Send error message through Slack if there is a sync error

Author: joojis

src/checker/slack.ts

@@ -80,6 +80,7 @@ export function createSlack(
         return new SlackWebhook(tag, slackWebhookUrl);
     } else {
         console.log("Slack not connected");
+        console.log("You can set SLACK_WEBHOOK env variable to connect Slack");
         return new NullSlack();
     }
 }

src/context.ts

@@ -1,4 +1,5 @@
 import { SDK } from "codechain-sdk";
+import { createSlack, Slack } from "./checker/slack";
 import { IndexerConfig } from "./config";
 import models from "./models";
 import Worker from "./worker";
@@ -9,13 +10,21 @@ export class IndexerContext {
     }
     public sdk: SDK;
     public worker: Worker;
+    public slack: Slack;
 
     private constructor(public readonly options: IndexerConfig) {
         this.sdk = new SDK({
             server: options.codechain.host,
             networkId: options.codechain.networkId
         });
-        this.worker = new Worker({ sdk: this.sdk }, options.worker);
+        this.slack = createSlack(
+            `[${options.codechain.networkId}][indexer]`,
+            process.env.SLACK_WEBHOOK
+        );
+        this.worker = new Worker(
+            { sdk: this.sdk, slack: this.slack },
+            options.worker
+        );
     }
 
     public destroy = async () => {

src/worker/index.ts

@@ -3,6 +3,7 @@ import { SDK } from "codechain-sdk";
 import { Block } from "codechain-sdk/lib/core/classes";
 import * as _ from "lodash";
 import { Job, scheduleJob } from "node-schedule";
+import { Slack } from "../checker/slack";
 import { InvalidBlockNumber } from "../exception";
 import models from "../models";
 import { BlockAttribute } from "../models/block";
@@ -16,6 +17,7 @@ const ASYNC_LOCK_KEY = "worker";
 
 export interface WorkerContext {
     sdk: SDK;
+    slack: Slack;
 }
 
 export interface WorkerConfig {
@@ -58,6 +60,7 @@ export default class Worker {
                 }
                 lastError = err;
                 console.error("sync error: ", err);
+                this.context.slack.sendError(err && err.message);
             }
         });
         this.watchJob.invoke();