HTTP SQL Query Wrapper for Azure SQL Data Warehouse

• Introduction
• Quick Start
• Deployment
• Configuration
• Usage

Introduction

This project is a HTTP SQL query wrapper for Azure SQL Data Warehouse built with Node.js.

It helps you query Azure SQL Data Warehouse through HTTP request.

Quick Start

Step 1: System Requirement

Ubuntu

sudo apt-get build-essential libssl-dev git

CentOS

yum groupinstall "Development Tools"
yum install openssl-devel git

Step 2: nvm & Node.js

curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.0/install.sh | NVM_DIR=/usr/local/nvm bash
nvm install 7.6.0
nvm use 7.6.0
nvm alias default 7.6.0

Step 3: Node Modules

Install pm2:

npm install pm2 yarn -g
pm2 install pm2-logrotate
pm2 set pm2-logrotate:retain 5
pm2 startup

Install project modules, cd to the project folder, and do:

npm install

Step 4: Configuration

Specify your Azure SQL Data Warehouse configurations in config.json.

Step 5: Build & Run

Build:

npm run build

Start server:

pm2 start process.json --env production

Save current running app

pm2 save

Step 6: Execute Query

To execute a SQL command, you need to send a POST request to http://<ip-or-host>:5000/api/sql with a body as follows:

{
  "sql": "select * from my_table"
}

Deployment

To run this application, you need to have both Node.js Runtime and Node Modules ready.

nvm & Node.js

Pre-Requirement

To install nvm (Node Version Manager) and Node.js.

First, you will need to make sure your system has a C++ compiler and git installed.

Ubuntu

sudo apt-get build-essential libssl-dev git

CentOS

yum groupinstall "Development Tools"
yum install openssl-devel git

Install nvm

To install or upgrade nvm, you can use the install script using cURL:

curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.0/install.sh | NVM_DIR=/usr/local/nvm bash

or Wget:

wget -qO- https://raw.githubusercontent.com/creationix/nvm/v0.33.0/install.sh | NVM_DIR=/usr/local/nvm bash

The script clones the nvm repository to ~/.nvm and adds the source line to your profile (~/.bash_profile, ~/.zshrc, ~/.profile, or ~/.bashrc).

export NVM_DIR="$HOME/.nvm"
[ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh" # This loads nvm

You can customize the install source, directory, profile, and version using the NVM_SOURCE, NVM_DIR, PROFILE, and NODE_VERSION variables. Eg: curl ... | NVM_DIR=/usr/local/nvm bash for a global install.

Vefication nvm Installation

To verify that nvm has been installed, do:

command -v nvm

which should output 'nvm' if the installation was successful. Please note that which nvm will not work, since nvm is a sourced shell function, not an executable binary.

Install Node.js

To download, compile, and install the LTS (Long Term Support) release of Node.js, do:

nvm install --lts

And then in any new shell just use the installed version:

nvm use --lts

Vefication Node.js Installation

To verify that Node.js has been installed, do:

node -v

Which should output the version of installed Node.js if the installation was successful.

Node Modules

This project is managed by PM2, which allows you to keep applications alive forever, to reload them without downtime and to facilitate common system admin task.

It is recommended to install pm2 as global module and other project ones as local module.

Install Process Manager

To install pm2, do:

npm install pm2 -g

Install Project Modules

To install project modules, cd to the project folder, and do:

npm install

Keep PM2 Running with System Startup

PM2 can generate startup scripts and configure them in order to keep your process list intact across expected or unexpected machine restarts.

Login as the user you want to run this application, and do:

pm2 startup

Follow the instructions to complete the startup configuration.

When updating nodejs, the pm2 binary path might change (it will necessarily change if you are using nvm).
Therefore, we would advise you to run the startup command after any update.

Build

To optimize the performance, you need to build the project. To Build the project, cd to the project folder, and do:

npm run build

which should output built files under ./build folder.

Deployment Configuration

You can define several deployment environment configurations in process.json and run different processes separately as you need by doing:

pm2 start process.json --env production

Refer to pm2 documentation for more details.

Useful Attributes

| Field     | Type   | Example                                | Description                                                           |
---------------------------------------------------------------------------------------------------------------------------------------
| name      | string | "my-app"                               | application name                                                      |
| script    | string | "./api/app.js"                         | script path relative to pm2 start                                     |
| instances | number | -1                                     | number of app instance to be launched                                 |
| exec_mode | string | "cluster"                              | mode to start your app, can be "cluster" or "fork", default "fork"    |
| env       | object | {"NODE_ENV": "development", "ID": "1"} | env variables which will appear in your app, -1 to spread to all CPUs |
| env_      | object | {"NODE_ENV": "production", "ID": "2"}  | inject when doing pm2 restart app.json --env                          |

Switch environments

You may have noticed that you can declare environment-specific variables with the attribute env_* (e.g. env_production, env_staging…). They can be switched easily. You just need to specify the --env <environment_name> when acting on the application declaration.

# Inject what is declared in env_production
$ pm2 start process.json --env production

# Inject what is declared in env_staging
$ pm2 restart process.json --env staging

Example

{
  "apps": [{
    "script": "./build/index.js",
    "instances": -1,
    "exec_mode": "cluster",
    "env": {
      "name": "adw-api-dev",
      "ENV": "staging",
      "NODE_ENV": "development",
      "PORT": 3000,
      "LOG_LEVEL": "debug"
    },
    "env_daily": {
      "name": "adw-api-daily",
      "ENV": "daily",
      "NODE_ENV": "production",
      "PORT": 3000,
      "LOG_LEVEL": "info"
    },
    "env_staging": {
      "name": "adw-api-staging",
      "ENV": "staging",
      "NODE_ENV": "production",
      "PORT": 4000,
      "LOG_LEVEL": "info"
    },
    "env_production": {
      "name": "adw-api-production",
      "ENV": "production",
      "NODE_ENV": "production",
      "PORT": 5000,
      "LOG_LEVEL": "info"
    }
  }]
}

Configuration

Before starting this application, you have to specify your Azure SQL Data Warehouse configurations in config.json.

You can define several env configurations and switch to any of them easily by specify env variables in process.json.

Example

{
  "default": {
    "user": "username",
    "password": "password",
    "server": "hostname",
    "database": "database",
    "pool": {
      "max": 1024
    },
    "options": {
      "requestTimeout": 30000,
      "encrypt": true
    }
  },
  "daily": {
    "user": "username",
    "password": "password",
    "server": "hostname",
    "database": "database",
    "pool": {
      "max": 1024
    },
    "options": {
      "requestTimeout": 30000,
      "encrypt": true
    }
  },
  "staging": {
    "user": "username",
    "password": "password",
    "server": "hostname",
    "database": "database",
    "pool": {
      "max": 1024
    },
    "options": {
      "requestTimeout": 30000,
      "encrypt": true
    }
  },
  "production": {
    "user": "username",
    "password": "password",
    "server": "hostname",
    "database": "database",
    "pool": {
      "max": 1024
    },
    "options": {
      "requestTimeout": 30000,
      "encrypt": true
    }
  }
}

Usage

Finally, to manage this application, you just need 3 commands as follows.

Start

To start a new application, do:

pm2 start process.json --env <environment>

Reload

to gracefully reload a application without downtime, do:

pm2 reload <app-id>

Stop

To stop a application, do:

pm2 stop <app-id>

How to Query

To execute a SQL command, you need to send a POST request to http://<ip-or-host>:<port>/api/sql with a body as follows:

{
  "sql": "select * from my_table",
  "timeout": 30000, // optional, request timeout in milliseconds
  "user": "user", // optional, customized query credentials
  "password": "password" // optional, customized query credentials
}

Note: Do NOT send more than one queries at the same time, ONLY the result of the last query will be returned.

select * from my_table_1; select * from my_table_2

Which will ONLY return all rows from my_table_2.