Uploading data from firebase functions to firebase storage? - node.js

Question

I have a website running with node.js, with the backend running on Firebase Functions. I want to store a bunch of JSON to Firebase Storage. The below snippet works just fine when I'm running on localhost, but when I upload it to Firebase functions, it says Error: EROFS: read-only file system, open 'export-stock-trades.json. Anyone know how to get around this?
fs.writeFile(fileNameToReadWrite, JSON.stringify(jsonObjToUploadAsFile), function(err){
bucket.upload(fileNameToReadWrite, {
destination: destinationPath,
});
res.send({success: true});
});

Answer 1

I can't tell for sure, since much of the context of your function is missing, but it looks like you function is attempting to write a file to local disk first (fs.writeFile), then upload it (bucket.upload).
On Cloud Functions, code you write only has write access to /tmp,
which is os.tmpdir() in node. Read more about that in the
documentation:
The only writeable part of the filesystem is the /tmp directory, which
you can use to store temporary files in a function instance. This is a
local disk mount point known as a "tmpfs" volume in which data written
to the volume is stored in memory. Note that it will consume memory
resources provisioned for the function.
This is probably what's causing your code to fail.
Incidentally, if the data you want to upload is in memory, you don't have to write it to a file first as you're doing now. You can instead use file.save() for that.

Answer 2

Another way I feel this could work is to convert the JSON file into a buffer and then perform an action like this (the code snippet below). I wrote an article on how you can do this using Google Cloud Storage but it works fine with Firebase storage. The only thing you need to change is the "service-account-key.json" file.
The link to the article can be found here: Link to article on medium
const util = require('util')
const gc = require('./config/')
const bucket = gc.bucket('all-mighti') // should be your bucket name
/**
*
* #param { File } object file object that will be uploaded
* #description - This function does the following
* - It uploads a file to the image bucket on Google Cloud
* - It accepts an object as an argument with the
* "originalname" and "buffer" as keys
*/
export const uploadImage = (file) => new Promise((resolve, reject) => {
const { originalname, buffer } = file
const blob = bucket.file(originalname.replace(/ /g, "_"))
const blobStream = blob.createWriteStream({
resumable: false
})
blobStream.on('finish', () => {
const publicUrl = format(
`https://storage.googleapis.com/${bucket.name}/${blob.name}`
)
resolve(publicUrl)
})
.on('error', () => {
reject(`Unable to upload image, something went wrong`)
})
.end(buffer)
})