feat(parameters): DynamoDBProvider support

[dreamorosi]

Description of your changes

This PR implements the DynamoDBProvider class which will allow the future Parameters utility to support retrieving parameters from DynamoDB.

The DynamoDBProvider supports the following retrieval modes:

• get this class method allows customers to retrieve a single parameter by name and allows to specify transform, max age.

The provider comes with defaults thanks to which the user only has to specify the table name and the the name of the parameter to retrieve:

const parameters = new DynamoDBProvider({
  tableName: 'some-table'
});

The table named some-table expects an item that looks like this:

{ "id": "foo", "value": "bar" }

However, if users have items with other type of shapes, like for instance:

{ "key": "foo", "val": "bar" }

they can instantiate the provider like so:

const parameters = new DynamoDBProvider({
  tableName: 'some-table',
  keyAttr: 'key',
  valueAttr: 'val',
});

In both cases, they can retrieve the parameter using the get method:

const parameter = parameters.get('foo');
console.log(parameter); // bar

• getMultiple this class method allows customers to retrieve multiple parameters by path and allows to specify a shared config object that changes the behavior around transform, max age.

Similarly to what described above, the default come also for path-based retrieval:

const parameters = new DynamoDBProvider({
  tableName: 'some-table'
});

The table named some-table expects an item that looks like this:

{ "id": "foo", "sk": "a", "value": "value-param-a" }
{ "id": "foo", "sk": "b", "value": "value-param-b" }

Which will result, when used, in this:

const parameterObject = parameters.getMultiple('foo');
for (const [ key, val ] of Object.entries(parameterObject)) {
  console.log(key, val);
}
// a, value-param-a
// b, value-param-b

Just like before, if users have items with a different shape, say this:

{ "key": "foo", "sort": "a", "val": "value-param-a" }
{ "key": "foo", "sort": "b", "val": "value-param-b" }

They can customize the provider's behavior by instantiating it with different attribute names:

const parameters = new DynamoDBProvider({
  tableName: 'some-table',
  keyAttr: 'key',
  valueAttr: 'val',
  sortAttr: 'sort',
});

Both get and getMultiple also allow an optional options argument that allow to customize the provider's behavior around caching and transform/errors.

The options object also accepts a sdkOptions object, which allows the user to pass additional inputs to the SDK client API call (i.e. specify ConsistentRead). There are however some SDK options that cannot be passed as they are managed by the provider, these are:

• TableName
• ProjectionExpression
• Key (applies only to get)
• KeyConditionExpression (applies only to getMultiple)
• ExpressionAttributeValues (applies only to getMultiple)

How to verify this change

See the newly added unit test cases & optionally compare also the API surface with the implementation found in Powertools for Python.

Related issues, RFCs

Issue number: #1174

PR status

Is this ready for review?: YES
Is it a breaking change?: NO

Checklist

• My changes meet the tenets criteria
• I have performed a self-review of my own code
• I have commented my code where necessary, particularly in areas that should be flagged with a TODO, or hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding changes to the examples
• My changes generate no new warnings
• The code coverage hasn't decreased
• I have added tests that prove my change is effective and works
• New and existing unit tests pass locally and in Github Actions
• Any dependent changes have been merged and published
• The PR title follows the conventional commit semantics

Breaking change checklist

• I have documented the migration process
• I have added, implemented necessary warnings (if it can live side by side)

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[kennethwkz-mm]

This is really nice to have