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diff --git a/vendor/github.com/spf13/afero/README.md b/vendor/github.com/spf13/afero/README.md new file mode 100644 index 00000000..0c9b04b5 --- /dev/null +++ b/vendor/github.com/spf13/afero/README.md @@ -0,0 +1,452 @@ + + +A FileSystem Abstraction System for Go + +[](https://travis-ci.org/spf13/afero) [](https://ci.appveyor.com/project/spf13/afero) [](https://godoc.org/github.com/spf13/afero) [](https://gitter.im/spf13/afero?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge) + +# Overview + +Afero is an filesystem framework providing a simple, uniform and universal API +interacting with any filesystem, as an abstraction layer providing interfaces, +types and methods. Afero has an exceptionally clean interface and simple design +without needless constructors or initialization methods. + +Afero is also a library providing a base set of interoperable backend +filesystems that make it easy to work with afero while retaining all the power +and benefit of the os and ioutil packages. + +Afero provides significant improvements over using the os package alone, most +notably the ability to create mock and testing filesystems without relying on the disk. + +It is suitable for use in a any situation where you would consider using the OS +package as it provides an additional abstraction that makes it easy to use a +memory backed file system during testing. It also adds support for the http +filesystem for full interoperability. + + +## Afero Features + +* A single consistent API for accessing a variety of filesystems +* Interoperation between a variety of file system types +* A set of interfaces to encourage and enforce interoperability between backends +* An atomic cross platform memory backed file system +* Support for compositional (union) file systems by combining multiple file systems acting as one +* Specialized backends which modify existing filesystems (Read Only, Regexp filtered) +* A set of utility functions ported from io, ioutil & hugo to be afero aware + + +# Using Afero + +Afero is easy to use and easier to adopt. + +A few different ways you could use Afero: + +* Use the interfaces alone to define you own file system. +* Wrap for the OS packages. +* Define different filesystems for different parts of your application. +* Use Afero for mock filesystems while testing + +## Step 1: Install Afero + +First use go get to install the latest version of the library. + + $ go get github.com/spf13/afero + +Next include Afero in your application. +```go +import "github.com/spf13/afero" +``` + +## Step 2: Declare a backend + +First define a package variable and set it to a pointer to a filesystem. +```go +var AppFs = afero.NewMemMapFs() + +or + +var AppFs = afero.NewOsFs() +``` +It is important to note that if you repeat the composite literal you +will be using a completely new and isolated filesystem. In the case of +OsFs it will still use the same underlying filesystem but will reduce +the ability to drop in other filesystems as desired. + +## Step 3: Use it like you would the OS package + +Throughout your application use any function and method like you normally +would. + +So if my application before had: +```go +os.Open('/tmp/foo') +``` +We would replace it with: +```go +AppFs.Open('/tmp/foo') +``` + +`AppFs` being the variable we defined above. + + +## List of all available functions + +File System Methods Available: +```go +Chmod(name string, mode os.FileMode) : error +Chtimes(name string, atime time.Time, mtime time.Time) : error +Create(name string) : File, error +Mkdir(name string, perm os.FileMode) : error +MkdirAll(path string, perm os.FileMode) : error +Name() : string +Open(name string) : File, error +OpenFile(name string, flag int, perm os.FileMode) : File, error +Remove(name string) : error +RemoveAll(path string) : error +Rename(oldname, newname string) : error +Stat(name string) : os.FileInfo, error +``` +File Interfaces and Methods Available: +```go +io.Closer +io.Reader +io.ReaderAt +io.Seeker +io.Writer +io.WriterAt + +Name() : string +Readdir(count int) : []os.FileInfo, error +Readdirnames(n int) : []string, error +Stat() : os.FileInfo, error +Sync() : error +Truncate(size int64) : error +WriteString(s string) : ret int, err error +``` +In some applications it may make sense to define a new package that +simply exports the file system variable for easy access from anywhere. + +## Using Afero's utility functions + +Afero provides a set of functions to make it easier to use the underlying file systems. +These functions have been primarily ported from io & ioutil with some developed for Hugo. + +The afero utilities support all afero compatible backends. + +The list of utilities includes: + +```go +DirExists(path string) (bool, error) +Exists(path string) (bool, error) +FileContainsBytes(filename string, subslice []byte) (bool, error) +GetTempDir(subPath string) string +IsDir(path string) (bool, error) +IsEmpty(path string) (bool, error) +ReadDir(dirname string) ([]os.FileInfo, error) +ReadFile(filename string) ([]byte, error) +SafeWriteReader(path string, r io.Reader) (err error) +TempDir(dir, prefix string) (name string, err error) +TempFile(dir, prefix string) (f File, err error) +Walk(root string, walkFn filepath.WalkFunc) error +WriteFile(filename string, data []byte, perm os.FileMode) error +WriteReader(path string, r io.Reader) (err error) +``` +For a complete list see [Afero's GoDoc](https://godoc.org/github.com/spf13/afero) + +They are available under two different approaches to use. You can either call +them directly where the first parameter of each function will be the file +system, or you can declare a new `Afero`, a custom type used to bind these +functions as methods to a given filesystem. + +### Calling utilities directly + +```go +fs := new(afero.MemMapFs) +f, err := afero.TempFile(fs,"", "ioutil-test") + +``` + +### Calling via Afero + +```go +fs := afero.NewMemMapFs() +afs := &afero.Afero{Fs: fs} +f, err := afs.TempFile("", "ioutil-test") +``` + +## Using Afero for Testing + +There is a large benefit to using a mock filesystem for testing. It has a +completely blank state every time it is initialized and can be easily +reproducible regardless of OS. You could create files to your heart’s content +and the file access would be fast while also saving you from all the annoying +issues with deleting temporary files, Windows file locking, etc. The MemMapFs +backend is perfect for testing. + +* Much faster than performing I/O operations on disk +* Avoid security issues and permissions +* Far more control. 'rm -rf /' with confidence +* Test setup is far more easier to do +* No test cleanup needed + +One way to accomplish this is to define a variable as mentioned above. +In your application this will be set to afero.NewOsFs() during testing you +can set it to afero.NewMemMapFs(). + +It wouldn't be uncommon to have each test initialize a blank slate memory +backend. To do this I would define my `appFS = afero.NewOsFs()` somewhere +appropriate in my application code. This approach ensures that Tests are order +independent, with no test relying on the state left by an earlier test. + +Then in my tests I would initialize a new MemMapFs for each test: +```go +func TestExist(t *testing.T) { + appFS := afero.NewMemMapFs() + // create test files and directories + appFS.MkdirAll("src/a", 0755) + afero.WriteFile(appFS, "src/a/b", []byte("file b"), 0644) + afero.WriteFile(appFS, "src/c", []byte("file c"), 0644) + name := "src/c" + _, err := appFS.Stat(name) + if os.IsNotExist(err) { + t.Errorf("file \"%s\" does not exist.\n", name) + } +} +``` + +# Available Backends + +## Operating System Native + +### OsFs + +The first is simply a wrapper around the native OS calls. This makes it +very easy to use as all of the calls are the same as the existing OS +calls. It also makes it trivial to have your code use the OS during +operation and a mock filesystem during testing or as needed. + +```go +appfs := afero.NewOsFs() +appfs.MkdirAll("src/a", 0755)) +``` + +## Memory Backed Storage + +### MemMapFs + +Afero also provides a fully atomic memory backed filesystem perfect for use in +mocking and to speed up unnecessary disk io when persistence isn’t +necessary. It is fully concurrent and will work within go routines +safely. + +```go +mm := afero.NewMemMapFs() +mm.MkdirAll("src/a", 0755)) +``` + +#### InMemoryFile + +As part of MemMapFs, Afero also provides an atomic, fully concurrent memory +backed file implementation. This can be used in other memory backed file +systems with ease. Plans are to add a radix tree memory stored file +system using InMemoryFile. + +## Network Interfaces + +### SftpFs + +Afero has experimental support for secure file transfer protocol (sftp). Which can +be used to perform file operations over a encrypted channel. + +## Filtering Backends + +### BasePathFs + +The BasePathFs restricts all operations to a given path within an Fs. +The given file name to the operations on this Fs will be prepended with +the base path before calling the source Fs. + +```go +bp := afero.NewBasePathFs(afero.NewOsFs(), "/base/path") +``` + +### ReadOnlyFs + +A thin wrapper around the source Fs providing a read only view. + +```go +fs := afero.NewReadOnlyFs(afero.NewOsFs()) +_, err := fs.Create("/file.txt") +// err = syscall.EPERM +``` + +# RegexpFs + +A filtered view on file names, any file NOT matching +the passed regexp will be treated as non-existing. +Files not matching the regexp provided will not be created. +Directories are not filtered. + +```go +fs := afero.NewRegexpFs(afero.NewMemMapFs(), regexp.MustCompile(`\.txt$`)) +_, err := fs.Create("/file.html") +// err = syscall.ENOENT +``` + +### HttpFs + +Afero provides an http compatible backend which can wrap any of the existing +backends. + +The Http package requires a slightly specific version of Open which +returns an http.File type. + +Afero provides an httpFs file system which satisfies this requirement. +Any Afero FileSystem can be used as an httpFs. + +```go +httpFs := afero.NewHttpFs(<ExistingFS>) +fileserver := http.FileServer(httpFs.Dir(<PATH>))) +http.Handle("/", fileserver) +``` + +## Composite Backends + +Afero provides the ability have two filesystems (or more) act as a single +file system. + +### CacheOnReadFs + +The CacheOnReadFs will lazily make copies of any accessed files from the base +layer into the overlay. Subsequent reads will be pulled from the overlay +directly permitting the request is within the cache duration of when it was +created in the overlay. + +If the base filesystem is writeable, any changes to files will be +done first to the base, then to the overlay layer. Write calls to open file +handles like `Write()` or `Truncate()` to the overlay first. + +To writing files to the overlay only, you can use the overlay Fs directly (not +via the union Fs). + +Cache files in the layer for the given time.Duration, a cache duration of 0 +means "forever" meaning the file will not be re-requested from the base ever. + +A read-only base will make the overlay also read-only but still copy files +from the base to the overlay when they're not present (or outdated) in the +caching layer. + +```go +base := afero.NewOsFs() +layer := afero.NewMemMapFs() +ufs := afero.NewCacheOnReadFs(base, layer, 100 * time.Second) +``` + +### CopyOnWriteFs() + +The CopyOnWriteFs is a read only base file system with a potentially +writeable layer on top. + +Read operations will first look in the overlay and if not found there, will +serve the file from the base. + +Changes to the file system will only be made in the overlay. + +Any attempt to modify a file found only in the base will copy the file to the +overlay layer before modification (including opening a file with a writable +handle). + +Removing and Renaming files present only in the base layer is not currently +permitted. If a file is present in the base layer and the overlay, only the +overlay will be removed/renamed. + +```go + base := afero.NewOsFs() + roBase := afero.NewReadOnlyFs(base) + ufs := afero.NewCopyOnWriteFs(roBase, afero.NewMemMapFs()) + + fh, _ = ufs.Create("/home/test/file2.txt") + fh.WriteString("This is a test") + fh.Close() +``` + +In this example all write operations will only occur in memory (MemMapFs) +leaving the base filesystem (OsFs) untouched. + + +## Desired/possible backends + +The following is a short list of possible backends we hope someone will +implement: + +* SSH +* ZIP +* TAR +* S3 + +# About the project + +## What's in the name + +Afero comes from the latin roots Ad-Facere. + +**"Ad"** is a prefix meaning "to". + +**"Facere"** is a form of the root "faciō" making "make or do". + +The literal meaning of afero is "to make" or "to do" which seems very fitting +for a library that allows one to make files and directories and do things with them. + +The English word that shares the same roots as Afero is "affair". Affair shares +the same concept but as a noun it means "something that is made or done" or "an +object of a particular type". + +It's also nice that unlike some of my other libraries (hugo, cobra, viper) it +Googles very well. + +## Release Notes + +* **0.10.0** 2015.12.10 + * Full compatibility with Windows + * Introduction of afero utilities + * Test suite rewritten to work cross platform + * Normalize paths for MemMapFs + * Adding Sync to the file interface + * **Breaking Change** Walk and ReadDir have changed parameter order + * Moving types used by MemMapFs to a subpackage + * General bugfixes and improvements +* **0.9.0** 2015.11.05 + * New Walk function similar to filepath.Walk + * MemMapFs.OpenFile handles O_CREATE, O_APPEND, O_TRUNC + * MemMapFs.Remove now really deletes the file + * InMemoryFile.Readdir and Readdirnames work correctly + * InMemoryFile functions lock it for concurrent access + * Test suite improvements +* **0.8.0** 2014.10.28 + * First public version + * Interfaces feel ready for people to build using + * Interfaces satisfy all known uses + * MemMapFs passes the majority of the OS test suite + * OsFs passes the majority of the OS test suite + +## Contributing + +1. Fork it +2. Create your feature branch (`git checkout -b my-new-feature`) +3. Commit your changes (`git commit -am 'Add some feature'`) +4. Push to the branch (`git push origin my-new-feature`) +5. Create new Pull Request + +## Contributors + +Names in no particular order: + +* [spf13](https://github.com/spf13) +* [jaqx0r](https://github.com/jaqx0r) +* [mbertschler](https://github.com/mbertschler) +* [xor-gate](https://github.com/xor-gate) + +## License + +Afero is released under the Apache 2.0 license. See +[LICENSE.txt](https://github.com/spf13/afero/blob/master/LICENSE.txt) |