joibel / go-fsimpl

Go io/fs.FS filesystem implementations for various URL schemes

hairyhenderson/go-fsimpl

This module contains a collection of Go filesystem implementations that can be discovered dynamically by URL scheme.

These filesystems implement the fs.FS interface introduced in Go 1.16. This means that currently all implementations are read-only, however this may change in the future (see golang/go#45757 for progress).

Most implementations implement the fs.ReadDirFS interface, though the httpfs filesystem does not.

Some extensions are available to help add specific functionality to certain filesystems:

• WithContextFS - injects a context into a filesystem, for propagating cancellation in filesystems that support it.
• WithHeaderFS - sets the http.Header for all HTTP requests used by the filesystem. This can be useful for authentication, or for requesting specific content types.
• WithHTTPClientFS - sets the *http.Client for all HTTP requests to be made with.

Many of the filesystem packages also have their own extensions.

This module also provides ContentType, an extension to the fs.FileInfo type to help identify an appropriate MIME content type for a given file. For filesystems that support it, the HTTP Content-Type header is used for this. Otherwise, the type is guessed from the file extension.

History & Project Status

This module is in active development, and the API is still subject to breaking changes.

The filesystem pacakges should operate correctly, based on the tests, but there may be edge cases that are not covered. Please open an issue if you find one!

Most of these filesystems are based on code from gomplate, which supports all of these as datasources. This module is intended to eventually be used within gomplate.

Supported Filesystems

Here's the list of filesystems & URL schemes supported by this module:

Package	Scheme(s)	Description
awssmfs	aws+sm	AWS Secrets Manager
awssmpfs	aws+smp	AWS Systems Manager Parameter Store
blobfs	azblob	Azure Blob Storage
blobfs	gs	Google Cloud Storage
blobfs	s3	Amazon S3
consulfs	consul, consul+http, consul+https	HashiCorp Consul
filefs	file	local filesystem
gitfs	git, git+file, git+http, git+https, git+ssh	local/remote git repository
httpfs	http, https	HTTP server
vaultfs	vault, vault+http, vault+https	HashiCorp Vault

See the individual package documentation for more details.

Installation

Use go get to install the latest version of go-fsimpl:

$ go get -u github.com/hairyhenderson/go-fsimpl

Usage

If you know that you want an HTTP filesystem, for example:

import (
	"net/url"

	"github.com/hairyhenderson/go-fsimpl/httpfs"
)

func main() {
	base, _ := url.Parse("https://example.com")
	fsys, _ := httpfs.New(base)

	f, _ := fsys.Open("hello.txt")
	defer f.Close()

	// now do what you like with the file...
}

If you're not sure what filesystem type you need (for example, if you're dealing with a user-provided URL), you can use a filesystem mux:

import (
	"github.com/hairyhenderson/go-fsimpl"
	"github.com/hairyhenderson/go-fsimpl/blobfs"
	"github.com/hairyhenderson/go-fsimpl/filefs"
	"github.com/hairyhenderson/go-fsimpl/gitfs"
	"github.com/hairyhenderson/go-fsimpl/httpfs"
)

func main() {
	mux := fsimpl.NewMux()
	mux.Add(filefs.FS)
	mux.Add(httpfs.FS)
	mux.Add(blobfs.FS)
	mux.Add(gitfs.FS)

	// for example, a URL that points to a subdirectory at a specific tag in a
	// given git repo, hosted on GitHub and authenticated with SSH...
	fsys, err := mux.Lookup("git+ssh://[email protected]/foo/bar.git//baz#refs/tags/v1.0.0")
	if err != nil {
		log.Fatal(err)
	}

	f, _ := fsys.Open("hello.txt")
	defer f.Close()

	// now do what you like with the file...
}

Developing

You will require git including git daemon and consul executables on your path for running the tests.

License

The MIT License

Copyright (c) 2021-2022 Dave Henderson