VEXXHOST Private Cloud - How To Deploy a Clojure Web Application on Ubuntu 14.04

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• Clojure is a modern, functional programming for
  the JVM and a dialect of the Lisp (LISt
  Processing) that focuses on concurrent
  programming found in operating systems.
• Clojure is a functional programming language that
  features a concise syntax, elegant concurrency
  support and frictionless Java integration.
• It provides many built-in tools for using
  immutable objects that runs on the Java Virtual
  Machines designed to be a fantastic language in
  its own right, and not necessarily a glue
  language.
• You can build systems from the ground up in
  Clojure without ever touching Java code directly.
  Clojure is successfully used in industry by
  companies such as Walmart and Puppet Lab and
  other large software companies.

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• In this article we will be showing you the
  complete deployment steps of Clojure Web
  Application on Ubuntu 14.04.
• System Preparation
• Our first step is to prepare the system with its
  basic requirements before starting the
  application deployment. Lets follow the basic
  instructions to complete the basic system
  requirements.
• System Update
• Login to your Ubuntu server using the root or
  sudo user credentials and run the command below
  to update your Operating system.
• apt-get update

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• SUDO User
• It has always been a good practice to deploy a
  new application using the non-root user. To
  create a new sudo user on Ubuntu with a root user
  you can use the following steps to create new
  user and the assign sudo rights.
• adduser vxx
• You will be asked to provide the password and
  user information as show in the image.

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• For assigning the sudo rights to the newly
  created run the visudo command and add the
  following line in it.
• Allow members of group sudo to execute any
  command
• vxx ALL(ALLALL) ALL
• Hit the Ctrlx key to save and close the file
  folled by Y and Enter keys.

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Installing Required Packages The deployment of
Clojure web application mainly depends upon the
three software packages that is Java, Supervisor,
and Nginx. So, these must be installed on your
Ubuntu system for the success of this
deployment. We will be using the sudo user for
the next steps, lets switch to the newly created
sudo user and then run the command below to
install the required packages. sudo apt-get
install openjdk-7-jre-headless sudo apt-get
install nginx supervisor
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• Cloning Sample Clojure App
• We are going to use an example of Clojure project
  to deploy using its available git repository.
• You can download or directly clone its repository
  using git clone command.
• If you are out of git package then run the
  commands below to install the git package
  followed by the command to clone the sample
  Clojure repository.
• sudo apt-get install git
• git clone https//github.com/do-community/do-cl
  ojure-web.git

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• Now we need to compile and run this sample
  project by using the Leiningen, which a
  dependency management and build automation tool
  for Clojure apps that makes this easy for the JVM
  based code.
• So, we need to setup the Leiningen on our Ubuntu
  server by downloading its installation script
  using the below Curl command.
• sudo curl https//raw.githubusercontent.com/te
  chnomancy/leiningen/stable/bin/lein -o
  /usr/local/bin/lein
• Give the executable permissions to the
  installation script using the command below.
• sudo chmod ax /usr/local/bin/lein

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• Now run the command as shown below to compile
  your sample clojure project with lein on your
  Ubuntu server within its directory.
• cd do-clojure-web/ lein uberjar

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• Setup Clojure App Environment
• Create the directory structure to place your
  Clojure web application and its log files in it
  as shown.
• sudo mkdir -p /var/www/do-clojure-web/app/db
  /var/www/logs
• Then copy your Clojure application file and
  database file into the directories we have
  created above.
• sudo cp do-clojure-web/target/do-clojure-web-0.
  1.0-standalone.jar /var/www/do-clojure-web/app/
• sudo cp do-clojure-web/db/do-clojure-web.h2.db
  /var/www/do-clojure-web/app/db/
• Change the ownership of application path to
  www-data so that it can write to our built-in
  database using the www-data user on our system.
• sudo chown -R www-data /var/www/do-clojure-web/

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• Then change your directory to the Clojure
  application directory and create a symbolink of
  current clojure web application to the current
  running version of the application. So that its
  can be interrupted by the system after each
  update.
• cd /var/www/do-clojure-web/app/
• sudo ln -s do-clojure-web-0.1.0-standalone.jar
  do-clojure-web.jar
• Your clojure application is ready to be used for
  localhost. Run the command below to make sure
  that it works fine and then hit Ctrlc key to
  stop the process at this point.
• sudo java -jar do-clojure-web.jar

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• Configuring Supervisor for Clojure App
• In this step we will be using the Supervisor for
  managing the Clojure Application service as a
  best option for running Clojure Application on
  our Ubuntu server.
• Lets create a new file within the Clojure
  configuration directory using your command line
  editor, then add the following line in it as
  shown.
• sudo vim /etc/supervisor/conf.d/do-clojure-web.
  conf
• programdo-clojure-web
• command/usr/bin/java -jar do-clojure-web.jar
• directory/var/www/do-clojure-web/app
• userwww-data
• autostarttrue
• autorestarttrue
• startretries3
• redirect_stderrtrue
• stdout_logfile/var/www/logs/do-clojure-web.app.l
  og

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• Configuring Supervisor for Clojure App
• Save and close the file using the wq!.
• The configuration file indicates that the
  Supervisor service will run our application from
  within the /var/www/do-clojure-web/app
  directory and will make sure to generate the logs
  within the the mentioned log file.

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• Configuring Nginx as Reverse Proxy
• In this last step we will be configuring the
  Nginx web server to use as a reverse proxy,
  because the Clojure web application only accepts
  connections from localhost on port 5000 and we
  need to provide it external access by using
  Nginx.
• Open the default configuration file of Nginx,
  then add the following lined in it as shown below
  before the start of server.
• upstream http_backend
• server 127.0.0.15000
• keepalive 32

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• Configuring Nginx as Reverse Proxy
• Then comments out the lines all the lines
  starting from location and the add the below
  lines in it.
• location /
• proxy_pass http//http_backend
• proxy_http_version 1.1
• proxy_set_header Connection ""
• proxy_set_header X-Forwarded-For
  proxy_add_x_forwarded_for proxy_set_header
  Host http_host
• access_log /var/www/logs/do-clojure-web.access.l
  og
• error_log /var/www/logs/do-clojure-web.error.log
  

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• Configuring Nginx as Reverse Proxy
• Save and close the file after making these
  changes. The complete configuration changes would
  be like the same as shown the below image.

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• Start Services
• We need to restart services of Nginx and
  Supervisor, to do so run the commands as shown
  below.
• sudo service supervisor restart
• sudo service nginx restart

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• Testing Web Access
• After successfully starting up services, you need
  to open up your wbe browser followed by the IP of
  your localhost server or FQDN.
• You will be greeted with the home page of Clojure
  Web application as shown below.
• http//localhost/

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• Testing Web Access
• Click on the Add a Location button and give the
  values to x and y axis then click on the
  submit location button.

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• Testing Web Access
• If you want to view all your submitted locations
  then click on the View All Locations button.

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• Conclusion
• We have successfully deployed Clojure web
  application using a sample Clojure application on
  Ubuntu 14.04 with supervisor, Nginx and lein.
• You can deploy your custom applications may be
  that is a simple website or an application.
• We hope have got this article much helpful while
  deployment of Clojure Applications on your Ubuntu
  server.
• You can contact us in case of any issue and we
  will surely get back to you with its solution.
• Dont forget to follow us on Twitter for news,
  updates and announcements _at_vexxhost.