feature: Adds 'read' support

Author: NeedleInAJayStack

README.md

@@ -29,11 +29,25 @@ one by selecting `+ New Dashboard` from the Dashboard menu in the left panel.
 Once within the panel editor, select your Haystack data source in the Data Sources menu. Next, select the type of
 Haystack query that should be performed. The supported queries are:
 
+- Eval: Evaluate a free-form Axon expression. Grafana variables may be injected into the query, with the supported
+variables listed below. *Note: Not all Haystack servers support this functionality*
 - HisRead: Display the history of a single point over the selected time range.
-- Eval: Evaluate a free-form Axon expression. Grafana variables may be injected into the query, with the supported variables
-listed below. *Note: Not all Haystack servers support this functionality*
-  - `$__timeRange_start`: DateTime start of the selected Grafana time range
-  - `$__timeRange_end`: DateTime end of the selected Grafana time range
-  - `$__maxDataPoints`: Number representing the pixel width of Grafana's display panel.
-  - `$__interval`: Number representing Grafana's recommended data interval. This is the duration of the time range, divided by the number of pixels, delivered in units of minutes.
+- Read: Display the records matching a filter. Since this is not timeseries data, it can only be viewed in Grafana's
+"Table" view.
+
+#### Variables
+
+Some queries support injecting values from the Grafana UI. The following variables are supported:
+
+- `$__timeRange_start`: DateTime start of the selected Grafana time range
+- `$__timeRange_end`: DateTime end of the selected Grafana time range
+- `$__maxDataPoints`: Number representing the pixel width of Grafana's display panel.
+- `$__interval`: Number representing Grafana's recommended data interval. This is the duration of the time range, 
+divided by the number of pixels, delivered in units of minutes.
+
+To use them, simply use the value in the input string like this:
+
+```
+[{ts: $__timeRange_start, v0: 0}, {ts: $__timeRange_end, v0: 10}].toGrid
+```
 

pkg/plugin/datasource.go

@@ -99,6 +99,7 @@ type QueryModel struct {
 	Type    string `json:"type"`
 	Eval    string `json:"eval"`
 	HisRead string `json:"hisRead"`
+	Read    string `json:"read"`
 }
 
 func (datasource *Datasource) query(ctx context.Context, pCtx backend.PluginContext, query backend.DataQuery) backend.DataResponse {
@@ -136,6 +137,13 @@ func (datasource *Datasource) query(ctx context.Context, pCtx backend.PluginCont
 			return backend.ErrDataResponse(backend.StatusBadRequest, fmt.Sprintf("HisRead failure: %v", err.Error()))
 		}
 		grid = hisRead
+	case "Read":
+		read, err := datasource.read(model.Read, variables)
+		if err != nil {
+			log.DefaultLogger.Error(err.Error())
+			return backend.ErrDataResponse(backend.StatusBadRequest, fmt.Sprintf("Read failure: %v", err.Error()))
+		}
+		grid = read
 	default:
 		log.DefaultLogger.Warn("No valid input, returning empty Grid")
 		grid = haystack.EmptyGrid()
@@ -191,6 +199,13 @@ func (datasource *Datasource) hisRead(id string, timeRange backend.TimeRange) (h
 	return datasource.client.HisReadAbsDateTime(ref, start, end)
 }
 
+func (datasource *Datasource) read(filter string, variables map[string]string) (haystack.Grid, error) {
+	for name, val := range variables {
+		filter = strings.ReplaceAll(filter, name, val)
+	}
+	return datasource.client.Read(filter)
+}
+
 func dataFrameFromGrid(grid haystack.Grid) (*data.Frame, error) {
 	fields := []*data.Field{}
 

src/components/QueryEditor.tsx

@@ -17,10 +17,14 @@ export function QueryEditor({ query, onChange, onRunQuery }: Props) {
   const onHisReadChange = (event: ChangeEvent<HTMLInputElement>) => {
     onChange({ ...query, type: 'HisRead', hisRead: event.target.value });
   };
+  const onReadChange = (event: ChangeEvent<HTMLInputElement>) => {
+    onChange({ ...query, type: 'Read', read: event.target.value });
+  };
 
   const queryTypes = [
     { label: 'Eval', value: 0, description: 'Evaluate an Axon expression' },
-    { label: 'HisRead', value: 1, description: 'Read the histories of a list of points' }
+    { label: 'HisRead', value: 1, description: 'Read the histories of a list of points' },
+    { label: 'Read', value: 2, description: 'Read the records matched by a filter' }
   ];
   const queryTypeDefault = queryTypes[0];
   function queryTypeFromLabel(label: string) {
@@ -58,7 +62,15 @@ export function QueryEditor({ query, onChange, onRunQuery }: Props) {
         return (
         <Field>
           <InlineField label="Point ID" labelWidth="auto" tooltip="The ID of the point to read">
-            <Input width={100} prefix={<Icon name="angle-right" />} onChange={onHisReadChange} value={query.hisRead} placeholder={DEFAULT_QUERY.hisRead} />
+            <Input width={100} prefix={"@"} onChange={onHisReadChange} value={query.hisRead} placeholder={DEFAULT_QUERY.hisRead} />
+          </InlineField>
+        </Field>
+        );
+      case 2: // Read
+        return (
+        <Field>
+          <InlineField label="Filter" labelWidth="auto" tooltip="A filter for the desired records">
+            <Input width={100} prefix={<Icon name="filter" />} onChange={onReadChange} value={query.read} placeholder={DEFAULT_QUERY.read} />
           </InlineField>
         </Field>
         );

src/types.ts

@@ -4,12 +4,14 @@ export interface MyQuery extends DataQuery {
   type: string; // Defines the type of query that should be executed
   eval: string;
   hisRead: string;
+  read: string;
 }
 
 export const DEFAULT_QUERY: Partial<MyQuery> = {
   type: "Eval",
   eval: "[{ts: $__timeRange_start, v0: 0}, {ts: $__timeRange_end, v0: 10}].toGrid",
-  hisRead: "abcdef-123456"
+  hisRead: "abcdef-123456",
+  read: "point and temp and air and outside"
 };
 
 /**