Revision 781cc0be8323a771d0861df343d620dd86b36cf1 authored by Joe Betz on 06 June 2018, 16:54:59 UTC, committed by Joe Betz on 06 June 2018, 16:54:59 UTC
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README.md
# etcd/clientv3
[![Godoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](https://godoc.org/github.com/coreos/etcd/clientv3)
`etcd/clientv3` is the official Go etcd client for v3.
## Install
```bash
go get github.com/coreos/etcd/clientv3
```
## Get started
Create client using `clientv3.New`:
```go
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`](http://www.grpc.io) for remote procedure calls. And `clientv3` uses
[`grpc-go`](https://github.com/grpc/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:
```go
ctx, cancel := context.WithTimeout(context.Background(), timeout)
resp, err := kvc.Put(ctx, "sample_key", "sample_value")
cancel()
if err != nil {
// handle error!
}
// use the response
```
etcd uses `cmd/vendor` directory to store external dependencies, which are
to be compiled into etcd release binaries. `client` can be imported without
vendoring. For full compatibility, it is recommended to vendor builds using
etcd's vendored packages, using tools like godep, as in
[vendor directories](https://golang.org/cmd/go/#hdr-Vendor_Directories).
For more detail, please read [Go vendor design](https://golang.org/s/go15vendor).
## Error Handling
etcd client returns 2 types of errors:
1. context error: canceled or deadline exceeded.
2. gRPC error: see [api/v3rpc/rpctypes](https://godoc.org/github.com/coreos/etcd/etcdserver/api/v3rpc/rpctypes).
Here is the example code to handle client errors:
```go
resp, err := kvc.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](https://github.com/grpc-ecosystem/go-grpc-prometheus). See the [examples](https://github.com/coreos/etcd/blob/master/clientv3/example_metrics_test.go).
## Examples
More code examples can be found at [GoDoc](https://godoc.org/github.com/coreos/etcd/clientv3).
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