Closed
Description
Expected Behavior
When receiving a TransformParameterError I should be able to see the correct stack trace that points me to where the error was thrown.
Current Behavior
The error thrown when there's a transform error in the getMultiple code path is wrapping the original TransformParameterError error in another instance of itself, mangling the stack trace and making it harder to identify the issue.
{
"errorType": "TransformParameterError",
"errorMessage": "Unable to transform value using 'auto' transform: Unable to transform value using 'auto' transform: Unexpected token 'm', \"my-parameter-value\" is not valid JSON",
"name": "TransformParameterError",
"stack": [
"TransformParameterError: Unable to transform value using 'auto' transform: Unable to transform value using 'auto' transform: Unexpected token 'm', \"my-parameter-value\" is not valid JSON",
" at n.getMultiple (file:///var/task/index.mjs:2:6279)",
" at process.processTicksAndRejections (node:internal/process/task_queues:95:5)",
" at async file:///var/task/index.mjs:2:10917"
]
}should be something like (notice the correct transformValue location):
{
"errorType": "TransformParameterError",
"errorMessage": "Unable to transform value using 'auto' transform: Unexpected token 'm', \"my-parameter-value\" is not valid JSON",
"name": "TransformParameterError",
"stack": [
"TransformParameterError: Unable to transform value using 'auto' transform: Unexpected token 'm', \"my-parameter-value\" is not valid JSON",
" at transformValue (/node_modules/@aws-lambda-powertools/parameters/lib/esm/base/transformValue.js:58:19)",
" at n.getMultiple (/node_modules/@aws-lambda-powertools/parameters/lib/esm/base/BaseProvider.js:126:40)",
" at process.processTicksAndRejections (node:internal/process/task_queues:95:5)",
" at async <anonymous> (/src/index.ts:8:20)"
]
}Code snippet
import { getStringFromEnv } from '@aws-lambda-powertools/commons/utils/env';
import { getParameters } from '@aws-lambda-powertools/parameters/ssm';
const parameterPrefix = getStringFromEnv({
key: 'SSM_PARAMETER_PREFIX',
});
const parameters = await getParameters(parameterPrefix, {
transform: 'auto',
throwOnTransformError: true,
});
export const handler = async () => {
console.log('Parameters:', parameters);
return {
statusCode: 200,
body: JSON.stringify(parameters),
};
};Steps to Reproduce
- Deploy a stack with two parameters
Example
import { Stack, type StackProps, CfnOutput, RemovalPolicy } from 'aws-cdk-lib';
import type { Construct } from 'constructs';
import { Runtime, Tracing } from 'aws-cdk-lib/aws-lambda';
import { NodejsFunction, OutputFormat } from 'aws-cdk-lib/aws-lambda-nodejs';
import { LogGroup, RetentionDays } from 'aws-cdk-lib/aws-logs';
import { StringParameter } from 'aws-cdk-lib/aws-ssm';
import { Effect, PolicyStatement } from 'aws-cdk-lib/aws-iam';
export class ParamsStack extends Stack {
constructor(scope: Construct, id: string, props?: StackProps) {
super(scope, id, props);
const fnName = 'ParamsFn';
const logGroup = new LogGroup(this, 'MyLogGroup', {
logGroupName: `/aws/lambda/${fnName}`,
removalPolicy: RemovalPolicy.DESTROY,
retention: RetentionDays.ONE_DAY,
});
const myParameter = new StringParameter(this, 'MySsmParameter', {
parameterName: '/my/custom/parameter.json',
stringValue: JSON.stringify({
key1: 'value1',
}),
// You can specify other properties like description, tier, etc.
});
const myOtherParameter = new StringParameter(this, 'MyOtherSsmParameter', {
parameterName: '/my/custom/parameter2.json',
stringValue: 'my-parameter-value',
// You can specify other properties like description, tier, etc.
});
const fn = new NodejsFunction(this, 'MyFunction', {
functionName: fnName,
logGroup,
runtime: Runtime.NODEJS_20_X,
entry: './src/index.ts',
handler: 'handler',
tracing: Tracing.ACTIVE,
environment: {
SSM_PARAMETER_PREFIX: '/my/custom/',
},
bundling: {
minify: true,
mainFields: ['module', 'main'],
sourceMap: true,
format: OutputFormat.ESM,
banner:
"import { createRequire } from 'module';const require = createRequire(import.meta.url);",
},
});
fn.addToRolePolicy(
new PolicyStatement({
actions: ['ssm:GetParametersByPath'],
resources: ['*'],
effect: Effect.ALLOW,
})
);
/* myParameter.grantRead(fn);
myOtherParameter.grantRead(fn); */
new CfnOutput(this, 'FunctionArn', {
value: fn.functionArn,
});
}
}- Add the function shown above
- Run it and observe the error formatting
Possible Solution
We should change this statement to just throw error.
Powertools for AWS Lambda (TypeScript) version
latest
AWS Lambda function runtime
22.x
Packaging format used
npm
Execution logs
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Status
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