mirror of https://github.com/hashicorp/consul
50 lines
1.7 KiB
Go
50 lines
1.7 KiB
Go
package cache
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import (
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"time"
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"golang.org/x/time/rate"
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"github.com/hashicorp/consul/lib/ttlcache"
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)
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// cacheEntry stores a single cache entry.
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//
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// Note that this isn't a very optimized structure currently. There are
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// a lot of improvements that can be made here in the long term.
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type cacheEntry struct {
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// Fields pertaining to the actual value
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Value interface{}
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// State can be used to store info needed by the cache type but that should
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// not be part of the result the client gets. For example the Connect Leaf
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// type needs to store additional data about when it last attempted a renewal
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// that is not part of the actual IssuedCert struct it returns. It's opaque to
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// the Cache but allows types to store additional data that is coupled to the
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// cache entry's lifetime and will be aged out by TTL etc.
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State interface{}
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Error error
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Index uint64
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// Metadata that is used for internal accounting
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Valid bool // True if the Value is set
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Fetching bool // True if a fetch is already active
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Waiter chan struct{} // Closed when this entry is invalidated
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// Expiry contains information about the expiration of this
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// entry. This is a pointer as its shared as a value in the
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// ExpiryHeap as well.
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Expiry *ttlcache.Entry
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// FetchedAt stores the time the cache entry was retrieved for determining
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// it's age later.
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FetchedAt time.Time
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// RefreshLostContact stores the time background refresh failed. It gets reset
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// to zero after a background fetch has returned successfully, or after a
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// background request has be blocking for at least 5 seconds, which ever
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// happens first.
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RefreshLostContact time.Time
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// FetchRateLimiter limits the rate at which fetch is called for this entry.
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FetchRateLimiter *rate.Limiter
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}
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