add conection resolver

docker-compose.yml

@@ -15,14 +15,12 @@ services:
     env_file:
       - .env
   common-db:
-    container_name: common-db
+    container_name: common_db
     image: postgres
     environment:
       POSTGRES_USER: common_db
       POSTGRES_PASSWORD: common_db
-      PGDATA: /data/postgres
     volumes:
-      - ./data/db/common/:/data/postgres
       - ./init.sql:/docker-entrypoint-initdb.d/init.sql
     ports:
       - "5432:5432"
@@ -33,9 +31,8 @@ services:
     environment:
       POSTGRES_USER: tenant-1-db
       POSTGRES_PASSWORD: tenant-1-db
-      PGDATA: /data/postgres
     volumes:
-      - ./data/db/tenant-1:/data/postgres
+      - ./tenant_1_data.sql:/docker-entrypoint-initdb.d/init.sql
     ports:
       - "5433:5432"
     restart: unless-stopped
@@ -45,9 +42,8 @@ services:
     environment:
       POSTGRES_USER: tenant-2-db
       POSTGRES_PASSWORD: tenant-2-db
-      PGDATA: /data/postgres
     volumes:
-      - ./data/db/tenant-2:/data/postgres
+      - ./tenant_2_data.sql:/docker-entrypoint-initdb.d/init.sql
     ports:
       - "5434:5432"
     restart: unless-stopped

init.sql

@@ -13,4 +13,3 @@ CREATE TABLE tenants (
 INSERT INTO tenants (slug, db_name, db_host, db_username, db_password, db_port) VALUES
   ('tenant1', 'tenant-1-db', 'tenant-1-db', 'tenant-1-db', 'tenant-1-db', 5433),
   ('tenant2', 'tenant-2-db', 'tenant-2-db', 'tenant-2-db', 'tenant-2-db', 5434);
-view rawblock4.sql hosted with ❤ by GitHub

src/index.js

@@ -1,5 +1,8 @@
 import express from 'express';
 import bodyParser from 'body-parser';
+import * as userService from './services/users';
+import { connectAllDb } from './infra/connectionManager';
+import * as connectionResolver from './middlewares/connectionResolver';
 
 const PORT = 8080;
 
@@ -15,3 +18,12 @@ app.get('/', (req, res) => {
 app.listen(PORT, () => {
     console.log(`Express server started at port: ${PORT}`);
 });
+
+app.use(bodyParser.json());
+
+connectAllDb();
+
+app.use(connectionResolver.resolve);
+
+app.get('/users', userService.getAll);
+

src/infra/connectionManager.js

@@ -0,0 +1,53 @@
+import knex from 'knex';
+
+import commonDBConnection from './commonDBConnection';
+import { getNamespace } from 'continuation-local-storage';
+
+let connectionMap;
+
+export const connectAllDb = async () => {
+    let tenants;
+    try {
+        tenants = await commonDBConnection.select('*').from('tenants');
+    } catch (e) {
+        console.log('error', e);
+        return;
+    }
+    connectionMap =
+        tenants
+            .map(tenant => {
+                return {
+                    [tenant.slug]: knex(createConnectionConfig(tenant))
+                }
+            })
+            .reduce((prev, next) => {
+                return Object.assign({}, prev, next);
+            }, {});
+}
+
+const createConnectionConfig = (tenant) => {
+    return {
+        client: process.env.DB_CLIENT,
+        connection: {
+            host: tenant.db_host,
+            port: tenant.db_port,
+            user: tenant.db_username,
+            database: tenant.db_name,
+            password: tenant.db_password
+        },
+        pool: {min: 2, max: 20}
+    };
+}
+
+export  const getConnectionBySlug = (slug) => {
+    return connectionMap ? connectionMap[slug] : null;
+}
+
+export const getConnection = () => {
+    const nameSpace = getNamespace('unique context');
+    const conn = nameSpace.get('connection');
+    if (!conn) {
+        throw 'Connection is not set for any tenant database.';
+    }
+    return conn;
+}

src/middlewares/connectionResolver.js

@@ -0,0 +1,19 @@
+import { createNamespace } from 'continuation-local-storage';
+
+import { getConnectionBySlug } from '../infra/connectionManager';
+
+
+let nameSpace = createNamespace('unique context');
+
+
+export const  resolve = (req, res, next) => {
+    const slug = req.query.slug;
+    if (!slug) {
+        res.json({ message: `Please provide tenant's slug to connect.` });
+        return;
+    }
+    nameSpace.run(() => {
+        nameSpace.set('connection', getConnectionBySlug(slug));
+        next();
+    });
+}

src/services/users.js

@@ -0,0 +1,5 @@
+import {getConnection} from '../infra/connectionManager';
+
+export const getAll = async (req, res) => {
+    res.json({body: await getConnection().select('*').from('users')});
+}

tenant_1_data.sql

@@ -0,0 +1,10 @@
+CREATE TABLE users(
+  id INT PRIMARY KEY,
+  first_name VARCHAR(255) NOT NULL,
+  last_name VARCHAR(255) NOT NULL,
+  email VARCHAR(255) NOT NULL,
+  address VARCHAR(400)
+);
+
+INSERT INTO users(id,first_name, last_name, email, address) VALUES
+ (1,'Kevin', 'Martins', 'kevinmmartins@gmail.com', 'BR');

tenant_2_data.sql

@@ -0,0 +1,10 @@
+CREATE TABLE users(
+  id INT PRIMARY KEY,
+  first_name VARCHAR(255) NOT NULL,
+  last_name VARCHAR(255) NOT NULL,
+  email VARCHAR(255) NOT NULL,
+  address VARCHAR(400)
+);
+
+INSERT INTO users(id,first_name, last_name, email, address) VALUES
+ (1,'Kauan', 'Martins', 'kauanmmartins@egmail.com', 'USA');