Empty a set of DynamoDB tables

empty-a-set-of-dynamo-tables.txt

It's a PITA to delete all items in an AWS DynamoDB table without deleting the table. 
True, you can delete and re-create the table, but resource ARNs will change (like DyanmoDB Streams), which 
can disrupt other resources depending on those ARNs.

I found https://www.npmjs.com/package/dynamodb-empty which does (most of) the job. 
Note: 

1. The README there is wrong, as of this writing. The correct syntax is:

$ dynamodb-empty --table {tablename}

(The --table is missing in the README)

2. If you don't supply --table, the usage text says you need to supply --name, which is also wrong.

3. It will not delete items from tables that also have a sort key. You can DuckDuckGo why that is, 
and there's some code that people have written to do that too. I might copy dynamodb-empty and add that feature and 
publish it myself at some point (will update this gist), as well as the group feature below.

Grouping Extension:

I added this to my ~/.bashrc to allow you to empty the contents of a similarly-named group of tables, e.g. "test-iris"

function _ddb-empty {
    echo "Deleting all items for tables whose table name contains $1..."
    for x in $(aws dynamodb list-tables | grep $1 | tr -d ',' | tr -d '"'); do dynamodb-empty --table $x; done
    echo "Done."
}
alias ddb-empty=_ddb-empty

Usage:

$ ddb-empty {table-name-contains-string}
e.g.:
$ ddb-empty test-iris

Enjoy!