The ShardSelector
Middleware
provides a framework for automatically swapping shards. Rails provides a basic framework to determine which shard to switch to and allows for applications to write custom strategies for swapping if needed.
The ShardSelector
takes a set of options (currently only `lock` is supported) that can be used by the middleware to alter behavior. `lock` is true by default and will prohibit the request from switching shards once inside the block. If `lock` is false, then shard swapping will be allowed. For tenant based sharding, `lock` should always be true to prevent application code from mistakenly switching between tenants.
Options can be set in the config:
config.active_record.shard_selector = { lock: true }
Applications must also provide the code for the resolver as it depends on application specific models. An example resolver would look like this:
config.active_record.shard_resolver = ->(request) {
subdomain = request.subdomain
tenant = Tenant.find_by_subdomain!(subdomain)
tenant.shard
}
Attributes
[R] | options | |
[R] | resolver |