View source for Non Java projects Proposal

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'''Note this document is under construction''' --[[User:Gch.mikrosimage.fr|Guillaume CHATELET]]

== Purpose ==

While trying to use Buckminster for both my Java and C++ projects, I realized that Java projects within Eclipse were pretty straightforward but C/C++ projects were much more difficult to manage.

=== Why is it so hard to use Buckminster with non Java projects ? ===

Component materialization is much harder in non Java environments because :
* there are no standard way to describe C/C++ projects so you have to write the CSpec file anyway ( contrary to Eclipse Java projects which provides a way to auto generate the CSpec )
* compiling, testing, your code requires to execute programs from outside ( shell scripts, compiler, unit tests and so forth ).
* some of the resources you need to materialize are libraries that are only available as zipped url resources.
** which implies you have to download and unzip them : Buckminster cannot do that for the moment despites its exactly what you expect it to do. So to overcome this issue you have to write ant tasks.


=== Work flow currently used ===
The toolchain I created to manage C/C++ projects dependencies is as follows :
* Create Spec components to describe dependencies
* Specify actions like build / clean / rebuild
** those actions have prerequisites pointing to other components (eg: the path to the libTiff include folder)
* Write ant scripts called from buckminster to
** retrieve libraries from urls or retrieve files from archives pointed by url
** execute commands with specific environment variables (eg. calling the compiler with paths to libraries)
*** those environments variables are retrieved from Buckminster's action's prerequisites section via [[Ant actor API (Buckminster)]]
* Create the script to compile the code ( Makefile or Boost Jamfile or SCons file )


== Proposal ==

This page is a proposal to extends Buckminster in order to bring users from the non Java world a better experience.

=== Executor Actor ===

This actor would add the possibility to execute programs directly from the CSpec without writing Ant Scripts.

==== Features ====
* Executes programs or shell scripts
* Sets arguments
** arguments can refer to prerequisites
* Sets environment variables for the execution
** environments variables values can refer to prerequisites
* Sets execution directory

==== Example ====

<source lang="xml">
<cs:public name="build" actor="executor">
      <cs:actorProperties>
            <cs:property key="env" value="TIFF_LIB=${tiff.lib};TIFF_INCLUDE=${tiff.include};
                                          VERSION=${VERSION};OSGI_VERSION=${buckminster.version}"/>
            <cs:property key="shell" value="${compiler} -j2 debug"/>
      </cs:actorProperties>
      <cs:properties>
            <cs:property key="VERSION" value="1.0.0"/>
      </cs:properties>
      <cs:prerequisites>
            <cs:attribute component="mingw-5.1.4" name="compiler" alias="compiler" />
            <cs:attribute component="libtiff-3.6.1" name="include" alias="tiff.include" />
            <cs:attribute component="libtiff-3.6.1" name="lib" alias="tiff.lib" />
      </cs:prerequisites>
</cs:public>
</source>

==== Valid properties ====
This syntax integrates into [[Buckminster component meta-data language 1.0 (Reference)#Public.2FPrivate_Actions|Buckminster's CSpec Actions]].

* '''env''' : a list of semi-colon separated environment variable
* '''exec''' : the program to execute
* '''execDir''' : the program execution directory (if not set : the component directory)
* '''shell''' : a batch file to execute
'''Note''' that you have to choose between '''exec''' or '''shell''' keyword.

All those properties can contain variables.

Those variables are set by surrounding properties or named path with '''${}'''. See examples [[Non_Java_projects_Proposal#Example|above]].

=== Fetcher Actor ===

This actor is used to materialize resources into the component. I'm still not sure this behavior should be provided by an actor or through the materialization process. It seems the actor can be used at will so it's more flexible than the materialization but this point can be discussed.

==== Features ====
* fetch single (for the moment)
* log to https sites
* unzip, untar, untargz, untarbz2 files (add 7zip support ?)
** possibility to specify destination directory
** possibility to filter the archive content
** keep hierarchy or flatten folders

==== Example ====

<source lang="xml">
<cs:public name="download" actor="fetcher">
   <cs:actorProperties>
      <cs:property key="dir" value="data"/>
      <cs:property key="option" value="uncompress;flatten;include=*.html;include=*.c"/>
      <cs:property key="url" value="http://download.osgeo.org/libtiff/tiff-3.8.2.tar.gz"/>
   </cs:actorProperties>
</cs:public>
</source>

==== Valid Properties ====

* '''url''' : the resource to fetch
* '''dir''' : the directory where the file(s) should be placed
** if not set '''dir''' points to component's location
* '''options''' : a set of options to customize the fetch operation, valid options are :
** '''uncompress''' : specify that the resource pointed by the url is an archive and that it should be uncompressed
** '''flatten''' : valid only with uncompress. If specified the folder hierarchy is flatten
** '''include''' : a regular expression to include specific files only. Note that you can specify many include directives in the options line.
*** eg : include=*.html
If the resource you are accessing is protected with basic authentication, you can also specify :
* '''login''' : the login to use with basic authentication
* '''pass''' : the password to use with basic authentication
'''Note''' that both properties have to be set to enable authentication.

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