The #15544 has removed the `build_cov` build. And after go1.20, we use
`-cover` buildflag to enable coverage exporter. We don't need to
maintain main_test.go anymore.
```bash
➜ pwd
/home/fuwei/go/src/go.etcd.io/etcd/etcdctl
➜ go build -o /tmp/etcdctl -cover ./
➜ mkdir /tmp/etcdctl-covdata
➜ GOCOVERDIR=/tmp/etcdctl-covdata /tmp/etcdctl get /health
➜ go tool covdata percent -i=/tmp/etcdctl-covdata
go.etcd.io/etcd/etcdctl/v3 coverage: 66.7% of statements
go.etcd.io/etcd/etcdctl/v3/ctlv3 coverage: 83.3% of statements
go.etcd.io/etcd/etcdctl/v3/ctlv3/command coverage: 15.4% of statements
```
REF: https://go.dev/testing/coverage/
Signed-off-by: Wei Fu <fuweid89@gmail.com>
Fix mixin cluster parameter otherwise generated mixins looks like this:
```json
{"type":"prometheus","uid":"${datasource}"},"label":"cluster","name":"job","query":"label_values(etcd_server_has_leader{job=~\".*etcd.*\"}, job)","refresh":2,"type":"query"}]},"time":{"from":"now-15m","to":"now"},"timezone": "`}}{{ .Values.grafana.defaultDashboardsTimezone }}{{`","title":"etcd","uid":"c2f4e12cdf69feb95caa41a5a1b423d9"}`}}
```
where name is job when the variable name used in dashboard queries is cluster.
Signed-off-by: QuentinBisson <quentin@giantswarm.io>
Add two separate probes, one for liveness and one for readiness. The liveness probe would check that the local individual node is up and running, or else restart the node, while the readiness probe would check that the cluster is ready to serve traffic. This would make etcd health-check fully Kubernetes API complient.
Signed-off-by: Siyuan Zhang <sizhang@google.com>
From the Go specification [1]:
"1. For a nil slice, the number of iterations is 0."
`len` returns 0 if the slice or map is nil [2]. Therefore, checking
`len(v) > 0` around a loop is unnecessary.
[1]: https://go.dev/ref/spec#For_range
[2]: https://pkg.go.dev/builtin#len
Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>
The proc.Stop just sends the SIGTERM to etcd server. The etcd server
needs time to teardown. If we don't wait for it, the etcd server will
hold the port and then next test case, like TestGrpcProxyAutoSync, will
fail to listen on the port 20000.
```bash
file_/__w/etcd/etcd/tests/fixtures/server.crt_--peer-key-file_/__w/etcd/etcd/tests/fixtures/server.key.insecure_--cert-file_/__w/etcd/etcd/tests/fixtures/server2.crt_--key-file_/__w/etcd/etcd/tests/fixtures/server2.key.insecure_--tls-min-version_TLS1.2_--tls-max-version_TLS1.3) (32856): {"level":"info","ts":"2023-10-13T06:12:32.718845Z","caller":"embed/etcd.go:394","msg":"closing etcd server","name":"e1","data-dir":"/tmp/TestEtcdTLSVersion284993522/001","advertise-peer-urls":["https://127.0.0.1:20000"],"advertise-client-urls":["https://0.0.0.0:0"]}
2023-10-13T06:12:32.7399709Z --- PASS: TestEtcdTLSVersion (1.03s)
2023-10-13T06:12:32.7400181Z === RUN TestGrpcProxyAutoSync
2023-10-13T06:12:32.7401203Z logger.go:130: 2023-10-13T06:12:32.719Z INFO starting server... {"name": "TestGrpcProxyAutoSync-test-0"}
2023-10-13T06:12:32.7408306Z logger.go:130: 2023-10-13T06:12:32.719Z INFO spawning process {"args": ["/__w/etcd/etcd/bin/etcd", "--name=TestGrpcProxyAutoSync-test-0", "--listen-client-urls=http://localhost:20000", "--advertise-client-urls=http://localhost:20000", "--listen-peer-urls=http://localhost:20001", "--initial-advertise-peer-urls=http://localhost:20001", "--initial-cluster-token=new", "--data-dir", "/tmp/TestGrpcProxyAutoSync1139610722/001", "--snapshot-count=10000", "--initial-cluster-token=new", "--initial-cluster=TestGrpcProxyAutoSync-test-0=http://localhost:20001", "--initial-cluster-state=new"], "working-dir": "/__w/etcd/etcd/tests/e2e", "name": "TestGrpcProxyAutoSync-test-0", "environment-variables": ["ETCD_VERIFY=all", "EXPECT_DEBUG=true", "PATH=/__t/go/1.21.3/x64/bin:/go/bin:/__t/go/1.21.3/x64/bin:/go/bin:/usr/local/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin", "ETCD_UNSUPPORTED_ARCH=amd64"]}
...
2023-10-13T06:12:32.7559855Z /__w/etcd/etcd/bin/etcd (TestGrpcProxyAutoSync-test-0) (32863): {"level":"fatal","ts":"2023-10-13T06:12:32.735191Z","caller":"etcdmain/etcd.go:181","msg":"discovery failed","error":"listen tcp 127.0.0.1:20000: bind: address already in use","stacktrace":"go.etcd.io/etcd/server/v3/etcdmain.startEtcdOrProxyV2\n\tgo.etcd.io/etcd/server/v3/etcdmain/etcd.go:181\ngo.etcd.io/etcd/server/v3/etcdmain.Main\n\tgo.etcd.io/etcd/server/v3/etcdmain/main.go:40\nmain.main\n\tgo.etcd.io/etcd/server/v3/main.go:31\nruntime.main\n\truntime/proc.go:267"}
```
Signed-off-by: Wei Fu <fuweid89@gmail.com>
