better metrics trnslation / quering

server/src/models/analytic_unit_model.ts

@@ -1,4 +1,4 @@
-import { Metric } from './metric_model';
+import { GrafanaMetric } from './grafana_metric_model';
 import { Collection, makeDBQ } from '../services/data_service';
 
 
@@ -19,7 +19,7 @@ export class AnalyticUnit {
     public name: string,
     public panelUrl: string,
     public type: string,
-    public metric: Metric,
+    public metric: GrafanaMetric,
     public id?: AnalyticUnitId,
     public lastPredictionTime?: number,
     public status?: AnalyticUnitStatus,
@@ -60,7 +60,7 @@ export class AnalyticUnit {
       obj.name,
       obj.panelUrl,
       obj.type,
-      Metric.fromObject(obj.metric),
+      GrafanaMetric.fromObject(obj.metric),
       obj._id,
       obj.lastPredictionTime,
       obj.status as AnalyticUnitStatus,

server/src/models/grafana_metric_model.ts

@@ -0,0 +1,85 @@
+export type GrafanaDatasource = {
+  url: string,
+  type: string,
+  params: {
+    db: string,
+    q: string,
+    epoch: string
+  }
+}
+
+export type GrafanaMetricId = string;
+
+export class GrafanaMetric {
+
+  private _metricQuery: MetricQuery = undefined;
+
+  constructor(
+    public datasource: GrafanaDatasource,
+    public targets: any[],
+    public id?: GrafanaMetricId
+  ) {
+    if(datasource === undefined) {
+      throw new Error('datasource is undefined');
+    }
+    if(targets === undefined) {
+      throw new Error('targets is undefined');
+    }
+    if(targets.length === 0) {
+      throw new Error('targets is empty');
+    }
+  }
+
+  public get metricQuery() {
+    if(this._metricQuery === undefined) {
+      this._metricQuery = new MetricQuery(this);
+    }
+    return this._metricQuery;
+  }
+
+  public toObject() {
+    return {
+      datasource: this.datasource,
+      targets: this.targets,
+      _id: this.id
+    };
+  }
+
+  static fromObject(obj: any): GrafanaMetric {
+    if(obj === undefined) {
+      throw new Error('obj is undefined');
+    }
+    return new GrafanaMetric(
+      obj.datasource,
+      obj.targets,
+      obj._id
+    );
+  }
+}
+
+export class MetricQuery {
+
+  private static INFLUX_QUERY_TIME_REGEX = /time >[^A-Z]+/;
+
+  private _queryParts: string[];
+
+  constructor(metric: GrafanaMetric) {
+    if (metric.datasource.type !== 'influxdb') {
+      throw new Error(`Queries of type "${metric.datasource.type}" are not supported yet.`);
+    }
+    var queryStr = metric.datasource.params.q;
+    this._queryParts = queryStr.split(MetricQuery.INFLUX_QUERY_TIME_REGEX);
+    if(this._queryParts.length == 1) {
+      throw new Error(
+        `Query "${queryStr}" is not replaced with LIMIT/OFFSET oeprators. Missing time clause.`
+      );
+    }
+    if(this._queryParts.length > 2) {
+      throw new Error(`Query "${queryStr}" has multiple time clauses. Can't parse.`);
+    }
+  }
+
+  getQuery(limit: number, offset: number): string {
+    return `${this._queryParts[0]} TRUE ${this._queryParts[1]} LIMIT ${limit} OFFSET ${offset}`;
+  }
+}

server/src/models/metric_model.ts

@@ -1,48 +0,0 @@
-type Datasource = {
-  url: string,
-  type: string,
-  params: {
-    db: string,
-    q: string,
-    epoch: string
-  }
-}
-
-export type MetricId = string;
-
-export class Metric {
-  constructor(
-    public datasource: Datasource,
-    public targets: any[],
-    public id?: MetricId
-  ) {
-    if(datasource === undefined) {
-      throw new Error('datasource is undefined');
-    }
-    if(targets === undefined) {
-      throw new Error('targets is undefined');
-    }
-    if(targets.length === 0) {
-      throw new Error('targets is empty');
-    }
-  }
-
-  public toObject() {
-    return {
-      datasource: this.datasource,
-      targets: this.targets,
-      _id: this.id
-    };
-  }
-
-  static fromObject(obj: any): Metric {
-    if(obj === undefined) {
-      throw new Error('obj is undefined');
-    }
-    return new Metric(
-      obj.datasource,
-      obj.targets,
-      obj._id
-    );
-  }
-}

server/src/services/grafana_service.ts

@@ -1,23 +1,19 @@
-import { Metric } from '../models/metric_model';
+import { GrafanaMetric } from '../models/grafana_metric_model';
 import { HASTIC_API_KEY } from '../config';
 import { URL } from 'url';
 import axios from 'axios';
 
 
 const CHUNK_SIZE = 50000;
-const QUERY_TIME_REPLACE_REGEX = /(WHERE time >[^A-Z]+)/;
+
 
 /**
  * @param metric to query to Grafana
  * @returns [time, value][] array
  */
-export async function queryByMetric(metric: Metric, panelUrl: string): Promise<[number, number][]> {
+export async function queryByMetric(metric: GrafanaMetric, panelUrl: string): Promise<[number, number][]> {
   let datasource = metric.datasource;
 
-  if (datasource.type !== 'influxdb') {
-    throw new Error(`${datasource.type} queries are not supported yet`);
-  }
-
   let origin = new URL(panelUrl).origin;
   let url = `${origin}/${datasource.url}`;
 
@@ -30,15 +26,9 @@ export async function queryByMetric(metric: Metric, panelUrl: string): Promise<[
   let data = [];
   while (offset <= records) {
     let paramsClone = Object.assign({}, params);
-    let replacedQ = paramsClone.q.replace(QUERY_TIME_REPLACE_REGEX, `LIMIT ${limit} OFFSET ${offset}`);
-    if(replacedQ === paramsClone.q) {
-      throw new Error(`Query "${paramsClone.q}" is not replaced with LIMIT/OFFSET oeprators`)
-    }
-    paramsClone.q = replacedQ;
-
+    paramsClone.q = metric.metricQuery.getQuery(limit, offset);
     let chunk = await queryGrafana(url, paramsClone);
     data = data.concat(chunk);
-
     offset += CHUNK_SIZE;
   }
 
@@ -64,13 +54,13 @@ async function queryGrafana(url: string, params: any) {
     res = await axios.get(url, { params, headers });
   } catch (e) {
     if(e.response.status === 401) {
-      throw new Error('Unauthorized. Check the $HASTIC_API_KEY');
+      throw new Error('Unauthorized. Check the $HASTIC_API_KEY.');
     }
     throw new Error(e.message);
   }
 
   if (res.data.results === undefined) {
-    throw new Error('results field is undefined in response');
+    throw new Error('results field is undefined in response.');
   }
 
   // TODO: support more than 1 metric (each res.data.results item is a metric)