func()

in internal/vfs/zip/vfs.go [199:257]

• 38 lines of code
• 9 McCabe index (conditional complexity)

func (zfs *zipVFS) findOrCreateArchive(key string) (*zipArchive, error) {
	// This needs to happen in lock to ensure that
	// concurrent access will not remove it
	// it is needed due to the bug https://github.com/patrickmn/go-cache/issues/48
	zfs.cacheLock.Lock()
	defer zfs.cacheLock.Unlock()

	archive, expiry, found := zfs.cache.GetWithExpiration(key)
	if found {
		status, zipErr := archive.(*zipArchive).openStatus()
		switch status {
		case archiveOpening:
			metrics.ZipCacheRequests.WithLabelValues("archive", "hit-opening").Inc()

		case archiveOpenError:
			// this means that archive is likely corrupted
			// we keep it for duration of cache entry expiry (negative cache)
			metrics.ZipCacheRequests.WithLabelValues("archive", "hit-open-error").Inc()

		case archiveOpened:
			if time.Until(expiry) < zfs.cacheRefreshInterval {
				zfs.cache.SetDefault(key, archive)
				metrics.ZipCacheRequests.WithLabelValues("archive", "hit-refresh").Inc()
			} else {
				metrics.ZipCacheRequests.WithLabelValues("archive", "hit").Inc()
			}

		case archiveCorrupted:
			// this means that archive is likely changed
			// we should invalidate it immediately
			log.WithError(zipErr).WithFields(log.Fields{
				"archive_key": key,
			}).Error("archive corrupted")
			metrics.ZipCacheRequests.WithLabelValues("archive", "corrupted").Inc()
			archive = nil
		}
	}

	if archive == nil {
		archive = newArchive(zfs, zfs.openTimeout)

		// We call delete to ensure that expired item
		// is properly evicted as there's a bug in a cache library:
		// https://github.com/patrickmn/go-cache/issues/48
		zfs.cache.Delete(key)

		// if adding the archive to the cache fails it means it's already been added before
		// this is done to find concurrent additions.
		if zfs.cache.Add(key, archive, zfs.cacheExpirationInterval) != nil {
			metrics.ZipCacheRequests.WithLabelValues("archive", "already-cached").Inc()
			return nil, errAlreadyCached
		}

		metrics.ZipCacheRequests.WithLabelValues("archive", "miss").Inc()
		metrics.ZipCachedEntries.WithLabelValues("archive").Inc()
	}

	return archive.(*zipArchive), nil
}