Attempting to fix mysql issue by changing our usage of mysql2 to use the promise version, making sure disconnection always occurs correctly and using a slightly different syntax/approach.

packages/server/src/integrations/mysql.ts

@@ -16,7 +16,7 @@ import {
 import { DatasourcePlus } from "./base/datasourcePlus"
 
 module MySQLModule {
-  const mysql = require("mysql2")
+  const mysql = require("mysql2/promise")
   const Sql = require("./base/sql")
 
   interface MySQLConfig {
@@ -29,7 +29,7 @@ module MySQLModule {
   }
 
   const SCHEMA: Integration = {
-    docs: "https://github.com/mysqljs/mysql",
+    docs: "https://github.com/sidorares/node-mysql2",
     plus: true,
     friendlyName: "MySQL",
     description:
@@ -80,36 +80,9 @@ module MySQLModule {
     },
   }
 
-  function internalQuery(
-    client: any,
-    query: SqlQuery,
-    connect: boolean = true
-  ): Promise<any[] | any> {
-    // Node MySQL is callback based, so we must wrap our call in a promise
-    return new Promise((resolve, reject) => {
-      if (connect) {
-        client.connect()
-      }
-      return client.query(
-        query.sql,
-        query.bindings || {},
-        (error: any, results: object[]) => {
-          if (error) {
-            reject(error)
-          } else {
-            resolve(results)
-          }
-          if (connect) {
-            client.end()
-          }
-        }
-      )
-    })
-  }
-
   class MySQLIntegration extends Sql implements DatasourcePlus {
     private config: MySQLConfig
-    private readonly client: any
+    private client: any
     public tables: Record<string, Table> = {}
     public schemaErrors: Record<string, string> = {}
 
@@ -119,17 +92,46 @@ module MySQLModule {
       if (config.ssl && Object.keys(config.ssl).length === 0) {
         delete config.ssl
       }
-      this.client = mysql.createConnection(config)
+      this.config = config
+    }
+
+    async connect() {
+      this.client = await mysql.createConnection(this.config)
+    }
+
+    async disconnect() {
+      await this.client.end()
+    }
+
+    async internalQuery(
+      query: SqlQuery,
+      connect: boolean = true
+    ): Promise<any[] | any> {
+      try {
+        if (connect) {
+          await this.connect()
+        }
+        // Node MySQL is callback based, so we must wrap our call in a promise
+        const response = await this.client.query(
+          query.sql,
+          query.bindings || []
+        )
+        return response[0]
+      } finally {
+        if (connect) {
+          await this.disconnect()
+        }
+      }
     }
 
     async buildSchema(datasourceId: string, entities: Record<string, Table>) {
       const tables: { [key: string]: Table } = {}
       const database = this.config.database
-      this.client.connect()
+      await this.connect()
 
+      try {
         // get the tables first
-      const tablesResp = await internalQuery(
+        const tablesResp = await this.internalQuery(
-        this.client,
           { sql: "SHOW TABLES;" },
           false
         )
@@ -141,14 +143,16 @@ module MySQLModule {
         for (let tableName of tableNames) {
           const primaryKeys = []
           const schema: TableSchema = {}
-        const descResp = await internalQuery(
+          const descResp = await this.internalQuery(
-          this.client,
             { sql: `DESCRIBE \`${tableName}\`;` },
             false
           )
           for (let column of descResp) {
             const columnName = column.Field
-          if (column.Key === "PRI" && primaryKeys.indexOf(column.Key) === -1) {
+            if (
+              column.Key === "PRI" &&
+              primaryKeys.indexOf(column.Key) === -1
+            ) {
               primaryKeys.push(columnName)
             }
             const constraints = {
@@ -174,38 +178,41 @@ module MySQLModule {
             }
           }
         }
-
+      } finally {
-      this.client.end()
+        await this.disconnect()
+      }
       const final = finaliseExternalTables(tables, entities)
       this.tables = final.tables
       this.schemaErrors = final.errors
     }
 
     async create(query: SqlQuery | string) {
-      const results = await internalQuery(this.client, getSqlQuery(query))
+      const results = await this.internalQuery(getSqlQuery(query))
       return results.length ? results : [{ created: true }]
     }
 
     async read(query: SqlQuery | string) {
-      return internalQuery(this.client, getSqlQuery(query))
+      return this.internalQuery(getSqlQuery(query))
     }
 
     async update(query: SqlQuery | string) {
-      const results = await internalQuery(this.client, getSqlQuery(query))
+      const results = await this.internalQuery(getSqlQuery(query))
       return results.length ? results : [{ updated: true }]
     }
 
     async delete(query: SqlQuery | string) {
-      const results = await internalQuery(this.client, getSqlQuery(query))
+      const results = await this.internalQuery(getSqlQuery(query))
       return results.length ? results : [{ deleted: true }]
     }
 
     async query(json: QueryJson) {
-      this.client.connect()
+      await this.connect()
-      const queryFn = (query: any) => internalQuery(this.client, query, false)
+      try {
-      const output = await this.queryWithReturning(json, queryFn)
+        const queryFn = (query: any) => this.internalQuery(query, false)
-      this.client.end()
+        return await this.queryWithReturning(json, queryFn)
-      return output
+      } finally {
+        await this.disconnect()
+      }
     }
   }
 

packages/server/src/integrations/utils.ts

@@ -40,7 +40,7 @@ const SQL_TYPE_MAP = {
 export enum SqlClients {
   MS_SQL = "mssql",
   POSTGRES = "pg",
-  MY_SQL = "mysql",
+  MY_SQL = "mysql2",
   ORACLE = "oracledb",
 }