Time monitor failure handling

src/common/models/time-tag/time-tag.mocha.ts

@@ -24,12 +24,12 @@ describe("TimeTag", () => {
       {
         name: "dodo",
         time: new Date("2015-10-15T19:20:00Z"),
-        updated: new Date("2015-10-15T19:20:13Z")
+        lastTimeChecked: new Date("2015-10-15T19:20:13Z")
       },
       {
         name: "wikipedia",
         time: new Date("2015-10-15T19:21:00Z"),
-        updated: new Date("2015-10-15T19:21:13Z")
+        lastTimeChecked: new Date("2015-10-15T19:21:13Z")
       }
     ]);
   });

src/common/models/time-tag/time-tag.ts

@@ -17,20 +17,16 @@
 
 import { BaseImmutable, Property, PropertyType } from "immutable-class";
 
-export type Special = "static" | "realtime";
-
 export interface TimeTagValue {
   name: string;
   time?: Date;
-  updated?: Date;
-  special?: Special;
+  lastTimeChecked?: Date;
 }
 
 export interface TimeTagJS {
   name: string;
   time?: Date | string;
-  updated?: Date | string;
-  special?: Special;
+  lastTimeChecked?: Date | string;
 }
 
 export class TimeTag extends BaseImmutable<TimeTagValue, TimeTagJS> {
@@ -42,8 +38,7 @@ export class TimeTag extends BaseImmutable<TimeTagValue, TimeTagJS> {
   static PROPERTIES: Property[] = [
     { name: "name" },
     { name: "time", type: PropertyType.DATE, defaultValue: null },
-    { name: "updated", type: PropertyType.DATE, defaultValue: null },
-    { name: "special", defaultValue: null }
+    { name: "lastTimeChecked", type: PropertyType.DATE, defaultValue: null }
   ];
 
   static fromJS(parameters: TimeTagJS): TimeTag {
@@ -52,19 +47,19 @@ export class TimeTag extends BaseImmutable<TimeTagValue, TimeTagJS> {
 
   public name: string;
   public time: Date;
-  public updated: Date;
-  public special: Special;
+  public lastTimeChecked: Date;
 
   constructor(parameters: TimeTagValue) {
     super(parameters);
-    if (this.time && !this.updated) this.updated = this.time;
+    if (this.time && !this.lastTimeChecked) this.lastTimeChecked = this.time;
   }
 
-  public changeTime(time: Date, now: Date): TimeTag {
-    var value = this.valueOf();
-    value.time = time;
-    value.updated = now;
-    return new TimeTag(value);
+  public changeTime(time: Date, lastTimeChecked: Date): TimeTag {
+    return new TimeTag({
+      name: this.name,
+      time,
+      lastTimeChecked
+    });
   }
 }
 

src/common/models/timekeeper/timekeeper.mocha.ts

@@ -29,13 +29,13 @@ describe("Timekeeper", () => {
       },
       {
         timeTags: {
-          lol: { name: "lol", time: new Date("2016-01-01T01:02:03Z"), updated: new Date("2016-01-01T01:02:03Z") }
+          lol: { name: "lol", time: new Date("2016-01-01T01:02:03Z"), lastTimeChecked: new Date("2016-01-01T01:02:03Z") }
         },
         nowOverride: null
       },
       {
         timeTags: {
-          lol: { name: "lol", time: new Date("2016-01-01T01:02:03Z"), updated: new Date("2016-01-01T01:02:03Z") }
+          lol: { name: "lol", time: new Date("2016-01-01T01:02:03Z"), lastTimeChecked: new Date("2016-01-01T01:02:03Z") }
         },
         nowOverride: new Date("2016-01-01T01:02:03Z")
       }

src/common/models/timekeeper/timekeeper.ts

@@ -64,8 +64,8 @@ export class Timekeeper implements Instance<TimekeeperValue, TimekeeperJS> {
 
   getTime(name: string): Date {
     const timeTag = this.timeTags.get(name);
-    if (!timeTag || timeTag.special === "realtime") return this.now();
-    return timeTag.time || this.now();
+    if (!timeTag || !timeTag.time) return this.now();
+    return timeTag.time;
   }
 
   private changeTimeTags(timeTags: Map<string, TimeTag>): Timekeeper {

src/common/utils/time-monitor/time-monitor.ts

@@ -27,9 +27,11 @@ export class TimeMonitor {
   public timekeeper: Timekeeper;
   private regularCheckInterval: number;
   private checks: Map<string, Nullary<Promise<Date>>>;
+  private logger: Logger;
   private doingChecks = false;
 
-  constructor(private logger: Logger) {
+  constructor(logger: Logger) {
+    this.logger = logger.addPrefix("TimeMonitor");
     this.checks = new Map();
     this.regularCheckInterval = 60000;
     this.timekeeper = Timekeeper.EMPTY;
@@ -49,23 +51,24 @@ export class TimeMonitor {
     return this;
   }
 
-  private doCheck = ({ name }: TimeTag): Promise<void> => {
+  private doCheck = ({ name, time: previousTime }: TimeTag): Promise<void> => {
     const { logger, checks } = this;
     const check = checks.get(name);
     if (!check) return Promise.resolve(null);
     return check().then(updatedTime => {
       logger.log(`Got the latest time for '${name}' (${updatedTime.toISOString()})`);
       this.timekeeper = this.timekeeper.updateTime(name, updatedTime);
     }).catch(e => {
-        logger.error(`Error getting time for '${name}': ${e.message}`);
+        logger.error(`Failed getting time for '${name}', using previous time.`, `Error: ${e.message}`);
+        this.timekeeper = this.timekeeper.updateTime(name, previousTime);
       }
     );
   }
 
   private isStale = (timeTag: TimeTag): boolean => {
     const { timekeeper, regularCheckInterval } = this;
     const now = timekeeper.now().valueOf();
-    return !timeTag.time || now - timeTag.updated.valueOf() > regularCheckInterval;
+    return !timeTag.time || now - timeTag.lastTimeChecked.valueOf() > regularCheckInterval;
   }
 
   private doChecks = (): void => {