go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/cv/internal/gerrit/caching.go (about)

     1  // Copyright 2021 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package gerrit
    16  
    17  import (
    18  	"context"
    19  	"time"
    20  
    21  	"go.chromium.org/luci/common/data/caching/lru"
    22  )
    23  
    24  // CachingFactory caches clients produced by another Factory.
    25  func CachingFactory(lruSize int, f Factory) Factory {
    26  	return &cachingFactory{Factory: f, cache: lru.New[string, Client](lruSize)}
    27  }
    28  
    29  type cachingFactory struct {
    30  	Factory
    31  	cache *lru.Cache[string, Client]
    32  }
    33  
    34  // MakeClient implements Factory.
    35  func (c cachingFactory) MakeClient(ctx context.Context, gerritHost string, luciProject string) (Client, error) {
    36  	key := luciProject + "/" + gerritHost
    37  	client, err := c.cache.GetOrCreate(ctx, key, func() (value Client, ttl time.Duration, err error) {
    38  		// Default ttl of 0 means never expire. Note that specific authorization
    39  		// token is still loaded per each request (see transport() function).
    40  		value, err = c.Factory.MakeClient(ctx, gerritHost, luciProject)
    41  		return
    42  	})
    43  	if err != nil {
    44  		return nil, err
    45  	}
    46  	return client, nil
    47  }