I just finished watching Eric Rudder’s keynote on Indigo at VS Live in San Francisco. As with all keynotes, it had glitz and glamour and gave a high-level view of what Microsoft is thinking.

(for those who don’t know, Eric is the Microsoft VP in charge of developer-related stuff including Indigo)

Among the various things discussed was the migration roadmap from today’s communication technologies to Indigo. I thought it was instructive.

From asmx web services the proposed changes are minor. Just a couple lines of code change and away you go. Very nice.

From WSE to Indigo is harder, since you end up removing lots of WSE code and replacing it with an attribute or two. The end result is nice because your code is much shorter, but it is more work to migrate.

From Enterprise Services (COM+, ServicedComponent) the changes are minor – just a couple lines of changed code. But the semantic differences are substantial because you can now mark methods as transactional rather than the whole class. Very nice!

From System.Messaging (MSMQ) to Indigo the changes are comparable in scope to the WSE change. You remove lots of code and replace it with an attribute or two. Again the results are very nice because you save lots of code, but the migration involves some work.

From .NET Remoting to Indigo the changes are comparable to the asmx migration. Only a couple lines of code need to change and away you go. This does assume you listened to advice from people like Ingo Rammer, Richard Turner and myself and avoided creating custom sinks, custom formatters or custom channels. If you ignored all this good advice then you’ll get what you deserve I guess

As Eric pointed out however, Indigo is designed for the loosely coupled web service/SOA mindset, not necessarily for the more tightly coupled n-tier client/server mindset. He suggested that many users of Remoting may not migrate to Indigo – directly implying that Remoting may remain the better n-tier client/server technology.

I doubt he is right. Regardless of what Indigo is designed for, it is clear to me that it offers substantial benefits to the n-tier client/server world. These benefits include security, reliable messaging, simplified 2-phase transactions and so forth. The fact that Indigo can be used for n-tier client/server even if it is a bit awkward or not really its target usage won’t stop people. And from today’s keynote I must say that it looks totally realistic to (mis)use Indigo for n-tier client/server work.