I have a very simple node lambda function which reads the contents of packaged file in it. I upload the code as zip file. The directory structure is as follows.
index.js
readme.txt
Then have in my index.js file:
fs.readFile('/var/task/readme.txt', function (err, data) {
if (err) throw err;
});
I keep getting the following error NOENT: no such file or directory, open '/var/task/readme.txt'.
I tried ./readme.txt also.
What am I missing ?
Try this, it works for me:
'use strict'
let fs = require("fs");
let path = require("path");
exports.handler = (event, context, callback) => {
// To debug your problem
console.log(path.resolve("./readme.txt"));
// Solution is to use absolute path using `__dirname`
fs.readFile(__dirname +'/readme.txt', function (err, data) {
if (err) throw err;
});
};
to debug why your code is not working, add below link in your handler
console.log(path.resolve("./readme.txt"));
On AWS Lambda node process might be running from some other folder and it looks for readme.txt file from that folder as you have provided relative path, solution is to use absolute path.
What worked for me was the comment by Vadorrequest to use process.env.LAMBDA_TASK_ROOT. I wrote a function to get a template file in a /templates directory when I'm running it locally on my machine with __dirname or with the process.env.LAMBDA_TASK_ROOT variable when running on Lambda:
function loadTemplateFile(templateName) {
const fileName = `./templates/${templateName}`
let resolved
if (process.env.LAMBDA_TASK_ROOT) {
resolved = path.resolve(process.env.LAMBDA_TASK_ROOT, fileName)
} else {
resolved = path.resolve(__dirname, fileName)
}
console.log(`Loading template at: ${resolved}`)
try {
const data = fs.readFileSync(resolved, 'utf8')
return data
} catch (error) {
const message = `Could not load template at: ${resolved}, error: ${JSON.stringify(error, null, 2)}`
console.error(message)
throw new Error(message)
}
}
This is an oldish question but comes up first when attempting to sort out whats going on with file paths on Lambda.
Additional Steps for Serverless Framework
For anyone using Serverless framework to deploy (which probably uses webpack to build) you will also need to add the following to your webpack config file (just after target: node):
// assume target: 'node', is here
node: {
__dirname: false,
},
Without this piece using __dirname with Serverless will STILL not get you the desired absolute directory path.
I went through this using serverless framework and it really was the file that was not sent in the compression. Just add the following line in serverless.yml:
package:
individually: false
include:
- src/**
const filepath = path.resolve('../../filename.text');
const fileData2 = fs.readFileSync(process.env.LAMBDA_TASK_ROOT + filepath, 'utf-8');
I was using fs.promises.readFile(). Couldn't get it to error out at out. The file was there, and LAMBDA_TASK_ROOT seemed right to me as well. After I changed to fs.readFileSync(), it worked.
I hade the same problem and I tried applying all these wonderful solutions above - which didn't work.
The problem was that I setup one of the folder name with one letter in upper case which was really lowercase.
So when I tried to fetch the content of /src/SOmething/some_file.txt
While the folder was really /src/Something/ - I got this error...
Windows (local environment) is case insensitive while AWS is not!!!....
Related
I try to copy and replace some variable in multiples files. For this, i use esj module replace my vars.
But i don't know if ejs module is correct for my case. I would like just copy "template" initial file and replace variable in file.
My exemple using NodeJS :
const symfonyPluginPath = path.join(
__dirname,
'../plugins/symfony/template'
);
const testPath = path.join(__dirname, '../plugins/test');
shell.rm('-rf', testPath);
shell.mkdir(testPath);
shell.cp('-r', `${symfonyPluginPath}/*`, testPath);
shell.cp('-r', `${symfonyPluginPath}/.*`, testPath);
shell.cd(testPath);
// #ts-ignore
fs.readdir(testPath, (error, files) => {
files.forEach((file) => {
const compiled = ejs.compile(
fs.readFileSync(`${testPath}/${file}`, 'utf8')
);
const test = compiled({ appName: 'test' });
console.log(test);
});
});
This code work for only 1 file, but in forEach i've an error EISDIR: illegal operation on a directory, read.
I don't know if my approch is good and if ejs is the correct module for this.
Anyone can help me ?
Thank you community !
EISDIR stands for "Error, Is Directory". This means that NPM is trying to do something to a file but it is a directory.
Try in this format ---
path.join('x/y/z', '/plugins/test')
I am trying to write a file in node.js using fs.writeFile, I use the following code:
const fs = require('filer');
const jsonString = JSON.stringify(myObj)
fs.writeFile('/myFile.txt', jsonString, function (err) {
if (err) throw err;
console.log('Saved!');
});
}
I am sure the file is created, because I can read it by fs.readFile referring to the same address, but I cannot find it on the disk by using windows search. What I understood, if I change the localhost port it saves the files in another location. I already tried "process.cwd()", but it didn't work.
I really appreciate it if someone could help.
try to use : __dirname instead of process.cwd()
const fs = require('fs');
const path = require('path');
const filePath = path.join(__dirname, '/myFile.txt');
console.log(filePath);
const jsonString = JSON.stringify({ name: "kalo" })
fs.writeFile(filePath, jsonString, (err) => {
if (err) throw err;
console.log('The file has been saved!');
});
And I would like to know why are you using 'filer' instead of default fs module?
fs module is native module that provides file handling in node js. so you don't need to install it specifically. This code perfectly worked and it prints absolute location of the file as well.Just run this code if it doesn't work, I think you should re install node js. I have updated the answer.You can also use fs.writeFileSync method as well.
From documentation: "String form paths are interpreted as UTF-8 character sequences identifying the absolute or relative filename. Relative paths will be resolved relative to the current working directory as determined by calling process.cwd()."
So in order to determine your working directory (i.e. where fs create files by default) call (works for me):
console.log(process.cwd());
Then if you would like to change your working directory, you can call (works for me as well):
process.chdir('path_to_new_directory');
Path can be relative or absolute.
This is also from documentation: "The process.chdir() method changes the current working directory of the Node.js process or throws an exception if doing so fails (for instance, if the specified directory does not exist)."
I'm trying to download files to the filesystem in an electron app. My code, in the main thread, looks like this:
const dir = `${__dirname}/media`;
if (!fs.existsSync(dir)){
fs.mkdirSync(dir);
}
const file = fs.createWriteStream(`${dir}/${name}`);
file.on("open", function() {
const request = http.get(url, function(response) {
response.pipe(file);
response.on('end', function() {
file.close();
...
});
});
request.on('error', function(err) {
...
});
});
This works when running in development using electron . But after I build it with electron-builder, I get the error in an alert:
Uncaught Exception:
Error: ENOENT, media/uploads_2016_02_BASF_Holistic_Program.jpg not found in /Users/nicholasstephan/Desktop/XXXXXXX/dist/Mac/XXXXXX.app/Contents/Resources/app.asar
at notFoundError (ELECTRON_ASAR.js:109:19)
at Object.module.(anonymous function) [as open] (ELECTRON_ASAR.js:209:16)
at WriteStream.open (fs.js:1890:6)
at new WriteStream (fs.js:1876:10)
at Object.fs.createWriteStream (fs.js:1831:10)
at next (/Users/nicholasstephan/Desktop/XXXXXXXX/dist/Mac/XXXXXXXX.app/Contents/Resources/app.asar/media.js:19:18)
at /Users/nicholasstephan/Desktop/XXXXXXXX/dist/Mac/XXXXXXXX.app/Contents/Resources/app.asar/media.js:52:4
...
where the media.js, ln 19, being referred to is the const file = fs.createWriteStream(${dir}/${name}); line in the code.
I've tried the solutions offered in about a dozen other similar stackoverflow answers, but none have fixed the problem.
What's going on here?
Thanks.
The built Electron app uses the Asar format. Asar is an archive format (it's really just one big file) though in Electron you are able to read from it as if it were a standard directory.
I presume (though I have not seen it explicitly documented) that it is not possible to write to an Asar with the fs functions. In any case there are almost certainly more appropriate locations to write data.
Try writing to a different path. Electron provides a number of useful paths using app.getPath(name) so you could for example write to the userData directory which holds configuration files for your app.
I am new to Node.js, so I'm not familiar with a lot of stuff.
So basically I want to create a directory in the current working directory:
var mkdirp = require('mkdirp');
console.log("Going to create directory /tmp/test");
mkdirp('/tmp/test',function(err){
if (err) {
return console.error(err);
}
console.log("Directory created successfully!");
});
My current directory is C:\Users\Owner\Desktop\Tutorials\NodeJS on Windows, which means I run node main.js in that directory.
(main.js is in C:\Users\Owner\Desktop\Tutorials\NodeJS)
After I run the code, it generates C:\tmp\test, which is in C:\.
But I want to create it in the current directory, so the result I want is C:\Users\Owner\Desktop\Tutorials\NodeJS\tmp\test.
I just don't know how to do that...
You can use process.cwd() to output the directory where your command has been executed (in your case, the directory where you run node main.js) so your code might look like this:
var mkdirp = require('mkdirp');
var path = require('path');
console.log("Going to create directory /tmp/test");
mkdirp(path.join(process.cwd(), '/tmp/test'), function(err){
if (err) {
return console.error(err);
}
console.log("Directory created successfully!");
});
If you need just the directory where the main.js file is located and not where you execute it (by calling node main.js), you can use the __dirname variable instead of process.cwd().
It's a good idea to use the path.join() function to make sure the path delimiters are set correctly, especially when you're on a Windows system which may treat forward slashes as options.
var mkdirp = require('mkdirp');
var path = require('path');
console.log("Going to create directory /tmp/test");
mkdirp(path.join(__dirname, '/tmp/test'),function(err){
if (err) {
return console.error(err);
}
console.log("Directory created successfully!");
});
You could use path.join(__dirname, '/tmp/test') where __dirname would return The name of the directory that the currently executing script resides in.
You need to include module 'path' to make path.join() work.
Reference
__dirname
I have a file(data.file an image), I would like to save this image. Now an image with the same name could exist before it. I would like to overwrite if so or create it if it does not exist since before. I read that the flag "w" should do this.
Code:
fs.writeFile('/avatar/myFile.png', data.file, {
flag: "w"
}, function(err) {
if (err) {
return console.log(err);
}
console.log("The file was saved!");
});
Error:
[Error: ENOENT: no such file or directory, open '/avatar/myFile.png']
errno: -2,
code: 'ENOENT',
syscall: 'open',
path: '/avatar/myFile.png'
This is probably because you are trying to write to root of file system instead of your app directory '/avatar/myFile.png' -> __dirname + '/avatar/myFile.png' should do the trick, also check if folder exists. node.js won't create parent folder for you.
Many of us are getting this error because parent path does not exist. E.g. you have /tmp directory available but there is no folder "foo" and you are writing to /tmp/foo/bar.txt.
To solve this, you can use mkdirp - adapted from How to write file if parent folder doesn't exist?
Option A) Using Callbacks
const mkdirp = require('mkdirp');
const fs = require('fs');
const getDirName = require('path').dirname;
function writeFile(path, contents, cb) {
mkdirp(getDirName(path), function (err) {
if (err) return cb(err);
fs.writeFile(path, contents, cb);
});
}
Option B) Using Async/Await
Or if you have an environment where you can use async/await:
const mkdirp = require('mkdirp');
const fs = require('fs');
const writeFile = async (path, content) => {
await mkdirp(path);
fs.writeFileSync(path, content);
}
I solved a similar problem where I was trying to create a file with a name that contained characters that are not allowed. Watch out for that as well because it gives the same error message.
I ran into this error when creating some nested folders asynchronously right before creating the files. The destination folders wouldn't always be created before promises to write the files started. I solved this by using mkdirSync instead of 'mkdir' in order to create the folders synchronously.
try {
fs.mkdirSync(DestinationFolder, { recursive: true } );
} catch (e) {
console.log('Cannot create folder ', e);
}
fs.writeFile(path.join(DestinationFolder, fileName), 'File Content Here', (err) => {
if (err) throw err;
});
Actually, the error message for the file names that are not allowed in Linux/ Unix system comes up with the same error which is extremely confusing. Please check the file name if it has any of the reserved characters. These are the reserved /, >, <, |, :, & characters for Linux / Unix system. For a good read follow this link.
It tells you that the avatar folder does not exist.
Before writing a file into this folder, you need to check that a directory called "avatar" exists and if it doesn't, create it:
if (!fs.existsSync('/avatar')) {
fs.mkdirSync('/avatar', { recursive: true});
}
you can use './' as a prefix for your path.
in your example, you will write:
fs.writeFile('./avatar/myFile.png', data.file, (err) => {
if (err) {
return console.log(err);
}
console.log("The file was saved!");
});
I had this error because I tried to run:
fs.writeFile(file)
fs.unlink(file)
...lots of code... probably not async issue...
fs.writeFile(file)
in the same script. The exception occurred on the second writeFile call. Removing the first two calls solved the problem.
In my case, I use async fs.mkdir() and then, without waiting for this task to complete, I tried to create a file fs.writeFile()...
As SergeS mentioned, using / attempts to write in your system root folder, but instead of using __dirname, which points to the path of the file where writeFile is invoked, you can use process.cwd() to point to the project's directory. Example:
writeFile(`${process.cwd()}/pictures/myFile.png`, data, (err) => {...});
If you want to avoid string concatenations/interpolations, you may also use path.join(process.cwd(), 'pictures', 'myFile.png') (more details, including directory creation, in this digitalocean article).