WIP

pkg/servers/servers.go

@@ -0,0 +1,64 @@
+package servers
+
+import (
+	"sync"
+	"time"
+)
+
+// Servers contains a collection of servers to Postgres.
+type Servers struct {
+	m       sync.Mutex
+	servers map[string]*Server
+	opts    []ServerOpt
+}
+
+// NewServers creates a collection of servers to Postgres.
+func NewServers(opts ...ServerOpt) *Servers {
+	return &Servers{
+		servers: make(map[string]*Server),
+		opts:    opts,
+	}
+}
+
+// GetServer returns established connection from a collection.
+func (s *Servers) GetServer(dsn string) (*Server, error) {
+	s.m.Lock()
+	defer s.m.Unlock()
+	var err error
+	var ok bool
+	errCount := 0 // start at zero because we increment before doing work
+	retries := 3
+	var server *Server
+	for {
+		if errCount++; errCount > retries {
+			return nil, err
+		}
+		server, ok = s.servers[dsn]
+		if !ok {
+			server, err = NewServer(dsn, s.opts...)
+			if err != nil {
+				time.Sleep(time.Duration(errCount) * time.Second)
+				continue
+			}
+			s.servers[dsn] = server
+		}
+		if err = server.Ping(); err != nil {
+			delete(s.servers, dsn)
+			time.Sleep(time.Duration(errCount) * time.Second)
+			continue
+		}
+		break
+	}
+	return server, nil
+}
+
+// Close disconnects from all known servers.
+func (s *Servers) Close() {
+	s.m.Lock()
+	defer s.m.Unlock()
+	for _, server := range s.servers {
+		if err := server.Close(); err != nil {
+			log.Errorf("failed to close connection to %q: %v", server, err)
+		}
+	}
+}