loglist_manager.go

Documentation: github.com/google/certificate-transparency-go/submission

     1  // Copyright 2019 Google LLC. All Rights Reserved.
     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 submission
    16  
    17  import (
    18  	"context"
    19  	"fmt"
    20  	"sync"
    21  	"time"
    22  
    23  	"github.com/google/certificate-transparency-go/schedule"
    24  	"github.com/google/trillian/monitoring"
    25  )
    26  
    27  var (
    28  	logRefOnce         sync.Once
    29  	logListLastRefresh monitoring.Gauge // Unix time
    30  )
    31  
    32  // logRefInitMetrics initializes all the exported metrics.
    33  func logRefInitMetrics(ctx context.Context, mf monitoring.MetricFactory) {
    34  	logListLastRefresh = mf.NewGauge("log_list_last_refresh", "Unix timestamp for last successful Log-list refresh")
    35  }
    36  
    37  // LogListManager runs loglist updates and keeps two latest versions of Log
    38  // list.
    39  type LogListManager struct {
    40  	Errors    chan error
    41  	LLUpdates chan LogListData
    42  
    43  	llRefreshInterval time.Duration
    44  
    45  	llr        LogListRefresher
    46  	latestLL   *LogListData
    47  	previousLL *LogListData
    48  	mu         sync.Mutex // guards latestLL and previousLL
    49  
    50  	mtf monitoring.MetricFactory
    51  }
    52  
    53  // NewLogListManager creates and inits a LogListManager instance.
    54  func NewLogListManager(llr LogListRefresher, mf monitoring.MetricFactory) *LogListManager {
    55  	if mf == nil {
    56  		mf = monitoring.InertMetricFactory{}
    57  	}
    58  	return &LogListManager{
    59  		Errors:    make(chan error, 1),
    60  		LLUpdates: make(chan LogListData, 1),
    61  		llr:       llr,
    62  		mtf:       mf,
    63  	}
    64  }
    65  
    66  // Run starts regular LogList checks and associated versions archiving.
    67  // Emits errors and Loglist-updates into its corresponding channels, expected
    68  // to have readers listening.
    69  func (llm *LogListManager) Run(ctx context.Context, llRefresh time.Duration) {
    70  	llm.llRefreshInterval = llRefresh
    71  	logRefOnce.Do(func() { logRefInitMetrics(ctx, llm.mtf) })
    72  	go schedule.Every(ctx, llm.llRefreshInterval, llm.refreshLogListAndNotify)
    73  }
    74  
    75  // refreshLogListAndNotify runs single Log-list refresh and propagates data and
    76  // errors to corresponding channels
    77  func (llm *LogListManager) refreshLogListAndNotify(ctx context.Context) {
    78  	if lld, err := llm.RefreshLogList(ctx); err != nil {
    79  		llm.Errors <- err
    80  	} else if lld != nil {
    81  		llm.LLUpdates <- llm.ProduceClientLogList()
    82  	}
    83  }
    84  
    85  // GetTwoLatestLogLists returns last version of Log list and a previous one.
    86  func (llm *LogListManager) GetTwoLatestLogLists() (*LogListData, *LogListData) {
    87  	llm.mu.Lock()
    88  	defer llm.mu.Unlock()
    89  	return llm.latestLL, llm.previousLL
    90  }
    91  
    92  // RefreshLogList reads Log List one time and runs updates if necessary.
    93  func (llm *LogListManager) RefreshLogList(ctx context.Context) (*LogListData, error) {
    94  	if llm.llr == nil {
    95  		return nil, fmt.Errorf("the LogListManager has no LogListRefresher")
    96  	}
    97  	ll, err := llm.llr.Refresh()
    98  	if err != nil {
    99  		return nil, err
   100  	}
   101  	logListLastRefresh.Set(float64(time.Now().Unix()))
   102  	if ll == nil {
   103  		// No updates
   104  		return nil, nil
   105  	}
   106  	llm.mu.Lock()
   107  	defer llm.mu.Unlock()
   108  	llm.previousLL = llm.latestLL
   109  	llm.latestLL = ll
   110  	return llm.latestLL, nil
   111  }
   112  
   113  // ProduceClientLogList applies client filtration on Log list.
   114  func (llm *LogListManager) ProduceClientLogList() LogListData {
   115  	// TODO(Mercurrent): Add filtration
   116  	clientLL := *(llm.latestLL)
   117  	return clientLL
   118  }
   119  
   120  // Source exposes internal Log list path.
   121  func (llm *LogListManager) Source() string {
   122  	return llm.llr.Source()
   123  }
   124  
   125  // LastJSON returns last version of Log list in JSON.
   126  func (llm *LogListManager) LastJSON() []byte {
   127  	return llm.llr.LastJSON()
   128  }
   129
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