[auscope-geosciml] [ExternalEmail] Re: GeoSciML RC2 schemas - O&Mv2 schema location update [SEC=UNCLASSIFIED]

Sen, Marcus A. mase at bgs.ac.uk
Wed Jun 22 04:52:24 EDT 2011


I think this is agreeing with the previous emails but we haven't always been consistent with practice so to summarize:

XML Schemas have in the schemaLocation attribute values that depend on the actual deployment location. If we used these values directly during development then we would have to edit the schemaLocation attributes everytime we moved them and when they were copied across to the final deployment location which would be error prone and inconvenient.

The solution is for Schema developers to use catalog files to rewrite schemaLocation attribute values to working local or version control repository locations.

So:

- Development Schemas should put the expected final deployment location where they are expected to be deployed when finished in the schemaLocation attribute. (For our current work http://schemas.geosciml.org/*/3.0/*.) The schema documents will be kept in version control (organisation of the vc directories is another subject not worth changing now but could be discussed in Edinburgh). Developers will probably download working copies to local storage as well. Developers should use a catalog while working with development versions of the Schemas.

- When finished for a particular release the schemas can be copied to the http://schemas.geosciml.org/*/version/* locations and developers and users will be able to use them without a catalog. It would be best if the time of this copy was announced to developers so they can do a final test without catalog in the final locations to check there aren't any unexpected errors (e.g. a copy mistake, or everyone having made an error in their catalog files while testing development copies) straight after deployment and the schemas removed and corrected before re-deploying if there is an error found.

- Currently we have also been copying development versions (release candidates) to the final deployment location of our 3.0 schemas on schemas.geosciml.org. Strictly speaking this is a bit dodgy as users outside the development group might browse the schemas.geosciml.org directories and use the apparent 3.0 versions they find there and then find that the schemas change (in incompatible ways) without any notice. As these aren't well publicised locations for a large base of users we can probably get away with this for this time but I don't think this should be done in future. 

Marcus

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