Enterprise SOA, Continuous Integration and DXSI

September 5, 2008

Creating an approach to CI’ing large scale enterprise SOA initiatives has unearthed a potentially significant efficiency gain in the semantic layer. Semantics relate to instance data – and specifically in the context of re-usable, extensible service interfaces the semantic challenge eclipses that of achieving syntactical alignment between consumer and provider.

Evidence shows that the vast proportion of integration failures picked up in testing environments (having taken the hit to mobilise a complex deployment of a range of components) are related to data/semantics, not syntax.

As such I’ve been focusing on how to front-end the verification of a consumer ‘understanding’ the provider structurally and semantically from day 1 of the design process. The CI framework I’m putting together makes use of a traditional set of artifact presence/quality assessment, but significantly introduces the concept of the Semantic Mock (SMOCK) – which is an executable component based on the service contract with the addition of a set of evolving semantic expressions and constraints.

This SMOCKartifact allows a service provider to incrementally evolve the detail of the SMOCK whilst having the CI framework automatically acquiring consumer artifacts such as static instance docs or dynamic harnesses (both manifesting earlier in the delivery process than the final service implementation (and I mean on day 1 or 2 of a 90 day cycle as opposed to being identified through fall-out in formal test-environments or worse than that – in production environments for example).

Over time as both consumer and provider evolve through and beyond the SMOCK phase, the level of confidence in design integrity is exponentially improved – simply based on the fact that we’ve had continuous automated verification (and hence integration) of consumer and provider ‘contractal bindings’ for weeks or months. This ultimately leads to a more effective use of formal testing resource and time in adding value as opposed to fire-fighting and kicking back avoidable broken interfaces.

The tool I’m using to protoype ths SMOCK is Progress DXSI. This semantic integration capability occupies a significant niche by focusing on the semantic or data contract associated with all but the most trivial service interfaces. DXSI allows a provider domain-expert to enrich base artifacts (WSDL/XSD) and export runnable SMOCK components which can then be automatically acquired, hosted and exercised (by my CI environment) to verify consumer artifacts published by prospective consumers of the service. Best of all kicking back compliance reports based on the semantic constraints being exercised in each ‘test case’ such that my ‘CI Build Report’ includes a definition of why ‘your’ understanding of ‘my’ semantic contract is flawed…

Beyond SMOCK verification – DXSI also allows me to make a seamless transition into a production runtime too but that’s another story…

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