Drools Decision Table Deployment (AWS Lambda)

[Timothy Soh]

Hi there, 

I am trying to deploy a drools project (built using eclipse) onto AWS Lambda but ran into some permission issues with Lambda. 

I was hoping to get some feedback on how to workaround the issue from the drools perspective.

First, let me describe my AWS Lambda function and my deployment structure:

• I package my drools project into a jar => droolsdemo.jar
  
• My drools project has only one decision table (demo.xls) under /src/main/resources/demorule
  
• I create a AWS Lambda project that includes droolsdemo.jar as a dependency
• My AWS Lambda project is a simple wrapper that receives input, creates a KieSession, triggers all rules, and then returns rule outputs.
• I upload the AWS Lambda project to AWS

When I trigger the AWS Lambda, I get a `permissions denied` error while trying to access demorule/demo.xls (full stack trace below). 

This error is triggered in the code when the KieSession is created:

kSession = kContainer.newKieSession("demorule");

I believe that the above line of code extracts the excel file into the default directory /var/task and tries to read it. AWS Lambda by default restricts permissions on files in the default directory. 

Current workarounds for this issue involve creating files in the /tmp directory instead.

Is it possible to direct Drools to extract the excel file to a specific directory? 

Otherwise, is it possible to direct Drools to create a KieSession with a filepath as an input instead of a session-name (having the .xls/.drl file residing outside of the project) ?

Any help/feedback would be greatly appreciated,

Cheers,

Timothy

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"errorMessage": "/var/task/demorule/demo.xls (Permission denied)",

        "errorType": "java.io.FileNotFoundException",

        "stackTrace": [

          "java.io.RandomAccessFile.open0(Native Method)",

          "java.io.RandomAccessFile.open(RandomAccessFile.java:316)",

          "java.io.RandomAccessFile.<init>(RandomAccessFile.java:243)",

          "org.apache.poi.poifs.nio.FileBackedDataSource.newSrcFile(FileBackedDataSource.java:130)",

          "org.apache.poi.poifs.nio.FileBackedDataSource.<init>(FileBackedDataSource.java:46)",

          "org.apache.poi.poifs.filesystem.NPOIFSFileSystem.<init>(NPOIFSFileSystem.java:218)",

          "org.apache.poi.poifs.filesystem.NPOIFSFileSystem.<init>(NPOIFSFileSystem.java:166)",

          "org.apache.poi.ss.usermodel.WorkbookFactory.create(WorkbookFactory.java:278)",

          "org.apache.poi.ss.usermodel.WorkbookFactory.create(WorkbookFactory.java:250)",

          "org.apache.poi.ss.usermodel.WorkbookFactory.create(WorkbookFactory.java:229)",

          "org.drools.decisiontable.parser.xls.ExcelParser.parseFile(ExcelParser.java:95)",

          "org.drools.decisiontable.SpreadsheetCompiler.parseResource(SpreadsheetCompiler.java:123)",

          "org.drools.decisiontable.SpreadsheetCompiler.compile(SpreadsheetCompiler.java:110)",

          "org.drools.decisiontable.SpreadsheetCompiler.compile(SpreadsheetCompiler.java:83)",

          "org.drools.decisiontable.DecisionTableProviderImpl.compileResource(DecisionTableProviderImpl.java:78)",

          "org.drools.decisiontable.DecisionTableProviderImpl.loadFromResource(DecisionTableProviderImpl.java:44)",

          "org.drools.compiler.compiler.DecisionTableFactory.loadFromResource(DecisionTableFactory.java:37)",

          "org.drools.compiler.builder.impl.KnowledgeBuilderImpl.decisionTableToPackageDescr(KnowledgeBuilderImpl.java:404)",

          "org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl$12.map(CompositeKnowledgeBuilderImpl.java:437)",

          "org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl.buildResource(CompositeKnowledgeBuilderImpl.java:322)",

          "org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl.buildPackageDescr(CompositeKnowledgeBuilderImpl.java:307)",

          "org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl.buildPackages(CompositeKnowledgeBuilderImpl.java:114)",

          "org.drools.compiler.builder.impl.CompositeKnowledgeBuilderImpl.build(CompositeKnowledgeBuilderImpl.java:105)",

          "org.drools.compiler.kie.builder.impl.AbstractKieModule.buildKnowledgePackages(AbstractKieModule.java:243)",

          "org.drools.compiler.kie.builder.impl.KieContainerImpl.createKieBase(KieContainerImpl.java:484)",

          "org.drools.compiler.kie.builder.impl.KieContainerImpl.getKieBase(KieContainerImpl.java:447)",

          "org.drools.compiler.kie.builder.impl.KieContainerImpl.newKieSession(KieContainerImpl.java:604)",

          "org.drools.compiler.kie.builder.impl.KieContainerImpl.newKieSession(KieContainerImpl.java:575)",

[Timothy Soh]

worked around this issue by using .drl files instead. I compiled all .xls files to .drl files and used .drl files in the jar for AWS Lambda