fs.writeFile 后 Google 云功能崩溃

Question

I have a bit of a strange bug. I am using firebase's cloud functions for some data processing. Within the function, I need to (a) write a CSV to the tmp/ folder on the disk, (b) upload this file to google cloud storage.

I am using fs.writeFile to write to disk. This works fine--the data is correctly written to the tmp folder. BUT, the whole function crashes if it doesnt immediately resolve. So if there's a next step in function (like waiting for the upload to finish with google cloud storage), the function crashes.

I've been able to replicate the bug with the following simple version:

async.waterfall([
   function (callback) {
       fs.writeFile("tmp/testfile.txt", "hello world", function(err) {
           callback(null);
       });
   },
   function (callback) {
       setTimeout(function(){
           callback(null)
       }, 10000);
   }
], function(err){console.log("done!"})

Any thoughts on what could be going wrong will be super appreciated!

Answer 1

For posterity, the problem was that I was setting the tmp folder as simply "tmp". Turns out, you need to find the temp folder using os.tmpdir(). Once you do that, it works fine.