mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
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f6a641de62
This should reduce CPU load at vmagent and at remote side when the remote side doesn't accept HTTP requests. Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1289
344 lines
13 KiB
Go
344 lines
13 KiB
Go
package promscrape
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import (
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"context"
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"crypto/tls"
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"flag"
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"fmt"
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"io"
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"io/ioutil"
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"net/http"
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"net/url"
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"strings"
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"time"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/flagutil"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/proxy"
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"github.com/VictoriaMetrics/fasthttp"
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"github.com/VictoriaMetrics/metrics"
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)
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var (
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maxScrapeSize = flagutil.NewBytes("promscrape.maxScrapeSize", 16*1024*1024, "The maximum size of scrape response in bytes to process from Prometheus targets. "+
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"Bigger responses are rejected")
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disableCompression = flag.Bool("promscrape.disableCompression", false, "Whether to disable sending 'Accept-Encoding: gzip' request headers to all the scrape targets. "+
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"This may reduce CPU usage on scrape targets at the cost of higher network bandwidth utilization. "+
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"It is possible to set 'disable_compression: true' individually per each 'scrape_config' section in '-promscrape.config' for fine grained control")
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disableKeepAlive = flag.Bool("promscrape.disableKeepAlive", false, "Whether to disable HTTP keep-alive connections when scraping all the targets. "+
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"This may be useful when targets has no support for HTTP keep-alive connection. "+
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"It is possible to set 'disable_keepalive: true' individually per each 'scrape_config' section in '-promscrape.config' for fine grained control. "+
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"Note that disabling HTTP keep-alive may increase load on both vmagent and scrape targets")
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streamParse = flag.Bool("promscrape.streamParse", false, "Whether to enable stream parsing for metrics obtained from scrape targets. This may be useful "+
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"for reducing memory usage when millions of metrics are exposed per each scrape target. "+
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"It is posible to set 'stream_parse: true' individually per each 'scrape_config' section in '-promscrape.config' for fine grained control")
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)
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type client struct {
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// hc is the default client optimized for common case of scraping targets with moderate number of metrics.
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hc *fasthttp.HostClient
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// sc (aka `stream client`) is used instead of hc if ScrapeWork.ParseStream is set.
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// It may be useful for scraping targets with millions of metrics per target.
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sc *http.Client
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scrapeURL string
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scrapeTimeoutSecondsStr string
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host string
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requestURI string
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authHeader string
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proxyAuthHeader string
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denyRedirects bool
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disableCompression bool
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disableKeepAlive bool
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}
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func newClient(sw *ScrapeWork) *client {
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var u fasthttp.URI
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u.Update(sw.ScrapeURL)
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host := string(u.Host())
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requestURI := string(u.RequestURI())
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isTLS := string(u.Scheme()) == "https"
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var tlsCfg *tls.Config
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if isTLS {
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tlsCfg = sw.AuthConfig.NewTLSConfig()
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}
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proxyAuthHeader := ""
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proxyURL := sw.ProxyURL
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if !isTLS && proxyURL.IsHTTPOrHTTPS() {
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// Send full sw.ScrapeURL in requests to a proxy host for non-TLS scrape targets
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// like net/http package from Go does.
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// See https://en.wikipedia.org/wiki/Proxy_server#Web_proxy_servers
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pu := proxyURL.URL()
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host = pu.Host
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requestURI = sw.ScrapeURL
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isTLS = pu.Scheme == "https"
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if isTLS {
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tlsCfg = sw.ProxyAuthConfig.NewTLSConfig()
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}
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proxyAuthHeader = proxyURL.GetAuthHeader(sw.ProxyAuthConfig)
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proxyURL = proxy.URL{}
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}
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if !strings.Contains(host, ":") {
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if !isTLS {
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host += ":80"
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} else {
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host += ":443"
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}
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}
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dialFunc, err := newStatDialFunc(proxyURL, sw.ProxyAuthConfig)
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if err != nil {
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logger.Fatalf("cannot create dial func: %s", err)
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}
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hc := &fasthttp.HostClient{
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Addr: host,
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Name: "vm_promscrape",
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Dial: dialFunc,
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IsTLS: isTLS,
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TLSConfig: tlsCfg,
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MaxIdleConnDuration: 2 * sw.ScrapeInterval,
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ReadTimeout: sw.ScrapeTimeout,
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WriteTimeout: 10 * time.Second,
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MaxResponseBodySize: maxScrapeSize.N,
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MaxIdempotentRequestAttempts: 1,
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}
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var sc *http.Client
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if *streamParse || sw.StreamParse {
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var proxyURLFunc func(*http.Request) (*url.URL, error)
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if proxyURL := sw.ProxyURL.URL(); proxyURL != nil {
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proxyURLFunc = http.ProxyURL(proxyURL)
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}
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sc = &http.Client{
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Transport: &http.Transport{
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TLSClientConfig: tlsCfg,
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Proxy: proxyURLFunc,
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TLSHandshakeTimeout: 10 * time.Second,
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IdleConnTimeout: 2 * sw.ScrapeInterval,
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DisableCompression: *disableCompression || sw.DisableCompression,
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DisableKeepAlives: *disableKeepAlive || sw.DisableKeepAlive,
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DialContext: statStdDial,
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// Set timeout for receiving the first response byte,
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// since the duration for reading the full response can be much bigger because of stream parsing.
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1017#issuecomment-767235047
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ResponseHeaderTimeout: sw.ScrapeTimeout,
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},
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// Set 10x bigger timeout than the sw.ScrapeTimeout, since the duration for reading the full response
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// can be much bigger because of stream parsing.
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1017#issuecomment-767235047
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Timeout: 10 * sw.ScrapeTimeout,
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}
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if sw.DenyRedirects {
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sc.CheckRedirect = func(req *http.Request, via []*http.Request) error {
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return http.ErrUseLastResponse
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}
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}
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}
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return &client{
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hc: hc,
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sc: sc,
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scrapeURL: sw.ScrapeURL,
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scrapeTimeoutSecondsStr: fmt.Sprintf("%.3f", sw.ScrapeTimeout.Seconds()),
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host: host,
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requestURI: requestURI,
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authHeader: sw.AuthConfig.Authorization,
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proxyAuthHeader: proxyAuthHeader,
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denyRedirects: sw.DenyRedirects,
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disableCompression: sw.DisableCompression,
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disableKeepAlive: sw.DisableKeepAlive,
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}
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}
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func (c *client) GetStreamReader() (*streamReader, error) {
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deadline := time.Now().Add(c.hc.ReadTimeout)
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ctx, cancel := context.WithDeadline(context.Background(), deadline)
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req, err := http.NewRequestWithContext(ctx, "GET", c.scrapeURL, nil)
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if err != nil {
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cancel()
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return nil, fmt.Errorf("cannot create request for %q: %w", c.scrapeURL, err)
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}
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// The following `Accept` header has been copied from Prometheus sources.
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// See https://github.com/prometheus/prometheus/blob/f9d21f10ecd2a343a381044f131ea4e46381ce09/scrape/scrape.go#L532 .
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// This is needed as a workaround for scraping stupid Java-based servers such as Spring Boot.
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/608 for details.
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// Do not bloat the `Accept` header with OpenMetrics shit, since it looks like dead standard now.
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req.Header.Set("Accept", "text/plain;version=0.0.4;q=1,*/*;q=0.1")
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// Set X-Prometheus-Scrape-Timeout-Seconds like Prometheus does, since it is used by some exporters such as PushProx.
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1179#issuecomment-813117162
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req.Header.Set("X-Prometheus-Scrape-Timeout-Seconds", c.scrapeTimeoutSecondsStr)
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if c.authHeader != "" {
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req.Header.Set("Authorization", c.authHeader)
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}
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if c.proxyAuthHeader != "" {
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req.Header.Set("Proxy-Authorization", c.proxyAuthHeader)
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}
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resp, err := c.sc.Do(req)
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if err != nil {
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cancel()
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return nil, fmt.Errorf("cannot scrape %q: %w", c.scrapeURL, err)
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}
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if resp.StatusCode != http.StatusOK {
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metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_scrapes_total{status_code="%d"}`, resp.StatusCode)).Inc()
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respBody, _ := ioutil.ReadAll(resp.Body)
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_ = resp.Body.Close()
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cancel()
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return nil, fmt.Errorf("unexpected status code returned when scraping %q: %d; expecting %d; response body: %q",
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c.scrapeURL, resp.StatusCode, http.StatusOK, respBody)
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}
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scrapesOK.Inc()
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return &streamReader{
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r: resp.Body,
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cancel: cancel,
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}, nil
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}
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func (c *client) ReadData(dst []byte) ([]byte, error) {
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deadline := time.Now().Add(c.hc.ReadTimeout)
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req := fasthttp.AcquireRequest()
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req.SetRequestURI(c.requestURI)
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req.Header.SetHost(c.host)
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// The following `Accept` header has been copied from Prometheus sources.
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// See https://github.com/prometheus/prometheus/blob/f9d21f10ecd2a343a381044f131ea4e46381ce09/scrape/scrape.go#L532 .
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// This is needed as a workaround for scraping stupid Java-based servers such as Spring Boot.
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/608 for details.
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// Do not bloat the `Accept` header with OpenMetrics shit, since it looks like dead standard now.
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req.Header.Set("Accept", "text/plain;version=0.0.4;q=1,*/*;q=0.1")
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// Set X-Prometheus-Scrape-Timeout-Seconds like Prometheus does, since it is used by some exporters such as PushProx.
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// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1179#issuecomment-813117162
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req.Header.Set("X-Prometheus-Scrape-Timeout-Seconds", c.scrapeTimeoutSecondsStr)
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if c.authHeader != "" {
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req.Header.Set("Authorization", c.authHeader)
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}
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if c.proxyAuthHeader != "" {
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req.Header.Set("Proxy-Authorization", c.proxyAuthHeader)
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}
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if !*disableCompression && !c.disableCompression {
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req.Header.Set("Accept-Encoding", "gzip")
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}
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if *disableKeepAlive || c.disableKeepAlive {
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req.SetConnectionClose()
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}
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resp := fasthttp.AcquireResponse()
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swapResponseBodies := len(dst) == 0
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if swapResponseBodies {
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// An optimization: write response directly to dst.
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// This should reduce memory uage when scraping big targets.
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dst = resp.SwapBody(dst)
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}
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err := doRequestWithPossibleRetry(c.hc, req, resp, deadline)
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statusCode := resp.StatusCode()
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if err == nil && (statusCode == fasthttp.StatusMovedPermanently || statusCode == fasthttp.StatusFound) {
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if c.denyRedirects {
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err = fmt.Errorf("cannot follow redirects if `follow_redirects: false` is set")
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} else {
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// Allow a single redirect.
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// It is expected that the redirect is made on the same host.
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// Otherwise it won't work.
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if location := resp.Header.Peek("Location"); len(location) > 0 {
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req.URI().UpdateBytes(location)
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err = c.hc.DoDeadline(req, resp, deadline)
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statusCode = resp.StatusCode()
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}
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}
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}
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if swapResponseBodies {
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dst = resp.SwapBody(dst)
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}
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fasthttp.ReleaseRequest(req)
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if err != nil {
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fasthttp.ReleaseResponse(resp)
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if err == fasthttp.ErrTimeout {
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scrapesTimedout.Inc()
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return dst, fmt.Errorf("error when scraping %q with timeout %s: %w", c.scrapeURL, c.hc.ReadTimeout, err)
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}
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if err == fasthttp.ErrBodyTooLarge {
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return dst, fmt.Errorf("the response from %q exceeds -promscrape.maxScrapeSize=%d; "+
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"either reduce the response size for the target or increase -promscrape.maxScrapeSize", c.scrapeURL, maxScrapeSize.N)
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}
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return dst, fmt.Errorf("error when scraping %q: %w", c.scrapeURL, err)
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}
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if ce := resp.Header.Peek("Content-Encoding"); string(ce) == "gzip" {
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var err error
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if swapResponseBodies {
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zb := gunzipBufPool.Get()
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zb.B, err = fasthttp.AppendGunzipBytes(zb.B[:0], dst)
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dst = append(dst[:0], zb.B...)
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gunzipBufPool.Put(zb)
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} else {
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dst, err = fasthttp.AppendGunzipBytes(dst, resp.Body())
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}
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if err != nil {
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fasthttp.ReleaseResponse(resp)
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scrapesGunzipFailed.Inc()
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return dst, fmt.Errorf("cannot ungzip response from %q: %w", c.scrapeURL, err)
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}
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scrapesGunzipped.Inc()
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} else if !swapResponseBodies {
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dst = append(dst, resp.Body()...)
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}
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fasthttp.ReleaseResponse(resp)
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if statusCode != fasthttp.StatusOK {
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metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_scrapes_total{status_code="%d"}`, statusCode)).Inc()
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return dst, fmt.Errorf("unexpected status code returned when scraping %q: %d; expecting %d; response body: %q",
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c.scrapeURL, statusCode, fasthttp.StatusOK, dst)
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}
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scrapesOK.Inc()
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return dst, nil
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}
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var gunzipBufPool bytesutil.ByteBufferPool
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var (
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scrapesTimedout = metrics.NewCounter(`vm_promscrape_scrapes_timed_out_total`)
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scrapesOK = metrics.NewCounter(`vm_promscrape_scrapes_total{status_code="200"}`)
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scrapesGunzipped = metrics.NewCounter(`vm_promscrape_scrapes_gunziped_total`)
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scrapesGunzipFailed = metrics.NewCounter(`vm_promscrape_scrapes_gunzip_failed_total`)
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scrapeRetries = metrics.NewCounter(`vm_promscrape_scrape_retries_total`)
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)
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func doRequestWithPossibleRetry(hc *fasthttp.HostClient, req *fasthttp.Request, resp *fasthttp.Response, deadline time.Time) error {
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sleepTime := time.Second
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for {
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// Use DoDeadline instead of Do even if hc.ReadTimeout is already set in order to guarantee the given deadline
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// across multiple retries.
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err := hc.DoDeadline(req, resp, deadline)
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if err == nil {
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return nil
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}
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if err != fasthttp.ErrConnectionClosed && !strings.Contains(err.Error(), "broken pipe") {
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return err
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}
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// Retry request if the server closes the keep-alive connection unless deadline exceeds.
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maxSleepTime := time.Until(deadline)
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if sleepTime > maxSleepTime {
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return fmt.Errorf("the server closes all the connection attempts: %w", err)
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}
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sleepTime += sleepTime
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if sleepTime > maxSleepTime {
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maxSleepTime = maxSleepTime
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}
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time.Sleep(sleepTime)
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scrapeRetries.Inc()
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}
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}
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type streamReader struct {
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r io.ReadCloser
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cancel context.CancelFunc
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bytesRead int64
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}
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func (sr *streamReader) Read(p []byte) (int, error) {
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n, err := sr.r.Read(p)
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sr.bytesRead += int64(n)
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return n, err
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}
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func (sr *streamReader) MustClose() {
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sr.cancel()
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if err := sr.r.Close(); err != nil {
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logger.Errorf("cannot close reader: %s", err)
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}
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}
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