mirror of https://github.com/status-im/consul.git
66 lines
2.6 KiB
Go
66 lines
2.6 KiB
Go
package cache
|
|
|
|
import (
|
|
"time"
|
|
)
|
|
|
|
// Request is a cacheable request.
|
|
//
|
|
// This interface is typically implemented by request structures in
|
|
// the agent/structs package.
|
|
type Request interface {
|
|
// CacheInfo returns information used for caching this request.
|
|
CacheInfo() RequestInfo
|
|
}
|
|
|
|
// RequestInfo represents cache information for a request. The caching
|
|
// framework uses this to control the behavior of caching and to determine
|
|
// cacheability.
|
|
type RequestInfo struct {
|
|
// Key is a unique cache key for this request. This key should
|
|
// be globally unique to identify this request, since any conflicting
|
|
// cache keys could result in invalid data being returned from the cache.
|
|
// The Key does not need to include ACL or DC information, since the
|
|
// cache already partitions by these values prior to using this key.
|
|
Key string
|
|
|
|
// Token is the ACL token associated with this request.
|
|
//
|
|
// Datacenter is the datacenter that the request is targeting.
|
|
//
|
|
// Both of these values are used to partition the cache. The cache framework
|
|
// today partitions data on these values to simplify behavior: by
|
|
// partitioning ACL tokens, the cache doesn't need to be smart about
|
|
// filtering results. By filtering datacenter results, the cache can
|
|
// service the multi-DC nature of Consul. This comes at the expense of
|
|
// working set size, but in general the effect is minimal.
|
|
Token string
|
|
Datacenter string
|
|
|
|
// MinIndex is the minimum index being queried. This is used to
|
|
// determine if we already have data satisfying the query or if we need
|
|
// to block until new data is available. If no index is available, the
|
|
// default value (zero) is acceptable.
|
|
MinIndex uint64
|
|
|
|
// Timeout is the timeout for waiting on a blocking query. When the
|
|
// timeout is reached, the last known value is returned (or maybe nil
|
|
// if there was no prior value). This "last known value" behavior matches
|
|
// normal Consul blocking queries.
|
|
Timeout time.Duration
|
|
|
|
// MaxAge if set limits how stale a cache entry can be. If it is non-zero and
|
|
// there is an entry in cache that is older than specified, it is treated as a
|
|
// cache miss and re-fetched. It is ignored for cachetypes with Refresh =
|
|
// true.
|
|
MaxAge time.Duration
|
|
|
|
// MustRevalidate forces a new lookup of the cache even if there is an
|
|
// existing one that has not expired. It is implied by HTTP requests with
|
|
// `Cache-Control: max-age=0` but we can't distinguish that case from the
|
|
// unset case for MaxAge. Later we may support revalidating the index without
|
|
// a full re-fetch but for now the only option is to refetch. It is ignored
|
|
// for cachetypes with Refresh = true.
|
|
MustRevalidate bool
|
|
}
|