S3FS

Implementation of Node.JS FS interface using Amazon Simple Storage Service (S3) for storage.

Lead Maintainer: David Pate

Purpose

S3FS provides a drop-in replacement for the File System (FS) implementation that is available with Node.JS allowing a distributed file-system to be used by Node.JS applications through the well-known FS interface used by Node.JS.

Minimum IAM Policy

Below is a policy for AWS Identity and Access Management which provides the minimum privileges needed to use S3FS.

{
  "Statement": [
    {
      "Action": [
        "s3:ListBucket"
      ],
      "Effect": "Allow",
      "Resource": [
        "arn:aws:s3:::your-bucket"
      ]
    },
    {
      "Action": [
        "s3:AbortMultipartUpload",
        "s3:CreateBucket",
        "s3:DeleteBucket",
        "s3:DeleteBucketPolicy",
        "s3:DeleteObject",
        "s3:GetBucketPolicy",
        "s3:GetLifecycleConfiguration",
        "s3:GetObject",
        "s3:ListBucket",
        "s3:ListBucketMultipartUploads",
        "s3:ListMultipartUploadParts",
        "s3:PutBucketPolicy",
        "s3:PutLifecycleConfiguration",
        "s3:PutObject"
      ],
      "Effect": "Allow",
      "Resource": [
        "arn:aws:s3:::your-bucket/*"
      ]
    }
  ]
}

Currently Supported Methods

The methods below from Node.JS's FS interface are the only currently supported methods matching the signature and functionality of the fs module. All of the methods support either usage through callbacks or promises. There isn't any support for synchronous actions currently as there isn't a need.

Example Callback Usage

var S3FS = require('s3fs');
var fsImpl = new S3FS('test-bucket', options);
fsImpl.writeFile('message.txt', 'Hello Node', function (err) {
  if (err) throw err;
  console.log('It\'s saved!');
});

Example Promise Usage

var S3FS = require('s3fs');
var fsImpl = new S3FS('test-bucket', options);
fsImpl.writeFile('message.txt', 'Hello Node').then(function() {
  console.log('It\'s saved!');
}, function(reason) {
  throw reason;
});

• fs.createReadStream(path, [options])
• fs.createWriteStream(path, [options])
• fs.exists(path, callback)
• fs.stat(path, callback)
• fs.lstat(path, callback)
• fs.mkdir(path, [mode], callback)
• fs.readdir(path, callback)
• fs.readFile(filename, [options], callback)
• fs.rmdir(path, callback)
• fs.unlink(path, callback)
• fs.writeFile(filename, data, [options], callback)

Custom Supported Methods

Besides the methods from Node.JS's FS interface we also support some custom expansions to the interface providing various methods such as recursive methods and S3 specific methods. They are described below.

s3fs.clone(path)

Provides a clone of the instance of S3FS which has relative access to the specified directory.

• path String. Optional. The relative path to extend the current working directory

// Create an instance of S3FS which has a current working directory of `test-folder` within the S3 bucket `test-bucket`
var fsImpl = new S3FS('test-bucket/test-folder', options);
// Creates a copy (which uses the same instance of S3FS) which has a current working directory of `test-folder/styles`
var fsImplStyles = fsImpl.clone('styles');

s3fs.copyFile(sourcePath, destinationPath[, callback])

Allows a file to be copied from one path to another path within the same bucket. Paths are relative to the bucket originally provided.

• sourceFile String. Required. Relative path to the source file
• destinationFile String. Required. Relative path to the destination file
• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.copyFile('test-folder/test-file.txt', 'other-folder/test-file.txt').then(function() {
  // File was successfully copied
}, function(reason) {
  // Something went wrong
});

s3fs.copyDir(sourcePath, destinationPath[, callback])

Recursively copies a directory from the source path to the destination path.

• sourcePath String. Required. The source directory to be copied
• destinationPath String. Required. The destination directory to be copied to
• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.copyDir('test-folder', 'other-folder').then(function() {
  // Directory was successfully copied
}, function(reason) {
  // Something went wrong
});

s3fs.create(options[, callback])

Creates a new bucket on S3.

• options Object. Optional. The options to be used when creating the bucket. See AWS SDK
• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.create().then(function() {
  // Bucket was successfully created
}, function(reason) {
  // Something went wrong
});

s3fs.delete([callback])

Deletes a bucket on S3, can only be deleted when empty. If you need to delete one that isn't empty use destroy([callback]) instead.

• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.delete().then(function() {
  // Bucket was successfully deleted
}, function(reason) {
  // Something went wrong
});

s3fs.destroy([callback])

Recursively deletes all files within the bucket and then deletes the bucket.

• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.destroy().then(function() {
  // Bucket was successfully destroyed
}, function(reason) {
  // Something went wrong
});

s3fs.headObject(path[, callback])

Retrieves the details about an object, but not the contents.

• path String. Required. Path to the object to retrieve the head for
• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.headObject('test-file.txt').then(function(details) {
  // Details contains details such as the `ETag` about the object. See [AWS SDK](http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/S3.html#headObject-property) for details.
}, function(reason) {
  // Something went wrong
});

s3fs.listContents(path, marker[, callback])

Retrieves a list of all objects within the specific path. The result is similar to that of headObject(path[, callback]) expect that it contains an array of objects.

• path String. Required. The path to list all of the objects for
• marker String. Required. The key to start with when listing objects
• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.listContents('/', '/').then(function(data) {
  // Data.Contents contains details such as the `ETag` about the object. See [AWS SDK](http://docs.aws.amazon.com/AWSJavaScriptSDK/latest/AWS/S3.html#headObject-property) for details.
}, function(reason) {
  // Something went wrong
});

s3fs.putBucketLifecycle(name, prefix, days[, callback])

Adds/Updates a lifecycle on a bucket.

• name String. Required. The name of the lifecycle. The value cannot be longer than 255 characters.
• prefix String. Required. Prefix identifying one or more objects to which the rule applies.
• days Indicates the lifetime, in days, of the objects that are subject to the rule. The value must be a non-zero positive integer.
• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS(options, 'test-bucket');
// Remove the Cached contents in the `/cache` directory each day.
fsImpl.putBucketLifecycle('expire cache', 'cache', 1).then(function() {
  // Bucket Lifecycle was successfully added/updated
}, function(reason) {
  // Something went wrong
});

s3fs.readdirp(path[, callback])

Recursively reads a directory.

• path String. Required. The path to the directory to read from

var fsImpl = new S3FS('test-bucket', options);
fsImpl.readdirp('test-folder').then(function(files) {
  // Files contains a list of all of the files similar to [`fs.readdir(path, callback)`](http://nodejs.org/api/fs.html#fs_fs_readdir_path_callback) but with recursive contents
}, function(reason) {
  // Something went wrong
});

s3fs.mkdirp(path[, callback])

Recursively creates a directory.

• path The path to the directory to create
• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.mkdirp('test-folder').then(function() {
  // Directory has been recursively created
}, function(reason) {
  // Something went wrong
});

s3fs.rmdirp(path[, callback])

Recursively deletes a directory.

• path The path to the directory to delete
• callback Function. Optional. Callback to be used, if not provided will return a Promise

var fsImpl = new S3FS('test-bucket', options);
fsImpl.rmdirp('test-folder').then(function() {
  // Directory has been recursively deleted
}, function(reason) {
  // Something went wrong
});

Testing

This repository uses Mocha as its test runner. Tests can be run by executing the following command:

npm test

This will run all tests and report on their success/failure in the console, additionally it will include our Code Coverage.

Code Coverage

This repository uses Istanbul as its code coverage tool. Code Coverage will be calculated when executing the following command:

npm test

This will report the Code Coverage to the console similar to the following:

=============================== Coverage summary ===============================
Statements   : 78.07% ( 356/456 )
Branches     : 50.23% ( 107/213 )
Functions    : 74.77% ( 83/111 )
Lines        : 78.07% ( 356/456 )
================================================================================

Additionally, an interactive HTML report will be generated in ./coverage/lcov-report/index.html which allows browsing the coverage by file.

License

MIT

Copyright

Copyright (c) 2014 Riptide Software Inc.