From a9904badc9846fc1bf918a66c29e5b4e1dce1490 Mon Sep 17 00:00:00 2001
From: Evgeny Smyshlyaev <amper43@gmail.com>
Date: Fri, 18 Jan 2019 20:43:01 +0300
Subject: [PATCH] Save threshold alert state #340 (#342)

* threshold fixes

* rm webhook debug logging

* fix threshold detection

* .env -> .gitignore

* add alert service

* fix

* fix
---
 .../src/controllers/analytics_controller.ts   | 12 ++-
 server/src/services/alert_service.ts          | 90 +++++++++++++++++++
 2 files changed, 100 insertions(+), 2 deletions(-)
 create mode 100644 server/src/services/alert_service.ts

diff --git a/server/src/controllers/analytics_controller.ts b/server/src/controllers/analytics_controller.ts
index b437d64..3540abb 100644
--- a/server/src/controllers/analytics_controller.ts
+++ b/server/src/controllers/analytics_controller.ts
@@ -5,7 +5,7 @@ import * as Segment from '../models/segment_model';
 import * as Threshold from '../models/threshold_model';
 import * as AnalyticUnit from '../models/analytic_unit_model';
 import { AnalyticsService } from '../services/analytics_service';
-import { sendWebhook } from '../services/notification_service';
+import { AlertService } from '../services/alert_service';
 import { HASTIC_API_KEY, GRAFANA_URL } from '../config';
 import { DataPuller } from '../services/data_puller';
 
@@ -23,6 +23,7 @@ export type TaskResolver = (taskResult: TaskResult) => void;
 const taskResolvers = new Map<AnalyticsTaskId, TaskResolver>();
 
 let analyticsService: AnalyticsService = undefined;
+let alertService: AlertService = undefined;
 let dataPuller: DataPuller;
 
 
@@ -74,12 +75,17 @@ async function onMessage(message: AnalyticsMessage) {
 
 export function init() {
   analyticsService = new AnalyticsService(onMessage);
+
+  alertService = new AlertService();
+  alertService.startAlerting();
+
   dataPuller = new DataPuller(analyticsService);
   dataPuller.runPuller();
 }
 
 export function terminate() {
   analyticsService.close();
+  alertService.stopAlerting();
 }
 
 async function runTask(task: AnalyticsTask): Promise<TaskResult> {
@@ -300,7 +306,7 @@ async function processDetectionResult(analyticUnitId: AnalyticUnit.AnalyticUnitI
   const analyticUnit = await AnalyticUnit.findById(analyticUnitId);
   if (!_.isEmpty(segments) && analyticUnit.alert) {
     try {
-      sendWebhook(analyticUnit.name, _.last(segments));
+      alertService.recieveAlert(analyticUnit, _.last(segments));
     } catch(err) {
       console.error(`error while sending webhook: ${err.message}`);
     }
@@ -336,8 +342,10 @@ export async function setAlert(analyticUnitId: AnalyticUnit.AnalyticUnitId, aler
     if(alert) {
       const analyticUnit = await AnalyticUnit.findById(analyticUnitId);
       dataPuller.addUnit(analyticUnit);
+      alertService.addAnalyticUnit(analyticUnit);
     } else {
       dataPuller.deleteUnit(analyticUnitId);
+      alertService.removeAnalyticUnit(analyticUnitId);
     }
   }
 }
diff --git a/server/src/services/alert_service.ts b/server/src/services/alert_service.ts
new file mode 100644
index 0000000..73da7cd
--- /dev/null
+++ b/server/src/services/alert_service.ts
@@ -0,0 +1,90 @@
+import { sendWebhook } from './notification_service';
+
+import * as _ from 'lodash';
+import * as AnalyticUnit from '../models/analytic_unit_model';
+import { Segment } from '../models/segment_model';
+
+
+export class Alert {
+  constructor(protected analyticUnit: AnalyticUnit.AnalyticUnit, protected sender) {};
+  public recieve(segment: Segment) {
+    this.sender(this.analyticUnit, segment);
+  };
+  public update(now: number) {};
+}
+
+class PatternAlert extends Alert {};
+
+
+class ThresholdAlert extends Alert {
+  EXPIRE_PERIOD_MS = 60000;
+  lastOccurence = 0;
+
+  public recieve(segment: Segment) {
+    if(this.lastOccurence === 0) {
+      this.lastOccurence = segment.from;
+      this.sender(this.analyticUnit, segment);
+    } else {
+
+      if(segment.from - this.lastOccurence > this.EXPIRE_PERIOD_MS) {
+        console.debug(`difference detween threshold occurences ${segment.from - this.lastOccurence}, send alert`);
+        this.sender(this.analyticUnit, segment);
+      }
+
+      this.lastOccurence = segment.from;
+    }
+  }
+
+  public update(now: number) {}
+}
+
+
+export class AlertService {
+
+  private _alerts: { [id: string]: Alert; };
+  private _alertingEnable: boolean;
+  private _sender: any;
+
+  constructor() {
+    this._alerts = {}
+    this._alertingEnable = false;
+    this._sender = (analyticUnit: AnalyticUnit.AnalyticUnit, segment: Segment) => {
+      if(this._alertingEnable) {
+        sendWebhook(analyticUnit.name, segment);
+      }
+    }
+  }
+
+  public recieveAlert(analyticUnit: AnalyticUnit.AnalyticUnit, segment: Segment) {
+    let id = analyticUnit.id;
+
+    if(!_.has(this._alerts, id)) {
+      this.addAnalyticUnit(analyticUnit);
+    }
+
+    this._alerts[id].recieve(segment);
+  };
+
+  public addAnalyticUnit(analyticUnit: AnalyticUnit.AnalyticUnit) {
+    let detector = AnalyticUnit.getDetectorByType(analyticUnit.type);
+    let alertsType = {};
+
+    alertsType[AnalyticUnit.DetectorType.THRESHOLD] = ThresholdAlert;
+    alertsType[AnalyticUnit.DetectorType.PATTERN] = PatternAlert;
+
+    this._alerts[analyticUnit.id] = new alertsType[detector](analyticUnit, this._sender);
+  }
+
+  public removeAnalyticUnit(analyticUnitId: AnalyticUnit.AnalyticUnitId) {
+    delete this._alerts[analyticUnitId];
+  }
+
+  public stopAlerting() {
+    this._alertingEnable = false;
+    this._alerts = {};
+  }
+
+  public startAlerting() {
+    this._alertingEnable = true;
+  }
+}