Plugins: Make renderer service load renderer plugin (#77854)

* rendering service loads renderer plugin

* update naming

* tidy

* apply PR feedback

* fix missing feature manager

* fix step

* set plugin

pkg/services/pluginsintegration/renderer/renderer.go

@@ -0,0 +1,128 @@
+package renderer
+
+import (
+	"context"
+	"errors"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/plugins/backendplugin/pluginextensionv2"
+	"github.com/grafana/grafana/pkg/plugins/backendplugin/provider"
+	"github.com/grafana/grafana/pkg/plugins/config"
+	"github.com/grafana/grafana/pkg/plugins/envvars"
+	"github.com/grafana/grafana/pkg/plugins/manager/loader"
+	"github.com/grafana/grafana/pkg/plugins/manager/pipeline/bootstrap"
+	"github.com/grafana/grafana/pkg/plugins/manager/pipeline/discovery"
+	"github.com/grafana/grafana/pkg/plugins/manager/pipeline/initialization"
+	"github.com/grafana/grafana/pkg/plugins/manager/pipeline/termination"
+	"github.com/grafana/grafana/pkg/plugins/manager/pipeline/validation"
+	"github.com/grafana/grafana/pkg/plugins/manager/registry"
+	"github.com/grafana/grafana/pkg/plugins/manager/signature"
+	"github.com/grafana/grafana/pkg/plugins/manager/sources"
+	"github.com/grafana/grafana/pkg/services/featuremgmt"
+	"github.com/grafana/grafana/pkg/services/rendering"
+)
+
+func ProvideService(cfg *config.Cfg, registry registry.Service, licensing plugins.Licensing,
+	features featuremgmt.FeatureToggles) (*Manager, error) {
+	l, err := createLoader(cfg, registry, licensing, features)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Manager{
+		cfg:    cfg,
+		loader: l,
+		log:    log.New("plugins.renderer"),
+	}, nil
+}
+
+type Manager struct {
+	cfg    *config.Cfg
+	loader loader.Service
+	log    log.Logger
+
+	renderer *Plugin
+}
+
+type Plugin struct {
+	plugin *plugins.Plugin
+
+	started bool
+}
+
+func (p *Plugin) Client() (pluginextensionv2.RendererPlugin, error) {
+	if !p.started {
+		return nil, errors.New("renderer plugin not started")
+	}
+
+	if p.plugin.Renderer == nil {
+		return nil, errors.New("renderer client not available")
+	}
+
+	return p.plugin.Renderer, nil
+}
+
+func (p *Plugin) Start(ctx context.Context) error {
+	p.started = true
+	return p.plugin.Start(ctx)
+}
+
+func (p *Plugin) Version() string {
+	return p.plugin.JSONData.Info.Version
+}
+
+func (m *Manager) Renderer(ctx context.Context) (rendering.Plugin, bool) {
+	if m.renderer != nil {
+		return m.renderer, true
+	}
+
+	ps, err := m.loader.Load(ctx, sources.NewLocalSource(plugins.ClassExternal, []string{m.cfg.PluginsPath}))
+	if err != nil {
+		m.log.Error("Failed to load renderer plugin", "error", err)
+		return nil, false
+	}
+
+	if len(ps) >= 1 {
+		m.renderer = &Plugin{plugin: ps[0]}
+		return m.renderer, true
+	}
+
+	return nil, false
+}
+
+func createLoader(cfg *config.Cfg, pr registry.Service, l plugins.Licensing,
+	features featuremgmt.FeatureToggles) (loader.Service, error) {
+	d := discovery.New(cfg, discovery.Opts{
+		FindFilterFuncs: []discovery.FindFilterFunc{
+			discovery.NewPermittedPluginTypesFilterStep([]plugins.Type{plugins.TypeRenderer}),
+			func(ctx context.Context, class plugins.Class, bundles []*plugins.FoundBundle) ([]*plugins.FoundBundle, error) {
+				return discovery.NewDuplicatePluginFilterStep(pr).Filter(ctx, bundles)
+			},
+		},
+	})
+	b := bootstrap.New(cfg, bootstrap.Opts{
+		DecorateFuncs: []bootstrap.DecorateFunc{}, // no decoration required
+	})
+	v := validation.New(cfg, validation.Opts{
+		ValidateFuncs: []validation.ValidateFunc{
+			validation.SignatureValidationStep(signature.NewValidator(signature.NewUnsignedAuthorizer(cfg))),
+		},
+	})
+	i := initialization.New(cfg, initialization.Opts{
+		InitializeFuncs: []initialization.InitializeFunc{
+			initialization.BackendClientInitStep(envvars.NewProvider(cfg, l), provider.New(provider.RendererProvider)),
+			initialization.PluginRegistrationStep(pr),
+		},
+	})
+	t, err := termination.New(cfg, termination.Opts{
+		TerminateFuncs: []termination.TerminateFunc{
+			termination.DeregisterStep(pr),
+		},
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	return loader.New(d, b, v, i, t), nil
+}