db61ee106c
Overwrite authority when it's IP. When user dials with "grpc.WithDialer", "grpc.DialContext" "cc.parsedTarget" update only happens once. This is problematic, because when TLS is enabled, retries happen through "grpc.WithDialer" with static "cc.parsedTarget" from the initial dial call. If the server authenticates by IP addresses, we want to set a new endpoint as a new authority. Otherwise "transport: authentication handshake failed: x509: certificate is valid for 127.0.0.1, 192.168.121.180, not 192.168.223.156" when the new dial target is "192.168.121.180" whose certificate host name is also "192.168.121.180" but client tries to authenticate with previously set "cc.parsedTarget" field "192.168.223.156" Signed-off-by: Gyuho Lee <leegyuho@amazon.com> |
||
---|---|---|
.. | ||
balancer | ||
clientv3util | ||
concurrency | ||
credentials | ||
integration | ||
leasing | ||
mirror | ||
namespace | ||
naming | ||
ordering | ||
snapshot | ||
yaml | ||
README.md | ||
auth.go | ||
client.go | ||
client_test.go | ||
cluster.go | ||
compact_op.go | ||
compact_op_test.go | ||
compare.go | ||
config.go | ||
doc.go | ||
example_auth_test.go | ||
example_cluster_test.go | ||
example_kv_test.go | ||
example_lease_test.go | ||
example_maintenance_test.go | ||
example_metrics_test.go | ||
example_test.go | ||
example_watch_test.go | ||
kv.go | ||
lease.go | ||
logger.go | ||
main_test.go | ||
maintenance.go | ||
op.go | ||
op_test.go | ||
options.go | ||
retry.go | ||
retry_interceptor.go | ||
sort.go | ||
txn.go | ||
txn_test.go | ||
utils.go | ||
watch.go | ||
watch_test.go |
README.md
etcd/clientv3
etcd/clientv3
is the official Go etcd client for v3.
Install
go get go.etcd.io/etcd/clientv3
Get started
Create client using clientv3.New
:
cli, err := clientv3.New(clientv3.Config{
Endpoints: []string{"localhost:2379", "localhost:22379", "localhost:32379"},
DialTimeout: 5 * time.Second,
})
if err != nil {
// handle error!
}
defer cli.Close()
etcd v3 uses gRPC
for remote procedure calls. And clientv3
uses
grpc-go
to connect to etcd. Make sure to close the client after using it.
If the client is not closed, the connection will have leaky goroutines. To specify client request timeout,
pass context.WithTimeout
to APIs:
ctx, cancel := context.WithTimeout(context.Background(), timeout)
resp, err := cli.Put(ctx, "sample_key", "sample_value")
cancel()
if err != nil {
// handle error!
}
// use the response
For full compatibility, it is recommended to vendor builds using etcd's vendored packages, using tools like golang/dep
, as in vendor directories.
Error Handling
etcd client returns 2 types of errors:
- context error: canceled or deadline exceeded.
- gRPC error: see api/v3rpc/rpctypes.
Here is the example code to handle client errors:
resp, err := cli.Put(ctx, "", "")
if err != nil {
switch err {
case context.Canceled:
log.Fatalf("ctx is canceled by another routine: %v", err)
case context.DeadlineExceeded:
log.Fatalf("ctx is attached with a deadline is exceeded: %v", err)
case rpctypes.ErrEmptyKey:
log.Fatalf("client-side error: %v", err)
default:
log.Fatalf("bad cluster endpoints, which are not etcd servers: %v", err)
}
}
Metrics
The etcd client optionally exposes RPC metrics through go-grpc-prometheus. See the examples.
Namespacing
The namespace package provides clientv3
interface wrappers to transparently isolate client requests to a user-defined prefix.
Request size limit
Client request size limit is configurable via clientv3.Config.MaxCallSendMsgSize
and MaxCallRecvMsgSize
in bytes. If none given, client request send limit defaults to 2 MiB including gRPC overhead bytes. And receive limit defaults to math.MaxInt32
.
Examples
More code examples can be found at GoDoc.