// +build kvdb_etcd package etcd import ( "fmt" "net" "net/url" "sync/atomic" "time" "go.etcd.io/etcd/embed" ) const ( // readyTimeout is the time until the embedded etcd instance should start. readyTimeout = 10 * time.Second // defaultEtcdPort is the start of the range for listening ports of // embedded etcd servers. Ports are monotonically increasing starting // from this number and are determined by the results of getFreePort(). defaultEtcdPort = 2379 // defaultNamespace is the namespace we'll use in our embedded etcd // instance. Since it is only used for testing, we'll use the namespace // name "test/" for this. Note that the namespace can be any string, // the trailing / is not required. defaultNamespace = "test/" ) var ( // lastPort is the last port determined to be free for use by a new // embedded etcd server. It should be used atomically. lastPort uint32 = defaultEtcdPort ) // getFreePort returns the first port that is available for listening by a new // embedded etcd server. It panics if no port is found and the maximum available // TCP port is reached. func getFreePort() int { port := atomic.AddUint32(&lastPort, 1) for port < 65535 { // If there are no errors while attempting to listen on this // port, close the socket and return it as available. addr := fmt.Sprintf("127.0.0.1:%d", port) l, err := net.Listen("tcp4", addr) if err == nil { err := l.Close() if err == nil { return int(port) } } port = atomic.AddUint32(&lastPort, 1) } // No ports available? Must be a mistake. panic("no ports available for listening") } // NewEmbeddedEtcdInstance creates an embedded etcd instance for testing, // listening on random open ports. Returns the backend config and a cleanup // func that will stop the etcd instance. func NewEmbeddedEtcdInstance(path string, clientPort, peerPort uint16) ( *Config, func(), error) { cfg := embed.NewConfig() cfg.Dir = path // To ensure that we can submit large transactions. cfg.MaxTxnOps = 8192 cfg.MaxRequestBytes = 16384 * 1024 // Listen on random free ports if no ports were specified. if clientPort == 0 { clientPort = uint16(getFreePort()) } if peerPort == 0 { peerPort = uint16(getFreePort()) } clientURL := fmt.Sprintf("127.0.0.1:%d", clientPort) peerURL := fmt.Sprintf("127.0.0.1:%d", peerPort) cfg.LCUrls = []url.URL{{Host: clientURL}} cfg.LPUrls = []url.URL{{Host: peerURL}} etcd, err := embed.StartEtcd(cfg) if err != nil { return nil, nil, err } select { case <-etcd.Server.ReadyNotify(): case <-time.After(readyTimeout): etcd.Close() return nil, nil, fmt.Errorf("etcd failed to start after: %v", readyTimeout) } connConfig := &Config{ Host: "http://" + clientURL, InsecureSkipVerify: true, Namespace: defaultNamespace, } return connConfig, func() { etcd.Close() }, nil }