Failure response @param envcdError of envcd error @param err of handler error @return *EnvcdResult.

Failure0 response @param envcdError of envcd error @return *EnvcdResult.

InternalFailure response @return *EnvcdResult.

InternalFailure0 response @return *EnvcdResult.

Success response @param data @return *EnvcdResult.

todo refactor etcd path and exchange path error.

EnvcdResult for response.