AWS Lambda fs.readfile issue

问题

I'm packing some files in my lambda package that I need. I've used some example floating around to nearly get it working.

I'm able to verify the path of a file OK

const deviceCert = path.resolve(certType + "-deviceCert.key");

which logs out to

"message": "Resolved path to TEST-deviceCert.key: /var/task/TEST-deviceCert.key"

when I attempt to read the file using

fs.readFile(deviceCert, (err, data) => {

    if (err) {

        log.error(`Verify deviceCert failure: ${err}`);
        responseBody = Helper.buildCORSResponse(502, JSON.stringify({ message: "Unable to locate file required" }));

        return callback(null, responseBody);

    }

});

I get the following error

Error: ENOENT: no such file or directory, open '/var/task/TEST-deviceCert.key'"

If I can verify the path then why cant I read it?

Any ideas??

回答1:

Copied from the node.js path.resolve() API documentation:

The path.resolve() method resolves a sequence of paths or path segments into an absolute path.

In other words, resolve concatenates a sequence of strings into one string, formatted as an absolute path. However, it does not check whether or not there is a file at this location. You can use either fs.stat() or fs.access() to verify the presence and access of the file.

回答2:

eventually confirmed that serverless was packaging the files I needed.

Using fs.readdir I was able to debug the issue and find the path that the packaging process was creating in the Lambda package

/var/task/src//Certs/

Hope this helps someone in the future!!

来源：https://stackoverflow.com/questions/54933879/aws-lambda-fs-readfile-issue

标签

javascript

file

aws-lambda