Add table-model query support to the Grafana data source plugin

connectors/grafana-plugin/README.md

@@ -69,7 +69,7 @@ Click the `New Dashboard` icon on the top right, and select `Add an empty panel`
 
 <img style="width:100%; max-width:800px; max-height:600px; margin-left:auto; margin-right:auto; display:block;" src="https://github.com/apache/iotdb-bin-resources/blob/main/docs/UserGuide/Ecosystem%20Integration/Grafana-plugin/add%20empty%20panel.png?raw=true">
 
-Grafana plugin supports SQL: Full Customized mode and SQL: Drop-down List mode, and the default mode is SQL: Full Customized mode.
+Grafana plugin supports SQL: Full Customized mode and SQL: Drop-down List mode for the tree model, and SQL: Table Model mode for the table model. The default mode is SQL: Full Customized mode.
 
 <img style="width:100%; max-width:800px; max-height:600px; margin-left:auto; margin-right:auto; display:block;" src="https://github.com/apache/iotdb-bin-resources/blob/main/docs/UserGuide/Ecosystem%20Integration/Grafana-plugin/grafana_input_style.png?raw=true">
 
@@ -119,6 +119,37 @@ Select a time series in the TIME-SERIES selection box, select a function in the
 
 <img style="width:100%; max-width:800px; max-height:600px; margin-left:auto; margin-right:auto; display:block;" src="https://github.com/apache/iotdb-bin-resources/blob/main/docs/UserGuide/Ecosystem%20Integration/Grafana-plugin/grafana_input2.png?raw=true">
 
+##### SQL: Table Model
+
+Queries IoTDB's table model (IoTDB 2.x) through the native Go client ([apache/iotdb-client-go](https://github.com/apache/iotdb-client-go)). Enter a standard SQL statement in the SQL input box, for example:
+
+```sql
+SELECT time, device_id, temperature FROM table1 WHERE $__timeFilter(time)
+```
+
+Unlike the tree-model modes, which go through the REST service, this mode connects to the IoTDB RPC port (6667 by default). The data source's `rpc address` option sets that endpoint explicitly; when it is left empty, the URL's host with port 6667 is used.
+
+DATABASE input box: the database to run the statement against. Required — every query first runs `USE <database>` on its pooled session, so results stay deterministic regardless of which session the pool hands out. Fully-qualified `database.table` references are still allowed and take precedence over the session database.
+
+SQL input box: a single table-model SELECT statement. The following macros are expanded by the plugin before the statement is sent:
+
+| Macro | Expands to |
+| ----- | ---------- |
+| `$__timeFilter(col)` | `(col >= <panel start> AND col <= <panel end>)`; `col` defaults to `time` when omitted |
+| `$__timeFrom`, `$__timeFrom()` | the panel range start as an ISO 8601 UTC timestamp literal |
+| `$__timeTo`, `$__timeTo()` | the panel range end as an ISO 8601 UTC timestamp literal |
+
+The macros expand to ISO 8601 timestamp literals (e.g. `2020-09-13T12:26:40.000+00:00`), which the server interprets in its own configured `timestamp_precision` — so time filtering works unchanged on `ms`, `us` and `ns` servers, and TIMESTAMP values are likewise converted by the client using the server-reported precision.
+
+FORMAT option:
+
+* `Time series` (default): rows are sorted by the first TIMESTAMP column, and a result that contains tag/string columns next to numeric columns is pivoted into one series per tag combination — so a query returning several devices renders as separate lines in a time-series panel. Note that the pivot requires timestamps without nulls; results are sorted by the plugin, so an `ORDER BY` clause is not needed.
+* `Table`: rows are returned exactly as the server sent them (use this with the table panel, or when your `ORDER BY` should be preserved).
+
+Result columns are typed from the result set's data types: TIMESTAMP columns become Grafana time fields, INT32/INT64 become integers, FLOAT/DOUBLE become floats, BOOLEAN becomes booleans, and TEXT/STRING/DATE/BLOB render as strings.
+
+There is no server-imposed row cap on this path; add a `LIMIT` clause when querying wide time ranges over dense data to bound the result size.
+
 #### Support for variables and template functions
 
 Both SQL: Full Customized and SQL: Drop-down List input methods support the variable and template functions of grafana. In the following example, raw input method is used, and aggregation is similar.

connectors/grafana-plugin/go.mod

@@ -19,11 +19,15 @@ go 1.21
 
 toolchain go1.21.0
 
-require github.com/grafana/grafana-plugin-sdk-go v0.250.0
+require (
+	github.com/apache/iotdb-client-go/v2 v2.0.8
+	github.com/grafana/grafana-plugin-sdk-go v0.250.0
+)
 
 require (
 	github.com/BurntSushi/toml v1.3.2 // indirect
 	github.com/apache/arrow/go/v15 v15.0.2 // indirect
+	github.com/apache/thrift v0.17.0 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect

connectors/grafana-plugin/pkg/plugin/plugin.go

@@ -28,8 +28,10 @@ import (
 	"net/http"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
+	"github.com/apache/iotdb-client-go/v2/client"
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/httpclient"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/instancemgmt"
@@ -70,7 +72,8 @@ func ApacheIoTDBDatasource(ctx context.Context, d backend.DataSourceInstanceSett
 	if password, exists := d.DecryptedSecureJSONData["password"]; exists {
 		authorization = "Basic " + base64.StdEncoding.EncodeToString([]byte(dm.Username+":"+password))
 	}
-	return &IoTDBDataSource{CallResourceHandler: iotdbResourceHandler(authorization, httpClient), Username: dm.Username, Ulr: dm.Url, httpClient: httpClient}, nil
+	password := d.DecryptedSecureJSONData["password"]
+	return &IoTDBDataSource{CallResourceHandler: iotdbResourceHandler(authorization, httpClient), Username: dm.Username, Ulr: dm.Url, RPCAddress: dm.RPCAddress, password: password, httpClient: httpClient}, nil
 }
 
 // SampleDatasource is an example datasource which can respond to data queries, reports
@@ -79,7 +82,14 @@ type IoTDBDataSource struct {
 	backend.CallResourceHandler
 	Username   string
 	Ulr        string
+	RPCAddress string
+	password   string
 	httpClient *http.Client
+
+	// Native-client session pool for the table-model mode, created lazily by
+	// getTablePool on the first table query.
+	tablePoolMu sync.Mutex
+	tablePool   *client.TableSessionPool
 }
 
 // Dispose here tells plugin SDK that plugin wants to clean up resources when a new instance
@@ -88,6 +98,12 @@ type IoTDBDataSource struct {
 func (d *IoTDBDataSource) Dispose() {
 	// Clean up datasource instance resources.
 	d.httpClient.CloseIdleConnections()
+	d.tablePoolMu.Lock()
+	defer d.tablePoolMu.Unlock()
+	if d.tablePool != nil {
+		d.tablePool.Close()
+		d.tablePool = nil
+	}
 }
 
 // QueryData handles multiple queries and returns multiple responses.
@@ -113,6 +129,10 @@ func (d *IoTDBDataSource) QueryData(ctx context.Context, req *backend.QueryDataR
 type dataSourceModel struct {
 	Username string `json:"username"`
 	Url      string `json:"url"`
+	// RPCAddress is the IoTDB RPC endpoint (host or host:port) the native
+	// client used by the table-model mode connects to. When empty, the URL's
+	// host with the default RPC port 6667 is used.
+	RPCAddress string `json:"rpcAddress"`
 }
 
 type groupBy struct {
@@ -134,6 +154,9 @@ type queryParam struct {
 	FillClauses  string   `json:"fillClauses"`
 	GroupBy      groupBy  `json:"groupBy"`
 	Hide         bool     `json:"hide"`
+	Database     string   `json:"database"`
+	Sql          string   `json:"sql"`
+	Format       string   `json:"format"`
 }
 
 type QueryDataReq struct {
@@ -200,6 +223,17 @@ func verifyQuery(query backend.DataQuery) (qp *queryParam, errMsg string) {
 				return nil, "Input error, FROM is required"
 			}
 		}
+	} else if qp.SqlType == TableModelSqlType {
+		if strings.TrimSpace(qp.Sql) == "" {
+			return nil, "Input error, SQL is required"
+		}
+		// The database is required: every query then USEs it on its pooled
+		// session, so a session's leftover USE state from a previous query
+		// can never influence the result (PooledTableSession.Close only
+		// resets the database when the pool has one configured).
+		if strings.TrimSpace(qp.Database) == "" {
+			return nil, "Input error, DATABASE is required"
+		}
 	} else {
 		return nil, "none"
 	}
@@ -231,6 +265,10 @@ func (d *IoTDBDataSource) query(cxt context.Context, pCtx backend.PluginContext,
 	qp.StartTime = query.TimeRange.From.UnixNano() / 1000000
 	qp.EndTime = query.TimeRange.To.UnixNano() / 1000000
 
+	if qp.SqlType == TableModelSqlType {
+		return d.queryTableModel(cxt, qp)
+	}
+
 	if qp.SqlType == "SQL: Drop-down List" {
 		qp.Control = ""
 		var expressions []string = qp.Paths[len(qp.Paths)-1:]