Hi Steve, Paul, the set of context attributes is supposed to allow the user to point to a specific security token, in a wide set of environments. You are right: apart from 'Type', different grid environments will require different attributes to be set. For example, a MyProxy context would probably specify 'Server', 'UserID' and 'UserPass', while a X509 proxy context would point the 'UserProxy' attribute to the proxie's location in the file system. We hope that the set of attributes cover all currently used Grid middlewares (we had the OGF security area check the attributes for completeness). If not, that needs fixing. Note that these attributes are what the SAGA _user_ sees on API level, and what he is supposed to use to specify what token to use. In most cases (by far, e.g. 99%), the user should not need to set the attributes at all (apart from type possibly), and the SAGA implementation should be able to pick up the security tokens from default locations etc. It is a different story altogether on implementation level though: a context representation within the SAGA implementation may well keep additional attributes, like (for the examples above) the MyProxy server version, or the X509 proxy file checksum. That might be useful information for the implementation to keep, and to pass around with the context - but these attributes do not need exposure on API level (that is why the context attributes are not extensible). I think the latter is what causes confusion for Paul in the implementation (will send a separate mail on that on the devel list). Did I answer your questions? Cheers, Andre. Quoting [Steve Fisher] (Feb 05 2009):
I have had no response - does anybody know why this set of attributes has been defined?
Steve
2009/2/3 Steve Fisher <dr.s.m.fisher@gmail.com>:
Hi,
I have been looking at the spec for details of the Context class. I don't understand why it has specific attributes defined when only "Type" is common to all contexts. Attributes such as "Server", "CertRepository" etc should not be there. The implementation can document which attributes are needed. Have I missed something?
Steve
-- Nothing is ever easy.