diff options
Diffstat (limited to 'internal/store/store.go')
| -rw-r--r-- | internal/store/store.go | 69 |
1 files changed, 33 insertions, 36 deletions
diff --git a/internal/store/store.go b/internal/store/store.go index 942eeef5..3e8367e8 100644 --- a/internal/store/store.go +++ b/internal/store/store.go @@ -1,3 +1,4 @@ +// Package store implements cross-process state tracking for hakurei container instances. package store import ( @@ -14,16 +15,16 @@ import ( "hakurei.app/internal/lockedfile" ) -// storeMutexName is the pathname of the file backing [lockedfile.Mutex] of a stateStore and storeHandle. -const storeMutexName = "lock" +// MutexName is the pathname of the file backing [lockedfile.Mutex] of a [Store] and [Handle]. +const MutexName = "lock" -// A stateStore keeps track of [hst.State] via a well-known filesystem accessible to all hakurei priv-side processes. -// Access to store data and related resources are synchronised on a per-segment basis via storeHandle. -type stateStore struct { +// A Store keeps track of [hst.State] via a well-known filesystem accessible to all hakurei priv-side processes. +// Access to store data and related resources are synchronised on a per-segment basis via [Handle]. +type Store struct { // Pathname of directory that the store is rooted in. base *check.Absolute - // All currently known instances of storeHandle, keyed by their identity. + // All currently known instances of Handle, keyed by their identity. handles sync.Map // Inter-process mutex to synchronise operations against the entire store. @@ -37,9 +38,9 @@ type stateStore struct { mkdirErr error } -// bigLock acquires fileMu on stateStore. +// bigLock acquires fileMu on [Store]. // A non-nil error returned by bigLock is of type [hst.AppError]. -func (s *stateStore) bigLock() (unlock func(), err error) { +func (s *Store) bigLock() (unlock func(), err error) { s.mkdirOnce.Do(func() { s.mkdirErr = os.MkdirAll(s.base.String(), 0700) }) if s.mkdirErr != nil { return nil, &hst.AppError{Step: "create state store directory", Err: s.mkdirErr} @@ -51,14 +52,14 @@ func (s *stateStore) bigLock() (unlock func(), err error) { return } -// identityHandle loads or initialises a storeHandle for identity. -// A non-nil error returned by identityHandle is of type [hst.AppError]. -func (s *stateStore) identityHandle(identity int) (*storeHandle, error) { - h := new(storeHandle) +// Handle loads or initialises a [Handle] for identity. +// A non-nil error returned by Handle is of type [hst.AppError]. +func (s *Store) Handle(identity int) (*Handle, error) { + h := newHandle(s.base, identity) h.mu.Lock() if v, ok := s.handles.LoadOrStore(identity, h); ok { - h = v.(*storeHandle) + h = v.(*Handle) } else { // acquire big lock to initialise previously unknown segment handle if unlock, err := s.bigLock(); err != nil { @@ -67,11 +68,7 @@ func (s *stateStore) identityHandle(identity int) (*storeHandle, error) { defer unlock() } - h.identity = identity - h.path = s.base.Append(strconv.Itoa(identity)) - h.fileMu = lockedfile.MutexAt(h.path.Append(storeMutexName).String()) - - err := os.MkdirAll(h.path.String(), 0700) + err := os.MkdirAll(h.Path.String(), 0700) h.mu.Unlock() if err != nil && !errors.Is(err, fs.ErrExist) { // handle methods will likely return ENOENT @@ -82,18 +79,18 @@ func (s *stateStore) identityHandle(identity int) (*storeHandle, error) { return h, nil } -// segmentIdentity is produced by the iterator returned by stateStore.segments. -type segmentIdentity struct { +// SegmentIdentity is produced by the iterator returned by [Store.Segments]. +type SegmentIdentity struct { // Identity of the current segment. - identity int + Identity int // Error encountered while processing this segment. - err error + Err error } -// segments returns an iterator over all segmentIdentity known to the store. -// To obtain a storeHandle on a segment, caller must then call identityHandle. +// Segments returns an iterator over all [SegmentIdentity] known to the [Store]. +// To obtain a [Handle] on a segment, caller must then call [Store.Handle]. // A non-nil error returned by segments is of type [hst.AppError]. -func (s *stateStore) segments() (iter.Seq[segmentIdentity], int, error) { +func (s *Store) Segments() (iter.Seq[SegmentIdentity], int, error) { // read directory contents, should only contain storeMutexName and identity var entries []os.DirEntry @@ -115,36 +112,36 @@ func (s *stateStore) segments() (iter.Seq[segmentIdentity], int, error) { l-- } - return func(yield func(segmentIdentity) bool) { + return func(yield func(SegmentIdentity) bool) { // for error reporting const step = "process store segment" for _, ent := range entries { - si := segmentIdentity{identity: -1} + si := SegmentIdentity{Identity: -1} // should only be the big lock if !ent.IsDir() { - if ent.Name() == storeMutexName { + if ent.Name() == MutexName { continue } // this should never happen - si.err = &hst.AppError{Step: step, Err: syscall.EISDIR, + si.Err = &hst.AppError{Step: step, Err: syscall.EISDIR, Msg: "skipped non-directory entry " + strconv.Quote(ent.Name())} goto out } // failure paths either indicates a serious bug or external interference if v, err := strconv.Atoi(ent.Name()); err != nil { - si.err = &hst.AppError{Step: step, Err: err, + si.Err = &hst.AppError{Step: step, Err: err, Msg: "skipped non-identity entry " + strconv.Quote(ent.Name())} goto out } else if v < hst.IdentityMin || v > hst.IdentityMax { - si.err = &hst.AppError{Step: step, Err: syscall.ERANGE, + si.Err = &hst.AppError{Step: step, Err: syscall.ERANGE, Msg: "skipped out of bounds entry " + strconv.Itoa(v)} goto out } else { - si.identity = v + si.Identity = v } out: @@ -155,8 +152,8 @@ func (s *stateStore) segments() (iter.Seq[segmentIdentity], int, error) { }, l, nil } -// newStore returns the address of a new instance of stateStore. -// Multiple instances of stateStore rooted in the same directory is supported, but discouraged. -func newStore(base *check.Absolute) *stateStore { - return &stateStore{base: base, fileMu: lockedfile.MutexAt(base.Append(storeMutexName).String())} +// New returns the address of a new instance of [Store]. +// Multiple instances of [Store] rooted in the same directory is possible, but unsupported. +func New(base *check.Absolute) *Store { + return &Store{base: base, fileMu: lockedfile.MutexAt(base.Append(MutexName).String())} } |
