Recording and Slides for F# DSLs talk at F# |> Bristol

Here’s the recorded live stream of the F# DSLs session I did at the F# |> Bristol user group last night.

(apologies for the first few mins where I forgot to share my screen to the Hangout…)

and here’s the slides to go with the talk:

Slides for F# DSL talk at LambdaDays

Hi, thanks to everyone who turned up to my talk at LambdaDays this afternoon, here are the slides.


You can find the source code for the projects I discussed below:

DynamoDB.SQL : source code & nuget package

SimpleWorkflow.Extensions : source code & nuget package

CloudWatch.Selector : source code & nuget package & CLI tool (chocolatey)

New releases – DynamoDB.SQL and Darkseid

Hi, just a quick update on two of my libraries aimed at making AWS easier to work with from .Net.



DynamoDB.SQL is a SQL-like external DSL for querying & scanning data in Amazon DynamoDB. Version 3.0.0 has been released, which moves away from the monolithic .Net AWSSDK (v2.x.x), and onto the DynamoDB specific package.

You can continue to use v2.x packages for DynamoDB.SQL, I’ll apply any bug fixes to both v2.x and v3.x packages. However, any new features in the future – such as support for the mid-level Table abstractions in the AWSSDK – will be added to v3.x only.

Over the coming weeks and months, I’ll continue the effort to migrate my fleet of AWS-related tools and libraries to the service-specific packages.



Darkseid is a producer library for Amazon Kinesis, it works hand-in-hand with ReactoKinesix which provides the consumer side of the story.

Courtesy of Dustin’s PR, version 0.3.0 has been released which adds synchronous methods for pushing events to Kinesis (so that services that aren’t ready to go async all the way can still integrate with Kinesis using Darkseid).


That’s it, folks, hope you all had a nice weekend. If you haven’t seen Deadpool yet, you should, it is amazing 

Slides for my Craft-Conf meetup talk on DSLs and F#

DynamoDB.SQL 2.0.0 is out!

Hi everyone, happy new year!

I was really glad to find a couple of days to work on some of my open source projects and put together a new version of DynamoDB.SQL which brings it inline with the latest version of the .Net AWSSDK amongst other things. You can download and install it from Nuget here.


Breaking Changes

There are two breaking changes:

  1. DynamoDB v1 is no longer supported as they have been deprecated from the AWSSDK, which means the v1 syntax (which uses the special keywords @hashkey and @rangekey to refer to the table’s hash and range keys) is also deprecated and you should use the v2 syntax going forward.
  2. The clumsy and frankly unnecessary DynamoDbV2.SQL.Execution namespace is gone! Instead, the extension methods for AmazonDynamoDBClient and DynamoDBContext now exist in the same namespaces so you no longer have to import another namespace just to use the extension methods.


Bug Fixes

Selecting specific attributes in a Scan now works, please see respective C# and F# examples.

The old InvalidQuery and InvalidScan exceptions (which didn’t play so well with C# since the error message was not very useful at all) have been replaced with C# friendly InvalidQueryException and InvalidScanException types exposes the underlying parsing errors in the error messages.


Global Secondary Index

AWS announced Global Secondary Index support on December 12th, 2013, and it’s supported in DynamoDB.SQL via the existing INDEX query option, for example:


However, global indexes work very differently to local secondary indexes, for starters they require their own throughput rather than use the existing throughput for the table (for more details refer to its documentation).

Also, it does not support consistent reads, so when querying against the index you must add the NoConsistentRead option in your query otherwise you’ll receive an error from the DynamoDB service.

Lastly, when you create the global secondary index you have to choose which attributes are projected into the index and unlike local secondary index, attributes that have not been projected into the index will not be retrieved from the table at extra read units cost, you will receive an error from the service instead. Please refer to the guidelines page for Global Secondary Index.



I’ve also revamped the README document to make it more detailed and useful and added a bunch more examples for both C# and F#, hope you like the new layout.