From 7106d5a6e7585dce5fdd552cca30063dd352dc23 Mon Sep 17 00:00:00 2001 From: René 'Necoro' Neumann Date: Mon, 22 Feb 2021 22:54:43 +0100 Subject: Split cache and feed packages --- internal/feed/cache/cache.go | 179 ++++++++++++++++++++++ internal/feed/cache/cache_v1.go | 323 ++++++++++++++++++++++++++++++++++++++++ internal/feed/cache/state.go | 146 ++++++++++++++++++ 3 files changed, 648 insertions(+) create mode 100644 internal/feed/cache/cache.go create mode 100644 internal/feed/cache/cache_v1.go create mode 100644 internal/feed/cache/state.go (limited to 'internal/feed/cache') diff --git a/internal/feed/cache/cache.go b/internal/feed/cache/cache.go new file mode 100644 index 0000000..e7fe673 --- /dev/null +++ b/internal/feed/cache/cache.go @@ -0,0 +1,179 @@ +package cache + +import ( + "bufio" + "encoding/gob" + "errors" + "fmt" + "os" + "path/filepath" + "time" + + "github.com/nightlyone/lockfile" + + "github.com/Necoro/feed2imap-go/internal/feed" + "github.com/Necoro/feed2imap-go/pkg/log" +) + +type Version byte + +const ( + currentVersion Version = 1 +) + +type Impl interface { + cachedFeed(*feed.Feed) CachedFeed + transformToCurrent() (Impl, error) + Version() Version + Info() string + SpecificInfo(interface{}) string +} + +type Cache struct { + Impl + lock lockfile.Lockfile + locked bool +} + +type CachedFeed interface { + // Checked marks the feed as being a failure or a success on last check. + Checked(withFailure bool) + // Failures of this feed up to now. + Failures() int + // The Last time, this feed has been checked + Last() time.Time + // Filter the given items against the cached items. + Filter(items []feed.Item, ignoreHash bool, alwaysNew bool) []feed.Item + // Commit any changes done to the cache state. + Commit() + // The Feed, that is cached. + Feed() *feed.Feed +} + +func cacheForVersion(version Version) (Impl, error) { + switch version { + case v1Version: + return newV1Cache(), nil + default: + return nil, fmt.Errorf("unknown cache version '%d'", version) + } +} + +func lockName(fileName string) (string, error) { + return filepath.Abs(fileName + ".lck") +} + +func lock(fileName string) (lock lockfile.Lockfile, err error) { + var lockFile string + + if lockFile, err = lockName(fileName); err != nil { + return + } + log.Debugf("Handling lock file '%s'", lockFile) + + if lock, err = lockfile.New(lockFile); err != nil { + err = fmt.Errorf("Creating lock file: %w", err) + return + } + + if err = lock.TryLock(); err != nil { + err = fmt.Errorf("Locking cache: %w", err) + return + } + + return +} + +func (cache *Cache) store(fileName string) error { + if cache.Impl == nil { + return fmt.Errorf("trying to store nil cache") + } + if cache.Version() != currentVersion { + return fmt.Errorf("trying to store cache with unsupported version '%d' (current: '%d')", cache.Version(), currentVersion) + } + + f, err := os.Create(fileName) + if err != nil { + return fmt.Errorf("trying to store cache to '%s': %w", fileName, err) + } + defer f.Close() + + writer := bufio.NewWriter(f) + if err = writer.WriteByte(byte(currentVersion)); err != nil { + return fmt.Errorf("writing to '%s': %w", fileName, err) + } + + encoder := gob.NewEncoder(writer) + if err = encoder.Encode(cache.Impl); err != nil { + return fmt.Errorf("encoding cache: %w", err) + } + + writer.Flush() + log.Printf("Stored cache to '%s'.", fileName) + + return cache.Unlock() +} + +func (cache *Cache) Unlock() error { + if cache.locked { + if err := cache.lock.Unlock(); err != nil { + return fmt.Errorf("Unlocking cache: %w", err) + } + } + cache.locked = false + return nil +} + +func newCache() (Cache, error) { + cache, err := cacheForVersion(currentVersion) + if err != nil { + return Cache{}, err + } + return Cache{ + Impl: cache, + locked: false, + }, nil +} + +func LoadCache(fileName string) (Cache, error) { + f, err := os.Open(fileName) + if err != nil { + if errors.Is(err, os.ErrNotExist) { + // no cache there yet -- make new + return newCache() + } + return Cache{}, fmt.Errorf("opening cache at '%s': %w", fileName, err) + } + defer f.Close() + + lock, err := lock(fileName) + if err != nil { + return Cache{}, err + } + + log.Printf("Loading cache from '%s'", fileName) + + reader := bufio.NewReader(f) + version, err := reader.ReadByte() + if err != nil { + return Cache{}, fmt.Errorf("reading from '%s': %w", fileName, err) + } + + cache, err := cacheForVersion(Version(version)) + if err != nil { + return Cache{}, err + } + + decoder := gob.NewDecoder(reader) + if err = decoder.Decode(cache); err != nil { + return Cache{}, fmt.Errorf("decoding for version '%d' from '%s': %w", version, fileName, err) + } + + if cache, err = cache.transformToCurrent(); err != nil { + return Cache{}, fmt.Errorf("cannot transform from version %d to %d: %w", version, currentVersion, err) + } + + log.Printf("Loaded cache (version %d), transformed to version %d.", version, currentVersion) + + return Cache{cache, lock, true}, nil +} diff --git a/internal/feed/cache/cache_v1.go b/internal/feed/cache/cache_v1.go new file mode 100644 index 0000000..d754b00 --- /dev/null +++ b/internal/feed/cache/cache_v1.go @@ -0,0 +1,323 @@ +package cache + +import ( + "crypto/sha256" + "encoding/base64" + "encoding/hex" + "fmt" + "strconv" + "strings" + "time" + + "github.com/google/uuid" + + "github.com/Necoro/feed2imap-go/internal/feed" + "github.com/Necoro/feed2imap-go/pkg/log" + "github.com/Necoro/feed2imap-go/pkg/util" +) + +const ( + v1Version Version = 1 + startFeedId uint64 = 1 +) + +type feedId uint64 + +func (id feedId) String() string { + return strconv.FormatUint(uint64(id), 16) +} + +func idFromString(s string) feedId { + id, _ := strconv.ParseUint(s, 16, 64) + return feedId(id) +} + +type v1Cache struct { + Ids map[feed.Descriptor]feedId + NextId uint64 + Feeds map[feedId]*cachedFeed +} + +type cachedFeed struct { + feed *feed.Feed + id feedId // not saved, has to be set on loading + LastCheck time.Time + currentCheck time.Time + NumFailures int // can't be named `Failures` b/c it'll collide with the interface + Items []cachedItem + newItems []cachedItem +} + +type itemHash [sha256.Size]byte + +func (h itemHash) String() string { + return hex.EncodeToString(h[:]) +} + +type cachedItem struct { + Guid string + Title string + Link string + Date time.Time + UpdatedCache time.Time + Hash itemHash + ID uuid.UUID +} + +func (item cachedItem) String() string { + return fmt.Sprintf(`{ + ID: %s + Title: %q + Guid: %q + Link: %q + Date: %s + Hash: %s +}`, + base64.RawURLEncoding.EncodeToString(item.ID[:]), + item.Title, item.Guid, item.Link, util.TimeFormat(item.Date), item.Hash) +} + +func (cf *cachedFeed) Checked(withFailure bool) { + cf.currentCheck = time.Now() + if withFailure { + cf.NumFailures++ + } else { + cf.NumFailures = 0 + } +} + +func (cf *cachedFeed) Commit() { + if cf.newItems != nil { + cf.Items = cf.newItems + cf.newItems = nil + } + cf.LastCheck = cf.currentCheck +} + +func (cf *cachedFeed) Failures() int { + return cf.NumFailures +} + +func (cf *cachedFeed) Last() time.Time { + return cf.LastCheck +} + +func (cf *cachedFeed) Feed() *feed.Feed { + return cf.feed +} + +func (cache *v1Cache) Version() Version { + return v1Version +} + +func (cache *v1Cache) Info() string { + b := strings.Builder{} + for descr, id := range cache.Ids { + b.WriteString(fmt.Sprintf("%3s: %s (%s)\n", id.String(), descr.Name, descr.Url)) + } + return b.String() +} + +func (cache *v1Cache) SpecificInfo(i interface{}) string { + id := idFromString(i.(string)) + + b := strings.Builder{} + feed := cache.Feeds[id] + + for descr, fId := range cache.Ids { + if id == fId { + b.WriteString(descr.Name) + b.WriteString(" -- ") + b.WriteString(descr.Url) + b.WriteByte('\n') + break + } + } + + b.WriteString(fmt.Sprintf(` +Last Check: %s +Num Failures: %d +Num Items: %d +`, + util.TimeFormat(feed.LastCheck), + feed.NumFailures, + len(feed.Items))) + + for _, item := range feed.Items { + b.WriteString("\n--------------------\n") + b.WriteString(item.String()) + } + return b.String() +} + +func newV1Cache() *v1Cache { + cache := v1Cache{ + Ids: map[feed.Descriptor]feedId{}, + Feeds: map[feedId]*cachedFeed{}, + NextId: startFeedId, + } + return &cache +} + +func (cache *v1Cache) transformToCurrent() (Impl, error) { + return cache, nil +} + +func (cache *v1Cache) getItem(id feedId) *cachedFeed { + feed, ok := cache.Feeds[id] + if !ok { + feed = &cachedFeed{} + cache.Feeds[id] = feed + } + feed.id = id + return feed +} + +func (cache *v1Cache) cachedFeed(f *feed.Feed) CachedFeed { + fDescr := f.Descriptor() + id, ok := cache.Ids[fDescr] + if !ok { + var otherId feed.Descriptor + changed := false + for otherId, id = range cache.Ids { + if otherId.Name == fDescr.Name { + log.Warnf("Feed %s seems to have changed URLs: new '%s', old '%s'. Updating.", + fDescr.Name, fDescr.Url, otherId.Url) + changed = true + break + } else if otherId.Url == fDescr.Url { + log.Warnf("Feed with URL '%s' seems to have changed its name: new '%s', old '%s'. Updating.", + fDescr.Url, fDescr.Name, otherId.Name) + changed = true + break + } + } + if changed { + delete(cache.Ids, otherId) + } else { + id = feedId(cache.NextId) + cache.NextId++ + } + + cache.Ids[fDescr] = id + } + + cf := cache.getItem(id) + cf.feed = f + f.SetExtID(id) + return cf +} + +func newCachedItem(item *feed.Item) cachedItem { + var ci cachedItem + + ci.ID = item.ID + ci.Title = item.Item.Title + ci.Link = item.Item.Link + if item.DateParsed() != nil { + ci.Date = *item.DateParsed() + } + ci.Guid = item.Item.GUID + + contentByte := []byte(item.Item.Description + item.Item.Content) + ci.Hash = sha256.Sum256(contentByte) + + return ci +} + +func (item *cachedItem) similarTo(other *cachedItem, ignoreHash bool) bool { + return other.Title == item.Title && + other.Link == item.Link && + other.Date.Equal(item.Date) && + (ignoreHash || other.Hash == item.Hash) +} + +func (cf *cachedFeed) deleteItem(index int) { + copy(cf.Items[index:], cf.Items[index+1:]) + cf.Items[len(cf.Items)-1] = cachedItem{} + cf.Items = cf.Items[:len(cf.Items)-1] +} + +func (cf *cachedFeed) Filter(items []feed.Item, ignoreHash, alwaysNew bool) []feed.Item { + if len(items) == 0 { + return items + } + + cacheItems := make(map[cachedItem]*feed.Item, len(items)) + for idx := range items { + // remove complete duplicates on the go + cacheItems[newCachedItem(&items[idx])] = &items[idx] + } + log.Debugf("%d items after deduplication", len(cacheItems)) + + filtered := make([]feed.Item, 0, len(items)) + cacheadd := make([]cachedItem, 0, len(items)) + app := func(item *feed.Item, ci cachedItem, oldIdx *int) { + if oldIdx != nil { + item.UpdateOnly = true + prevId := cf.Items[*oldIdx].ID + ci.ID = prevId + item.ID = prevId + log.Debugf("oldIdx: %d, prevId: %s, item.id: %s", *oldIdx, prevId, item.Id()) + cf.deleteItem(*oldIdx) + } + filtered = append(filtered, *item) + cacheadd = append(cacheadd, ci) + } + +CACHE_ITEMS: + for ci, item := range cacheItems { + log.Debugf("Now checking %s", ci) + + if ci.Guid != "" { + for idx, oldItem := range cf.Items { + if oldItem.Guid == ci.Guid { + log.Debugf("Guid matches with: %s", oldItem) + if !oldItem.similarTo(&ci, ignoreHash) { + item.AddReason("guid (upd)") + app(item, ci, &idx) + } else { + log.Debugf("Similar, ignoring item %s", base64.RawURLEncoding.EncodeToString(oldItem.ID[:])) + } + + continue CACHE_ITEMS + } + } + + log.Debug("Found no matching GUID, including.") + item.AddReason("guid") + app(item, ci, nil) + continue + } + + for idx, oldItem := range cf.Items { + if oldItem.similarTo(&ci, ignoreHash) { + log.Debugf("Similarity matches, ignoring: %s", oldItem) + continue CACHE_ITEMS + } + + if oldItem.Link == ci.Link { + if alwaysNew { + log.Debugf("Link matches, but `always-new`.") + item.AddReason("always-new") + continue + } + log.Debugf("Link matches, updating: %s", oldItem) + item.AddReason("link (upd)") + app(item, ci, &idx) + + continue CACHE_ITEMS + } + } + + log.Debugf("No match found, inserting.") + item.AddReason("new") + app(item, ci, nil) + } + + log.Debugf("%d items after filtering", len(filtered)) + + cf.newItems = append(cacheadd, cf.Items...) + + return filtered +} diff --git a/internal/feed/cache/state.go b/internal/feed/cache/state.go new file mode 100644 index 0000000..c2e7de8 --- /dev/null +++ b/internal/feed/cache/state.go @@ -0,0 +1,146 @@ +package cache + +import ( + "sync" + + "github.com/Necoro/feed2imap-go/internal/feed" + "github.com/Necoro/feed2imap-go/pkg/config" + "github.com/Necoro/feed2imap-go/pkg/log" +) + +type State struct { + feeds map[string]*feed.Feed + cachedFeeds map[string]CachedFeed + cache Cache + cfg *config.Config +} + +func (state *State) Foreach(f func(CachedFeed)) { + for _, feed := range state.cachedFeeds { + f(feed) + } +} + +func (state *State) ForeachGo(goFunc func(CachedFeed)) { + var wg sync.WaitGroup + wg.Add(len(state.feeds)) + + f := func(feed CachedFeed, wg *sync.WaitGroup) { + goFunc(feed) + wg.Done() + } + + for _, feed := range state.cachedFeeds { + go f(feed, &wg) + } + wg.Wait() +} + +func (state *State) LoadCache(fileName string, forceNew bool) error { + var ( + cache Cache + err error + ) + + if forceNew { + cache, err = newCache() + } else { + cache, err = LoadCache(fileName) + } + + if err != nil { + return err + } + state.cache = cache + + for name, feed := range state.feeds { + state.cachedFeeds[name] = cache.cachedFeed(feed) + } + + // state.feeds should not be used after loading the cache --> enforce a panic + state.feeds = nil + + return nil +} + +func (state *State) StoreCache(fileName string) error { + return state.cache.store(fileName) +} + +func (state *State) UnlockCache() { + _ = state.cache.Unlock() +} + +func (state *State) Fetch() int { + state.ForeachGo(handleFeed) + + ctr := 0 + for _, cf := range state.cachedFeeds { + success := cf.Feed().FetchSuccessful() + cf.Checked(!success) + + if success { + ctr++ + } + } + + return ctr +} + +func handleFeed(cf CachedFeed) { + feed := cf.Feed() + log.Printf("Fetching %s from %s", feed.Name, feed.Url) + + err := feed.Parse() + if err != nil { + if feed.Url == "" || cf.Failures() >= feed.Global.MaxFailures { + log.Error(err) + } else { + log.Print(err) + } + } +} + +func filterFeed(cf CachedFeed) { + cf.Feed().Filter(cf.Filter) +} + +func (state *State) Filter() { + if log.IsDebug() { + // single threaded for better output + state.Foreach(filterFeed) + } else { + state.ForeachGo(filterFeed) + } +} + +func NewState(cfg *config.Config) (*State, error) { + state := State{ + feeds: map[string]*feed.Feed{}, + cachedFeeds: map[string]CachedFeed{}, + cache: Cache{}, // loaded later on + cfg: cfg, + } + + for name, parsedFeed := range cfg.Feeds { + feed, err := feed.Create(parsedFeed, cfg.GlobalOptions) + if err != nil { + return nil, err + } + state.feeds[name] = feed + } + + return &state, nil +} + +func (state *State) RemoveUndue() { + for name, feed := range state.cachedFeeds { + if feed.Feed().Disable || !feed.Feed().NeedsUpdate(feed.Last()) { + delete(state.cachedFeeds, name) + } + } +} + +func (state *State) NumFeeds() int { + return len(state.cachedFeeds) +} -- cgit v1.2.3-70-g09d2