Kumar Gaurav created CAMEL-22029:
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Summary: aws dynamodb scan an query not implemented with
attributes-to-get and projection and filter expressions
Key: CAMEL-22029
URL: https://issues.apache.org/jira/browse/CAMEL-22029
Project: Camel
Issue Type: Improvement
Components: camel-aws
Affects Versions: 4.4.5
Environment: Affected versions 4.4.5 and above. It shall be released
as part of new LTS release.
Thing is - Camel dynamodb component still based on legacy aws parameters. IT
shall be upgraded to use/support new parameters.
Reporter: Kumar Gaurav
{*}Context{*}:
1- QUERY operation:
Users want to query the data using key column only to bring all the attributes
related to items with that key.
However, Camel DynamoDB component makes it mandatory to send attributes-to-get.
2- Scan operation:
users want to scan a DynamoDB table and return only a *subset of attributes.*
However, aws-camel-sdk for DynamoDB does not support this parameter.
{*}Problem{*}:
QUERY -
aws-sdk has a validation that if attribute-to-get is being passed it cannot
have 0 items. therefore, we are getting an exception as ddb component always
adds this attributes with zero items if it is not supplied from kamelet.
SCAN -
We need to fix _ScanCommand_ class of camel-aws-ddb lib to support his
operation which is already supported by aws-sdk for dynamodab .
{*}Solution{*}:
Modify the class and refactor the below code to send attribute-to-get only if
it is provided by customer. If it is not supplied (header '' is empty or null),
this parameter shall not be sent as part of ddb query request object.
*As an iHub developer* -
I want to modify the camel aws-ddb-component query request code and release it
as hotfix.
*For reference:*
[*AttributesToGet*|https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Query.html#API_Query_RequestSyntax]
This is a legacy parameter. Use {{ProjectionExpression}} instead. For more
information, see
[AttributesToGet|https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.AttributesToGet.html]
in the {_}Amazon DynamoDB Developer Guide{_}.
Type: Array of strings
Array Members: Minimum number of 1 item.
Length Constraints: Maximum length of 65535.
Required: No
The legacy conditional parameter {{AttributesToGet}} is an array of one or more
attributes to retrieve from DynamoDB. If no attribute names are provided, then
all attributes will be returned. If any of the requested attributes are not
found, they will not appear in the result.
[http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.AttributesToGet.html]
scan operation supports attributes-to-get -
*[https://docs.aws.amazon.com/amazondynamodb/latest/APIReference/API_Scan.html]*
*Proposed solution*
*1.* Scan operation(ScanCommand class) need to be enhanced to support
attributes-to-get and additionally projection and filter expression.
Scan operation has been enhanced to use the latest projection expression and
filter expresion supported by aws .
The new inputs would follow the pattern given as:
{
"projection-expression": "#id, #fname",
"filter-expression": "#fname = :val",
"select": "SPECIFIC_ATTRIBUTES",
"expression-attribute-names": {
"#id": "Id",
"#fname": "FirstName"
},
"expression-attribute-values": {
":val": {
"S": "Kim"
}
}}
2. Enhance QueryComand class to accept global secondary indexes and
attributes-to-get with empty values. When attributes-to-get is null or empty
- it shall not throw a validation exception.
{color:#007200}// Check if we have set an Index Name{color}
{color:#000000} {color}{color:#0000ff}if{color}{color:#000000}
(exchange.getIn().getHeader(Ddb2Constants.INDEX_NAME,
String.{color}{color:#0000ff}class{color}{color:#000000}) != null) {{color}
{color:#000000}
query.indexName(exchange.getIn().getHeader(Ddb2Constants.INDEX_NAME,
String.{color}{color:#0000ff}class{color}{color:#000000}));{color}
{color:#000000} }{color}
{color:#000000} {color}{color:#007200}//skip adding attribute-to-get from
'CamelAwsDdbAttributeNames' if the header is null or empty list.{color}
{color:#000000}
{color}{color:#0000ff}if{color}{color:#000000}(exchange.getIn().getHeader(Ddb2Constants.ATTRIBUTE_NAMES)
!= null &&{color}
{color:#000000}
!exchange.getIn().getHeader(Ddb2Constants.ATTRIBUTE_NAMES,
Collection.{color}{color:#0000ff}class{color}{color:#000000}).isEmpty()){{color}
{color:#000000}
query.attributesToGet(determineAttributeNames());{color}
{color:#000000} }{color}
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