Chore: Refactor backend plugin manager/tsdb query data (#34944)

Move QueryData method into backend plugin manager which HandleRequest uses to 
query data from plugin SDK supported data sources. This allowed us to remove a lot 
of code no longer needed.

Ref #21510

Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>

pkg/plugins/backendplugin/manager/manager.go

@@ -17,7 +17,6 @@ import (
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana/pkg/infra/log"
 	"github.com/grafana/grafana/pkg/models"
-	"github.com/grafana/grafana/pkg/plugins"
 	"github.com/grafana/grafana/pkg/plugins/backendplugin"
 	"github.com/grafana/grafana/pkg/plugins/backendplugin/instrumentation"
 	"github.com/grafana/grafana/pkg/registry"
@@ -151,6 +150,10 @@ func (m *manager) Get(pluginID string) (backendplugin.Plugin, bool) {
 	p, ok := m.plugins[pluginID]
 	m.pluginsMu.RUnlock()
 
+	if ok && p.IsDecommissioned() {
+		return nil, false
+	}
+
 	return p, ok
 }
 
@@ -181,21 +184,6 @@ func (m *manager) getAzureEnvironmentVariables() []string {
 	return variables
 }
 
-//nolint: staticcheck // plugins.DataPlugin deprecated
-func (m *manager) GetDataPlugin(pluginID string) interface{} {
-	p, _ := m.Get(pluginID)
-
-	if p == nil {
-		return nil
-	}
-
-	if dataPlugin, ok := p.(plugins.DataPlugin); ok {
-		return dataPlugin
-	}
-
-	return nil
-}
-
 // start starts a managed backend plugin
 func (m *manager) start(ctx context.Context, p backendplugin.Plugin) {
 	if !p.IsManaged() {
@@ -244,10 +232,7 @@ func (m *manager) stop(ctx context.Context) {
 
 // CollectMetrics collects metrics from a registered backend plugin.
 func (m *manager) CollectMetrics(ctx context.Context, pluginID string) (*backend.CollectMetricsResult, error) {
-	m.pluginsMu.RLock()
-	p, registered := m.plugins[pluginID]
-	m.pluginsMu.RUnlock()
-
+	p, registered := m.Get(pluginID)
 	if !registered {
 		return nil, backendplugin.ErrPluginNotRegistered
 	}
@@ -279,10 +264,7 @@ func (m *manager) CheckHealth(ctx context.Context, pluginContext backend.PluginC
 		}, nil
 	}
 
-	m.pluginsMu.RLock()
-	p, registered := m.plugins[pluginContext.PluginID]
-	m.pluginsMu.RUnlock()
-
+	p, registered := m.Get(pluginContext.PluginID)
 	if !registered {
 		return nil, backendplugin.ErrPluginNotRegistered
 	}
@@ -308,15 +290,39 @@ func (m *manager) CheckHealth(ctx context.Context, pluginContext backend.PluginC
 	return resp, nil
 }
 
+func (m *manager) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
+	p, registered := m.Get(req.PluginContext.PluginID)
+	if !registered {
+		return nil, backendplugin.ErrPluginNotRegistered
+	}
+
+	var resp *backend.QueryDataResponse
+	err := instrumentation.InstrumentQueryDataRequest(p.PluginID(), func() (innerErr error) {
+		resp, innerErr = p.QueryData(ctx, req)
+		return
+	})
+
+	if err != nil {
+		if errors.Is(err, backendplugin.ErrMethodNotImplemented) {
+			return nil, err
+		}
+
+		if errors.Is(err, backendplugin.ErrPluginUnavailable) {
+			return nil, err
+		}
+
+		return nil, errutil.Wrap("failed to query data", err)
+	}
+
+	return resp, nil
+}
+
 type keepCookiesJSONModel struct {
 	KeepCookies []string `json:"keepCookies"`
 }
 
 func (m *manager) callResourceInternal(w http.ResponseWriter, req *http.Request, pCtx backend.PluginContext) error {
-	m.pluginsMu.RLock()
-	p, registered := m.plugins[pCtx.PluginID]
-	m.pluginsMu.RUnlock()
-
+	p, registered := m.Get(pCtx.PluginID)
 	if !registered {
 		return backendplugin.ErrPluginNotRegistered
 	}

pkg/plugins/backendplugin/manager/manager_test.go

@@ -367,6 +367,7 @@ type testPlugin struct {
 	decommissioned bool
 	backend.CollectMetricsHandlerFunc
 	backend.CheckHealthHandlerFunc
+	backend.QueryDataHandlerFunc
 	backend.CallResourceHandlerFunc
 	mutex sync.RWMutex
 }
@@ -441,6 +442,14 @@ func (tp *testPlugin) CheckHealth(ctx context.Context, req *backend.CheckHealthR
 	return nil, backendplugin.ErrMethodNotImplemented
 }
 
+func (tp *testPlugin) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
+	if tp.QueryDataHandlerFunc != nil {
+		return tp.QueryDataHandlerFunc(ctx, req)
+	}
+
+	return nil, backendplugin.ErrMethodNotImplemented
+}
+
 func (tp *testPlugin) CallResource(ctx context.Context, req *backend.CallResourceRequest, sender backend.CallResourceResponseSender) error {
 	if tp.CallResourceHandlerFunc != nil {
 		return tp.CallResourceHandlerFunc(ctx, req, sender)