feat(mysql): add an ability to use existing Pool instance

.changeset/silent-wasps-roll.md

@@ -0,0 +1,6 @@
+---
+'@graphql-mesh/mysql': minor
+'@graphql-mesh/types': minor
+---
+
+feat(mysql): add an ability to use existing Pool instance

packages/handlers/mysql/package.json

@@ -17,6 +17,7 @@
   },
   "dependencies": {
     "@graphql-mesh/types": "0.17.1",
+    "@graphql-mesh/utils": "0.6.0",
     "graphql-compose": "7.22.1",
     "graphql-fields": "2.0.3",
     "mysql": "2.18.1",

packages/handlers/mysql/src/index.ts

@@ -15,6 +15,7 @@ import {
   GraphQLTime,
 } from 'graphql-scalars';
 import { execute } from 'graphql';
+import { loadFromModuleExportExpression } from '@graphql-mesh/utils';
 
 const SCALARS = {
   bigint: 'BigInt',
@@ -110,7 +111,11 @@ export default class MySQLHandler implements MeshHandler {
 
   async getMeshSource(): Promise<MeshSource> {
     const schemaComposer = new SchemaComposer<MysqlContext>();
-    const pool = createPool(this.config);
+    const pool: Pool = this.config.pool
+      ? typeof this.config.pool === 'string'
+        ? await loadFromModuleExportExpression(this.config.pool)
+        : this.config.pool
+      : createPool(this.config);
     pool.on('connection', connection => {
       upgrade(connection);
       introspection(connection);

packages/handlers/mysql/yaml-config.graphql

@@ -3,9 +3,14 @@ extend type Handler {
 }
 
 type MySQLHandler @md {
-  host: String!
-  port: Int!
-  user: String!
+  host: String
+  port: Int
+  user: String
   password: String
-  database: String!
+  database: String
+  """
+  Use existing `Pool` instance
+  Format: modulePath#exportName
+  """
+  pool: Any
 }

packages/types/src/config-schema.json

@@ -1174,9 +1174,20 @@
         },
         "database": {
           "type": "string"
+        },
+        "pool": {
+          "anyOf": [
+            {
+              "type": "object",
+              "additionalProperties": true
+            },
+            {
+              "type": "string"
+            }
+          ],
+          "description": "Use existing `Pool` instance\nFormat: modulePath#exportName"
         }
-      },
-      "required": ["host", "port", "user", "database"]
+      }
     },
     "Neo4jHandler": {
       "additionalProperties": false,

packages/types/src/config.ts

@@ -467,11 +467,16 @@ export interface TypeConverterResolversOpts1 {
   pagination?: boolean | PaginationResolverOpts;
 }
 export interface MySQLHandler {
-  host: string;
-  port: number;
-  user: string;
+  host?: string;
+  port?: number;
+  user?: string;
   password?: string;
-  database: string;
+  database?: string;
+  /**
+   * Use existing `Pool` instance
+   * Format: modulePath#exportName
+   */
+  pool?: any;
 }
 /**
  * Handler for Neo4j