Started LDAP support

sso-proxy/backend/interface.go

@@ -0,0 +1,28 @@
+package backend
+
+import "time"
+
+// Session holds info about the logged-in user that won't change
+type Session struct {
+	SessionID  string
+	Expiration time.Time
+	UserID     string
+	LdapDN     string
+}
+
+// SessionCache holds volatile information about the logged-in user
+type SessionCache struct {
+	Valid       bool
+	Groups      []string
+	DisplayName string
+	Email       string
+}
+
+type Backend interface {
+	PutSession(session Session, cache SessionCache) error
+	GetSession(id string) (Session, *SessionCache, error)
+	EndSession(id string)
+	NewSessionID() (string, error)
+	DoMaintenance()
+	Ping() error
+}