Cloudgizer: An introduction to a new open source web development tool

Cloudgizer offers high performance, a small footprint, and safer, more productive programming in C.
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Databases as a service

Jason Baker. CC BY-SA 4.0.

Cloudgizer is a free open source tool for building web applications. It combines the ease of scripting languages with the performance of C, helping manage the development effort and run-time resources for cloud applications.

Cloudgizer works on Red Hat/CentOS Linux with the Apache web server and MariaDB database. It is licensed under Apache License version 2.

Hello World

In this example, we output an HTTP header and Hello World, followed by a horizontal line:

#include "cld.h"

void home()

   Hello World!

Cloudgizer code is written as a C comment with /*< and >*/ at the beginning and ending, respectively.

Writing output to the web client is as simple as directly writing HTML code in your source. There are no API calls or special markups for that—simplicity is good because HTML (or JavaScript, CSS, etc.) will probably comprise a good chunk of your code.

How it works

Cloudgizer source files (with a .v extension) are translated into C code by the cld command-line tool. C code is then compiled and linked with the web server and your application is ready to be used. For instance, generated code for the source file named home.v would be __home.c, if you'd like to examine it.

Much of your code will be written as "markups," small snippets of intuitive and descriptive code that let you easily do things like the following:

  • database queries
  • web programming
  • encoding and encryption
  • executing programs
  • safe string manipulation
  • file operations
  • sending emails

and other common tasks. For less common tasks, there is an API that covers broader functionality. And ultimately, you can write any C code and use any libraries you wish to complete your task.

The main() function is generated by Cloudgizer and is a part of the framework, which provides Apache and database integration and other services. One such service is tracing and debugging (including memory garbage collection, underwrite/overwrite detection, run-time HTML linting, etc.). A program crash produces a full stack, including the source code lines, and the crash report is emailed to you the moment it happens.

A Cloudgizer application is linked with the Apache server as an Apache module in a pre-fork configuration. This means the Apache web server will pre-fork a number of processes and direct incoming requests to them. The Apache module mechanism provides high-performance request handling for applications.

All Cloudgizer applications run under the same Linux user, with each application separated under its own application directory. This user is also the Apache user; i.e., the user running the web server.

Each application has its own database with the name matching that of the application. Cloudgizer establishes and maintains database connections across requests, increasing performance.

Development process

The process of compiling your source code and building an installation file is automated. By using the cldpackapp script, you’ll transform your code into pure C code and create an installation file (a .tar.gz file). The end user will install this file with the help of a configuration file called appinfo, producing a working web application. This process is straightforward:


Development process, Cloudgizer

The deployment process is designed to be automated if needed, with configurable parameters.

Getting started

The development starts with installing the Example application. This sets up the development environment; you start with a Hello World and build up your application from there.

The Example application also serves as a smoke test because it has a number of code snippets that test various Cloudgizer features. It also gives you a good amount of example code (hence the name).

There are two files to be aware of as you start:

  • cld_handle_request.v is where incoming requests (such as GET, POST, or a command-line execution) are processed.
  • sourcelist lists all your source code so that Cloudgizer can make your application.

In addition to cld_handle_request.v, oops.v implements an error handler, and file_too_large.v implements a response to an upload that's too large. These are already implemented in the Example application, and you can keep them as they are or tweak them.

Use cldbuild to recompile source-file (.v) changes, and cldpackapp to create an installer file for testing or release delivery via cldgoapp:

cloudgizer development

Deployment via cldgoapp lets you install an application from scratch or update from one version to another.


Here's a stock-ticker application that updates and reports on ticker prices. It is included in the Example application.

The code

The request handler checks the URL query parameter page, and if it's stock, it calls function stock():

#include "cld.h"

void cld_handle_request()
  input-param page
  if-string page="stock"
      c stock ();
      report-error "Unrecognized page %s", page

The implementation of function stock() would be in file stock.v. The code adds a stock ticker if the URL query parameter action is add or shows all stock tickers if it is show.

#include "cld.h" 

void stock()


       input-param action

       if-string action=""
           input-param stock_name
           input-param stock_price

           run-query#add_data = "insert into stock \
               (stock_name, stock_price) values \
               (<?stock_name?>, <?stock_price?>) \
               on duplicate key update \

               query-result#add_data, error as \
                   define err

               if atoi(err) != 0
                   report-error "Cannot update \
                       stock price, error [%s]",err

               Stock price updated!
       else-if-string action=""
                   <td>Stock name</td>
                   <td>Stock price</td>
           run-query#show_data = "select stock_name, \
               stock_price from stock"

                   query-result#show_data, stock_name 
                   query-result#show_data, stock_price 
           <div>Unrecognized request!</div>

The database table

The SQL table used would be:

create table stock (stock_name varchar(100) primary key, stock_price bigint);

Making and packaging

To include stock.v in your Cloudgizer application, simply add it to the sourcelist file:

SOURCE_FILES=stock.v ....
stock.o : stock.v $(CLDINCLUDE)/cld.h $(HEADER_FILES)

To recompile changes to your code, use:


To package your application for deployment, use:


When packaging an application, all additional objects you create (other than source code files), should be included in the file. This file sets up anything that the Cloudgizer application installer doesn't do; in this case, create the above SQL table. For example, the following code in your might suffice:

echo -e "drop table if exists stock;\ncreate table stock (stock_name varchar(100) primary key, stock_price bigint);" | mysql -u root -p$CLD_DB_ROOT_PWD -D $CLD_APP_NAME

In, you can use any variables from the appinfo file (an installation configuration file). Those variables always include CLD_DB_ROOT_PWD (the root password database, which is always automatically cleared after installation for security), CLD_APP_NAME (the application and database name), CLD_SERVER (the URL of the installation server), CLD_EMAIL (the administration and notification email address), and others. You also have CLD_APP_HOME_DIR (the application's home directory) and CLD_APP_INSTALL_DIR (the location where the installation .tar.gz file had been unzipped so you can copy files from it). You can include any other variables in the appinfo file that you find useful.

Using the application

If your application name is 'myapp' running on, then the URL to update a stock ticker would be this:

and the URL to show all stock tickers would be this:

(The URL path for all Cloudgizer applications always starts with go.; in this case, go.myapp.)

Download and more examples

For more examples or download and installation details, visit You'll also find the above example included in the installation (see the Example application source code).

For a much larger real-world example, check out the source code for Rentomy, a free open source cloud application for rental property managers, written entirely in Cloudgizer and consisting of over 32,000 lines of code.

Why use Cloudgizer?

Here's why Rentomy is written in Cloudgizer:

Originally, the goal was to use one of the popular scripting languages or process virtual machines like Java, and to host Rentomy as a Software-as-a-Service (Saas) free of charge.

Since there are nearly 50 million rental units in the US alone, a free service like this needs superior software performance.

So squeezing more power from CPUs and using less RAM became very important. And with Moore's Law slowing down, the bloat of popular web languages is costing more computing resources—we're talking about process-virtual machines, interpreters, p-code generators, etc.

Debugging can be a pain because more layers of abstraction exist between you and what's really going on. Not every library can be easily used, so some functional and interoperability limitations remain.

On the other hand, in terms of big performance and a small footprint, there is no match for C. Most libraries are written in C for the same reason, so virtually any library you need is available, and debugging is straightforward.

However, C has issues with memory and overall safety (overwrites, underwrites, garbage collection, etc.), usability (it is low-level), application packaging, etc. And equally important, much of the development cost lies in the ease of writing and debugging the code and in its accessibility to novices.

From this perspective, Cloudgizer was born. Greater performance and a smaller footprint mean cheaper computing power. Easy, stable coding brings Zen to the development process, as does the ability to manage it better.

In hindsight, using Cloudgizer to build Rentomy was like using a popular scripting language without the issues.

Zigguro develops Free Open Source software development tools and business applications. Go to to learn more.


Looks cool but inline HTML seems like a bad idea. Why not use a template system like liquid built in c for speed.

Second, golang has great features for this entire process and is nearly as fast

There are many ways to write web applications, and you pointed out some of the tools and languages. Depending on your priorities, your choices may vary.

If the performance is a priority and simplicity is desired, Cloudgizer may be a better choice.

When different software pieces (such as the ones you mentioned) are put together, typically the complexity goes up, performance goes down, interoperability is almost never 100%, and more skills are needed. This means the cost goes up and time to market is longer.

Cloudgizer integrates pieces needed to build enterprise web applications. When you look at it that way, inline HTML is cleaner and faster than doing it by mixing up tools and frameworks, unless you want to for some reason.

The barrier to entry is low in a number of ways.

To start with, Cloudgizer is a C framework, so even though it has add-on constructs, it's not a new language, rather the end result of pre-processing is always pure C code.

The simplicity comes from things like inline HTML and HTML-like markups. Simpler is better. Plus the infrastructure details are taken care of.

The goal is for a beginner to get an intuitive grasp of the code in seconds. This is feasible with Cloudgizer, because C language is the basis for most other languages, and HTML is used by a very broad group of people.

While many languages and tools have good performance or even "close" performance, it is safe to say none is as good as C. The same goes for achieving a small footprint, which is desirable but commonly neglected.

Web languages and tools are often frameworks built as virtual machines, p-code generators, interpreters, and then frameworks are built on top of such frameworks. The loss of performance and the bloat are on the rise. Especially with hardware not keeping up with the bloat, and due to fundamental physics limitations, it's getting worse.

For cloud applications, high performance and low footprint are only going to get more important when it comes to power usage, the price of hardware and the happiness of end-user.

In a legacy web application, a company would get its own dedicated server with resources to spare.

In the cloud, money matters more. And, lowering the cost isn't just a financial issue. Less power and less hardware means less pollution and less garbage.

Using C as a core language serves also the purpose of utility, which is important as far as confidence in being able to get things done. Being true and tried and with large number of quality libraries (especially open source), C delivers in utility. And C linkage is ubiquitous even if the library you want isn't written in C.

Consider the clarity of debugging with other web frameworks. In any language other than C, there are layers of abstraction that make direct debugging more round-about than it needs to be.

Cryptic messages from layers of interpreters, virtual machines and frameworks on top of frameworks aren't easy to deal with. This means you don't need help from people who wrote the framework(s) because there is nothing between you and the final code that runs your application.

Finally, and as way of illustration of the above, the web template system you mentioned (liquid) is written in Ruby, which is in turn written in C. Go language is written in C too.

Why not use C to start with, and circumvent the performance, footprint, stability, interoperability and usability issues in the first place, if you can make web development in C richer, easier, safer and more productive? That's what Cloudgizer is all about.

I know some programmers what have no exact idea how their codes works in machine level (allocation and memory usage, efficiency, and others) independent of programming language chosen.
Will be clearly benefic to the modern programmers go back to the programming origins to understand more and better about computing archtecture.

Agreed. That would be a benefit for sure.

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