docker run -it ubuntu  

root@719059da250d:/#  

root@719059da250d:/# lsb_release -a  
No LSB modules are available.  
Distributor ID:    Ubuntu  
Description:    Ubuntu 14.04.4 LTS  
Release:    14.04  
Codename:    trusty  
root@719059da250d:/# exit  

docker run -it haskell  
docker run -it java  
docker run -it python  

docker run --name db -d -e 
MYSQL_ROOT_PASSWORD=123 -p 3306:3306 
mysql:latest  

$ docker ps
CONTAINER ID  IMAGE         ...  NAMES  
36e68b966fd0  mysql:latest  ...  db

$ docker exec -it db /bin/bash

root@36e68b966fd0:/# mysql -uroot -p123  
mysql> show databases;  
+--------------------+
| Database           |
+--------------------+
| information_schema |
+--------------------+
1 rows in set (0.01 sec)

mysql> exit  
Bye  
root@36e68b966fd0:/# exit  

test-database\setup.sql  
test-database\start.sh  
test-database\stop.sh  

#!/bin/sh

# Run the MySQL container, with a database named 'users' and credentials
# for a users-service user which can access it.
echo "Starting DB..."  
docker run --name db -d \  
  -e MYSQL_ROOT_PASSWORD=123 \
  -e MYSQL_DATABASE=users -e MYSQL_USER=users_service -e MYSQL_PASSWORD=123 \
  -p 3306:3306 \
  mysql:latest

# Wait for the database service to start up.
echo "Waiting for DB to start up..."  
docker exec db mysqladmin --silent --wait=30 -uusers_service -p123 ping || exit 1

# Run the setup script.
echo "Setting up initial data..."  
docker exec -i db mysql -uusers_service -p123 users < setup.sql  

create table directory (user_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, email TEXT, phone_number TEXT);  
insert into directory (email, phone_number) values ('homer@thesimpsons.com', '+1 888 123 1111');  
insert into directory (email, phone_number) values ('marge@thesimpsons.com', '+1 888 123 1112');  
insert into directory (email, phone_number) values ('maggie@thesimpsons.com', '+1 888 123 1113');  
insert into directory (email, phone_number) values ('lisa@thesimpsons.com', '+1 888 123 1114');  
insert into directory (email, phone_number) values ('bart@thesimpsons.com', '+1 888 123 1115');  

#!/bin/sh

# Stop the db and remove the container.
docker stop db && docker rm db

test-database/          # contains the code seen in Step 1  
users-service/          # root of our node.js microservice  
- package.json          # dependencies, metadata
- index.js              # main entrypoint of the app
- api/                  # our apis and api tests
- config/               # config for the app
- repository/           # abstraction over our db
- server/               # server setup code

//  repository.js
//
//  Exposes a single function - 'connect', which returns
//  a connected repository. Call 'disconnect' on this object when you're done.
'use strict';

var mysql = require('mysql');

//  Class which holds an open connection to a repository
//  and exposes some simple functions for accessing data.
class Repository {  
  constructor(connection) {
    this.connection = connection;
  }

  getUsers() {
    return new Promise((resolve, reject) => {

      this.connection.query('SELECT email, phone_number FROM directory', (err, results) => {
        if(err) {
          return reject(new Error("An error occured getting the users: " + err));
        }

        resolve((results || []).map((user) => {
          return {
            email: user.email,
            phone_number: user.phone_number
          };
        }));
      });

    });
  }

  getUserByEmail(email) {

    return new Promise((resolve, reject) => {

      //  Fetch the customer.
      this.connection.query('SELECT email, phone_number FROM directory WHERE email = ?', [email], (err, results) => {

        if(err) {
          return reject(new Error("An error occured getting the user: " + err));
        }

        if(results.length === 0) {
          resolve(undefined);
        } else {
          resolve({
            email: results[0].email,
            phone_number: results[0].phone_number
          });
        }

      });

    });
  }

  disconnect() {
    this.connection.end();
  }
}

//  One and only exported function, returns a connected repo.
module.exports.connect = (connectionSettings) => {  
  return new Promise((resolve, reject) => {
    if(!connectionSettings.host) throw new Error("A host must be specified.");
    if(!connectionSettings.user) throw new Error("A user must be specified.");
    if(!connectionSettings.password) throw new Error("A password must be specified.");
    if(!connectionSettings.port) throw new Error("A port must be specified.");

    resolve(new Repository(mysql.createConnection(connectionSettings)));
  });
};

repository.connect({  
  host: "127.0.0.1",
  database: "users",
  user: "users_service",
  password: "123",
  port: 3306
}).then((repo) => {
  repo.getUsers().then(users) => {
    console.log(users);
  });
  repo.getUserByEmail('homer@thesimpsons.com').then((user) => {
    console.log(user);
  })
  //  ...when you are done...
  repo.disconnect();
});

server/server.js:
//  server.js

var express = require('express');  
var morgan = require('morgan');

module.exports.start = (options) => {

  return new Promise((resolve, reject) => {

    //  Make sure we have a repository and port provided.
    if(!options.repository) throw new Error("A server must be started with a connected repository.");
    if(!options.port) throw new Error("A server must be started with a port.");

    //  Create the app, add some logging.
    var app = express();
    app.use(morgan('dev'));

    //  Add the APIs to the app.
    require('../api/users')(app, options);

    //  Start the app, creating a running server which we return.
    var server = app.listen(options.port, () => {
      resolve(server);
    });

  });
};

var server = require('./server/server);  
server.start({port: 8080, repo: repository}).then((svr) => {  
  // we've got a running http server :)
});

//  users.js
//
//  Defines the users api. Add to a server by calling:
//  require('./users')
'use strict';

//  Only export - adds the API to the app with the given options.
module.exports = (app, options) => {

  app.get('/users', (req, res, next) => {
    options.repository.getUsers().then((users) => {
      res.status(200).send(users.map((user) => { return {
          email: user.email,
          phoneNumber: user.phone_number
        };
      }));
    })
    .catch(next);
  });

  app.get('/search', (req, res) => {

    //  Get the email.
    var email = req.query.email;
    if (!email) {
      throw new Error("When searching for a user, the email must be specified, e.g: '/search?email=homer@thesimpsons.com'.");
    }

    //  Get the user from the repo.
    options.repository.getUserByEmail(email).then((user) => {

      if(!user) { 
        res.status(404).send('User not found.');
      } else {
        res.status(200).send({
          email: user.email,
          phoneNumber: user.phone_number
        });
      }
    })
    .catch(next);

  });
};

//  config.js
//
//  Simple application configuration. Extend as needed.
module.exports = {  
    port: process.env.PORT || 8123,
  db: {
    host: process.env.DATABASE_HOST || '127.0.0.1',
    database: 'users',
    user: 'users_service',
    password: '123',
    port: 3306
  }
};

//    index.js
//
//  Entrypoint to the application. Opens a repository to the MySQL
//  server and starts the server.
var server = require('./server/server');  
var repository = require('./repository/repository');  
var config = require('./config/config');

//  Lots of verbose logging when we're starting up...
console.log("--- Customer Service---");  
console.log("Connecting to customer repository...");

//  Log unhandled exceptions.
process.on('uncaughtException', function(err) {  
  console.error('Unhandled Exception', err);
});
process.on('unhandledRejection', function(err, promise){  
  console.error('Unhandled Rejection', err);
});

repository.connect({  
  host: config.db.host,
  database: config.db.database,
  user: config.db.user,
  password: config.db.password,
  port: config.db.port
}).then((repo) => {
  console.log("Connected. Starting server...");

  return server.start({
    port: config.port,
    repository: repo
  });

}).then((app) => {
  console.log("Server started successfully, running on port " + config.port + ".");
  app.on('close', () => {
    repository.disconnect();
  });
});

HTTP GET /users                              # gets all users  
HTTP GET /search?email=homer@thesimpons.com  # searches by email  

cd ./users-service  
npm install         # setup everything  
npm test            # unit test - no need for a test database running  
npm start           # run the server - you must have a test database running  
npm run debug       # run the server in debug mode, opens a browser with the inspector  
npm run lint        # check to see if the code is beautiful  

cd test-database/  
./start.sh

cd ../users-service/  
npm start