Documentation
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Overview ¶
Package backend is for authors of thread.Storage backends: it resolves the open options an application passes — thread.Salvage, thread.FsyncOnFlush, thread.NoLock, thread.OpenLogger — into the configuration a backend acts on. Applications never import it; they pass thread's options to a backend's Open, and every backend accepts the same vocabulary because every backend resolves it here.
A backend's Open looks like jsonl's:
func Open(dir string, opts ...thread.OpenOption) (thread.Storage, error) {
cfg := backend.Resolve(opts...)
...
}
(jsonl and sqlite import the package under another name: each already calls its own Storage type backend.)
An option a backend has no use for is accepted and documented as a no-op there, never rejected: sqlite commits every append, so the fsync cadence means nothing to it. The conformance table a backend must pass is thread/threadtest's.
Index ¶
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Config ¶
type Config struct {
// Salvage downgrades a malformed line from a load failure
// (thread.ErrCorrupt) to a skip reported in the LoadReport. The
// unknown and the newer stay loud: thread.ErrNewerFormat is never
// salvaged.
Salvage bool
// SyncEveryAppend is the durability cadence: true (the default)
// fsyncs every Append before it returns; false defers the fsync to
// the thread.Flusher capability — the turn-end cadence a Session
// drives.
SyncEveryAppend bool
// NoLock turns off the backend's cross-process writer lock
// (thread.NoLock): the caller vouches that one process writes.
NoLock bool
// Logger receives the backend's own reports — a repaired torn
// tail, a taken-over lock. Never nil: the default is
// slog.Default(), read at open.
Logger *slog.Logger
}
Config is the resolved configuration of an open: the defaults with every option applied. Resolve returns it; a backend reads it once, at open.
func Resolve ¶
func Resolve(opts ...thread.OpenOption) Config
Resolve folds opts over the defaults — every append fsynced, the lock on, no salvage, slog.Default() — in the order given; a nil option is skipped.
Source Files