caddy/caddytls/storage.go
Matthew Holt abdf13ea30 Improve TLS storage provider errors
We renamed caddytls.ErrStorageNotFound to caddytls.ErrNotExist to more
closely mirror the os package. We changed it to an interface wrapper
so that the custom error message can be preserved. Returning only "data
not found" was useless in debugging because we couldn't know the
concrete value of the error (like what it was trying to load).

Users can do a type assertion to determine if the error value is a "not
found" error instead of doing an equality check.
2016-09-08 18:50:04 -06:00

103 lines
4.4 KiB
Go

package caddytls
import "net/url"
// StorageCreator is a function type that is used in the Config to instantiate
// a new Storage instance. This function can return a nil Storage even without
// an error.
type StorageCreator func(caURL *url.URL) (Storage, error)
// SiteData contains persisted items pertaining to an individual site.
type SiteData struct {
// Cert is the public cert byte array.
Cert []byte
// Key is the private key byte array.
Key []byte
// Meta is metadata about the site used by Caddy.
Meta []byte
}
// UserData contains persisted items pertaining to a user.
type UserData struct {
// Reg is the user registration byte array.
Reg []byte
// Key is the user key byte array.
Key []byte
}
// Storage is an interface abstracting all storage used by Caddy's TLS
// subsystem. Implementations of this interface store both site and
// user data.
type Storage interface {
// SiteExists returns true if this site exists in storage.
// Site data is considered present when StoreSite has been called
// successfully (without DeleteSite having been called, of course).
SiteExists(domain string) (bool, error)
// LoadSite obtains the site data from storage for the given domain and
// returns it. If data for the domain does not exist, an error value
// of type ErrNotExist is returned. For multi-server storage, care
// should be taken to make this load atomic to prevent race conditions
// that happen with multiple data loads.
LoadSite(domain string) (*SiteData, error)
// StoreSite persists the given site data for the given domain in
// storage. For multi-server storage, care should be taken to make this
// call atomic to prevent half-written data on failure of an internal
// intermediate storage step. Implementers can trust that at runtime
// this function will only be invoked after LockRegister and before
// UnlockRegister of the same domain.
StoreSite(domain string, data *SiteData) error
// DeleteSite deletes the site for the given domain from storage.
// Multi-server implementations should attempt to make this atomic. If
// the site does not exist, an error value of type ErrNotExist is returned.
DeleteSite(domain string) error
// LockRegister is called before Caddy attempts to obtain or renew a
// certificate. This function is used as a mutex/semaphore for making
// sure something else isn't already attempting obtain/renew. It should
// return true (without error) if the lock is successfully obtained
// meaning nothing else is attempting renewal. It should return false
// (without error) if this domain is already locked by something else
// attempting renewal. As a general rule, if this isn't multi-server
// shared storage, this should always return true. To prevent deadlocks
// for multi-server storage, all internal implementations should put a
// reasonable expiration on this lock in case UnlockRegister is unable to
// be called due to system crash. Errors should only be returned in
// exceptional cases. Any error will prevent renewal.
LockRegister(domain string) (bool, error)
// UnlockRegister is called after Caddy has attempted to obtain or renew
// a certificate, regardless of whether it was successful. If
// LockRegister essentially just returns true because this is not
// multi-server storage, this can be a no-op. Otherwise this should
// attempt to unlock the lock obtained in this process by LockRegister.
// If no lock exists, the implementation should not return an error. An
// error is only for exceptional cases.
UnlockRegister(domain string) error
// LoadUser obtains user data from storage for the given email and
// returns it. If data for the email does not exist, an error value
// of type ErrNotExist is returned. Multi-server implementations
// should take care to make this operation atomic for all loaded
// data items.
LoadUser(email string) (*UserData, error)
// StoreUser persists the given user data for the given email in
// storage. Multi-server implementations should take care to make this
// operation atomic for all stored data items.
StoreUser(email string, data *UserData) error
// MostRecentUserEmail provides the most recently used email parameter
// in StoreUser. The result is an empty string if there are no
// persisted users in storage.
MostRecentUserEmail() string
// ErrNotExist is returned by Storage implementations when
// a resource is not found. It is similar to os.ErrNotExist
// except this is a type, not a variable.
type ErrNotExist interface {
error
}