AWS Lambda Custom Nodejs Container Shows Runtime Error - node.js

Question

I have built a AWS Lambda function with custom container image. I am trying to convert an excel file to pdf with Libreoffice - getting the file from S3 and saving it to a file and converting it to pdf and then uploading it back to S3.
Here the code.
const fs = require('fs');
const getStream = require('get-stream');
const { Readable } = require('stream')
const { S3Client, GetObjectCommand, PutObjectCommand } = require("#aws-sdk/client-s3");
const libre = require('libreoffice-convert');
const path = require('path');
exports.handler = async (event) => {
const bucket = event.queryStringParameters.bucket;
const file = event.queryStringParameters.file;
const convertedFile = event.queryStringParameters.convertedFile;
if (event.queryStringParameters['warmup'] !== undefined) {
return {
result: true,
message: 'warmed up'
}
}
const client = new S3Client({ region: "ap-south-1" });
const command = new GetObjectCommand({ Bucket: bucket, Key: file });
const response = await client.send(command);
const objectData = response.Body;
const writeStream = fs.createWriteStream("/tmp/sample.xlsx");
objectData.pipe(writeStream);
var end = new Promise((resolve, reject) => {
objectData.on('close', resolve(true));
objectData.on('end', resolve(true));
objectData.on('error', reject(false));
});
let completed = await end;
if (completed) {
const extend = '.pdf'
const outputPath = `/tmp/sample${extend}`;
const enterPath = '/tmp/sample.xlsx';
var readingFile = new Promise((resolve, reject) => {
fs.readFile(enterPath, (err, data)=>{
if (err) {
reject(false);
}
resolve(data);
});
});
var fileData = await readingFile;
var converting = new Promise((resolve, reject) => {
libre.convert(fileData, extend, undefined, (err, done) => {
if (err) {
reject(false)
}
fs.writeFileSync(outputPath, done);
resolve(true)
});
})
var converted = await converting;
if (converted) {
var convertedFileStream = fs.createReadStream(outputPath);
const uploadCommand = new PutObjectCommand({ Bucket: bucket, Key: convertedFile, Body: convertedFileStream });
const lastResponse = await client.send(uploadCommand);
const returnResponse = {
result: true,
message: 'success',
bucket: event.queryStringParameters.bucket,
file: event.queryStringParameters.file,
convertedFile: event.queryStringParameters.convertedFile
};
if (event.queryStringParameters['returnEvent'] !== undefined) {
returnResponse['returnEvent'] = event;
}
return returnResponse;
}
}
return completed;
};
However, I am getting this error at time. Sometimes, it is success, but, sometimes it throws this error.
{
"errorType": "Error",
"errorMessage": "false",
"stack": [
"Error: false",
" at _homogeneousError (/function/node_modules/aws-lambda-ric/lib/Runtime/CallbackContext.js:56:16)",
" at postError (/function/node_modules/aws-lambda-ric/lib/Runtime/CallbackContext.js:72:34)",
" at done (/function/node_modules/aws-lambda-ric/lib/Runtime/CallbackContext.js:99:13)",
" at fail (/function/node_modules/aws-lambda-ric/lib/Runtime/CallbackContext.js:113:13)",
" at /function/node_modules/aws-lambda-ric/lib/Runtime/CallbackContext.js:148:24",
" at processTicksAndRejections (internal/process/task_queues.js:97:5)"
]
}
I dont know Nodejs on a great deal so I think if the code is not written the correct way. Any ideas what I am doing wrong here ?

Answer 1

Like #hoangdv when I logged errors I came to know that the file saving to the disk was not correct. So, I changed the area of the code where it saves to like this and then it worked.
const client = new S3Client({ region: "ap-south-1" });
const command = new GetObjectCommand({ Bucket: bucket, Key: file });
const { Body } = await client.send(command);
await new Promise((resolve, reject) => {
Body.pipe(fs.createWriteStream(filePath))
.on('error', err => reject(err))
.on('close', () => resolve())
})
const excelFile = fs.readFileSync(filePath);