234 lines
7.2 KiB
Go
234 lines
7.2 KiB
Go
/*
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* MinIO Cloud Storage, (C) 2018-2020 MinIO, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package rest
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"math/rand"
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"net/http"
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"net/url"
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"sync/atomic"
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"time"
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xhttp "github.com/minio/minio/cmd/http"
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"github.com/minio/minio/cmd/logger"
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xnet "github.com/minio/minio/pkg/net"
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)
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// DefaultTimeout - default REST timeout is 10 seconds.
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const DefaultTimeout = 10 * time.Second
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const (
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offline = iota
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online
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closed
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)
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// Hold the number of failed RPC calls due to networking errors
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var networkErrsCounter uint64
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// GetNetworkErrsCounter returns the number of failed RPC requests
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func GetNetworkErrsCounter() uint64 {
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return atomic.LoadUint64(&networkErrsCounter)
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}
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// ResetNetworkErrsCounter resets the number of failed RPC requests
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func ResetNetworkErrsCounter() {
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atomic.StoreUint64(&networkErrsCounter, 0)
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}
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// NetworkError - error type in case of errors related to http/transport
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// for ex. connection refused, connection reset, dns resolution failure etc.
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// All errors returned by storage-rest-server (ex errFileNotFound, errDiskNotFound) are not considered to be network errors.
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type NetworkError struct {
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Err error
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}
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func (n *NetworkError) Error() string {
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return n.Err.Error()
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}
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// Unwrap returns the error wrapped in NetworkError.
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func (n *NetworkError) Unwrap() error {
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return n.Err
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}
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// Client - http based RPC client.
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type Client struct {
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connected int32 // ref: https://golang.org/pkg/sync/atomic/#pkg-note-BUG
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// HealthCheckFn is the function set to test for health.
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// If not set the client will not keep track of health.
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// Calling this returns true or false if the target
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// is online or offline.
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HealthCheckFn func() bool
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// HealthCheckInterval will be the duration between re-connection attempts
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// when a call has failed with a network error.
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HealthCheckInterval time.Duration
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// HealthCheckTimeout determines timeout for each call.
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HealthCheckTimeout time.Duration
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// MaxErrResponseSize is the maximum expected response size.
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// Should only be modified before any calls are made.
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MaxErrResponseSize int64
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// ExpectTimeouts indicates if context timeouts are expected.
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// This will not mark the client offline in these cases.
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ExpectTimeouts bool
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httpClient *http.Client
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url *url.URL
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newAuthToken func(audience string) string
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}
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// URL query separator constants
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const (
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querySep = "?"
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)
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type restError string
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func (e restError) Error() string {
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return string(e)
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}
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func (e restError) Timeout() bool {
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return true
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}
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// Call - make a REST call with context.
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func (c *Client) Call(ctx context.Context, method string, values url.Values, body io.Reader, length int64) (reply io.ReadCloser, err error) {
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if !c.IsOnline() {
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return nil, &NetworkError{Err: &url.Error{Op: method, URL: c.url.String(), Err: restError("remote server offline")}}
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}
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req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.url.String()+method+querySep+values.Encode(), body)
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if err != nil {
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return nil, &NetworkError{err}
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}
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req.Header.Set("Authorization", "Bearer "+c.newAuthToken(req.URL.RawQuery))
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req.Header.Set("X-Minio-Time", time.Now().UTC().Format(time.RFC3339))
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if length > 0 {
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req.ContentLength = length
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}
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resp, err := c.httpClient.Do(req)
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if err != nil {
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if c.HealthCheckFn != nil && xnet.IsNetworkOrHostDown(err, c.ExpectTimeouts) {
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atomic.AddUint64(&networkErrsCounter, 1)
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if c.MarkOffline() {
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logger.LogIf(ctx, fmt.Errorf("Marking %s temporary offline; caused by %w", c.url.String(), err))
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}
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}
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return nil, &NetworkError{err}
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}
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final := resp.Trailer.Get("FinalStatus")
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if final != "" && final != "Success" {
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defer xhttp.DrainBody(resp.Body)
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return nil, errors.New(final)
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}
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if resp.StatusCode != http.StatusOK {
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// If server returns 412 pre-condition failed, it would
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// mean that authentication succeeded, but another
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// side-channel check has failed, we shall take
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// the client offline in such situations.
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// generally all implementations should simply return
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// 403, but in situations where there is a dependency
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// with the caller to take the client offline purpose
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// fully it should make sure to respond with '412'
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// instead, see cmd/storage-rest-server.go for ideas.
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if c.HealthCheckFn != nil && resp.StatusCode == http.StatusPreconditionFailed {
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logger.LogIf(ctx, fmt.Errorf("Marking %s temporary offline; caused by PreconditionFailed with disk ID mismatch", c.url.String()))
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c.MarkOffline()
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}
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defer xhttp.DrainBody(resp.Body)
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// Limit the ReadAll(), just in case, because of a bug, the server responds with large data.
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b, err := ioutil.ReadAll(io.LimitReader(resp.Body, c.MaxErrResponseSize))
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if err != nil {
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if c.HealthCheckFn != nil && xnet.IsNetworkOrHostDown(err, c.ExpectTimeouts) {
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if c.MarkOffline() {
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logger.LogIf(ctx, fmt.Errorf("Marking %s temporary offline; caused by %w", c.url.String(), err))
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}
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}
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return nil, err
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}
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if len(b) > 0 {
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return nil, errors.New(string(b))
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}
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return nil, errors.New(resp.Status)
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}
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return resp.Body, nil
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}
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// Close closes all idle connections of the underlying http client
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func (c *Client) Close() {
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atomic.StoreInt32(&c.connected, closed)
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}
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// NewClient - returns new REST client.
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func NewClient(url *url.URL, tr http.RoundTripper, newAuthToken func(aud string) string) *Client {
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// Transport is exactly same as Go default in https://golang.org/pkg/net/http/#RoundTripper
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// except custom DialContext and TLSClientConfig.
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return &Client{
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httpClient: &http.Client{Transport: tr},
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url: url,
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newAuthToken: newAuthToken,
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connected: online,
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MaxErrResponseSize: 4096,
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HealthCheckInterval: 200 * time.Millisecond,
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HealthCheckTimeout: time.Second,
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}
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}
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// IsOnline returns whether the client is likely to be online.
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func (c *Client) IsOnline() bool {
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return atomic.LoadInt32(&c.connected) == online
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}
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// MarkOffline - will mark a client as being offline and spawns
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// a goroutine that will attempt to reconnect if HealthCheckFn is set.
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// returns true if the node changed state from online to offline
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func (c *Client) MarkOffline() bool {
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// Start goroutine that will attempt to reconnect.
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// If server is already trying to reconnect this will have no effect.
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if c.HealthCheckFn != nil && atomic.CompareAndSwapInt32(&c.connected, online, offline) {
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r := rand.New(rand.NewSource(time.Now().UnixNano()))
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go func() {
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for {
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if atomic.LoadInt32(&c.connected) == closed {
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return
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}
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if c.HealthCheckFn() {
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if atomic.CompareAndSwapInt32(&c.connected, offline, online) {
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logger.Info("Client %s online", c.url.String())
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}
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return
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}
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time.Sleep(time.Duration(r.Float64() * float64(c.HealthCheckInterval)))
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}
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}()
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return true
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}
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return false
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}
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