Permission denied when trying to create a file from a Greengrass v2 lambda component

Question

Hello, 
we've written a NO_CONTAINER Lambda based component for Greengrass v2 in Java.

This component does attempt to persist a file to local storage but fails as it doesn't seem to be allowed to do so.

2024-07-31T16:07:41.380Z [ERROR] (pool-3-thread-22) com.redbite.AccessFacilitator: Caused by: java.io.IOException: Permission denied. {serviceInstance=0, serviceName=com.redbite.AccessFacilitator, currentState=RUNNING}
2024-07-31T16:07:41.382Z [ERROR] (pool-3-thread-22) com.redbite.AccessFacilitator:      at java.base/java.io.UnixFileSystem.createFileExclusively(Native Method). {serviceInstance=0, serviceName=com.redbite.AccessFacilitator, currentState=RUNNING}
2024-07-31T16:07:41.384Z [ERROR] (pool-3-thread-22) com.redbite.AccessFacilitator:      at java.base/java.io.File.createNewFile(File.java:1043). {serviceInstance=0, serviceName=com.redbite.AccessFacilitator, currentState=RUNNING}

Is it possible to configure it so that it's allowed to write to local storage?

Also I wonder if using a regular Greengrass v2 component instead of a Lambda one would give us more options.

sidsriv · Answer

You will need to implement your own hook for AWS service related events for a native GGV2 component. But that should straightforward the AWS SDK. Lambda is a GGV1 concept which is not recommended GGV2.

sidsriv · Answer

Lambda component by default has a Read-Only permission to the device file system in which the lambda component is running. You need to update this configuration to Read-Write to be able to persist files on your device using a lambda component.

Ref: https://docs.aws.amazon.com/greengrass/v2/developerguide/import-lambda-function-console.html#import-lambda-console-run-isolated

That being said, I would recommend using a Greengrass V2 native instead of a lambda component. They are easier to develop and troubleshoot.

Permission denied when trying to create a file from a Greengrass v2 lambda component

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