blob

Overview ¶

Package blob is an implementation of the io.FS for Azure blob storage. This package foresakes all the options offered by the standard azure storage package to simplify use. If you need options not provided here, your best solution is probably to use the standard package.

This package supports two additional features over io.FS capabilities: - Writing files opened with OpenFile() - Locking files

This currently only support Block Blobs, not Append or Page. We may offer that in the future with enough demand.

NOTE: NUMBER ONE MISTAKE: FORGETTING .CLOSE() on WRITING A FILE, SO IT DOES NOT WRITE THE FILE.

Open a Blob storage container:

cred, err := msi.Token(msi.SystemAssigned{})
if err != nil {
	panic(err)
}

fsys, err := NewFS("account", "container", *cred)
if err != nil {
	// Do something
}

Read an entire file:

file, err := fsys.Open("users/jdoak.json")
if err != nil {
	// Do something
}

// You could also do fsys.ReadFile() for simplicity.
b, err := io.ReadAll(file)
if err != nil {
	// Do something
}

fmt.Println(string(b))

Stream a file to stdout:

file, err := fsys.Open("users/jdoak.json")
if err != nil {
	// Do something
}

if _, err := io.Copy(os.Stdout, file); err != nil {
	// Do something
}

Copy a file:

src, err := os.Open("path/to/some/file")
if err != nil {
	// Do something
}

dst, err := fsys.OpenFile("path/to/place/content", 0644, WithFlags(os.O_WRONLY | os.O_CREATE))
if err != nil {
	// Do something
}

if _, err := io.Copy(dst, src); err != nil {
	// Do something
}

// The file is not actually written until the file is closed, so it is
// important to know if Close() had an error.
if err := dst.Close(); err != nil {
	// Do something
}

Write a string to a file:

file, err := fsys.OpenFile("users/jdoak.json", 0644, WithFlags(os.O_WRONLY | os.O_CREATE))
if err != nil {
	// Do something
}

if _, err := io.WriteString(file, `{"Name":"John Doak"}`); err != nil {
	// Do something
}

// The file is not actually written until the file is closed, so it is
// important to know if Close() had an error.
if err := file.Close(); err != nil {
	// Do something
}

Walk the file system and log all directories:

err := fs.WalkDir(
	fsys,
	".",
	func(path string, d fs.DirEntry, err error) error {
		if !d.IsDir() {
			return nil
		}
		log.Println("dir: ", path)
		return nil
	},
)
if err != nil {
	// Do something
}