README
¶
github.com/zostay/fssafe
This is a small go package that provides a tools for saving files atomically. It also provides tooling for testing loading and saving of files using the same interface.
Installation
There's nothing to install, but to add it to your project:
go get github.com/zostay/fssafe
Usage
Then to use it in your code:
package main
import (
"fmt"
"io"
"github.com/zostay/fssafe"
)
func main() {
loaderSaver := fssafe.NewFileSystemLoaderSaver("file.txt")
// save a file, this will create a file named file.txt.new temporarily
w, err := loaderSaver.Saver()
if err != nil {
panic(err)
}
fmt.Fprintln(w, "Hello, World!")
w.Close()
// If file.txt already exists, it will be renamed to file.txt.old. The temporary
// file.txt.new will be renamed to file.txt
// load a file
r, err := loaderSaver.Loader()
if err != nil {
panic(err)
}
data, err := io.ReadAll(r)
if err != nil {
panic(err)
}
fmt.Println(string(data))
// Output: Hello, World!
}
Testing
Another loader/saver is provided that can be created using
NewTestingLoaderSaver(). The saver just writes to a memory buffer and the
loader reads from that memory buffer.
package main
import (
"fmt"
"io"
"github.com/zostay/fssafe"
)
func main() {
loaderSaver := fssafe.NewTestingLoaderSaver()
// save to a memory buffer
w, err := loaderSaver.Saver()
if err != nil {
panic(err)
}
fmt.Fprintln(w, "Hello, World!")
w.Close()
// load from the shared memory buffer
r, err := loaderSaver.Loader()
if err != nil {
panic(err)
}
data, err := io.ReadAll(r)
if err != nil {
panic(err)
}
fmt.Println(string(data))
// Output: Hello, World!
}
Copyright & License
Copyright 2020 Andrew Sterling Hanenkamp
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Documentation
¶
Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type BasicLoaderSaver ¶
type BasicLoaderSaver struct {
// contains filtered or unexported fields
}
BasicLoaderSaver provides the minimum functionality for a LoaderSaver.
func NewFileSystemLoaderSaver ¶
func NewFileSystemLoaderSaver(path string) *BasicLoaderSaver
NewFileSystemLoaderSaver builds a file system loader/saver that creates single file backups prior to writing and attempts to make saves atomic by writing data to a temporary file, which is then moved in to replace the save file.
This returns a LoaderSaver.
func (*BasicLoaderSaver) Loader ¶
func (ls *BasicLoaderSaver) Loader() (io.ReadCloser, error)
Loader provides a io.ReadCloser for reading a save file.
func (*BasicLoaderSaver) LoaderFunc ¶
func (ls *BasicLoaderSaver) LoaderFunc() Loader
LoaderFunc returns the Loader function used.
func (*BasicLoaderSaver) Saver ¶
func (ls *BasicLoaderSaver) Saver() (io.WriteCloser, error)
Saver provides an io.WriteCloser for writing a save file.
func (*BasicLoaderSaver) SaverFunc ¶
func (ls *BasicLoaderSaver) SaverFunc() Saver
SaverFunc returns the Saver function used.
type Loader ¶
type Loader func() (io.ReadCloser, error)
Loader is a function that returns a reader for a save file or database we want to safely read from.
type LoaderSaver ¶
type LoaderSaver interface {
Loader() (io.ReadCloser, error)
Saver() (io.WriteCloser, error)
LoaderFunc() Loader
SaverFunc() Saver
}
LoaderSaver is the interface that pairs a Loader with a Saver.
type Saver ¶
type Saver func() (io.WriteCloser, error)
Saver is a function that returns a writer to a save file or database we want to safely write to.
type TestingLoaderSaver ¶
type TestingLoaderSaver struct {
BasicLoaderSaver
// contains filtered or unexported fields
}
TestingLoaderSaver provides an in-memory loader and saver for testing.
func NewTestingLoaderSaver ¶
func NewTestingLoaderSaver() *TestingLoaderSaver
NewTestingLoaderSaver returns a new, blank TestingLoaderSaver.
func (*TestingLoaderSaver) Buffers ¶ added in v0.1.0
func (t *TestingLoaderSaver) Buffers() []*bytes.Buffer
Buffers returns each buffer written by the saver in the order it occurred.
func (*TestingLoaderSaver) CurrentReader ¶ added in v0.1.1
func (t *TestingLoaderSaver) CurrentReader() int
CurrentReader returns the index of the current reader and can be used as the key into ReadersClosed to determine which was or was not closed.
func (*TestingLoaderSaver) CurrentWriter ¶ added in v0.1.1
func (t *TestingLoaderSaver) CurrentWriter() int
CurrentWriter returns the index of the current writer and can be used as the key into WritersClosed to determine which was or was not closed.
func (*TestingLoaderSaver) ReadersClosed ¶ added in v0.1.1
func (t *TestingLoaderSaver) ReadersClosed() []bool
ReadersClosed returns a slice of booleans indicating whether each reader created was closed.
func (*TestingLoaderSaver) WritersClosed ¶ added in v0.1.1
func (t *TestingLoaderSaver) WritersClosed() []bool
WritersClosed returns a slice of booleans indicating whether each writer created was closed.
type TestingReader ¶
type TestingReader struct {
*bytes.Reader // the in-memory reader
Closed bool // whether the reader has been closed
}
TestingReader provides an in-memory reader for testing.
func (*TestingReader) Close ¶
func (t *TestingReader) Close() error
Close marks the reader as closed.
type TestingWriter ¶
type TestingWriter struct {
*bytes.Buffer // the in-memory writer
Closed bool // whether the writer has been closed
// contains filtered or unexported fields
}
TestingWriter provides an in-memory writer for testing.
func (*TestingWriter) Close ¶
func (t *TestingWriter) Close() error
Close marks the writer as closed.
Source Files