Time monitor failure handling (#819)

* Rename updated field to lastTimeChecked in TimeTag

* Remove unused special field in TimeTag

* Update time tag with old value in case of error, to reflect lastTimeCheck value

* Add prefix for TimeMonitor logger

* Don't use special field of TimeTag in Timekeeper

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 => {