mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
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d5dddb0953
This will simplify examining the returned errors such as httpserver.ErrorWithStatusCode . See https://blog.golang.org/go1.13-errors for details.
134 lines
3.9 KiB
Go
134 lines
3.9 KiB
Go
package discoveryutils
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import (
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"crypto/tls"
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"flag"
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"fmt"
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"net"
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"net/http"
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"strings"
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"sync"
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"time"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/netutil"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/timerpool"
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"github.com/VictoriaMetrics/fasthttp"
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)
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var (
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maxConcurrency = flag.Int("promscrape.discovery.concurrency", 100, "The maximum number of concurrent requests to Prometheus autodiscovery API (Consul, Kubernetes, etc.)")
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maxWaitTime = flag.Duration("promscrape.discovery.concurrentWaitTime", time.Minute, "The maximum duration for waiting to perform API requests "+
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"if more than -promscrape.discovery.concurrency requests are simultaneously performed")
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)
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var defaultClient = &http.Client{
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Timeout: 30 * time.Second,
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}
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// GetHTTPClient returns default client for http API requests.
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func GetHTTPClient() *http.Client {
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return defaultClient
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}
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// Client is http client, which talks to the given apiServer.
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type Client struct {
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hc *fasthttp.HostClient
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ac *promauth.Config
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apiServer string
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hostPort string
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}
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// NewClient returns new Client for the given apiServer and the given ac.
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func NewClient(apiServer string, ac *promauth.Config) (*Client, error) {
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var u fasthttp.URI
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u.Update(apiServer)
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hostPort := string(u.Host())
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isTLS := string(u.Scheme()) == "https"
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var tlsCfg *tls.Config
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if isTLS && ac != nil {
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tlsCfg = ac.NewTLSConfig()
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}
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if !strings.Contains(hostPort, ":") {
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port := "80"
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if isTLS {
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port = "443"
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}
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hostPort = net.JoinHostPort(hostPort, port)
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}
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hc := &fasthttp.HostClient{
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Addr: hostPort,
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Name: "vm_promscrape/discovery",
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DialDualStack: netutil.TCP6Enabled(),
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IsTLS: isTLS,
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TLSConfig: tlsCfg,
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ReadTimeout: time.Minute,
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WriteTimeout: 10 * time.Second,
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MaxResponseBodySize: 300 * 1024 * 1024,
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MaxConns: 2 * *maxConcurrency,
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}
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return &Client{
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hc: hc,
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ac: ac,
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apiServer: apiServer,
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hostPort: hostPort,
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}, nil
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}
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var (
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concurrencyLimitCh chan struct{}
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concurrencyLimitChOnce sync.Once
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)
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func concurrencyLimitChInit() {
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concurrencyLimitCh = make(chan struct{}, *maxConcurrency)
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}
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// GetAPIResponse returns response for the given absolute path.
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func (c *Client) GetAPIResponse(path string) ([]byte, error) {
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// Limit the number of concurrent API requests.
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concurrencyLimitChOnce.Do(concurrencyLimitChInit)
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t := timerpool.Get(*maxWaitTime)
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select {
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case concurrencyLimitCh <- struct{}{}:
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timerpool.Put(t)
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case <-t.C:
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timerpool.Put(t)
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return nil, fmt.Errorf("too many outstanding requests to %q; try increasing -promscrape.discovery.concurrentWaitTime=%s or -promscrape.discovery.concurrency=%d",
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c.apiServer, *maxWaitTime, *maxConcurrency)
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}
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defer func() { <-concurrencyLimitCh }()
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requestURL := c.apiServer + path
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var u fasthttp.URI
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u.Update(requestURL)
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var req fasthttp.Request
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req.SetRequestURIBytes(u.RequestURI())
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req.SetHost(c.hostPort)
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req.Header.Set("Accept-Encoding", "gzip")
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if c.ac != nil && c.ac.Authorization != "" {
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req.Header.Set("Authorization", c.ac.Authorization)
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}
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var resp fasthttp.Response
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// There is no need in calling DoTimeout, since the timeout is already set in c.hc.ReadTimeout above.
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if err := c.hc.Do(&req, &resp); err != nil {
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return nil, fmt.Errorf("cannot fetch %q: %w", requestURL, err)
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}
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var data []byte
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if ce := resp.Header.Peek("Content-Encoding"); string(ce) == "gzip" {
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dst, err := fasthttp.AppendGunzipBytes(nil, resp.Body())
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if err != nil {
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return nil, fmt.Errorf("cannot ungzip response from %q: %w", requestURL, err)
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}
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data = dst
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} else {
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data = append(data[:0], resp.Body()...)
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}
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statusCode := resp.StatusCode()
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if statusCode != fasthttp.StatusOK {
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return nil, fmt.Errorf("unexpected status code returned from %q: %d; expecting %d; response body: %q",
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requestURL, statusCode, fasthttp.StatusOK, data)
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}
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return data, nil
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}
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