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omniIRF2: Interface Repository for omniORB.

omniIFR2 is an implementation of the Interface Repository, for omniORB, a free CORBA ORB for C++ and Python. For full details, see Chapter 10 "The Interface Repository" in the CORBA specification v2.6:

http://www.omg.org/cgi-bin/doc?formal/01-12-35

omniIFR2 closely follows the specification, rather than just implementing the IDL. It checks the types that are loaded into it, and helps to detect problems and inconsistencies at an early stage.

TABLE OF CONTENTS

Building omniIFR
Configuration 2.1 Editing omniORB.cfg 2.2 omniifr.db - the types database.
Using omniIFR 3.1 Running the Server 3.2 `ifr' - The omniidl Backend 3.3 `ifrclt' - The Command-line client. 3.4 Using omniIFR from C++ & Python
What's Missing?
Contact

1. Building omniIFR

You need omniORB-4.0.4 (or later) in order to build omniIFR. You will also need omniORBpy-2.4 (or later) in order to use omniidl to populate the repository. Get them from Sourceforge:

http://sourceforge.net/project/showfiles.php?group_id=51138

To build omniIFR on Unix - Follow these steps:

Run the `configure' script. For a full list of available parameters, type `./configure --help'. Common parameters are:

    --prefix=PREFIX         install files in PREFIX [/usr/local].
    --with-omniorb=PATH     set the path to the local omniORB installation
                            [$OMNIORBBASE].

-q, --quiet, --silent do not print `checking...' messages.

Check the result of the configure script, and if everything looks OK, then proceed on to the next step.

2. Type `make'.

3. Become root and type `make install'.

Example

% cd omniifr
% ./configure
% make
% su root
# make install

The following files & directories are installed:

PREFIX/sbin/omniifr The omniIFR server.
PREFIX/lib/libomniifr.so PREFIX/include/omniifr/Repository.h (etc.) The omniifr library & header files.
PREFIX/lib/pythonX.Y/site-packages/omniidl_be/ifr.py PREFIX/lib/pythonX.Y/site-packages/omniidl_be/ifr.pyc A new backend for `omniidl' that populates the repository.
/var/lib/omniifr/. This directory is created for database files.

2. Configuration

2.1 Editing omniORB.cfg

You must choose a port for omniIFR. This example assumes that you have choosen port 11173. Once you have chosen a port, add the following entry into your omniORB.cfg file:

InitRef = InterfaceRepository=corbaloc::hostname:11173/DefaultRepository

This line enables omniORB to find the Interface Repository by using the `resolve_initial_reference()' method. Replace `hostname' with your machine's hostname.

2.2 omniifr.db - the types database.

A prebuilt version of `omniifr.db' is available as a separate download. This currently contains (most of) the OMG's `Cos Types'. To initialise your database with these types, simply copy the `omniifr.db' file into /var/lib/omniifr and start omniifr.

3. Using omniIFR

3.1 Running the Server

The binary is in PREFIX/sbin (if you used the configure --prefix parameter), or in /usr/local/sbin (by default). You must specify the end point to match the port that you chose for your omniORB.cfg file:

% omniifr -ORBendPoint giop:tcp::11173 -P /var/run/omniifr.pid &

The Repository starts empty, with no type data loaded into it. In order to populate it with types you need to use the omniidl compiler with the new `ifr' backend. You can save the Repository's database by sending it SIGUSR2, for example:

% kill -USR2 `cat /var/run/omniifr.pid`

The database is saved to the file /var/lib/omniifr/omniifr.db. Once saved, the database is reloaded each time omniIFR restarts.

omniIFR supports the following options:

syntax: omniIFR OPTIONS -ORBendPoint giop:tcp::11173

OPTIONS: -f Stay in the foreground. -l PATH full path to data directory [/var/lib/omniifr] -P PIDFILE keep track of running instance in PIDFILE. -r read only mode. -t FILE Send trace messages to FILE instead of syslog. -V display version -h display this help text

3.2 `ifr' - The omniidl Backend

You will be familiar with `omniidl' as the IDL compiler used to generate C++ or Python stubs. The -b option is used to select the `backend' which generates stubs for the target language. So, `omniidl -bcxx foo.idl' generates C++ stubs, and `omniidl -bpython' generates python stubs.

`ifr' is a backend that does not generate language stubs. Instead it inserts the contents of an IDL file into the Interface Repository. Here's an example:

% omniidl -bifr foo.idl

The `ifr' requires omniORBpy, in addition to omniORB.

3.3 `ifrclt' - The Command-line client.

syntax: browser/ifrclt.py [OPTIONS] [COMMAND] [ARGS]

A very simple interface repository browser. Modelled on shell directory listing commands: cd, ls, pwd.

OPTIONS

   -l       --long            ls: detailed output.
   -rLEVELS --recurse=LEVELS  ls: Drill down LEVELS.               [default: 0]
                              Set to -1 to recurse without limit.
  COMMANDS
   pwd              Show the current scope
   cd SCOPED_NAME   Change the current scope, relative to the current scope.
   cd ..            Change the current scope, up one level.
   cd               Change to the root scope (the Interface Repository itself).
   ls               List the contents of the current scope.

ls SCOPED_NAME List the contents of the named definition.

The current scope is stored in the file pointed to by environment variable IFRBROWSERSTATE [default: $HOME/.ifrbrowserstate].

Example

% omniidl -bifr /usr/local/share/idl/omniORB/COS/CosEventComm.idl <snip>
% browser/ifrclt.py cd ::CosEventComm
% browser/ifrclt.py pwd
::CosEventComm
% browser/ifrclt.py ls

exception Disconnected { ... };
interface PushConsumer ... ;
interface PushSupplier ... ;
interface PullSupplier ... ;
interface PullConsumer ... ;
% browser/ifrclt.py -l ls PushConsumer
interface PushConsumer {
void push(in any data)
raises(Disconnected);
void disconnect_push_consumer();
};

3.4 Using omniIFR from C++ & Python

An excellent introduction to the Interface Repository is available on the web from "C/C++ Users' Journal":

http://www.cuj.com/documents/s=8244/cujcexp2101vinoski/

That series of articles also contains useful information on DII, DSI & dynamic CORBA in general. I've also found the dynamic CORBA sections of the omniORB3 manual very useful. I'm not sure why they haven't found their way into the omniORB4 manual...

http://omniorb.sourceforge.net/omni30/omniORB/omniORB010.html http://omniorb.sourceforge.net/omni30/omniORB/omniORB011.html http://omniorb.sourceforge.net/omni30/omniORB/omniORB012.html

Of course the OMG's CORBA specification is the ultimate reference:

http://www.omg.org/cgi-bin/doc?formal/01-12-35

4. What's Missing?

The following interfaces are not yet implemented:

AbstractInterfaceDef
LocalInterfaceDef
ValueMemberDef
ValueDef
ValueBoxDef
NativeDef

The repository versions scheme is not implemented. Different versions of the same type are rejected as if the version numbers did not differ. (This is permitted by the specification, but it would be a useful feature.)

For a full list of issues, see the files BUGS and repository/TODO.txt

5. Contact

This is an alpha release. It's not yet properly tested. Don't rely on it, but do try it. If you find any bugs, or you have any comments then please let me know:

-Alex Tingle (email: alex.omniifr AT firetree.net)