Azure function don’t accept to create file on remote

I would download file on local the create a stream then send to an API.

In localhost files get created via blobClient.downloadToFile(defaultFile);

But When I deploy function it can not find file to stream, so I think that the download does not happen or in bad location.

I get this error

[Error: ENOENT: no such file or directory, open 'D:homesitewwwrootimportPbixexampleName.pbix'

Here’s my code

const blobServiceClient = BlobServiceClient.fromConnectionString(
  process.env.CONNEXION_STRING
);
const containerClient = blobServiceClient.getContainerClient(
  params.containerName
);
const blobClient = containerClient.getBlobClient(process.env.FILE_LOCATION); // get file from storage
let blobData;
var defaultFile = path.join(params.baseDir, `${params.reportName}.pbix`); // use path module
let stream;

try {
  blobData = await blobClient.downloadToFile(defaultFile);
  console.log(blobData);
  stream = fs.createReadStream(defaultFile);
} catch (error) {
  params.context.log(error);
  console.log(error);
}
var options = {
  method: "POST",
  url: `https://api.powerbi.com/v1.0/myorg/groups/${params.groupId}/imports?datasetDisplayName=${params.reportName}`,
  headers: {
    "Content-Type": "multipart/form-data",
    Authorization: `Bearer ${params.accessToken} `,
  },
  formData: {
    "": {
      value: stream,
      options: {
        filename: `${params.reportName}.pbix`,
        contentType: null,
      },
    },
  },
};
//check if file keep in mem
return new Promise(function (resolve, reject) {
  request(options, function (error, response) {
    if (error) {
      params.context.log(error);

      reject(error);
    } else {
      params.context.log(response);
      resolve(response.body);
    }
    fs.unlinkSync(defaultFile);
  });
});

I found this post having same issue , that’s why I user path module and passed __dirname to function params.baseDir.

Answer

If you want to download a file from Azure blob and read it as a stream, just try the code below, in this demo, I try to download a .txt file to a temp folder(you should create it first on Azure function)and print its content from the stream for a quick test:

module.exports = async function (context, req) {
    
    const { BlockBlobClient } = require("@azure/storage-blob")
    const fs = require('fs')
  

    const connStr = '<connection string>'
    const container = 'files'
    const blobName = 'test.txt'
    const tempPath = 'd:/home/temp/'
    const tempFilePath = tempPath + blobName

    const blobClient = new BlockBlobClient(connStr,container,blobName);

    await blobClient.downloadToFile(tempFilePath).then(async function(){
        context.log("download successfully")

        let stream =  fs.createReadStream(tempFilePath)
        //Print text content,just check if stream has been readed successfully
        context.log("text file content:")
        context.log(await streamToString(stream))

        //You can call your API here...
    })

    function streamToString (stream) {
        const chunks = [];
        return new Promise((resolve, reject) => {
          stream.on('data', (chunk) => chunks.push(Buffer.from(chunk)));
          stream.on('error', (err) => reject(err));
          stream.on('end', () => resolve(Buffer.concat(chunks).toString('utf8')));
        })
      }
    
    context.res = {       
        body: 'done'
    }

}

Result

File has been downloaded:

read as stream successfully: