* flag: improve StringFlags by support set default value when init
when init flagSet, set default value should be moved to StringFlags init
func, which is more friendly
personal proposal
* flag: code improved for StringFlags
These legacy flags support are here only because we do not want
CoreOS updates to break people.
Now people will be aware of that they switch to etcd3. Do not need
to support 0.x flags any more.
Support IPv6 address for ETCD_ADDR and ETCD_PEER_ADDR
pkg/flags: Support IPv6 address for ETCD_ADDR and ETCD_PEER_ADDR
pkg/flags: tests for IPv6 addr and bind-addr flags
pkg/flags: IPAddressPort.Host: do not enclose IPv6 address in square brackets
pkg/flags: set default bind address to [::] instead of 0.0.0.0
pkg/flags: we don't need fmt any more
also, one minor fix: net.JoinHostPort takes string as a port value
pkg/flags: fix ipv6 tests
pkg/flags: test both IPv4 and IPv6 addresses in TestIPAddressPortString
etcdmain: test: use [::] instead of 0.0.0.0
This function was fundamentally buggy, as a panic could be trivially
triggered by setting the wrong environment variable (e.g.
ETCD_BIND_ADDR=foo). Instead, let's propagate the error and present it
to the user in a cleaner way.
1. etcd fatals if there is critical error in the system and operator should
do something for it
2. etcd panics if there happens something unexpected, and it should be
reported to us to debug.
If any of this initialization fails, something very bad has happened,
and we should not continue as-is (this has previously manifested in
strange bugs)
