Add support for sending health check to datasource plugins. (#22771)

closes #21519
ref grafana/grafana-plugin-sdk-go#93

go.mod

@@ -32,7 +32,7 @@ require (
 	github.com/gorilla/websocket v1.4.1
 	github.com/gosimple/slug v1.4.2
 	github.com/grafana/grafana-plugin-model v0.0.0-20190930120109-1fc953a61fb4
-	github.com/grafana/grafana-plugin-sdk-go v0.26.0
+	github.com/grafana/grafana-plugin-sdk-go v0.28.0
 	github.com/hashicorp/go-hclog v0.0.0-20180709165350-ff2cf002a8dd
 	github.com/hashicorp/go-plugin v1.0.1
 	github.com/hashicorp/go-version v1.1.0

go.sum

@@ -133,14 +133,8 @@ github.com/gosimple/slug v1.4.2 h1:jDmprx3q/9Lfk4FkGZtvzDQ9Cj9eAmsjzeQGp24PeiQ=
 github.com/gosimple/slug v1.4.2/go.mod h1:ER78kgg1Mv0NQGlXiDe57DpCyfbNywXXZ9mIorhxAf0=
 github.com/grafana/grafana-plugin-model v0.0.0-20190930120109-1fc953a61fb4 h1:SPdxCL9BChFTlyi0Khv64vdCW4TMna8+sxL7+Chx+Ag=
 github.com/grafana/grafana-plugin-model v0.0.0-20190930120109-1fc953a61fb4/go.mod h1:nc0XxBzjeGcrMltCDw269LoWF9S8ibhgxolCdA1R8To=
-github.com/grafana/grafana-plugin-sdk-go v0.21.0 h1:5en5MdVFgeD9tuHDuJgwHYdIVjPs0PN0a7ZQ2bZNxNk=
+github.com/grafana/grafana-plugin-sdk-go v0.28.0 h1:vRyaOOzpvqKhh4619Woepqe7wen4juQyKFxPFPFz1wE=
-github.com/grafana/grafana-plugin-sdk-go v0.21.0/go.mod h1:G6Ov9M+FDOZXNw8eKXINO6XzqdUvTs7huwyQp5jLTBQ=
+github.com/grafana/grafana-plugin-sdk-go v0.28.0/go.mod h1:G6Ov9M+FDOZXNw8eKXINO6XzqdUvTs7huwyQp5jLTBQ=
-github.com/grafana/grafana-plugin-sdk-go v0.22.1-0.20200310164332-6b4c0d952d70 h1:VQFBaWHlxwjb4VB5HuXtuucMzXJ7xZGGASzbqA3VtVo=
-github.com/grafana/grafana-plugin-sdk-go v0.22.1-0.20200310164332-6b4c0d952d70/go.mod h1:G6Ov9M+FDOZXNw8eKXINO6XzqdUvTs7huwyQp5jLTBQ=
-github.com/grafana/grafana-plugin-sdk-go v0.24.0 h1:sgd9rAQMmB0rAIMd4JVMFM0Gc+CTHoDwN5oxkPjVrGw=
-github.com/grafana/grafana-plugin-sdk-go v0.24.0/go.mod h1:G6Ov9M+FDOZXNw8eKXINO6XzqdUvTs7huwyQp5jLTBQ=
-github.com/grafana/grafana-plugin-sdk-go v0.26.0 h1:zDOZMGgGOrFF5m7+iqcQSQA/AJiG9xplNibL8SbLmn4=
-github.com/grafana/grafana-plugin-sdk-go v0.26.0/go.mod h1:G6Ov9M+FDOZXNw8eKXINO6XzqdUvTs7huwyQp5jLTBQ=
 github.com/hashicorp/go-hclog v0.0.0-20180709165350-ff2cf002a8dd h1:rNuUHR+CvK1IS89MMtcF0EpcVMZtjKfPRp4MEmt/aTs=
 github.com/hashicorp/go-hclog v0.0.0-20180709165350-ff2cf002a8dd/go.mod h1:9bjs9uLqI8l75knNv3lV1kA55veR+WUPSiKIWcQHudI=
 github.com/hashicorp/go-plugin v1.0.1 h1:4OtAfUGbnKC6yS48p0CtMX2oFYtzFZVv6rok3cRWgnE=

pkg/api/api.go

@@ -265,6 +265,7 @@ func (hs *HTTPServer) registerRoutes() {
 		apiRoute.Any("/datasources/proxy/:id", reqSignedIn, hs.ProxyDataSourceRequest)
 		apiRoute.Any("/datasources/:id/resources", hs.CallDatasourceResource)
 		apiRoute.Any("/datasources/:id/resources/*", hs.CallDatasourceResource)
+		apiRoute.Any("/datasources/:id/health", hs.CheckDatasourceHealth)
 
 		// Folders
 		apiRoute.Group("/folders", func(folderRoute routing.RouteRegister) {

pkg/api/datasources.go

@@ -323,3 +323,78 @@ func convertModelToDtos(ds *models.DataSource) dtos.DataSource {
 
 	return dto
 }
+
+// CheckDatasourceHealth sends a health check request to the plugin datasource
+// /api/datasource/:id/health
+func (hs *HTTPServer) CheckDatasourceHealth(c *models.ReqContext) {
+	datasourceID := c.ParamsInt64("id")
+
+	ds, err := hs.DatasourceCache.GetDatasource(datasourceID, c.SignedInUser, c.SkipCache)
+	if err != nil {
+		if err == models.ErrDataSourceAccessDenied {
+			c.JsonApiErr(403, "Access denied to datasource", err)
+			return
+		}
+		c.JsonApiErr(500, "Unable to load datasource metadata", err)
+		return
+	}
+
+	plugin, ok := hs.PluginManager.GetDatasource(ds.Type)
+	if !ok {
+		c.JsonApiErr(500, "Unable to find datasource plugin", err)
+		return
+	}
+
+	config := &backendplugin.PluginConfig{
+		OrgID:    c.OrgId,
+		PluginID: plugin.Id,
+		DataSourceConfig: &backendplugin.DataSourceConfig{
+			ID:                      ds.Id,
+			Name:                    ds.Name,
+			URL:                     ds.Url,
+			Database:                ds.Database,
+			User:                    ds.User,
+			BasicAuthEnabled:        ds.BasicAuth,
+			BasicAuthUser:           ds.BasicAuthUser,
+			JSONData:                ds.JsonData,
+			DecryptedSecureJSONData: ds.DecryptedValues(),
+			Updated:                 ds.Updated,
+		},
+	}
+
+	resp, err := hs.BackendPluginManager.CheckHealth(c.Req.Context(), config)
+	if err != nil {
+		if err == backendplugin.ErrPluginNotRegistered {
+			c.JsonApiErr(404, "Plugin not found", err)
+			return
+		}
+
+		// Return status unknown instead?
+		if err == backendplugin.ErrDiagnosticsNotSupported {
+			c.JsonApiErr(404, "Health check not implemented", err)
+			return
+		}
+
+		// Return status unknown or error instead?
+		if err == backendplugin.ErrHealthCheckFailed {
+			c.JsonApiErr(500, "Plugin health check failed", err)
+			return
+		}
+
+		c.JsonApiErr(500, "Plugin healthcheck returned an unknown error", err)
+		return
+	}
+
+	payload := map[string]interface{}{
+		"status":      resp.Status.String(),
+		"message":     resp.Message,
+		"jsonDetails": resp.JSONDetails,
+	}
+
+	if resp.Status != backendplugin.HealthStatusOk {
+		c.JSON(503, payload)
+		return
+	}
+
+	c.JSON(200, payload)
+}

pkg/api/http_server.go

@@ -73,6 +73,7 @@ type HTTPServer struct {
 	Login                *login.LoginService      `inject:""`
 	License              models.Licensing         `inject:""`
 	BackendPluginManager backendplugin.Manager    `inject:""`
+	PluginManager        *plugins.PluginManager   `inject:""`
 }
 
 func (hs *HTTPServer) Init() error {

pkg/api/plugins.go

@@ -1,10 +1,12 @@
 package api
 
 import (
+	"errors"
 	"sort"
 	"time"
 
 	"github.com/grafana/grafana/pkg/components/simplejson"
+	"github.com/grafana/grafana/pkg/util/errutil"
 
 	"github.com/grafana/grafana/pkg/api/dtos"
 	"github.com/grafana/grafana/pkg/bus"
@@ -14,6 +16,41 @@ import (
 	"github.com/grafana/grafana/pkg/setting"
 )
 
+// ErrPluginNotFound is returned when an requested plugin is not installed.
+var ErrPluginNotFound error = errors.New("plugin not found, no installed plugin with that id")
+
+func (hs *HTTPServer) getPluginConfig(pluginID string, user *models.SignedInUser) (backendplugin.PluginConfig, error) {
+	pluginConfig := backendplugin.PluginConfig{}
+	plugin, exists := plugins.Plugins[pluginID]
+	if !exists {
+		return pluginConfig, ErrPluginNotFound
+	}
+
+	var jsonData *simplejson.Json
+	var decryptedSecureJSONData map[string]string
+	var updated time.Time
+
+	ps, err := hs.getCachedPluginSettings(pluginID, user)
+	if err != nil {
+		if err != models.ErrPluginSettingNotFound {
+			return pluginConfig, errutil.Wrap("Failed to get plugin settings", err)
+		}
+		jsonData = simplejson.New()
+		decryptedSecureJSONData = make(map[string]string)
+	} else {
+		decryptedSecureJSONData = ps.DecryptedValues()
+		updated = ps.Updated
+	}
+
+	return backendplugin.PluginConfig{
+		OrgID:                   user.OrgId,
+		PluginID:                plugin.Id,
+		JSONData:                jsonData,
+		DecryptedSecureJSONData: decryptedSecureJSONData,
+		Updated:                 updated,
+	}, nil
+}
+
 func (hs *HTTPServer) GetPluginList(c *models.ReqContext) Response {
 	typeFilter := c.Query("type")
 	enabledFilter := c.Query("enabled")
@@ -209,7 +246,17 @@ func ImportDashboard(c *models.ReqContext, apiCmd dtos.ImportDashboardCommand) R
 // /api/plugins/:pluginId/health
 func (hs *HTTPServer) CheckHealth(c *models.ReqContext) Response {
 	pluginID := c.Params("pluginId")
-	resp, err := hs.BackendPluginManager.CheckHealth(c.Req.Context(), pluginID)
+
+	config, err := hs.getPluginConfig(pluginID, c.SignedInUser)
+	if err != nil {
+		if err == ErrPluginNotFound {
+			return Error(404, "Plugin not found, no installed plugin with that id", nil)
+		}
+
+		return Error(500, "Failed to get plugin settings", err)
+	}
+
+	resp, err := hs.BackendPluginManager.CheckHealth(c.Req.Context(), &config)
 	if err != nil {
 		if err == backendplugin.ErrPluginNotRegistered {
 			return Error(404, "Plugin not found", err)
@@ -224,6 +271,8 @@ func (hs *HTTPServer) CheckHealth(c *models.ReqContext) Response {
 		if err == backendplugin.ErrHealthCheckFailed {
 			return Error(500, "Plugin health check failed", err)
 		}
+
+		return Error(500, "Plugin healthcheck returned an unknown error", err)
 	}
 
 	payload := map[string]interface{}{
@@ -239,39 +288,23 @@ func (hs *HTTPServer) CheckHealth(c *models.ReqContext) Response {
 	return JSON(200, payload)
 }
 
+// CallResource passes a resource call from a plugin to the backend plugin.
+//
 // /api/plugins/:pluginId/resources/*
 func (hs *HTTPServer) CallResource(c *models.ReqContext) {
 	pluginID := c.Params("pluginId")
-	plugin, exists := plugins.Plugins[pluginID]
+
-	if !exists {
+	config, err := hs.getPluginConfig(pluginID, c.SignedInUser)
-		c.JsonApiErr(404, "Plugin not found, no installed plugin with that id", nil)
+	if err != nil {
+		if err == ErrPluginNotFound {
+			c.JsonApiErr(404, "Plugin not found, no installed plugin with that id", nil)
+			return
+		}
+
+		c.JsonApiErr(500, "Failed to get plugin settings", err)
 		return
 	}
 
-	var jsonData *simplejson.Json
-	var decryptedSecureJSONData map[string]string
-	var updated time.Time
-
-	ps, err := hs.getCachedPluginSettings(pluginID, c.SignedInUser)
-	if err != nil {
-		if err != models.ErrPluginSettingNotFound {
-			c.JsonApiErr(500, "Failed to get plugin settings", err)
-			return
-		}
-		jsonData = simplejson.New()
-		decryptedSecureJSONData = make(map[string]string)
-	} else {
-		decryptedSecureJSONData = ps.DecryptedValues()
-		updated = ps.Updated
-	}
-
-	config := backendplugin.PluginConfig{
-		OrgID:                   c.OrgId,
-		PluginID:                plugin.Id,
-		JSONData:                jsonData,
-		DecryptedSecureJSONData: decryptedSecureJSONData,
-		Updated:                 updated,
-	}
 	hs.BackendPluginManager.CallResource(config, c, c.Params("*"))
 }
 

pkg/plugins/backendplugin/backend_plugin.go

@@ -185,14 +185,27 @@ func (p *BackendPlugin) CollectMetrics(ctx context.Context, ch chan<- prometheus
 	return nil
 }
 
-func (p *BackendPlugin) checkHealth(ctx context.Context) (*pluginv2.CheckHealthResponse, error) {
+func (p *BackendPlugin) checkHealth(ctx context.Context, config *PluginConfig) (*pluginv2.CheckHealthResponse, error) {
 	if p.diagnostics == nil || p.client == nil || p.client.Exited() {
 		return &pluginv2.CheckHealthResponse{
 			Status: pluginv2.CheckHealthResponse_UNKNOWN,
 		}, nil
 	}
 
-	res, err := p.diagnostics.CheckHealth(ctx, &pluginv2.CheckHealthRequest{})
+	jsonDataBytes, err := config.JSONData.ToDB()
+	if err != nil {
+		return nil, err
+	}
+
+	pconfig := &pluginv2.PluginConfig{
+		OrgId:                   config.OrgID,
+		PluginId:                config.PluginID,
+		JsonData:                jsonDataBytes,
+		DecryptedSecureJsonData: config.DecryptedSecureJSONData,
+		LastUpdatedMS:           config.Updated.UnixNano() / int64(time.Millisecond),
+	}
+
+	res, err := p.diagnostics.CheckHealth(ctx, &pluginv2.CheckHealthRequest{Config: pconfig})
 	if err != nil {
 		if st, ok := status.FromError(err); ok {
 			if st.Code() == codes.Unimplemented {

pkg/plugins/backendplugin/client.go

@@ -101,7 +101,7 @@ func NewRendererPluginDescriptor(pluginID, executablePath string, startFns Plugi
 }
 
 type DiagnosticsPlugin interface {
-	plugin.DiagnosticsServer
+	plugin.DiagnosticsClient
 }
 
 type ResourcePlugin interface {

pkg/plugins/backendplugin/manager.go

@@ -43,7 +43,7 @@ type Manager interface {
 	// StartPlugin starts a non-managed backend plugin
 	StartPlugin(ctx context.Context, pluginID string) error
 	// CheckHealth checks the health of a registered backend plugin.
-	CheckHealth(ctx context.Context, pluginID string) (*CheckHealthResult, error)
+	CheckHealth(ctx context.Context, pluginConfig *PluginConfig) (*CheckHealthResult, error)
 	// CallResource calls a plugin resource.
 	CallResource(pluginConfig PluginConfig, ctx *models.ReqContext, path string)
 }
@@ -151,9 +151,9 @@ func (m *manager) stop() {
 }
 
 // CheckHealth checks the health of a registered backend plugin.
-func (m *manager) CheckHealth(ctx context.Context, pluginID string) (*CheckHealthResult, error) {
+func (m *manager) CheckHealth(ctx context.Context, pluginConfig *PluginConfig) (*CheckHealthResult, error) {
 	m.pluginsMu.RLock()
-	p, registered := m.plugins[pluginID]
+	p, registered := m.plugins[pluginConfig.PluginID]
 	m.pluginsMu.RUnlock()
 
 	if !registered {
@@ -164,7 +164,7 @@ func (m *manager) CheckHealth(ctx context.Context, pluginID string) (*CheckHealt
 		return nil, ErrDiagnosticsNotSupported
 	}
 
-	res, err := p.checkHealth(ctx)
+	res, err := p.checkHealth(ctx, pluginConfig)
 	if err != nil {
 		p.logger.Error("Failed to check plugin health", "error", err)
 		return nil, ErrHealthCheckFailed

pkg/plugins/plugins.go

@@ -188,6 +188,15 @@ func (pm *PluginManager) scan(pluginDir string) error {
 	return nil
 }
 
+// GetDatasource returns a datasource based on passed pluginID if it exists
+//
+// This function fetches the datasource from the global variable DataSources in this package.
+// Rather then refactor all dependencies on the global variable we can use this as an transition.
+func (pm *PluginManager) GetDatasource(pluginID string) (*DataSourcePlugin, bool) {
+	ds, exist := DataSources[pluginID]
+	return ds, exist
+}
+
 func (scanner *PluginScanner) walker(currentPath string, f os.FileInfo, err error) error {
 	// We scan all the subfolders for plugin.json (with some exceptions) so that we also load embedded plugins, for
 	// example https://github.com/raintank/worldping-app/tree/master/dist/grafana-worldmap-panel worldmap panel plugin

vendor/github.com/google/go-cmp/cmp/cmpopts/equate.go

@@ -0,0 +1,89 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+// Package cmpopts provides common options for the cmp package.
+package cmpopts
+
+import (
+	"math"
+	"reflect"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func equateAlways(_, _ interface{}) bool { return true }
+
+// EquateEmpty returns a Comparer option that determines all maps and slices
+// with a length of zero to be equal, regardless of whether they are nil.
+//
+// EquateEmpty can be used in conjunction with SortSlices and SortMaps.
+func EquateEmpty() cmp.Option {
+	return cmp.FilterValues(isEmpty, cmp.Comparer(equateAlways))
+}
+
+func isEmpty(x, y interface{}) bool {
+	vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
+	return (x != nil && y != nil && vx.Type() == vy.Type()) &&
+		(vx.Kind() == reflect.Slice || vx.Kind() == reflect.Map) &&
+		(vx.Len() == 0 && vy.Len() == 0)
+}
+
+// EquateApprox returns a Comparer option that determines float32 or float64
+// values to be equal if they are within a relative fraction or absolute margin.
+// This option is not used when either x or y is NaN or infinite.
+//
+// The fraction determines that the difference of two values must be within the
+// smaller fraction of the two values, while the margin determines that the two
+// values must be within some absolute margin.
+// To express only a fraction or only a margin, use 0 for the other parameter.
+// The fraction and margin must be non-negative.
+//
+// The mathematical expression used is equivalent to:
+//	|x-y| ≤ max(fraction*min(|x|, |y|), margin)
+//
+// EquateApprox can be used in conjunction with EquateNaNs.
+func EquateApprox(fraction, margin float64) cmp.Option {
+	if margin < 0 || fraction < 0 || math.IsNaN(margin) || math.IsNaN(fraction) {
+		panic("margin or fraction must be a non-negative number")
+	}
+	a := approximator{fraction, margin}
+	return cmp.Options{
+		cmp.FilterValues(areRealF64s, cmp.Comparer(a.compareF64)),
+		cmp.FilterValues(areRealF32s, cmp.Comparer(a.compareF32)),
+	}
+}
+
+type approximator struct{ frac, marg float64 }
+
+func areRealF64s(x, y float64) bool {
+	return !math.IsNaN(x) && !math.IsNaN(y) && !math.IsInf(x, 0) && !math.IsInf(y, 0)
+}
+func areRealF32s(x, y float32) bool {
+	return areRealF64s(float64(x), float64(y))
+}
+func (a approximator) compareF64(x, y float64) bool {
+	relMarg := a.frac * math.Min(math.Abs(x), math.Abs(y))
+	return math.Abs(x-y) <= math.Max(a.marg, relMarg)
+}
+func (a approximator) compareF32(x, y float32) bool {
+	return a.compareF64(float64(x), float64(y))
+}
+
+// EquateNaNs returns a Comparer option that determines float32 and float64
+// NaN values to be equal.
+//
+// EquateNaNs can be used in conjunction with EquateApprox.
+func EquateNaNs() cmp.Option {
+	return cmp.Options{
+		cmp.FilterValues(areNaNsF64s, cmp.Comparer(equateAlways)),
+		cmp.FilterValues(areNaNsF32s, cmp.Comparer(equateAlways)),
+	}
+}
+
+func areNaNsF64s(x, y float64) bool {
+	return math.IsNaN(x) && math.IsNaN(y)
+}
+func areNaNsF32s(x, y float32) bool {
+	return areNaNsF64s(float64(x), float64(y))
+}

vendor/github.com/google/go-cmp/cmp/cmpopts/ignore.go

@@ -0,0 +1,207 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmpopts
+
+import (
+	"fmt"
+	"reflect"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/internal/function"
+)
+
+// IgnoreFields returns an Option that ignores exported fields of the
+// given names on a single struct type.
+// The struct type is specified by passing in a value of that type.
+//
+// The name may be a dot-delimited string (e.g., "Foo.Bar") to ignore a
+// specific sub-field that is embedded or nested within the parent struct.
+//
+// This does not handle unexported fields; use IgnoreUnexported instead.
+func IgnoreFields(typ interface{}, names ...string) cmp.Option {
+	sf := newStructFilter(typ, names...)
+	return cmp.FilterPath(sf.filter, cmp.Ignore())
+}
+
+// IgnoreTypes returns an Option that ignores all values assignable to
+// certain types, which are specified by passing in a value of each type.
+func IgnoreTypes(typs ...interface{}) cmp.Option {
+	tf := newTypeFilter(typs...)
+	return cmp.FilterPath(tf.filter, cmp.Ignore())
+}
+
+type typeFilter []reflect.Type
+
+func newTypeFilter(typs ...interface{}) (tf typeFilter) {
+	for _, typ := range typs {
+		t := reflect.TypeOf(typ)
+		if t == nil {
+			// This occurs if someone tries to pass in sync.Locker(nil)
+			panic("cannot determine type; consider using IgnoreInterfaces")
+		}
+		tf = append(tf, t)
+	}
+	return tf
+}
+func (tf typeFilter) filter(p cmp.Path) bool {
+	if len(p) < 1 {
+		return false
+	}
+	t := p.Last().Type()
+	for _, ti := range tf {
+		if t.AssignableTo(ti) {
+			return true
+		}
+	}
+	return false
+}
+
+// IgnoreInterfaces returns an Option that ignores all values or references of
+// values assignable to certain interface types. These interfaces are specified
+// by passing in an anonymous struct with the interface types embedded in it.
+// For example, to ignore sync.Locker, pass in struct{sync.Locker}{}.
+func IgnoreInterfaces(ifaces interface{}) cmp.Option {
+	tf := newIfaceFilter(ifaces)
+	return cmp.FilterPath(tf.filter, cmp.Ignore())
+}
+
+type ifaceFilter []reflect.Type
+
+func newIfaceFilter(ifaces interface{}) (tf ifaceFilter) {
+	t := reflect.TypeOf(ifaces)
+	if ifaces == nil || t.Name() != "" || t.Kind() != reflect.Struct {
+		panic("input must be an anonymous struct")
+	}
+	for i := 0; i < t.NumField(); i++ {
+		fi := t.Field(i)
+		switch {
+		case !fi.Anonymous:
+			panic("struct cannot have named fields")
+		case fi.Type.Kind() != reflect.Interface:
+			panic("embedded field must be an interface type")
+		case fi.Type.NumMethod() == 0:
+			// This matches everything; why would you ever want this?
+			panic("cannot ignore empty interface")
+		default:
+			tf = append(tf, fi.Type)
+		}
+	}
+	return tf
+}
+func (tf ifaceFilter) filter(p cmp.Path) bool {
+	if len(p) < 1 {
+		return false
+	}
+	t := p.Last().Type()
+	for _, ti := range tf {
+		if t.AssignableTo(ti) {
+			return true
+		}
+		if t.Kind() != reflect.Ptr && reflect.PtrTo(t).AssignableTo(ti) {
+			return true
+		}
+	}
+	return false
+}
+
+// IgnoreUnexported returns an Option that only ignores the immediate unexported
+// fields of a struct, including anonymous fields of unexported types.
+// In particular, unexported fields within the struct's exported fields
+// of struct types, including anonymous fields, will not be ignored unless the
+// type of the field itself is also passed to IgnoreUnexported.
+//
+// Avoid ignoring unexported fields of a type which you do not control (i.e. a
+// type from another repository), as changes to the implementation of such types
+// may change how the comparison behaves. Prefer a custom Comparer instead.
+func IgnoreUnexported(typs ...interface{}) cmp.Option {
+	ux := newUnexportedFilter(typs...)
+	return cmp.FilterPath(ux.filter, cmp.Ignore())
+}
+
+type unexportedFilter struct{ m map[reflect.Type]bool }
+
+func newUnexportedFilter(typs ...interface{}) unexportedFilter {
+	ux := unexportedFilter{m: make(map[reflect.Type]bool)}
+	for _, typ := range typs {
+		t := reflect.TypeOf(typ)
+		if t == nil || t.Kind() != reflect.Struct {
+			panic(fmt.Sprintf("invalid struct type: %T", typ))
+		}
+		ux.m[t] = true
+	}
+	return ux
+}
+func (xf unexportedFilter) filter(p cmp.Path) bool {
+	sf, ok := p.Index(-1).(cmp.StructField)
+	if !ok {
+		return false
+	}
+	return xf.m[p.Index(-2).Type()] && !isExported(sf.Name())
+}
+
+// isExported reports whether the identifier is exported.
+func isExported(id string) bool {
+	r, _ := utf8.DecodeRuneInString(id)
+	return unicode.IsUpper(r)
+}
+
+// IgnoreSliceElements returns an Option that ignores elements of []V.
+// The discard function must be of the form "func(T) bool" which is used to
+// ignore slice elements of type V, where V is assignable to T.
+// Elements are ignored if the function reports true.
+func IgnoreSliceElements(discardFunc interface{}) cmp.Option {
+	vf := reflect.ValueOf(discardFunc)
+	if !function.IsType(vf.Type(), function.ValuePredicate) || vf.IsNil() {
+		panic(fmt.Sprintf("invalid discard function: %T", discardFunc))
+	}
+	return cmp.FilterPath(func(p cmp.Path) bool {
+		si, ok := p.Index(-1).(cmp.SliceIndex)
+		if !ok {
+			return false
+		}
+		if !si.Type().AssignableTo(vf.Type().In(0)) {
+			return false
+		}
+		vx, vy := si.Values()
+		if vx.IsValid() && vf.Call([]reflect.Value{vx})[0].Bool() {
+			return true
+		}
+		if vy.IsValid() && vf.Call([]reflect.Value{vy})[0].Bool() {
+			return true
+		}
+		return false
+	}, cmp.Ignore())
+}
+
+// IgnoreMapEntries returns an Option that ignores entries of map[K]V.
+// The discard function must be of the form "func(T, R) bool" which is used to
+// ignore map entries of type K and V, where K and V are assignable to T and R.
+// Entries are ignored if the function reports true.
+func IgnoreMapEntries(discardFunc interface{}) cmp.Option {
+	vf := reflect.ValueOf(discardFunc)
+	if !function.IsType(vf.Type(), function.KeyValuePredicate) || vf.IsNil() {
+		panic(fmt.Sprintf("invalid discard function: %T", discardFunc))
+	}
+	return cmp.FilterPath(func(p cmp.Path) bool {
+		mi, ok := p.Index(-1).(cmp.MapIndex)
+		if !ok {
+			return false
+		}
+		if !mi.Key().Type().AssignableTo(vf.Type().In(0)) || !mi.Type().AssignableTo(vf.Type().In(1)) {
+			return false
+		}
+		k := mi.Key()
+		vx, vy := mi.Values()
+		if vx.IsValid() && vf.Call([]reflect.Value{k, vx})[0].Bool() {
+			return true
+		}
+		if vy.IsValid() && vf.Call([]reflect.Value{k, vy})[0].Bool() {
+			return true
+		}
+		return false
+	}, cmp.Ignore())
+}

vendor/github.com/google/go-cmp/cmp/cmpopts/sort.go

@@ -0,0 +1,147 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmpopts
+
+import (
+	"fmt"
+	"reflect"
+	"sort"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/internal/function"
+)
+
+// SortSlices returns a Transformer option that sorts all []V.
+// The less function must be of the form "func(T, T) bool" which is used to
+// sort any slice with element type V that is assignable to T.
+//
+// The less function must be:
+//	• Deterministic: less(x, y) == less(x, y)
+//	• Irreflexive: !less(x, x)
+//	• Transitive: if !less(x, y) and !less(y, z), then !less(x, z)
+//
+// The less function does not have to be "total". That is, if !less(x, y) and
+// !less(y, x) for two elements x and y, their relative order is maintained.
+//
+// SortSlices can be used in conjunction with EquateEmpty.
+func SortSlices(lessFunc interface{}) cmp.Option {
+	vf := reflect.ValueOf(lessFunc)
+	if !function.IsType(vf.Type(), function.Less) || vf.IsNil() {
+		panic(fmt.Sprintf("invalid less function: %T", lessFunc))
+	}
+	ss := sliceSorter{vf.Type().In(0), vf}
+	return cmp.FilterValues(ss.filter, cmp.Transformer("cmpopts.SortSlices", ss.sort))
+}
+
+type sliceSorter struct {
+	in  reflect.Type  // T
+	fnc reflect.Value // func(T, T) bool
+}
+
+func (ss sliceSorter) filter(x, y interface{}) bool {
+	vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
+	if !(x != nil && y != nil && vx.Type() == vy.Type()) ||
+		!(vx.Kind() == reflect.Slice && vx.Type().Elem().AssignableTo(ss.in)) ||
+		(vx.Len() <= 1 && vy.Len() <= 1) {
+		return false
+	}
+	// Check whether the slices are already sorted to avoid an infinite
+	// recursion cycle applying the same transform to itself.
+	ok1 := sort.SliceIsSorted(x, func(i, j int) bool { return ss.less(vx, i, j) })
+	ok2 := sort.SliceIsSorted(y, func(i, j int) bool { return ss.less(vy, i, j) })
+	return !ok1 || !ok2
+}
+func (ss sliceSorter) sort(x interface{}) interface{} {
+	src := reflect.ValueOf(x)
+	dst := reflect.MakeSlice(src.Type(), src.Len(), src.Len())
+	for i := 0; i < src.Len(); i++ {
+		dst.Index(i).Set(src.Index(i))
+	}
+	sort.SliceStable(dst.Interface(), func(i, j int) bool { return ss.less(dst, i, j) })
+	ss.checkSort(dst)
+	return dst.Interface()
+}
+func (ss sliceSorter) checkSort(v reflect.Value) {
+	start := -1 // Start of a sequence of equal elements.
+	for i := 1; i < v.Len(); i++ {
+		if ss.less(v, i-1, i) {
+			// Check that first and last elements in v[start:i] are equal.
+			if start >= 0 && (ss.less(v, start, i-1) || ss.less(v, i-1, start)) {
+				panic(fmt.Sprintf("incomparable values detected: want equal elements: %v", v.Slice(start, i)))
+			}
+			start = -1
+		} else if start == -1 {
+			start = i
+		}
+	}
+}
+func (ss sliceSorter) less(v reflect.Value, i, j int) bool {
+	vx, vy := v.Index(i), v.Index(j)
+	return ss.fnc.Call([]reflect.Value{vx, vy})[0].Bool()
+}
+
+// SortMaps returns a Transformer option that flattens map[K]V types to be a
+// sorted []struct{K, V}. The less function must be of the form
+// "func(T, T) bool" which is used to sort any map with key K that is
+// assignable to T.
+//
+// Flattening the map into a slice has the property that cmp.Equal is able to
+// use Comparers on K or the K.Equal method if it exists.
+//
+// The less function must be:
+//	• Deterministic: less(x, y) == less(x, y)
+//	• Irreflexive: !less(x, x)
+//	• Transitive: if !less(x, y) and !less(y, z), then !less(x, z)
+//	• Total: if x != y, then either less(x, y) or less(y, x)
+//
+// SortMaps can be used in conjunction with EquateEmpty.
+func SortMaps(lessFunc interface{}) cmp.Option {
+	vf := reflect.ValueOf(lessFunc)
+	if !function.IsType(vf.Type(), function.Less) || vf.IsNil() {
+		panic(fmt.Sprintf("invalid less function: %T", lessFunc))
+	}
+	ms := mapSorter{vf.Type().In(0), vf}
+	return cmp.FilterValues(ms.filter, cmp.Transformer("cmpopts.SortMaps", ms.sort))
+}
+
+type mapSorter struct {
+	in  reflect.Type  // T
+	fnc reflect.Value // func(T, T) bool
+}
+
+func (ms mapSorter) filter(x, y interface{}) bool {
+	vx, vy := reflect.ValueOf(x), reflect.ValueOf(y)
+	return (x != nil && y != nil && vx.Type() == vy.Type()) &&
+		(vx.Kind() == reflect.Map && vx.Type().Key().AssignableTo(ms.in)) &&
+		(vx.Len() != 0 || vy.Len() != 0)
+}
+func (ms mapSorter) sort(x interface{}) interface{} {
+	src := reflect.ValueOf(x)
+	outType := reflect.StructOf([]reflect.StructField{
+		{Name: "K", Type: src.Type().Key()},
+		{Name: "V", Type: src.Type().Elem()},
+	})
+	dst := reflect.MakeSlice(reflect.SliceOf(outType), src.Len(), src.Len())
+	for i, k := range src.MapKeys() {
+		v := reflect.New(outType).Elem()
+		v.Field(0).Set(k)
+		v.Field(1).Set(src.MapIndex(k))
+		dst.Index(i).Set(v)
+	}
+	sort.Slice(dst.Interface(), func(i, j int) bool { return ms.less(dst, i, j) })
+	ms.checkSort(dst)
+	return dst.Interface()
+}
+func (ms mapSorter) checkSort(v reflect.Value) {
+	for i := 1; i < v.Len(); i++ {
+		if !ms.less(v, i-1, i) {
+			panic(fmt.Sprintf("partial order detected: want %v < %v", v.Index(i-1), v.Index(i)))
+		}
+	}
+}
+func (ms mapSorter) less(v reflect.Value, i, j int) bool {
+	vx, vy := v.Index(i).Field(0), v.Index(j).Field(0)
+	return ms.fnc.Call([]reflect.Value{vx, vy})[0].Bool()
+}

vendor/github.com/google/go-cmp/cmp/cmpopts/struct_filter.go

@@ -0,0 +1,182 @@
+// Copyright 2017, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmpopts
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+// filterField returns a new Option where opt is only evaluated on paths that
+// include a specific exported field on a single struct type.
+// The struct type is specified by passing in a value of that type.
+//
+// The name may be a dot-delimited string (e.g., "Foo.Bar") to select a
+// specific sub-field that is embedded or nested within the parent struct.
+func filterField(typ interface{}, name string, opt cmp.Option) cmp.Option {
+	// TODO: This is currently unexported over concerns of how helper filters
+	// can be composed together easily.
+	// TODO: Add tests for FilterField.
+
+	sf := newStructFilter(typ, name)
+	return cmp.FilterPath(sf.filter, opt)
+}
+
+type structFilter struct {
+	t  reflect.Type // The root struct type to match on
+	ft fieldTree    // Tree of fields to match on
+}
+
+func newStructFilter(typ interface{}, names ...string) structFilter {
+	// TODO: Perhaps allow * as a special identifier to allow ignoring any
+	// number of path steps until the next field match?
+	// This could be useful when a concrete struct gets transformed into
+	// an anonymous struct where it is not possible to specify that by type,
+	// but the transformer happens to provide guarantees about the names of
+	// the transformed fields.
+
+	t := reflect.TypeOf(typ)
+	if t == nil || t.Kind() != reflect.Struct {
+		panic(fmt.Sprintf("%T must be a struct", typ))
+	}
+	var ft fieldTree
+	for _, name := range names {
+		cname, err := canonicalName(t, name)
+		if err != nil {
+			panic(fmt.Sprintf("%s: %v", strings.Join(cname, "."), err))
+		}
+		ft.insert(cname)
+	}
+	return structFilter{t, ft}
+}
+
+func (sf structFilter) filter(p cmp.Path) bool {
+	for i, ps := range p {
+		if ps.Type().AssignableTo(sf.t) && sf.ft.matchPrefix(p[i+1:]) {
+			return true
+		}
+	}
+	return false
+}
+
+// fieldTree represents a set of dot-separated identifiers.
+//
+// For example, inserting the following selectors:
+//	Foo
+//	Foo.Bar.Baz
+//	Foo.Buzz
+//	Nuka.Cola.Quantum
+//
+// Results in a tree of the form:
+//	{sub: {
+//		"Foo": {ok: true, sub: {
+//			"Bar": {sub: {
+//				"Baz": {ok: true},
+//			}},
+//			"Buzz": {ok: true},
+//		}},
+//		"Nuka": {sub: {
+//			"Cola": {sub: {
+//				"Quantum": {ok: true},
+//			}},
+//		}},
+//	}}
+type fieldTree struct {
+	ok  bool                 // Whether this is a specified node
+	sub map[string]fieldTree // The sub-tree of fields under this node
+}
+
+// insert inserts a sequence of field accesses into the tree.
+func (ft *fieldTree) insert(cname []string) {
+	if ft.sub == nil {
+		ft.sub = make(map[string]fieldTree)
+	}
+	if len(cname) == 0 {
+		ft.ok = true
+		return
+	}
+	sub := ft.sub[cname[0]]
+	sub.insert(cname[1:])
+	ft.sub[cname[0]] = sub
+}
+
+// matchPrefix reports whether any selector in the fieldTree matches
+// the start of path p.
+func (ft fieldTree) matchPrefix(p cmp.Path) bool {
+	for _, ps := range p {
+		switch ps := ps.(type) {
+		case cmp.StructField:
+			ft = ft.sub[ps.Name()]
+			if ft.ok {
+				return true
+			}
+			if len(ft.sub) == 0 {
+				return false
+			}
+		case cmp.Indirect:
+		default:
+			return false
+		}
+	}
+	return false
+}
+
+// canonicalName returns a list of identifiers where any struct field access
+// through an embedded field is expanded to include the names of the embedded
+// types themselves.
+//
+// For example, suppose field "Foo" is not directly in the parent struct,
+// but actually from an embedded struct of type "Bar". Then, the canonical name
+// of "Foo" is actually "Bar.Foo".
+//
+// Suppose field "Foo" is not directly in the parent struct, but actually
+// a field in two different embedded structs of types "Bar" and "Baz".
+// Then the selector "Foo" causes a panic since it is ambiguous which one it
+// refers to. The user must specify either "Bar.Foo" or "Baz.Foo".
+func canonicalName(t reflect.Type, sel string) ([]string, error) {
+	var name string
+	sel = strings.TrimPrefix(sel, ".")
+	if sel == "" {
+		return nil, fmt.Errorf("name must not be empty")
+	}
+	if i := strings.IndexByte(sel, '.'); i < 0 {
+		name, sel = sel, ""
+	} else {
+		name, sel = sel[:i], sel[i:]
+	}
+
+	// Type must be a struct or pointer to struct.
+	if t.Kind() == reflect.Ptr {
+		t = t.Elem()
+	}
+	if t.Kind() != reflect.Struct {
+		return nil, fmt.Errorf("%v must be a struct", t)
+	}
+
+	// Find the canonical name for this current field name.
+	// If the field exists in an embedded struct, then it will be expanded.
+	if !isExported(name) {
+		// Disallow unexported fields:
+		//	* To discourage people from actually touching unexported fields
+		//	* FieldByName is buggy (https://golang.org/issue/4876)
+		return []string{name}, fmt.Errorf("name must be exported")
+	}
+	sf, ok := t.FieldByName(name)
+	if !ok {
+		return []string{name}, fmt.Errorf("does not exist")
+	}
+	var ss []string
+	for i := range sf.Index {
+		ss = append(ss, t.FieldByIndex(sf.Index[:i+1]).Name)
+	}
+	if sel == "" {
+		return ss, nil
+	}
+	ssPost, err := canonicalName(sf.Type, sel)
+	return append(ss, ssPost...), err
+}

vendor/github.com/google/go-cmp/cmp/cmpopts/xform.go

@@ -0,0 +1,35 @@
+// Copyright 2018, The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE.md file.
+
+package cmpopts
+
+import (
+	"github.com/google/go-cmp/cmp"
+)
+
+type xformFilter struct{ xform cmp.Option }
+
+func (xf xformFilter) filter(p cmp.Path) bool {
+	for _, ps := range p {
+		if t, ok := ps.(cmp.Transform); ok && t.Option() == xf.xform {
+			return false
+		}
+	}
+	return true
+}
+
+// AcyclicTransformer returns a Transformer with a filter applied that ensures
+// that the transformer cannot be recursively applied upon its own output.
+//
+// An example use case is a transformer that splits a string by lines:
+//	AcyclicTransformer("SplitLines", func(s string) []string{
+//		return strings.Split(s, "\n")
+//	})
+//
+// Had this been an unfiltered Transformer instead, this would result in an
+// infinite cycle converting a string to []string to [][]string and so on.
+func AcyclicTransformer(name string, xformFunc interface{}) cmp.Option {
+	xf := xformFilter{cmp.Transformer(name, xformFunc)}
+	return cmp.FilterPath(xf.filter, xf.xform)
+}

vendor/github.com/grafana/grafana-plugin-sdk-go/data/frame.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 )
 
 // Frame represents a columnar storage with optional labels.
@@ -45,6 +46,15 @@ func (f *Frame) AppendRow(vals ...interface{}) {
 	}
 }
 
+// RowCopy returns an interface slice that contains the values of each Field for the given rowIdx.
+func (f *Frame) RowCopy(rowIdx int) []interface{} {
+	vals := make([]interface{}, len(f.Fields))
+	for i := range f.Fields {
+		vals[i] = f.CopyAt(i, rowIdx)
+	}
+	return vals
+}
+
 // AppendWarning adds warnings to the data frame.
 func (f *Frame) AppendWarning(message string, details string) {
 	f.Warnings = append(f.Warnings, Warning{Message: message, Details: details})
@@ -76,6 +86,44 @@ func (f *Frame) AppendRowSafe(vals ...interface{}) error {
 	return nil
 }
 
+// FilterRowsByField returns a copy of frame f (as per EmptyCopy()) that includes rows
+// where the filter returns true and no error. If filter returns an error, then an error is returned.
+func (f *Frame) FilterRowsByField(fieldIdx int, filter func(i interface{}) (bool, error)) (*Frame, error) {
+	filteredFrame := f.EmptyCopy()
+	rowLen, err := f.RowLen()
+	if err != nil {
+		return nil, err
+	}
+	for inRowIdx := 0; inRowIdx < rowLen; inRowIdx++ {
+		match, err := filter(f.At(fieldIdx, inRowIdx))
+		if err != nil {
+			return nil, err
+		}
+		if !match {
+			continue
+		}
+		filteredFrame.AppendRow(f.RowCopy(inRowIdx)...)
+	}
+	return filteredFrame, nil
+}
+
+// EmptyCopy returns a copy of Frame f but with Fields of zero length, and no copy of the FieldConfigs, Metadata, or Warnings.
+func (f *Frame) EmptyCopy() *Frame {
+	newFrame := &Frame{
+		Name:   f.Name,
+		RefID:  f.RefID,
+		Fields: make(Fields, 0, len(f.Fields)),
+	}
+
+	for _, field := range f.Fields {
+		copy := NewFieldFromFieldType(field.Type(), 0)
+		copy.Name = field.Name
+		copy.Labels = field.Labels.Copy()
+		newFrame.Fields = append(newFrame.Fields, copy)
+	}
+	return newFrame
+}
+
 // TypeIndices returns a slice of Field index positions for the given pTypes.
 func (f *Frame) TypeIndices(pTypes ...FieldType) []int {
 	indices := []int{}
@@ -319,6 +367,15 @@ func (l Labels) Equals(arg Labels) bool {
 	return true
 }
 
+// Copy returns a copy of the labels.
+func (l Labels) Copy() Labels {
+	c := make(Labels, len(l))
+	for k, v := range l {
+		c[k] = v
+	}
+	return c
+}
+
 // Contains returns true if all k=v pairs of the argument are in the receiver.
 func (l Labels) Contains(arg Labels) bool {
 	if len(arg) > len(l) {
@@ -483,5 +540,5 @@ func FrameTestCompareOptions() []cmp.Option {
 	})
 
 	unexportedField := cmp.AllowUnexported(Field{})
-	return []cmp.Option{confFloats, unexportedField}
+	return []cmp.Option{confFloats, unexportedField, cmpopts.EquateEmpty()}
 }

vendor/modules.txt

@@ -134,6 +134,7 @@ github.com/golang/snappy
 github.com/google/flatbuffers/go
 # github.com/google/go-cmp v0.3.1
 github.com/google/go-cmp/cmp
+github.com/google/go-cmp/cmp/cmpopts
 github.com/google/go-cmp/cmp/internal/diff
 github.com/google/go-cmp/cmp/internal/flags
 github.com/google/go-cmp/cmp/internal/function
@@ -147,7 +148,7 @@ github.com/gosimple/slug
 # github.com/grafana/grafana-plugin-model v0.0.0-20190930120109-1fc953a61fb4
 github.com/grafana/grafana-plugin-model/go/datasource
 github.com/grafana/grafana-plugin-model/go/renderer
-# github.com/grafana/grafana-plugin-sdk-go v0.26.0
+# github.com/grafana/grafana-plugin-sdk-go v0.28.0
 github.com/grafana/grafana-plugin-sdk-go/backend/plugin
 github.com/grafana/grafana-plugin-sdk-go/data
 github.com/grafana/grafana-plugin-sdk-go/genproto/pluginv2