluginDTO) File(name string) (fs.File, error) {
 		return nil, err
 	}
 
-	absPluginDir, err := filepath.Abs(p.pluginDir)
+	if p.fs == nil {
+		return nil, ErrFileNotExist
+	}
+
+	f, err := p.fs.Open(cleanPath)
 	if err != nil {
 		return nil, err
 	}
 
-	absFilePath := filepath.Join(absPluginDir, cleanPath)
-	// Wrapping in filepath.Clean to properly handle
-	// gosec G304 Potential file inclusion via variable rule.
-	f, err := os.Open(filepath.Clean(absFilePath))
-	if err != nil {
-		if os.IsNotExist(err) {
-			return nil, ErrFileNotExist
-		}
-		return nil, err
-	}
 	return f, nil
 }
 
@@ -337,6 +334,18 @@ func (p *Plugin) Client() (PluginClient, bool) {
 }
 
 func (p *Plugin) ExecutablePath() string {
+	if p.IsRenderer() {
+		return p.executablePath("plugin_start")
+	}
+
+	if p.IsSecretsManager() {
+		return p.executablePath("secrets_plugin_start")
+	}
+
+	return p.executablePath(p.Executable)
+}
+
+func (p *Plugin) executablePath(f string) string {
 	os := strings.ToLower(runtime.GOOS)
 	arch := runtime.GOARCH
 	extension := ""
@@ -344,15 +353,7 @@ func (p *Plugin) ExecutablePath() string {
 	if os == "windows" {
 		extension = ".exe"
 	}
-	if p.IsRenderer() {
-		return filepath.Join(p.PluginDir, fmt.Sprintf("%s_%s_%s%s", "plugin_start", os, strings.ToLower(arch), extension))
-	}
-
-	if p.IsSecretsManager() {
-		return filepath.Join(p.PluginDir, fmt.Sprintf("%s_%s_%s%s", "secrets_plugin_start", os, strings.ToLower(arch), extension))
-	}
-
-	return filepath.Join(p.PluginDir, fmt.Sprintf("%s_%s_%s%s", p.Executable, os, strings.ToLower(arch), extension))
+	return path.Join(p.FS.Base(), fmt.Sprintf("%s_%s_%s%s", f, os, strings.ToLower(arch), extension))
 }
 
 type PluginClient interface {
@@ -366,9 +367,10 @@ type PluginClient interface {
 func (p *Plugin) ToDTO() PluginDTO {
 	return PluginDTO{
 		logger:            p.Logger(),
-		pluginDir:         p.PluginDir,
-		JSONData:          p.JSONData,
+		fs:                p.FS,
+		supportsStreaming: p.client != nil && p.client.(backend.StreamHandler) != nil,
 		Class:             p.Class,
+		JSONData:          p.JSONData,
 		IncludedInAppID:   p.IncludedInAppID,
 		DefaultNavURL:     p.DefaultNavURL,
 		Pinned:            p.Pinned,
@@ -378,7 +380,6 @@ func (p *Plugin) ToDTO() PluginDTO {
 		SignatureError:    p.SignatureError,
 		Module:            p.Module,
 		BaseURL:           p.BaseURL,
-		supportsStreaming: p.client != nil && p.client.(backend.StreamHandler) != nil,
 	}
 }
 
@@ -387,7 +388,11 @@ func (p *Plugin) StaticRoute() *StaticRoute {
 		return nil
 	}
 
-	return &StaticRoute{Directory: p.PluginDir, PluginID: p.ID}
+	if p.FS == nil {
+		return nil
+	}
+
+	return &StaticRoute{Directory: p.FS.Base(), PluginID: p.ID}
 }
 
 func (p *Plugin) IsRenderer() bool {
@@ -414,15 +419,6 @@ func (p *Plugin) IsExternalPlugin() bool {
 	return p.Class == External
 }
 
-func (p *Plugin) Manifest() []byte {
-	d, err := os.ReadFile(filepath.Join(p.PluginDir, "MANIFEST.txt"))
-	if err != nil {
-		return []byte{}
-	}
-
-	return d
-}
-
 type Class string
 
 const (