Add db HC

src/context/database-context.ts

@@ -14,6 +14,7 @@ import { TokenRepository } from "./token-repository";
 import { BlocksRepository } from "./blocks-repository";
 
 export class DatabaseContext {
+  private dataSource: DataSource;
   public readonly transactions!: TransactionRepository;
   public readonly blockInfo!: BlocksRepository;
   public readonly boxes!: BoxRepository;
@@ -28,6 +29,7 @@ export class DatabaseContext {
   public readonly unconfirmedInputs!: UnconfirmedInputRepository;
 
   constructor(dataSource: DataSource) {
+    this.dataSource = dataSource;
     const context: RepositoryDataContext = {
       dataSource,
       graphQLDataLoader: new GraphQLDatabaseLoader(dataSource, { disableCache: true })
@@ -48,4 +50,8 @@ export class DatabaseContext {
     this.dataInputs = new BaseRepository(DataInputEntity, "dti", { context, defaults });
     this.inputs = new BaseRepository(InputEntity, "input", { context, defaults });
   }
+
+  checkConnection = () => {
+    return this.dataSource.isInitialized;
+  };
 }

src/health-check.ts

@@ -1,10 +1,18 @@
-export const checkHealth = () => {
-  const checks = {};
+import { DatabaseContext } from "./context/database-context";
 
-  const healthy = Object.values(checks).every(() => true);
+export const checkHealth = async(dataContext: DatabaseContext): Promise<boolean> => {
+  /**
+   * Things to check:
+   * - Database connection
+   * - Redis connection
+   * - Node connection
+   * - Block watcher
+   */
+  const checks = {
+    db: dataContext.checkConnection
+  };
 
-  return {
-    msg: "Custom message",
-    healthy
-  }
+  // const healthy = Object.values(checks).every(() => true);
+  // There's no feature in apollo-server-express to return custom error messages, so we leave it empty
+  throw new Error("");
 };

src/index.ts

@@ -11,12 +11,13 @@ import responseCachePlugin from "apollo-server-plugin-response-cache";
 import { GraphQLSchema } from "graphql";
 import depthLimit from "graphql-depth-limit";
 import { blockWatcher } from "./block-watcher";
-// import { redisClient } from "./caching";
+import { redisClient } from "./caching";
 import { DEFAULT_MAX_QUERY_DEPTH, MAX_CACHE_AGE } from "./consts";
 import { DatabaseContext } from "./context/database-context";
 import { initializeDataSource } from "./data-source";
 import { generateSchema } from "./graphql/schema";
 import { nodeService } from "./services";
+import { checkHealth } from "./health-check";
 
 const { TS_NODE_DEV, MAX_QUERY_DEPTH } = process.env;
 
@@ -40,9 +41,9 @@ async function startServer(schema: GraphQLSchema, dataContext: DatabaseContext)
         defaultMaxAge: MAX_CACHE_AGE,
         calculateHttpHeaders: true
       }),
-      // responseCachePlugin({
-      //   cache: new BaseRedisCache({ client: redisClient })
-      // }),
+      responseCachePlugin({
+        cache: new BaseRedisCache({ client: redisClient })
+      }),
       ApolloServerPluginLandingPageGraphQLPlayground()
     ],
     validationRules: [
@@ -56,19 +57,14 @@ async function startServer(schema: GraphQLSchema, dataContext: DatabaseContext)
         }
       )
     ],
-    onHealthCheck: () => {
-      return new Promise((resolve, reject) => {
-        if(1) resolve("Something should go here");
-        else reject();
-      })
-    }
+    onHealthCheck: checkHealth.bind(null, dataContext)
   });
   const { url } = await server.listen({ port: 3000 });
   console.log(`🚀 Server ready at ${url}`);
 }
 
 async function startBlockWatcher(dataContext: DatabaseContext) {
-  blockWatcher.start(dataContext.headers);
+  blockWatcher.start(dataContext.headers).onNewBlock(() => redisClient.flushdb());
 
   console.log("🚀 Block watcher started");
 }