Allow FileParser.Endpoints to be set via Ice::Properties

[mdorner]

If launched with --server as option, the icegridadmin command-line tool currently picks a random ephemeral port on localhost as endpoint. This PR enables it to read the endpoints from the property "FileParser.Endpoints" , and defaults to the old hard-coded endpoint, if it is not found.

I am forfeiting all rights to the code in alignment with CONTRIBUTING.md and the Contributor Agreement, and hope you can merge this trivial piece of code without requiring me to print and sign something.

[bernardnormier]

A cleaner way to provide this functionality would be to:

• use createObjectAdapter instead of createObjectAdapterWithEndpoints
• use an IceGridAdmin.Xxx name for the object adapter, for example IceGridAdmin.Server
• add this new OA name to the list of acceptable Ice-prefixed properties, see
  https://github.com/zeroc-ice/ice/blob/3.7/config/PropertyNames.xml#L469
  (you also need to regenerate and commit all the derived files with makeprops.py)
• add code to give the default value to IceGridAdmin.Server.Endpoints

You could also submit a pull request for branch 3.7 instead of master, assuming you'd like to see this functionality in 3.7.x.

[mdorner]

Ok, I can adjust the PR to do that. The first three points seem straightforward to me, but I am not entirely sure how to default the value. Is there some place where these defaults typically go?

[bernardnormier]

In general, you should set values for properties just before Communicator initialization because most Ice properties are read only during communicator initialization. Object adapter properties are read when the object adapter is created so here you could set the default value for IceGridAdmin.Server.Endpoints later.

Nevertheless, I suggest to set this default value before communicator initialization, i.e. change:
https://github.com/zeroc-ice/ice/blob/v3.7.1/cpp/src/IceGrid/Client.cpp#L244

_appName = args[0];
InitializationData id;
id.properties = createProperties(args);
id.properties->setProperty("Ice.Warn.Endpoints", "0"); // overwrite Ice.Warn.Endpoints
_communicator = initialize(id);

to something like:

_appName = args[0];
PropertiesPtr defaultProps = createProperties();
defaultProps->setProperty("IceGridAdmin.Server.Endpoints", "tcp -h localhost");
InitializationData initData;
initData.properties = createProperties(args, defaultProps);
initData.properties->setProperty("Ice.Warn.Endpoints", "0"); // overwrite Ice.Warn.Endpoints
_communicator = initialize(initData);

[mdorner]

I have made the changes as discussed, and hopefully as you would expect them.

As to where to merge them I am not sure what your branching-workflow is, but ideally I would like to see them going into both 3.6 and 3.7 eventually.

[bernardnormier]

Thanks for your contribution!

[mdorner]

And thank you for your constructive feedback and help!