Jenkins will use ssh to connect to the build node so it is good
practice to setup a private/public key to allow the Jenkins master
node to connect to the slave. On the master, copy the jenkins user's key:
ssh-copy-id target-host
The Ada build node is then added through the Jenkins UI in Manage Jenkins/Manage Nodes.
Jenkins jobs
The jenkins master is now building 7 projects automatically for Ubuntu 14.04:
Trusty Ada Jobs
In previous tutorials we have seen how to create and setup the project,
design the UML model to generate the Ada implementation and the database schema.
In this tutorial we will see how to design the page to create a review, implement the operations to create and populate the database with the new review.
In the Ada Web Application: Setting up the project we have seen how to create a new
AWA project. In this second article, we will see how to design the UML model, generate
the Ada code and create the database tables from our UML design.
Introduction
A Model driven engineering or MDE promotes the use of models to ease the development of software and systems.
The Unified Modeling Language is used to modelize various parts of the software. UML is a graphical type modelling language and it has many diagrams but we
are only going to use one of them: the Class Diagram.
The class diagram is probably the most powerful diagram to design, explain and
share the data model of any application. It defines the most important data types used
by an application with the relation they have with each other. In the class diagram, a
class represents an abstraction that encapsulates data member attributes and operations.
The class may have relations with others classes.
For the UML model, we are going to use ArgoUML
that is a free modelization tool that works pretty well. For the ArgoUML setup, we will use two profiles:
The Dynamo profile that describes the base data types for our UML model. These types are necessary for the code generator to work correctly.
The AWA profile that describes the tables and modules provided by AWA. We will need it to get the user UML class definition.
These UML profiles are located in the /usr/share/dynamo/base/uml
directory after Dynamo and AWA are installed. To configure ArgoUML, go in the Edit -> Settings menu
and add the directory in the Default XMI directories list. Beware that you must
restart ArgoUML to be able to use the new profiles.
Modelize the domain model in UML
The UML model must use a number of Dynamo artifacts for the code generation to work properly. The artifact describes some capabilities
and behavior for the code generator to perform its work. Stereotype names are enclosed within markers. Dynamo uses the following stereotypes:
The DataModel stereotype must be applied on the package which contains the model to generate. This stereotype activates the code generation (other packages are not generated).
The Table stereotype must be applied to the class. It controls which database table and Ada type will be generated.
The PK stereotype must be defined in at most one attribute of the class. This indicates the primary key for the database table. The attribute type must be an integer or a string. This is a limitation of the Ada code generator.
The Version stereotype must be applied on the attribute that is used for the optimistic locking implementation of the database layer.
In our UML model, the Review table is assigned the Table stereotype
so that an SQL table will be created as well as an Ada tagged type to represent our table. The id class attribute represents the primary key and thus has
the PK stereotype. The version class attribute is the database column
used by the optimistic locking implementation provided by ADO. This is why is has
the Version stereotype. The title, site, create_date,
text and allow_comments attributes represent the information we
want to store in the database table. They are general purpose attributes and thus
don't need any specific stereotype. For each attribute, the Dynamo
code generator will generate a getter and a setter operation that can be used in the Ada code.
To tune the generation, several UML tagged values can be selected and added on the table or on a table attribute. By applying a stereotype to the class, several tagged
values can be added. By selecting the Tagged Values tab in ArgoUML
we can edit and setup new values. For the Review table, the
dynamo.table.name tagged value defines the name of the SQL database table,
in our case atlas_review.
The text attribute in the Review table is a string that can hold some
pretty long text. To control the length of the SQL column, we can set the
dynamo.sql.length tagged value and tell what is that length.
Once the UML model is designed, it is saved in the project directory uml.
Dynamo will be able to read the ArgoUML file format (.zargo extension) so
there is no need to export the UML in XMI.
The Review application UML model
The final UML model of our review application is fairly simple.
We just added a table and a bean declaration. To benefit from the
user management
in AWA, we can use the AWA::Users::Models::User class that is defined in the AWA UML model.
The reviewed-by association will create an attribute reviewer
in our class. The code generator will generate a Get_Reviewer and
Set_Reviewer operation in the Ada code. The SQL table will contain
an additional column reviewer that will hold the primary key of the reviewer.
The Review_Bean class is an Ada Bean abstract class
that will be generated by the code generator. The Bean stereotype activates the bean code generator
and the generator will generate some code support that is necessary to turn the Review_Bean tagged
record into an Ada Bean aware type. We will see in the next
tutorial that we will only have to implement the save and delete operation that are described in this UML model.
Makefile setup
The Makefile.in that was generated by the Dynamocreate-project
command must be updated to setup a number of generation arguments for
the UML to Ada code generator. Edit the Makefile.in to change:
DYNAMO_ARGS=--package Atlas.Reviews.Models db uml/atlas.zargo
The --package option tells Dynamo to generate only the model for the
specified package. The db directory is the directory that will contain the
SQL model files.
Once the Makefile.in is updated, the Makefile must be updated
by using the following command:
./config.status
Or if you prefer, you may run again the configure script to re-configure
the whole project.
We need the code
To run the generator, we can use the generate make target:
make generate
The Dynamo code generator reads the
file uml/atlas.zargo and the UML model it contains and generates:
the Ada package Atlas.Reviews.Models which contains the definition of the Review table. The model files are created in the directory src/models which is separate from your Ada sources.
the SQL files to create the MySQL or SQLite database. Depending on the AWA modules which are used, the generated SQL files will contain additional tables that are used by the AWA modules. The SQL files are generated in the db/mysql and db/sqlite directories.
Let's create the database
Until now we designed our application UML model, we have our Ada code generated,
but we need a database with the tables for our application. We can do this
by using the create-database command in Dynamo. This command needs
several arguments:
The directory that contains the SQL model files. In our case, this is db.
The information to connect to the database, the database name, the user and its password. This information is passed in the form of a database connection string.
The name of the database administration account to connect to the server and create the new database.
The optional password for the database administration account.
If the MySQL server is running on your host and the admin account does not have any password, you can use the following command:
dynamo create-database db 'mysql://localhost/demo_atlas?user=demo&password=demo' root
The create-database creates the database (demo_atlas) with
the tables that are necessary for the application. It also creates the demo
user and give it the necessary MySQL grants to connect to the demo_atlas
database.
The Review Web Application UML video
To help you in building the UML model and see who the whole process looks like in reality,
I've created the following short video that details the above tutorial steps.
Conclusion
Thanks to ArgoUML and Dynamo, generating the Ada model and database tables becomes a simple and fun task. We have not written any line of code
yet in this Review Web Application project, everything has been generated but we achieved a big progress:
The Review Web Application server is built and can be launched,
The database is initialized and contains our application data model schema.
The next tutorial will explain how to design the review form, implement the operations to create and populate the database with the new review.
Ada Web Application is a complete framework that allows to write
web applications using the Ada language. Through a complete web application, the tutorial explains various
aspects in setting up and building an application by using AWA.
The tutorial is split in several articles and they are completed by short videos
to show how easy the whole process is.
The tutorial assumes that you have already installed the following software on your
computer:
The review web application allows users to write reviews about a product, a software or a web site and share them
to the Internet community.
The community can read the review, participate by adding comments and voting for the reviewed product or software.
The AWA framework provides several modules
that are ready to be used by our application. The login and user management is
handled by the framework so this simplifies a lot the design of our application.
We will see in the tutorial how we can leverage this to our review application.
Because users of our review web application have different roles,
we will need permissions to make sure that only reviewers can modify a review.
We will see how the AWA framework leverages the
Ada Security library to enforce the permissions.
The AWA framework also integrates three other
modules that we are going to use: the
tags,
the votes
and the comments.
Since many building blocks are already provided by the Ada framework, we will
be able to concentrate on our own review application module.
Project creation with Dynamo
The first step is to create the new project. Since creating a project from scratch is never easy
we will use the Dynamo tool to build our initial review web application.
Dynamo is a command line tool that provides several commands that help in several development tasks.
For the project creation we will give:
the output directory,
the project name,
the license to be used for the project,
the project author's email address.
Choose the project name with care as it defines the
name of the Ada root package that will be used by the project.
For the license, you have the choice between GPL v2,
GPL v3, MIT,
BSD 3 clauses,
Apache 2 or some proprietary license.
dynamo -o atlas create-project -l apache atlas Stephane.Carrez@gmail.com
(Of course, change the above email address by your own email address, this is an example!)
The Dynamo project creation will build the atlas directory and populate it with many files:
A set of configure, Makefile, GNAT project files to build the project,
A set of Ada files to build your Ada web application,
A set of presentation files for the web application.
Once the project is created, we must configure it to find the Ada compiler, libraries and so on. This is done
by the following commands:
cd atlas
./configure
At this step, you may even build your new project and start it. The make command will build the Ada
files and create the bin/atlas-server executable that represents the web application.
With the Ada Web Application framework, a web application is composed of modules where each module
brings a specific functionality to the application. AWA provides a module for
user management, another
for comments,
tags,
votes, and many others. The application can decide to use these modules or not. The AWA module helps in defining the architecture and designing your web application.
For the review web application we will create our own module dedicated for the review management.
The module will be an Ada child package of our root project package. From the Ada
point of view, the final module will be composed of the following packages:
A Modules package represents the business logic of the module. It is provides operations to access and manage the data owned by the module.
A Beans package holds the Ada beans that make the link between the presentation layer and business logic.
A Models package holds the data model to access the database content. This package is generated from UML and will be covered by a next tutorial.
To help in setting up a new AWA module, the Dynamo tool provides the
add-module command. You just have to give the name of the module,
which is the name of the Ada child package. Let's create our reviews module now:
dynamo add-module reviews
The command generates the new AWA module and modifies some existing files to
register the new module in the application. You can build your web application at this
stage even though the new module will not do anything yet for you.
Eclipse setup
Launch you Eclipse and create the new project by going to the File -> New -> Project
menu. Choose the Ada Project and uncheck the Use default location checkbox
so that you can browse your file system and select the atlas directory.
That's it. If everything went well, you should be able to see the projects files in
the Eclipse project explorer.
The Review Web Application setup video
To help you in setting up and see how the whole process looks like in reality,
I've created the following short video that details the above tutorial steps.
Conclusion
The whole process takes less than 3 minutes and gives you the basis to setup and build
your new web application. The next tutorial will explain how to use the UML to design
and generate the data model for our Review Web Application.
I've created and setup a Debian repository to give access to several Debian packages for
several Ada projects that I manage. The goal is to provide some easy and ready to use packages to
simplify and help in the installation of various Ada libraries. The Debian repository includes
the binary and development packages for Ada Utility Library,
Ada EL, Ada Security,
and Ada Server Faces.
Access to the repository
The repository packages are signed with PGP. To get the verification key and setup the apt-get tool, you
should run the following command:
A first repository provides Debian packages targeted at Ubuntu 13.04 raring.
They are built with the gnat-4.6 package and depend on libaws-2.10.2-4 and libxmlada4.1-dev. Add the following line to your /etc/apt/sources.list configuration:
deb http://apt.vacs.fr/ubuntu-raring raring main
Ubuntu 12.04 LTS Precise
A second repository contains the Debian packages for Ubuntu 12.04 precise.
They are built with the gnat-4.6 package and depend on libaws-2.10.2-1
and libxmlada4.1-dev. Add the following line to your /etc/apt/sources.list configuration:
deb http://apt.vacs.fr/ubuntu-precise precise main
Installation
Once you've added the configuration line, you can install the packages:
Ada Server Faces is a framework that allows to create Web applications using the same design patterns as the Java Server Faces (See JSR 252, JSR 314, or JSR 344). The presentation pages benefit from
the FaceletsWeb template system and the runtime takes advantages of the
Ada language safety and performance.
A new release is available with several features that help writing online applications:
Add support for Facebook and Google+ login
Javascript support for popup and editable fields
Added support to enable/disable mouseover effect in lists
New EL function util:iso8601
New component <w:autocomplete> for input text with autocompletion
New component <w:gravatar> to render a gravatar image
New component <w:like> to render a Facebook, Twitter or Google+ like button
New component <w:panel> to provide collapsible div panels
New components <w:tabView> and <w:tab> for tabs display
New component <w:accordion> to display accordion tabs
Add support for JSF <f:facet>, <f:convertDateTime>, <h:doctype>
Ada EL is a library that implements an expression language similar to JSP and JSF Unified Expression Languages (EL).
The expression language is the foundation used by Java Server Faces
and Ada Server Faces to make the necessary binding between presentation
pages in XML/HTML and the application code written in Java or Ada.
The presentation page uses an UEL expression
to retrieve the value provided by some application object (Java or Ada). In the following expression:
#{questionInfo.question.rating}
the EL runtime will first retrieve the object registered under the name questionInfo and look for the
question and then rating data members. The data value is then converted to a string.
A few days ago, I did a fresh installation of my Jenkins build environment for my Ada projects (this was necessary after a disk crash on my OVH
server). I took this opportunity to setup a FreeBSD build node. This article is probably incomplete but tends to collect a number of tips for the installation.
Virtual machine setup
The FreeBSD build node is running within a QEMU virtual machine. The choice of the host turns out to be important since
not all versions of QEMU are able to run a FreeBSD/NetBSD or OpenBSD system. There is a bug in QEMU PCI emulation that prevents the NetBSD network driver
to recognize the emulated network cards (See qemu-kvm 1.0 breaks openbsd, netbsd, freebsd).
Ubuntu 12.04 and 12.10 provide a version of Qemu that has the problem. This is solved in Ubuntu 13.04, so this is the host linux distribution that I've installed.
For the virtual machine disk, I've setup some LVM partition on the host as follows:
sudo lvcreate -Z n -L 20G -n freebsd vg01
this creates a disk volume of 20G and label it freebsd.
The next step is to download the FreeBSD Installation CD (I've installed the FreeBSD-10.0-RC2).
To manage the virtual machines, one can use the virsh command but the virt-manager graphical front-end provides an easier setup.
sudo virt-manager
The virtual machine is configured with:
CPU: x86_64
Memory: 1048576
Disk type: raw, source: /dev/vg01/freebsd
Network card model: e1000
Boot on the CD image
After the virtual machine starts, the FreeBSD installation proceeds (it was so simple that I took no screenshot at all).
Post installation
After the FreeBSD system is installed, it is almost ready to be used. Some additional packages are added
by using the pkg install command (which is very close to the Debian apt-get command).
pkg install jed
pkg install sudo bash tcpdump
By default the /proc is not setup and some application like the OpenJDK need to access it.
Edit the file /etc/fstab and add the following lines:
Jenkins uses a Java application that runs on each build node. It is necessary to install some Java JRE.
To use subversion on the build node, we must make sure to install some 1.6 version since the 1.8 and 1.7 version have incompatibilities with the Jenkins master. The following packages are necessary:
Jenkins needs a user to connect to the build node. The user is created by the adduser command. The Jenkins user does not need any privilege.
Jenkins master will use SSH to connect to the slave node. During the first connection, it installs the slave.jar
file which manages the launch of remote builds on the slave. For the SSH connection, the password authentication is possible but I've setup a public key authentication that I've setup on the FreeBSD node by using ssh-copy-id.
At this stage, the FreeBSD build node is ready to be added on the Jenkins master node (through the Jenkins UI Manage Jenkins/Manage Nodes).
MySQL Installation
The MySQL installation is necessary for some of my projects. This is easily done as follows:
AWA uses Ada Server Faces for the web framework. This framework is using several patterns from the Java world such as Java Server Faces and Java Servlets.
AWA provides a set of ready to use and extendable modules that are common to many web application. This includes managing the login, authentication, users, permissions.
AWA uses an Object Relational Mapping that helps in writing Ada applications on top of MySQL or SQLite databases. The ADO framework allows to map database objects into Ada records and access them easily.
AWA is a model driven engineering framework that allows to design the application data model using UML and generate the corresponding Ada code.
The new version of AWA provides:
New jobs plugin to manage asynchronous jobs,
New storage plugin to manage a storage space for application documents,
New votes plugin to allow voting on items,
New question plugin to provide a general purpose Q&A.
Dynamo is a tool to help developers write some types of Ada Applications which use the Ada Server Faces or
Ada Database Objects frameworks. Dynamo provides several commands to perform one specific task in the development process:
creation of an application, generation of database model, generation of Ada model, creation of database.
The new version of Dynamo provides:
A new command build-doc to extract some documentation from the sources,
The generation of MySQL and SQLite schemas from UML models,
The generation of Ada database mappings from UML models,
The generation of Ada beans from the UML models,
A new project template for command line tools using ADO,
A new distribution command to merge the resource bundles.
The most important feature is probably the Ada code generation from a UML class diagram. With this, you can design
the data model of an application using ArgoUML and generate the
Ada model files that will be used to access the database easily through the Ada Database Objects library. The tool will also generate the SQL database schema so that
everything is concistent from your UML model, to the Ada implementation and the database tables.
The short tutorial below indicates how to design a UML model with ArgoUML, generate
the Ada model files, the SQL files and create the MySQL database.
The Ada Database Objects is an Object Relational Mapping for the Ada05 programming language. It allows to map database objects into Ada records and access databases easily.
Most of the concepts developped for ADO come from the Java Hibernate ORM.
ADO supports MySQL and SQLite databases.
The new version brings:
Support to reload query definitions,
It optimizes session factory implementation,
It allows to customize the MySQL database connection by using MySQL SET
Ada Server Faces is an Ada implementation of several Java standard web frameworks.
The Java Servlet (JSR 315) defines the basis for a Java application to be plugged in Web servers. It standardizes the way an HTTP request and HTTP response are represented. It defines the mechanisms by which the requests and responses are passed from the Web server to the application possibly through some additional filters.
The Java Unified Expression Language (JSR 245) is a small expression language intended to be used in Web pages. Through the expressions, functions and methods it creates the link between the Web page template and the application data identified as beans.
The Java Server Faces (JSR 314 and JSR 344) is a component driven framework which provides a powerful mechanism for Web applications. Web pages are represented by facelet views (XHTML files) that are modelized as components when a request comes in. A lifecycle mechanism drives the request through converters and validators triggering events that are received by the application. Navigation rules define what result view must be rendered and returned.
Ada Server Faces gives to Ada developers a strong web framework which is frequently used in Java Web applications.
On their hand, Java developers could benefit from the high performance that Ada brings: apart from the language, they will use the same design patterns.
The new version of Ada Server Faces is available and brings the following changes:
The Security packages was moved in a separate project: Ada Security,
New demo to show OAuth and Facebook API integration,
Integrated jQuery 1.8.3 and jQuery UI 1.9.2,
New converter to display file sizes,
Javascript support was added for click-to-edit behavior,
Add support for JSF session beans,
Add support for servlet error page customization,
Allow navigation rules to handle exceptions raised by Ada bean actions,
Ada Security is a security framework which allows web applications to define and enforce security policies. The framework allows users to authenticate by using OpenID Authentication 2.0. Ada Security also defines a set of client methods for using the OAuth 2.0 protocol.
A security policy manager defines and implements the set of security rules that specify how to protect the system or the resources.
A user is authenticated in the application. Authentication can be based on OpenID or another system.
A security context holds the contextual information that allows the security policy manager to verify that the user is allowed to access the protected resource according to the policy rules.
The Ada Security framework can be downloaded at Ada Security project page.
AWA is architectured arround modules and plugins that allow to build, re-use and extend modules made of Ada code, Web pages or Javascript.
AWA provides a set of ready to use and extendable plugins that are common to many web application. This includes managing the login, authentication, users, permissions, a mail plugin, a blog plugin, a Javascript light editor.
AWA uses an Object Relational Mapping that helps in writing Ada applications on top of MySQL or SQLite databases. The ADO framework allows to map database objects into Ada records and access them easily.
AWA integrates a configurable event service which allows plugins to easily interact and connect with each other (either synchronously or asynchronously). The event service provided by AWA is heavily inspired from the Java Message Service.
To learn more on how to create easily a web application using AWA, look at the 4 minutes video.
The Atlas Web Application Demonstrator is a demonstration of
an application using this AWA framework. Sources of the Atlas demonstrator are available on GitHub project: Atlas.
