How to dynamically pass codeUri in SAM template - amazon-web-services

Question

I am trying to deploy lambda having a zip(contains jar file). Now if the static value of the artifact in CodeUri is provided, it works fine but the problem is that the artifact is not static in nature i.e the version of the jar file (along with its name ex: abc-<1.x.x>-prod.jar) will change whenever their is new build.
So, I want to pass the artifact name in CodeUri as dynamic value rather than static value.
I had tried splitting Bucket, Key & pass the value as parameter but it fails saying NoSuchKey while deployment.
Edit: Adding Sample Template
Transform: AWS::Serverless-2016-10-31
Description: engine-service
Parameters:
Environment:
Type: String
Default: ""
SecurityGroupIds:
Type: String
Default: ""
SubnetIds1:
Type: String
Default: ""
SubnetIds2:
Type: String
Default: ""
DBSubnetGroupName:
Type: String
Default: ""
RDSSecret:
Type: String
Default: ""
RDSInstance:
Type: String
Default: ""
API:
Type: String
Default: ""
Globals:
Function:
Timeout: 120
Resources:
TranslationEngineLambda:
Type: AWS::Serverless::Function
Properties:
FunctionName: !Sub "translation-engine-service-${Environment}"
CodeUri: target/abc-**1.0.0-SNAPSHOT**-prod.jar
Handler: com.abc.Main
Runtime: java11
MemorySize: 1024
Environment:
Variables:
BUCKET_NAME: "abc-dummy"
DB_SECRET: "abc-dummy"
FUNCTION_NAME: TranslateFunction
SPRING_PROFILES_ACTIVE: db
TEXT_EXTRACT_LAMBDA: !Sub arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:text-extract-service-${Environment}
TRANSLATE_OPTION: AWS
VpcConfig:
SecurityGroupIds:
- !Ref SecurityGroupIds
SubnetIds:
- !Ref SubnetIds1
- !Ref SubnetIds2
Policies:
- AWSLambda_FullAccess
- AmazonEC2FullAccess
- SecretsManagerReadWrite
- AmazonS3ReadOnlyAccess
- AmazonRDSFullAccess
TranslationEngineLambdaInvoke:
Type: "AWS::Lambda::Permission"
Properties:
Action: "lambda:InvokeFunction"
FunctionName: !GetAtt "TranslationEngineLambda.Arn"
Principal: "apigateway.amazonaws.com"
SourceArn: !Join ['', ['arn:aws:execute-api:MyRegion:MyAccountNumber:', Fn::ImportValue: !Ref API, '/*/POST/language-translator/v1/translate']]
Outputs:
TranslationEngineLambda:
Description: "Hello World Lambda Function ARN"
Value: !GetAtt TranslationEngineLambda.Arn
TranslationEngineLambdaIamRole:
Description: "Implicit IAM Role created for Hello World function"
Value: !GetAtt TranslationEngineLambdaRole.Arn`

Answer 1

Your question encompasses a few things.
First, if you're using CodeUri as you're doing in the template with a relative URL, AWS SAM will use that path to search from the directory in which the template resides to find the required files. If you're using Bucket/Key, AWS SAM will look in S3 to the specified Bucket and search for the Key. This is of course an entirely different way of working and assumes that you've already uploaded the artefact to that location yourself. You've presumably not done this, which results in the NoSuchKey error.
One of the more useful things about AWS SAM is that you can not only use it to deploy your code, but you can also use it to build your artefacts themselves. In that case, you have to point your CodeUri to the root of the folder in which your Lambda function code resides. AWS SAM will then - in the build step - create the necessary artefact (be it a jar of a zip). During the deployment, it will upload those artefacts to S3, update the CodeUris to reflect this and deploy the CloudFormation stack.
I don't think you can use CloudFormation parameters (with !Sub, !Join or similar) when using a relative CodeUri URL since the parameters are only interpreted in the cloud, and not during the AWS SAM build or package steps. So if you do not want to rely on AWS SAM to build your artefacts, you're probably better of also uploading them yourself.