SSE: Support for ML query node (#69963)

* introduce a new node-type ML and implement a command outlier that uses ML plugin as a source of data.
* add feature flag mlExpressions that guards the feature

pkg/expr/ml/node_test.go

@@ -0,0 +1,167 @@
+package ml
+
+import (
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/stretchr/testify/require"
+)
+
+func TestUnmarshalCommand(t *testing.T) {
+	appURL := "https://grafana.com"
+
+	updateJson := func(cmd string, f func(m map[string]interface{})) func(t *testing.T) []byte {
+		return func(t *testing.T) []byte {
+			var d map[string]interface{}
+			require.NoError(t, json.UnmarshalFromString(cmd, &d))
+			f(d)
+			data, err := json.Marshal(d)
+			require.NoError(t, err)
+			return data
+		}
+	}
+	t.Run("should parse outlier command", func(t *testing.T) {
+		cmd, err := UnmarshalCommand([]byte(outlierQuery), appURL)
+		require.NoError(t, err)
+		require.IsType(t, &OutlierCommand{}, cmd)
+		outlier := cmd.(*OutlierCommand)
+		require.Equal(t, 1234*time.Millisecond, outlier.interval)
+		require.Equal(t, appURL, outlier.appURL)
+		require.Equal(t, OutlierCommandConfiguration{
+			DatasourceType: "prometheus",
+			DatasourceUID:  "a4ce599c-4c93-44b9-be5b-76385b8c01be",
+			QueryParams: map[string]interface{}{
+				"expr":  "go_goroutines{}",
+				"range": true,
+				"refId": "A",
+			},
+			Algorithm: map[string]interface{}{
+				"name": "dbscan",
+				"config": map[string]interface{}{
+					"epsilon": 7.667,
+				},
+				"sensitivity": 0.83,
+			},
+			ResponseType: "binary",
+		}, outlier.config)
+	})
+	t.Run("should fallback to default if 'intervalMs' is not specified", func(t *testing.T) {
+		data := updateJson(outlierQuery, func(m map[string]interface{}) {
+			delete(m, "intervalMs")
+		})(t)
+		cmd, err := UnmarshalCommand(data, appURL)
+		require.NoError(t, err)
+		outlier := cmd.(*OutlierCommand)
+		require.Equal(t, defaultInterval, outlier.interval)
+	})
+	t.Run("fails when", func(t *testing.T) {
+		testCases := []struct {
+			name   string
+			config func(t *testing.T) []byte
+			err    string
+		}{
+			{
+				name: "field 'type' is missing",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					delete(cmd, "type")
+				}),
+				err: "required field 'type' is not specified or empty.  Should be one of [outlier]",
+			},
+			{
+				name: "field 'type' is not known",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					cmd["type"] = uuid.NewString()
+				}),
+				err: "unsupported command type. Should be one of [outlier]",
+			},
+			{
+				name: "field 'type' is not string",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					cmd["type"] = map[string]interface{}{
+						"data": 1,
+					}
+				}),
+				err: "failed to unmarshall Machine learning command",
+			},
+			{
+				name: "field 'config' is missing",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					delete(cmd, "config")
+				}),
+				err: "required field 'config' is not specified",
+			},
+			{
+				name: "field 'intervalMs' is not number",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					cmd["intervalMs"] = "test"
+				}),
+				err: "failed to unmarshall Machine learning command",
+			},
+			{
+				name: "field 'config.datasource_uid' is not specified",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					cfg := cmd["config"].(map[string]interface{})
+					delete(cfg, "datasource_uid")
+				}),
+				err: "required field `config.datasource_uid` is not specified",
+			},
+			{
+				name: "field 'config.algorithm' is not specified",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					cfg := cmd["config"].(map[string]interface{})
+					delete(cfg, "algorithm")
+				}),
+				err: "required field `config.algorithm` is not specified",
+			},
+			{
+				name: "field 'config.response_type' is not specified",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					cfg := cmd["config"].(map[string]interface{})
+					delete(cfg, "response_type")
+				}),
+				err: "required field `config.response_type` is not specified",
+			},
+			{
+				name: "fields 'config.query' and 'config.query_params' are not specified",
+				config: updateJson(outlierQuery, func(cmd map[string]interface{}) {
+					cfg := cmd["config"].(map[string]interface{})
+					delete(cfg, "query")
+					delete(cfg, "query_params")
+				}),
+				err: "neither of required fields `config.query_params` or `config.query` are specified",
+			},
+		}
+
+		for _, testCase := range testCases {
+			t.Run(testCase.name, func(t *testing.T) {
+				_, err := UnmarshalCommand(testCase.config(t), appURL)
+				require.ErrorContains(t, err, testCase.err)
+			})
+		}
+	})
+}
+
+const outlierQuery = `
+{
+	"type": "outlier",
+	"intervalMs": 1234,
+	"config": {
+		"datasource_uid": "a4ce599c-4c93-44b9-be5b-76385b8c01be",
+		"datasource_type": "prometheus",
+		"query_params": {
+			"expr": "go_goroutines{}",
+			"range": true,
+			"refId": "A"
+		},
+		"response_type": "binary",
+		"algorithm": {
+			"name": "dbscan",
+			"config": {
+				"epsilon": 7.667
+			},
+			"sensitivity": 0.83
+		}
+	}
+}
+`