class CouchDB::LocalReplica

• CouchDB::LocalReplica
• CouchDB::Database
• Reference
• Object

Overview

A Database backed by a local SQLite file that continuously syncs with a remote CouchDB in both directions. All reads operate on the local store for low latency and offline capability.

Checkpoints are stored on the remote adapter only (_local/ documents), so the local file can be deleted and recreated without losing sync progress.

Two write modes are available:

• local (default): #put/#remove write to local SQLite; background fibers push changes to the remote and pull remote changes down.
• upstream: #put/#remove write to the remote and block until the change has been replicated to local (via the pull fiber). Reads always come from local.

Use Database.local_replica to create instances.

db = CouchDB::Database.local_replica("notes.db",
  "https://user:pass@mycouch.example.com/notes")
db.on_sync_error { |dir, ex| Log.error { "#{dir}: #{ex.message}" } }
db.put(note)     # writes locally; background push syncs to remote
db.get("note-1") # reads from local
db.close         # stops sync fibers, closes both adapters

Defined in:

Constant Summary

SYNC_INITIAL_BACKOFF = 1.second

SYNC_MAX_BACKOFF = 60.seconds

UPSTREAM_WAIT_INTERVAL = 10.milliseconds

UPSTREAM_WAIT_TIMEOUT = 5000.milliseconds

Instance Method Summary

• #close

  Stops background sync fibers and closes both the local and remote adapters.

• #on_sync_error(&block : String, Exception -> Nil)

  Registers a block called when a background sync run fails.

• #put(doc : Document) : NamedTuple(ok: Bool, id: String, rev: String)

  In upstream mode: writes to the remote and blocks until the change has replicated to local.

• #remove(id : String, rev : String) : NamedTuple(ok: Bool)

  In upstream mode: removes on the remote and blocks until the tombstone has replicated to local.

Instance Method Detail