ACE+TAO Opensource Programming Notes
This book addresses issues related to TAO CORBA development and integration.
First, a word or two about the nature of open source projects. The main benefit of an open source project is that you get a working product you can use, complete with community support. This support often takes the form of user's support as well as developer support. Ideally, these support avenues also include documentation. Should the open source project in question lack some of the pieces mentioned above, its utility as an open source product (particularly as the product becomes more complex) is necessarily diminished.
ACE+TAO is a wonderful product which compares well to other open source products like Orbit or Mico. It encompasses much of the current standard and comes complete with all the services you would expect (and some extras too). Unfortunately, except for the most basic services (the naming service) there are precious few documented programming examples in their tutorial. While there are several source files in the examples directory, these are sadly not written with documented code (often without even a header describing the use for the example), and certainly not included in any web page explaining their code or use.
Object Computing, Inc. freely provides the Getting Started chapter of their TAO Developer's Guide (that can be purchased for around $20.00). This chapter is complete with code examples and walks the user through the steps needed to make a simple TAO client and server. The open-source TAO 1.4a distribution contains all examples referenced in the TAO Developer's Guide, while the FAQ contains some helpful information for beginners and experts alike.
Remedy IT provides freely the TAO Programmers Guide.
Additionally, the comp.soft-sys.ace and comp.object.corba newsgroups are monitored by groups and individuals able to field questions related to both TAO and CORBA, and the TAO mailing lists are available for questions, discussion, and reporting bugs related to TAO.
The following sections should expand on the single example provided with ACE+TAO (the quoter example) with sections designed to help the user with the event service, the notification service, and other real-time issues. Those reading this page wishing to make contributions in explaining various pieces of the TAO project are encouraged to make contributions to this page.
The only caveat is that you want to be careful with the "traditional build under a UNIX environment. It treats the install target dir as a sandbox it owns, so if you have chosen /usr/local, like you would with a typical automake project, understand that if there is a problem with the build, the last thing the traditional build env will do is to delete its sandbox (/usr/local).
The newer versions of ACE+TAO, V5.6.7 (mini-release), in theory now support automake style builds. In fact, for the first time, you can do the "configure; make; make install" dance and it just works! There are some annoying problems that have yet to be cleared up. As of this version, the -ORBDaemon switch doesn't work to send the distributions daemons into the background.
On the other hand, if you like a no fuss option, Ken Sedgwick over at bonsai.com has provided pre-built RPMs. The binaries provided aren't of the debug variety, so they don't take up the shocking amount of space an installation of ACE+TAO build with -g can. The bummer seems to be that the number of compiled in features seems to be a little light. That being said, its certainly a good way to get started, and will handle 90% of your applications.
Build Instructions on Linux
To make installing all of TAO easier use the following script. It will take a lot of time to build so using a script is a good option. The script can also be modified to compile only the necessary TAO features.
#!/bin/bash echo "Usage: sudo ./INSTALL-ACE+TAO-6.1.2.sh [INSTALL-DIR]"; echo "best to put it in /opt" ACETAO=ACE+TAO-6.1.2 # To change to the latest available install change the ACETAO # Tested and works with UBUNTU 10.04 and 12.04 if [ $# -eq 1 ]; then INSTALL_DIR=$1; else INSTALL_DIR=~/; fi # check if script is run as root! echo "default run sudo ./INSTALL-ACE+TAO-6.1.2.sh ~/"; echo "Tested with Ubuntu-but in theory work on all linux! NJOY !"; # go to $INSTALL_DIR to install ACE+TAO into cd $INSTALL_DIR; # download ACE+TAO to current directory echo "Download: wget http://download.dre.vanderbilt.edu/previous_versions/$ACETAO.tar.gz"; wget http://download.dre.vanderbilt.edu/previous_versions/$ACETAO.tar.gz if [ "$?" -ne 0 ]; then echo "ERROR: download failed!"; exit 1; fi # rm possible former installation rm -rf ACE_wrappers; rm -rf $ACETAO; # extract archive echo "UNTAR: tar -xzf $ACETAO.tar.gz"; tar -xzf $ACETAO.tar.gz if [ "$?" -ne 0 ]; then echo "ERROR: extraction failed!"; exit 1; fi # set environment variables cd ACE_wrappers; echo "export ACE_ROOT=$PWD" >> ~/.bashrc source ~/.bashrc echo "export TAO_ROOT=$ACE_ROOT/TAO" >> ~/.bashrc echo "export LD_LIBRARY_PATH=$ACE_ROOT/lib:$LD_LIBRARY_PATH" >> ~/.bashrc cd $ACE_ROOT; source ~/.bashrc # create config.h file echo "Config.h create--- $ACE_ROOT/ace/config.h" echo "#include <ace/config-linux.h>" > $ACE_ROOT/ace/config.h echo "" >> $ACE_ROOT/ace/config.h # create platform_macros.GNU file echo "create platform_macros.GNU for linux--$ACE_ROOT/include/makeinclude/platform_macros.GNU"; echo "INSTALL_PREFIX = /usr/local" > $ACE_ROOT/include/makeinclude/platform_macros.GNU echo "include \$(ACE_ROOT)/include/makeinclude/platform_linux.GNU" >> $ACE_ROOT/include/makeinclude/platform_macros.GNU echo "" >> $ACE_ROOT/include/makeinclude/platform_macros.GNU # compile ace kernel cd $ACE_ROOT/ace; make; if [ "$?" -ne 0 ]; then echo "FAILED to compile $ACE_ROOT/ace!"; exit 1; fi # compile gperf cd $ACE_ROOT/apps/gperf; make; if [ "$?" -ne 0 ]; then echo "FAILED to compile $ACE_ROOT/apps/gperf!"; exit 1; fi cd $ACE_ROOT/ace; make install; if [ "$?" -ne 0 ]; then echo "FAILED to install $ACE_ROOT/ace!"; exit 1; fi # compile TAO cd $TAO_ROOT; make; if [ "$?" -ne 0 ]; then echo "FAILED to compile $TAO_ROOT/TAO!"; exit 1; fi echo ""; echo "ACE+TAO successfully installed!!!";
Things to check after install
After completing the bulding of the TAO it is important to check if everything is done correctly, Hence run the "tests" available in ACE and TAO to check. If the system is built in Linux then the Naming service is not available by default, but the functionallity is provided by tao-cosnaming just like the IDL build is given by tao-idl. you can create a softlink for NamingService with tao_cosnaming by using
ln -s tao_cosnaming Naming_Service
- Run the tests (ACE_wrappers/tests and ACE_wrappers/TAO/tests)
- check all the links for the binaries (tao_idl, tao_cosnaming.. etc)
- Start with the examples
- Present in 2 locations just runing then playing around with them is a great start
- ACE_wrappers/TAO/DevGuideExamples/ and
Core Development Operations
In this section, the basic tasks which should allow the user to create most CORBA enabled applications are described.
- Before you start
- Create a server
- Create a client
- Dealing with IIOP Endpoints
- Starting the basic services
- Advertise your service on a naming service
- Find a service on a naming server
- A more useful client and server example
- Attaching your applications to the core services
- Configuring your app to work with an Implementation Repository
- Create a process with both client and server
- Create an event supplier
- Create an event consumer
- Create a notifier supplier
- Create a notifier consumer
The following sections describe the various services, their configuration, and, if not covered above, should include an example.