Erldyn

DynamoDB functions are converted to underscore_case functions of arity 1. The parameter is JSON as defined by the DynamoDB API, and the returns are either {ok, #{...}}, [{ok, #{...}}, ...], or {error, #{...}) <br/> where the maps are map versions of DynamoDB, JSON returns.

The batch functions (batch_get_item/1 and batch_write_item/1) can return partial results. The unprocessed items will be resubmitted automatically, consequently, these functions return a list of maps - one for each partial result.

Convenience methods (new_table/3, save_table/1, and add_parameter/3) are provided for simplifying the process of building the correct strcture for defining and creating tables.

Exponentional back-off is used such that appropriate failures, or partial results, are retried according to an exponential, back-off algorithm, not to exceed one minute total for the entire operation.

All http operations are PUTS, and Version 4 of the Signature authorizaion header is used.

Secret Key and Access Keys can be passed via map and config/1, if not found the os environment is interrogated for AWS_ACCESS_KEY_ID, and AWS_SECRET_ACCESS_KEY.

The DynamoDB Endpoint is provided via the same config/1 map parameter, and is parsed to determine service, streaming service, host and region.

PROCESS DICTIONARY IS USED, VALUES ARE CHANGED VIA CONFIG/1 put(access_key, ...) <br/> put(secret_key, ..) <br/> put(stream_endpoint, ...) <br/> put(endpoint, ...) <br/> put(host, ...) <br/> put(service, ..) <br/> put(region, ..) <br/>

Dependencies

Lager for logging, jsone for json <--> map translation, and rebar3 for building

Build

erldyn uses rebar3

$ make compile
$ make clean
$ make doc
$ make check
$ make run

Running

Assuming that $ make has been previously executed:

$ export AWS_SECRET_ACCESS_KEY="WIcKN27efefff499Pd9iqBpm3hEkas0rsDzoSA"
$ export AWS_ACCESS_KEY_ID="AKERTJFFIFATLGIJFJLA"

$ make run
erl -pa _build/default/lib/*/ebin
Erlang/OTP 18 [erts-7.1] [source-2882b0c] [64-bit] [smp:8:8] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V7.1  (abort with ^G)

1> erldyn:config(#{endpoint => "https://dynamodb.us-west-2.amazonaws.com/"}).
ok
2> erldyn:list_tables("{}").
{ok,#{<<"TableNames">> => [<<"Forum">>,<<"Reply">>,<<"Thread">>,<<"Wizzards">>]}}