Currently the discovery url is just one endpoint. But actually it
should be the same as the etcdctl, which means that it should be
a list of endpoints. When one endpoint is down, the clientv3 can
fail over to the next endpoint automatically.
Json encoding is the default zap encoding value and can not be changeable.
This PR enables configuring zap encoding to console via new flag `log-format`.
When a unary request takes more than predefined duration, this request
is defined as "expensive" and a warning is printed. The expensive request
duration is hard-coded to 300 ms. It can be not enough for example
for transactions with a lot of operations. The warnings just blow up
the log files and reduce throughput.
This fix allows user to configure the "expensive" request duration.
Signed-off-by: Alexey Roytman <roytman@il.ibm.com>
Flags `--experimental-enable-v2v3` and '-enable-v2' will raise a warning in 3.5,
in 3.6 they are schedule for decomissioning, such that v2store can stop be written in 3.7.
Deprecation plan in: https://github.com/etcd-io/etcd/issues/12913
