client.go: Degrade log level when passing unavailable endpoint to client

[july2993]

What problem does this PR solve?

when some endpoint passing into the client is unavailable
in calling NewClient() will log the error log, but the service is
supported to be still available if one of the endpoints can work.
error level log will be too serious and confuse the user.

What is changed and how it works?

client.go: Degrade log level when passing unavailable endpoint to client

Check List

Tests

• Manual test (add detailed scripts or steps below)
  log after this pr:

[2019/10/28 18:51:04.975 +08:00] [INFO] [client.go:144] ["[pd] create pd client with endpoints"] [pd-address="[localhost:9999,localhost:2379]"]
[2019/10/28 18:51:04.987 +08:00] [WARN] [client.go:200] ["[pd] failed to get cluster id"] [url=http://localhost:9999] [error="rpc error: code = Unavailable desc = all SubConns are in TransientFailure, latest connection error: connection error: desc = \"transport: Error while dialing dial tcp [::1]:9999: connect: connection refused\""] [errorVerbose="rpc error: code = Unavailable desc = all SubConns are in TransientFailure, latest connection error: connection error: desc = \"transport: Error while dialing dial tcp [::1]:9999: connect: connection refused\"\ngithub.com/pingcap/pd/client.(*client).getMembers\n\t/Users/huangjiahao/go/pkg/mod/github.com/july2993/pd@v1.1.0-beta.0.20191028103916-ec504e3dce8f/client/client.go:235\ngithub.com/pingcap/pd/client.(*client).initClusterID\n\t/Users/huangjiahao/go/pkg/mod/github.com/july2993/pd@v1.1.0-beta.0.20191028103916-ec504e3dce8f/client/client.go:197\ngithub.com/pingcap/pd/client.(*client).initRetry\n\t/Users/huangjiahao/go/pkg/mod/github.com/july2993/pd@v1.1.0-beta.0.20191028103916-ec504e3dce8f/client/client.go:184\ngithub.com/pingcap/pd/client.NewClient\n\t/Users/huangjiahao/go/pkg/mod/github.com/july2993/pd@v1.1.0-beta.0.20191028103916-ec504e3dce8f/client/client.go:157\nmain.main\n\t/Users/huangjiahao/go/src/github.com/pingcap/tidb-binlog/cmd/pd.go:10\nruntime.main\n\t/usr/local/go/src/runtime/proc.go:203\nruntime.goexit\n\t/usr/local/go/src/runtime/asm_amd64.s:1357"]
[2019/10/28 18:51:04.994 +08:00] [INFO] [client.go:252] ["[pd] switch leader"] [new-leader=http://127.0.0.1:2379] [old-leader=]
[2019/10/28 18:51:04.994 +08:00] [INFO] [client.go:163] ["[pd] init cluster id"] [cluster-id=6752802479515318396]

Code changes

Side effects

Related changes

• Need to cherry-pick to the release branch

[CLAassistant]

All committers have signed the CLA.

[codecov-io]

Codecov Report

Merging #1852 into master will decrease coverage by 0.09%.
The diff coverage is 0%.

@@            Coverage Diff            @@
##           master    #1852     +/-   ##
=========================================
- Coverage    78.1%   78.01%   -0.1%     
=========================================
  Files         168      168             
  Lines       17019    17019             
=========================================
- Hits        13293    13277     -16     
- Misses       2644     2654     +10     
- Partials     1082     1088      +6

Impacted Files	Coverage Δ
client/client.go	69.89% <0%> (-0.44%)	⬇️
server/kv/etcd_kv.go	72.72% <0%> (-9.1%)	⬇️
server/schedulers/random_merge.go	58.13% <0%> (-4.66%)	⬇️
server/tso/tso.go	76.11% <0%> (-1.5%)	⬇️
server/grpc_service.go	58.78% <0%> (-0.66%)	⬇️

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[sre-bot]

/run-all-tests

[sre-bot]

@july2993 merge failed.

[lhy1024]

/merge

[sre-bot]

Your auto merge job has been accepted, waiting for 1851

[sre-bot]

/run-all-tests

[sre-bot]

cherry pick to release-3.0 in PR #1856

[sre-bot]

cherry pick to release-2.1 failed

[sre-bot]

cherry pick to release-3.1 in PR #1857