Glossary

Tenant. One customer or environment your application serves. Configured as a key in config.tenants with a :constants hash. See Configuration.

Tenant key. The Symbol or String naming a tenant (:acme). Lookup is an exact match, so validate! rejects keys that differ only by case or type.

Constants. A tenant's values: shard and partner_code (required), plus mongo_db, redis_db, elasticsearch_prefix and environment. An omitted backend constant resets that backend to its default.

Context class. Your application's class (for example an ActiveSupport::CurrentAttributes) that ConsoleKit writes tenant values onto, so application code sees the same tenant as the connections.

Context attribute. The writer on the context class a backend owns, such as tenant_shard. Each attribute belongs to exactly one backend.

Backend. A data store ConsoleKit switches: SQL, MongoDB, Redis or Elasticsearch, or one you add. See Backends.

Handler. The class that switches one backend, a subclass of BaseConnectionHandler. See Writing a Handler.

Backend key. A handler's unique name in the registry: :sql, :mongo, :redis, :elasticsearch.

Constants key. The constant a handler reads its target from, such as :shard for SQL.

Target. The value a handler is asked to switch to for the current tenant. nil means reset to the default.

Transactional switch. validate → prepare → snapshot → apply context → connect → verify → commit. The new tenant becomes current only at the commit. See Architecture.

Snapshot / undo bundle. What each handler and the context held before the switch, captured before anything changes, deep-frozen, and kept on the committed tenant state.

Rollback. Restoring the undo bundle after a failed switch: handlers in reverse order, then the context. Every component is attempted, and failures are collected into rollback_failures.

Unwind. The rollback with_tenant runs when its block exits, returning to the enclosing tenant.

Verification. After connecting, each handler reads its live state back and must report the target. A mismatch raises ConnectionVerificationError. This is a local read, not a network call.

Dropped backend. A registered handler skipped because it is broken or unavailable for a stated reason. It is never switched, verified or rolled back, and verify_tenant! reports it.

Isolation model. Whether a backend's switch is visible only to the current thread (:scoped) or to the whole process (:process_global). See Concurrency and Isolation.

Native path / fallback path. The SQL handler's two ways to switch: connecting_to a registered shard (per thread, no pool churn) or establish_connection (process-wide, replaces the pool).

Diagnostic identity. A value a handler reports so the dashboard knows when a cached :full row is stale.

Prefix registry. ElasticsearchPrefixRegistry: the process-wide index prefix plus a record of which prefix each live thread asked for, used to warn about conflicts.

TenantState / StateStore. The immutable record of the current tenant (key, constants, undo bundle), and the per-thread slot that holds it.