allegro
Persistence
It would be great if bigcache had a feature where it could save it's state to disk so it could be restarted. I'm thinking there could be a storage interface which defined the API and then the initial implementation could be some base layout, like JSON or something.
type IStorage interface {
Prepare() error // lock the entire cache.
Save() (bool, error) // save the state to disk, return ok, error
Load() (bool, error) // load from wherever, return ok, error
}
This has come up a few times and it might be an interesting interface to explore.
How about changing the interface to
type IStorage interface {
Prepare() error // lock the entire cache.
Save(io.Writer) (bool, error) // save the state to disk, return ok, error
Load(io.Reader) (bool, error) // load from wherever, return ok, error
}
@neal-zhu yep, this is definitely better. I'm thinking do we need to path context too?
Using io.Writer makes us free to save our data anywhere we like(maybe local disk, or a remote node or main memory). So I think path context is unnecessary?
I'm totally open to modifications on it, when I wrote this it was to open discussion, so I'm not married to the final decision so much as it was to surface this is an interface we'd want to implement.
I do agree that we don't need a path context and the Reader/Writer implementation is more than enough for the initial use cases. Partially because then it allows for disk, streaming, or some other method.
locking entire cache during persistence might not be acceptable, can we use a child process just like redis?
type IStorage interface {
Save(string) chan error // fork a child process to dump entire cache
Load(string) (bool, error) // load from wherever, return ok, error
}
I think having both a full-lock and a no-lock option would be good, but I think a full-lock could also be achieved upstream, so I'm open to a first pass and seeing what the community says. :)