Plugins: Introduce plugin asset provider (#108063)

* introduce plugin asset provider

* simply with PR feedback

* fix linter

pkg/plugins/pluginassets/ifaces.go

@@ -0,0 +1,24 @@
+package pluginassets
+
+import "github.com/grafana/grafana/pkg/plugins"
+
+type Provider interface {
+	Module(plugin PluginInfo) (string, error)
+	AssetPath(plugin PluginInfo, assetPath ...string) (string, error)
+}
+
+type PluginInfo struct {
+	JsonData plugins.JSONData
+	Class    plugins.Class
+	FS       plugins.FS
+	Parent   *PluginInfo
+}
+
+func NewPluginInfo(jsonData plugins.JSONData, class plugins.Class, fs plugins.FS, parent *PluginInfo) PluginInfo {
+	return PluginInfo{
+		JsonData: jsonData,
+		Class:    class,
+		FS:       fs,
+		Parent:   parent,
+	}
+}

pkg/plugins/pluginassets/pluginassets.go

@@ -0,0 +1,28 @@
+package pluginassets
+
+import (
+	"path"
+	"path/filepath"
+
+	"github.com/grafana/grafana/pkg/plugins"
+)
+
+var _ Provider = (*LocalProvider)(nil)
+
+type LocalProvider struct{}
+
+func ProvideService() *LocalProvider {
+	return &LocalProvider{}
+}
+
+func (s *LocalProvider) Module(plugin PluginInfo) (string, error) {
+	if plugin.Class == plugins.ClassCore && filepath.Base(plugin.FS.Base()) != "dist" {
+		return path.Join("core:plugin", filepath.Base(plugin.FS.Base())), nil
+	}
+
+	return s.AssetPath(plugin, "module.js")
+}
+
+func (s *LocalProvider) AssetPath(plugin PluginInfo, assetPath ...string) (string, error) {
+	return path.Join("public/plugins", plugin.JsonData.ID, path.Join(assetPath...)), nil
+}

pkg/plugins/pluginassets/pluginassets_test.go

@@ -0,0 +1,132 @@
+package pluginassets
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/grafana/grafana/pkg/plugins"
+)
+
+func TestLocalProvider_Module(t *testing.T) {
+	tests := []struct {
+		name     string
+		plugin   PluginInfo
+		expected string
+	}{
+		{
+			name: "core plugin without dist in base path should use core:plugin prefix",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "grafana-testdata-datasource"},
+				Class:    plugins.ClassCore,
+				FS:       plugins.NewLocalFS("/grafana/plugins/grafana-testdata-datasource"),
+			},
+			expected: "core:plugin/grafana-testdata-datasource",
+		},
+		{
+			name: "core plugin with dist in base path should use standard path",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "grafana-testdata-datasource"},
+				Class:    plugins.ClassCore,
+				FS:       plugins.NewLocalFS("/grafana/plugins/grafana-testdata-datasource/dist"),
+			},
+			expected: "public/plugins/grafana-testdata-datasource/module.js",
+		},
+		{
+			name: "external plugin should always use standard path",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "external-plugin"},
+				Class:    plugins.ClassExternal,
+				FS:       plugins.NewLocalFS("/var/lib/grafana/plugins/external-plugin"),
+			},
+			expected: "public/plugins/external-plugin/module.js",
+		},
+		{
+			name: "CDN plugin should use standard path",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "cdn-plugin"},
+				Class:    plugins.ClassCDN,
+				FS:       plugins.NewLocalFS("/cdn/plugins/cdn-plugin"),
+			},
+			expected: "public/plugins/cdn-plugin/module.js",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &LocalProvider{}
+			got, err := p.Module(tt.plugin)
+			require.NoError(t, err)
+			assert.Equal(t, tt.expected, got)
+		})
+	}
+}
+
+func TestLocalProvider_AssetPath(t *testing.T) {
+	tests := []struct {
+		name      string
+		plugin    PluginInfo
+		assetPath []string
+		expected  string
+	}{
+		{
+			name: "single asset path",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "test-plugin"},
+			},
+			assetPath: []string{"img/logo.svg"},
+			expected:  "public/plugins/test-plugin/img/logo.svg",
+		},
+		{
+			name: "multiple asset path segments",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "test-plugin"},
+			},
+			assetPath: []string{"static", "img", "icon.png"},
+			expected:  "public/plugins/test-plugin/static/img/icon.png",
+		},
+		{
+			name: "empty asset path",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "test-plugin"},
+			},
+			assetPath: []string{},
+			expected:  "public/plugins/test-plugin",
+		},
+		{
+			name: "asset path with special characters",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "test-plugin"},
+			},
+			assetPath: []string{"dist/panel-options.json"},
+			expected:  "public/plugins/test-plugin/dist/panel-options.json",
+		},
+		{
+			name: "core plugin asset path",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "grafana-testdata-datasource"},
+				Class:    plugins.ClassCore,
+			},
+			assetPath: []string{"query-editor.js"},
+			expected:  "public/plugins/grafana-testdata-datasource/query-editor.js",
+		},
+		{
+			name: "deeply nested asset path",
+			plugin: PluginInfo{
+				JsonData: plugins.JSONData{ID: "test-plugin"},
+			},
+			assetPath: []string{"very", "deep", "nested", "path", "to", "file.js"},
+			expected:  "public/plugins/test-plugin/very/deep/nested/path/to/file.js",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := &LocalProvider{}
+			got, err := p.AssetPath(tt.plugin, tt.assetPath...)
+			require.NoError(t, err)
+			assert.Equal(t, tt.expected, got)
+		})
+	}
+}