Rendering: add capabilities check (#44470)

* #44449: add feature check to rendering service

* #44449: formatting

* #44449: rename feature -> capability (https://developer.mozilla.org/en-US/docs/Web/API/MediaStreamTrack/getCapabilities, https://developer.mozilla.org/en-US/docs/Web/API/InputDeviceInfo/getCapabilities)

* #44449: refactor

* #44449: remove commented code

* Update pkg/services/rendering/capabilities.go

Co-authored-by: Agnès Toulet <35176601+AgnesToulet@users.noreply.github.com>

* #44449: review fixes

Co-authored-by: Agnès Toulet <35176601+AgnesToulet@users.noreply.github.com>

pkg/services/alerting/notifier_test.go

@@ -345,6 +345,10 @@ type testRenderService struct {
 	renderErrorImageProvider func(error error) (*rendering.RenderResult, error)
 }
 
+func (s *testRenderService) HasCapability(feature rendering.CapabilityName) (rendering.CapabilitySupportRequestResult, error) {
+	return rendering.CapabilitySupportRequestResult{}, nil
+}
+
 func (s *testRenderService) IsAvailable() bool {
 	if s.isAvailableProvider != nil {
 		return s.isAvailableProvider()

pkg/services/rendering/capabilities.go

@@ -0,0 +1,55 @@
+package rendering
+
+import (
+	"errors"
+
+	"github.com/Masterminds/semver"
+)
+
+type Capability struct {
+	name             CapabilityName
+	semverConstraint string
+}
+
+type CapabilityName string
+
+const (
+	ScalingDownImages CapabilityName = "ScalingDownImages"
+	FullHeightImages  CapabilityName = "FullHeightImages"
+)
+
+var ErrUnknownCapability = errors.New("unknown capability")
+var ErrInvalidPluginVersion = errors.New("invalid plugin version")
+
+func (rs *RenderingService) HasCapability(capability CapabilityName) (CapabilitySupportRequestResult, error) {
+	if !rs.IsAvailable() {
+		return CapabilitySupportRequestResult{IsSupported: false, SemverConstraint: ""}, ErrRenderUnavailable
+	}
+
+	var semverConstraint string
+	for i := range rs.capabilities {
+		if rs.capabilities[i].name == capability {
+			semverConstraint = rs.capabilities[i].semverConstraint
+			break
+		}
+	}
+
+	if semverConstraint == "" {
+		return CapabilitySupportRequestResult{}, ErrUnknownCapability
+	}
+
+	compiledSemverConstraint, err := semver.NewConstraint(semverConstraint)
+	if err != nil {
+		rs.log.Error("Failed to parse semver constraint", "constraint", semverConstraint, "capability", capability, "error", err.Error())
+		return CapabilitySupportRequestResult{IsSupported: false, SemverConstraint: semverConstraint}, ErrUnknownCapability
+	}
+
+	imageRendererVersion := rs.Version()
+	compiledImageRendererVersion, err := semver.NewVersion(imageRendererVersion)
+	if err != nil {
+		rs.log.Error("Failed to parse plugin version", "version", imageRendererVersion, "error", err.Error())
+		return CapabilitySupportRequestResult{IsSupported: false, SemverConstraint: semverConstraint}, ErrInvalidPluginVersion
+	}
+
+	return CapabilitySupportRequestResult{IsSupported: compiledSemverConstraint.Check(compiledImageRendererVersion), SemverConstraint: semverConstraint}, nil
+}

pkg/services/rendering/capabilities_test.go

@@ -0,0 +1,136 @@
+package rendering
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+type dummyPluginManager struct{}
+
+func (d *dummyPluginManager) Renderer() *plugins.Plugin {
+	return nil
+}
+
+var dummyRendererUrl = "http://dummyurl.com"
+var testCapabilitySemverConstraint = "> 1.0.0"
+var testCapabilityName = CapabilityName("TestCap")
+var testCapabilityNameInvalidSemver = CapabilityName("TestCapInvalidSemver")
+
+func TestCapabilities(t *testing.T) {
+	cfg := setting.NewCfg()
+	rs := &RenderingService{
+		Cfg:                   cfg,
+		RendererPluginManager: &dummyPluginManager{},
+		log:                   log.New("test-capabilities-rendering-service"),
+		capabilities: []Capability{
+			{name: testCapabilityName, semverConstraint: testCapabilitySemverConstraint},
+			{name: testCapabilityNameInvalidSemver, semverConstraint: "asfasf"},
+		},
+	}
+
+	tests := []struct {
+		name            string
+		rendererUrl     string
+		rendererVersion string
+		capabilityName  CapabilityName
+		expectedError   error
+		expectedResult  CapabilitySupportRequestResult
+	}{
+		{
+			name:            "when image-renderer plugin is not available",
+			rendererUrl:     "",
+			rendererVersion: "",
+			capabilityName:  testCapabilityName,
+			expectedError:   ErrRenderUnavailable,
+			expectedResult: CapabilitySupportRequestResult{
+				IsSupported:      false,
+				SemverConstraint: "",
+			},
+		},
+		{
+			name:            "when image-renderer plugin version is not populated",
+			rendererUrl:     dummyRendererUrl,
+			rendererVersion: "",
+			capabilityName:  testCapabilityName,
+			expectedError:   ErrInvalidPluginVersion,
+			expectedResult: CapabilitySupportRequestResult{
+				IsSupported:      false,
+				SemverConstraint: testCapabilitySemverConstraint,
+			},
+		},
+		{
+			name:            "when image-renderer plugin version is not valid",
+			rendererUrl:     dummyRendererUrl,
+			rendererVersion: "abcd",
+			capabilityName:  testCapabilityName,
+			expectedError:   ErrInvalidPluginVersion,
+			expectedResult: CapabilitySupportRequestResult{
+				IsSupported:      false,
+				SemverConstraint: testCapabilitySemverConstraint,
+			},
+		},
+		{
+			name:            "when image-renderer version does not match target constraint",
+			rendererUrl:     dummyRendererUrl,
+			rendererVersion: "1.0.0",
+			capabilityName:  testCapabilityName,
+			expectedError:   nil,
+			expectedResult: CapabilitySupportRequestResult{
+				IsSupported:      false,
+				SemverConstraint: testCapabilitySemverConstraint,
+			},
+		},
+		{
+			name:            "when image-renderer version matches target constraint",
+			rendererUrl:     dummyRendererUrl,
+			rendererVersion: "2.0.0",
+			capabilityName:  testCapabilityName,
+			expectedError:   nil,
+			expectedResult: CapabilitySupportRequestResult{
+				IsSupported:      true,
+				SemverConstraint: testCapabilitySemverConstraint,
+			},
+		},
+		{
+			name:            "when capability is unknown",
+			rendererUrl:     dummyRendererUrl,
+			rendererVersion: "1.0.0",
+			capabilityName:  CapabilityName("unknown"),
+			expectedError:   ErrUnknownCapability,
+			expectedResult: CapabilitySupportRequestResult{
+				IsSupported:      false,
+				SemverConstraint: "",
+			},
+		},
+		{
+			name:            "when capability has invalid semver constraint",
+			rendererUrl:     dummyRendererUrl,
+			rendererVersion: "1.0.0",
+			capabilityName:  testCapabilityNameInvalidSemver,
+			expectedError:   ErrUnknownCapability,
+			expectedResult: CapabilitySupportRequestResult{
+				IsSupported:      false,
+				SemverConstraint: "asfasf",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			rs.Cfg.RendererUrl = tt.rendererUrl
+			rs.version = tt.rendererVersion
+			res, err := rs.HasCapability(tt.capabilityName)
+
+			if tt.expectedError == nil {
+				require.NoError(t, err)
+			} else {
+				require.ErrorIs(t, err, tt.expectedError)
+			}
+			require.Equal(t, tt.expectedResult, res)
+		})
+	}
+}

pkg/services/rendering/interface.go

@@ -96,6 +96,11 @@ type Session interface {
 	Dispose(ctx context.Context)
 }
 
+type CapabilitySupportRequestResult struct {
+	IsSupported      bool
+	SemverConstraint string
+}
+
 type Service interface {
 	IsAvailable() bool
 	Version() string
@@ -103,5 +108,6 @@ type Service interface {
 	RenderCSV(ctx context.Context, opts CSVOpts, session Session) (*RenderCSVResult, error)
 	RenderErrorImage(theme Theme, error error) (*RenderResult, error)
 	GetRenderUser(ctx context.Context, key string) (*RenderUser, bool)
+	HasCapability(capability CapabilityName) (CapabilitySupportRequestResult, error)
 	CreateRenderingSession(ctx context.Context, authOpts AuthOpts, sessionOpts SessionOpts) (Session, error)
 }

pkg/services/rendering/rendering.go

@@ -37,6 +37,7 @@ type RenderingService struct {
 	inProgressCount int32
 	version         string
 	versionMutex    sync.RWMutex
+	capabilities    []Capability
 
 	perRequestRenderKeyProvider renderKeyProvider
 	Cfg                         *setting.Cfg
@@ -81,6 +82,16 @@ func ProvideService(cfg *setting.Cfg, remoteCache *remotecache.RemoteCache, rm p
 			log:       logger,
 			keyExpiry: 5 * time.Minute,
 		},
+		capabilities: []Capability{
+			{
+				name:             FullHeightImages,
+				semverConstraint: ">= 3.4.0",
+			},
+			{
+				name:             ScalingDownImages,
+				semverConstraint: ">= 3.4.0",
+			},
+		},
 		Cfg:                   cfg,
 		RemoteCacheService:    remoteCache,
 		RendererPluginManager: rm,