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keygen.go
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keygen.go
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package keygen
import (
"errors"
)
type bufferEntry struct {
key Key
err error
}
// KeyGenerator fetches unique keys in batch from key generation service
// and buffer them in memory for fast response.
type KeyGenerator struct {
bufferSize int
buffer chan bufferEntry
keyFetcher KeyFetcher
}
// NewKey produces a unique key
func (r KeyGenerator) NewKey() (Key, error) {
if len(r.buffer) == 0 {
go func() {
r.fetchKeys()
}()
}
entry := <-r.buffer
return entry.key, entry.err
}
func (r KeyGenerator) fetchKeys() {
keys, err := r.keyFetcher.FetchKeys(r.bufferSize)
if err != nil {
r.buffer <- bufferEntry{
key: "",
err: err,
}
return
}
for _, key := range keys {
r.buffer <- bufferEntry{
key: key,
err: nil,
}
}
}
// NewKeyGenerator creates KeyGenerator
func NewKeyGenerator(bufferSize int, keyFetcher KeyFetcher) (KeyGenerator, error) {
if bufferSize < 1 {
return KeyGenerator{}, errors.New("buffer size can't be less than 1")
}
return KeyGenerator{
bufferSize: bufferSize,
buffer: make(chan bufferEntry, bufferSize),
keyFetcher: keyFetcher,
}, nil
}