overlay/README.md

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# Overlay
[![Go Reference](https://pkg.go.dev/badge/go.jolheiser.com/overlay.svg)](https://pkg.go.dev/go.jolheiser.com/overlay)
Overlay File System
Overlay is an easy way to implement a file system in such a way that
production assets can be overridden by assets on disk.
## Usage
```go
package main
import (
"embed"
"go.jolheiser.com/overlay"
)
//go:embed assets
var assets embed.FS
func main() {
ofs, err := overlay.New("/var/lib/myapp/custom", assets)
if err != nil {
panic(err)
}
...
}
```
If `/var/lib/myapp/custom` has an `assets` sub-directory, this implementation works.
However, if `/var/lib/myapp/custom` matches the `assets` directory layout,
you can use `WithSub` like so...
```go
package main
import (
"embed"
"go.jolheiser.com/overlay"
)
//go:embed assets
var assets embed.FS
func main() {
ofs, err := overlay.New("/var/lib/myapp/custom", assets, overlay.WithSub("assets"))
if err != nil {
panic(err)
}
...
}
```
## License
[MIT](LICENSE)