mirror of
https://github.com/gravitational/teleport.git
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Hugo Shaka
54ede1e11c
* Move automaticupgrades packages in `lib/automaticupgrades` * Fix `kube-agent-udpater` Dockerfile
69 lines
2.1 KiB
Go
69 lines
2.1 KiB
Go
/*
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* Teleport
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* Copyright (C) 2023 Gravitational, Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package cache
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import (
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"context"
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"sync"
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"time"
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"github.com/gravitational/trace"
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"github.com/jonboulle/clockwork"
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)
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// TimedMemoize wraps a function returning (value, error) and caches the
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// value AND the error for a specific time. This cache is mainly used to ensure
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// external calls rates are reasonable. The cache is thread-safe.
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type TimedMemoize[T any] struct {
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clock clockwork.Clock
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mutex sync.Mutex
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cachedValue T
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cachedError error
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validUntil time.Time
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cacheDuration time.Duration
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getter func(ctx context.Context) (T, error)
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}
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// Get does a cache lookup and updates the cache in case of cache miss.
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func (c *TimedMemoize[T]) Get(ctx context.Context) (T, error) {
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c.mutex.Lock()
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defer c.mutex.Unlock()
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if c.validUntil.After(c.clock.Now()) {
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// TimedMemoize hit, we return cached result
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return c.cachedValue, trace.Wrap(c.cachedError)
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}
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// Cache miss, we do a query and update the cache
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value, err := c.getter(ctx)
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c.validUntil = c.clock.Now().Add(c.cacheDuration)
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c.cachedValue = value
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c.cachedError = newCachedError(err, c.validUntil)
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return value, trace.Wrap(err)
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}
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// NewTimedMemoize builds and returns a TimedMemoize
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func NewTimedMemoize[T any](getter func(ctx context.Context) (T, error), duration time.Duration) *TimedMemoize[T] {
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return &TimedMemoize[T]{
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clock: clockwork.NewRealClock(),
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getter: getter,
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cacheDuration: duration,
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}
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}
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