VictoriaMetrics/lib/promscrape/client.go
Aliaksandr Valialkin e08287f017 lib/promscrape: reload auth tokens from files every second
Previously auth tokens were loaded at startup and couldn't be updated without vmagent restart.
Now there is no need in vmagent restart.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1297
2021-05-14 20:03:35 +03:00

347 lines
13 KiB
Go

package promscrape
import (
"context"
"crypto/tls"
"flag"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"strings"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/bytesutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/flagutil"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/proxy"
"github.com/VictoriaMetrics/fasthttp"
"github.com/VictoriaMetrics/metrics"
)
var (
maxScrapeSize = flagutil.NewBytes("promscrape.maxScrapeSize", 16*1024*1024, "The maximum size of scrape response in bytes to process from Prometheus targets. "+
"Bigger responses are rejected")
disableCompression = flag.Bool("promscrape.disableCompression", false, "Whether to disable sending 'Accept-Encoding: gzip' request headers to all the scrape targets. "+
"This may reduce CPU usage on scrape targets at the cost of higher network bandwidth utilization. "+
"It is possible to set 'disable_compression: true' individually per each 'scrape_config' section in '-promscrape.config' for fine grained control")
disableKeepAlive = flag.Bool("promscrape.disableKeepAlive", false, "Whether to disable HTTP keep-alive connections when scraping all the targets. "+
"This may be useful when targets has no support for HTTP keep-alive connection. "+
"It is possible to set 'disable_keepalive: true' individually per each 'scrape_config' section in '-promscrape.config' for fine grained control. "+
"Note that disabling HTTP keep-alive may increase load on both vmagent and scrape targets")
streamParse = flag.Bool("promscrape.streamParse", false, "Whether to enable stream parsing for metrics obtained from scrape targets. This may be useful "+
"for reducing memory usage when millions of metrics are exposed per each scrape target. "+
"It is posible to set 'stream_parse: true' individually per each 'scrape_config' section in '-promscrape.config' for fine grained control")
)
type client struct {
// hc is the default client optimized for common case of scraping targets with moderate number of metrics.
hc *fasthttp.HostClient
// sc (aka `stream client`) is used instead of hc if ScrapeWork.ParseStream is set.
// It may be useful for scraping targets with millions of metrics per target.
sc *http.Client
scrapeURL string
scrapeTimeoutSecondsStr string
host string
requestURI string
getAuthHeader func() string
getProxyAuthHeader func() string
denyRedirects bool
disableCompression bool
disableKeepAlive bool
}
func newClient(sw *ScrapeWork) *client {
var u fasthttp.URI
u.Update(sw.ScrapeURL)
host := string(u.Host())
requestURI := string(u.RequestURI())
isTLS := string(u.Scheme()) == "https"
var tlsCfg *tls.Config
if isTLS {
tlsCfg = sw.AuthConfig.NewTLSConfig()
}
getProxyAuthHeader := func() string { return "" }
proxyURL := sw.ProxyURL
if !isTLS && proxyURL.IsHTTPOrHTTPS() {
// Send full sw.ScrapeURL in requests to a proxy host for non-TLS scrape targets
// like net/http package from Go does.
// See https://en.wikipedia.org/wiki/Proxy_server#Web_proxy_servers
pu := proxyURL.URL()
host = pu.Host
requestURI = sw.ScrapeURL
isTLS = pu.Scheme == "https"
if isTLS {
tlsCfg = sw.ProxyAuthConfig.NewTLSConfig()
}
getProxyAuthHeader = func() string {
return proxyURL.GetAuthHeader(sw.ProxyAuthConfig)
}
proxyURL = proxy.URL{}
}
if !strings.Contains(host, ":") {
if !isTLS {
host += ":80"
} else {
host += ":443"
}
}
dialFunc, err := newStatDialFunc(proxyURL, sw.ProxyAuthConfig)
if err != nil {
logger.Fatalf("cannot create dial func: %s", err)
}
hc := &fasthttp.HostClient{
Addr: host,
Name: "vm_promscrape",
Dial: dialFunc,
IsTLS: isTLS,
TLSConfig: tlsCfg,
MaxIdleConnDuration: 2 * sw.ScrapeInterval,
ReadTimeout: sw.ScrapeTimeout,
WriteTimeout: 10 * time.Second,
MaxResponseBodySize: maxScrapeSize.N,
MaxIdempotentRequestAttempts: 1,
}
var sc *http.Client
if *streamParse || sw.StreamParse {
var proxyURLFunc func(*http.Request) (*url.URL, error)
if proxyURL := sw.ProxyURL.URL(); proxyURL != nil {
proxyURLFunc = http.ProxyURL(proxyURL)
}
sc = &http.Client{
Transport: &http.Transport{
TLSClientConfig: tlsCfg,
Proxy: proxyURLFunc,
TLSHandshakeTimeout: 10 * time.Second,
IdleConnTimeout: 2 * sw.ScrapeInterval,
DisableCompression: *disableCompression || sw.DisableCompression,
DisableKeepAlives: *disableKeepAlive || sw.DisableKeepAlive,
DialContext: statStdDial,
MaxIdleConnsPerHost: 100,
// Set timeout for receiving the first response byte,
// since the duration for reading the full response can be much bigger because of stream parsing.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1017#issuecomment-767235047
ResponseHeaderTimeout: sw.ScrapeTimeout,
},
// Set 10x bigger timeout than the sw.ScrapeTimeout, since the duration for reading the full response
// can be much bigger because of stream parsing.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1017#issuecomment-767235047
Timeout: 10 * sw.ScrapeTimeout,
}
if sw.DenyRedirects {
sc.CheckRedirect = func(req *http.Request, via []*http.Request) error {
return http.ErrUseLastResponse
}
}
}
return &client{
hc: hc,
sc: sc,
scrapeURL: sw.ScrapeURL,
scrapeTimeoutSecondsStr: fmt.Sprintf("%.3f", sw.ScrapeTimeout.Seconds()),
host: host,
requestURI: requestURI,
getAuthHeader: sw.AuthConfig.GetAuthHeader,
getProxyAuthHeader: getProxyAuthHeader,
denyRedirects: sw.DenyRedirects,
disableCompression: sw.DisableCompression,
disableKeepAlive: sw.DisableKeepAlive,
}
}
func (c *client) GetStreamReader() (*streamReader, error) {
deadline := time.Now().Add(c.hc.ReadTimeout)
ctx, cancel := context.WithDeadline(context.Background(), deadline)
req, err := http.NewRequestWithContext(ctx, "GET", c.scrapeURL, nil)
if err != nil {
cancel()
return nil, fmt.Errorf("cannot create request for %q: %w", c.scrapeURL, err)
}
// The following `Accept` header has been copied from Prometheus sources.
// See https://github.com/prometheus/prometheus/blob/f9d21f10ecd2a343a381044f131ea4e46381ce09/scrape/scrape.go#L532 .
// This is needed as a workaround for scraping stupid Java-based servers such as Spring Boot.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/608 for details.
// Do not bloat the `Accept` header with OpenMetrics shit, since it looks like dead standard now.
req.Header.Set("Accept", "text/plain;version=0.0.4;q=1,*/*;q=0.1")
// Set X-Prometheus-Scrape-Timeout-Seconds like Prometheus does, since it is used by some exporters such as PushProx.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1179#issuecomment-813117162
req.Header.Set("X-Prometheus-Scrape-Timeout-Seconds", c.scrapeTimeoutSecondsStr)
if ah := c.getAuthHeader(); ah != "" {
req.Header.Set("Authorization", ah)
}
if ah := c.getProxyAuthHeader(); ah != "" {
req.Header.Set("Proxy-Authorization", ah)
}
resp, err := c.sc.Do(req)
if err != nil {
cancel()
return nil, fmt.Errorf("cannot scrape %q: %w", c.scrapeURL, err)
}
if resp.StatusCode != http.StatusOK {
metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_scrapes_total{status_code="%d"}`, resp.StatusCode)).Inc()
respBody, _ := ioutil.ReadAll(resp.Body)
_ = resp.Body.Close()
cancel()
return nil, fmt.Errorf("unexpected status code returned when scraping %q: %d; expecting %d; response body: %q",
c.scrapeURL, resp.StatusCode, http.StatusOK, respBody)
}
scrapesOK.Inc()
return &streamReader{
r: resp.Body,
cancel: cancel,
}, nil
}
func (c *client) ReadData(dst []byte) ([]byte, error) {
deadline := time.Now().Add(c.hc.ReadTimeout)
req := fasthttp.AcquireRequest()
req.SetRequestURI(c.requestURI)
req.Header.SetHost(c.host)
// The following `Accept` header has been copied from Prometheus sources.
// See https://github.com/prometheus/prometheus/blob/f9d21f10ecd2a343a381044f131ea4e46381ce09/scrape/scrape.go#L532 .
// This is needed as a workaround for scraping stupid Java-based servers such as Spring Boot.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/608 for details.
// Do not bloat the `Accept` header with OpenMetrics shit, since it looks like dead standard now.
req.Header.Set("Accept", "text/plain;version=0.0.4;q=1,*/*;q=0.1")
// Set X-Prometheus-Scrape-Timeout-Seconds like Prometheus does, since it is used by some exporters such as PushProx.
// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1179#issuecomment-813117162
req.Header.Set("X-Prometheus-Scrape-Timeout-Seconds", c.scrapeTimeoutSecondsStr)
if ah := c.getAuthHeader(); ah != "" {
req.Header.Set("Authorization", ah)
}
if ah := c.getProxyAuthHeader(); ah != "" {
req.Header.Set("Proxy-Authorization", ah)
}
if !*disableCompression && !c.disableCompression {
req.Header.Set("Accept-Encoding", "gzip")
}
if *disableKeepAlive || c.disableKeepAlive {
req.SetConnectionClose()
}
resp := fasthttp.AcquireResponse()
swapResponseBodies := len(dst) == 0
if swapResponseBodies {
// An optimization: write response directly to dst.
// This should reduce memory uage when scraping big targets.
dst = resp.SwapBody(dst)
}
err := doRequestWithPossibleRetry(c.hc, req, resp, deadline)
statusCode := resp.StatusCode()
if err == nil && (statusCode == fasthttp.StatusMovedPermanently || statusCode == fasthttp.StatusFound) {
if c.denyRedirects {
err = fmt.Errorf("cannot follow redirects if `follow_redirects: false` is set")
} else {
// Allow a single redirect.
// It is expected that the redirect is made on the same host.
// Otherwise it won't work.
if location := resp.Header.Peek("Location"); len(location) > 0 {
req.URI().UpdateBytes(location)
err = c.hc.DoDeadline(req, resp, deadline)
statusCode = resp.StatusCode()
}
}
}
if swapResponseBodies {
dst = resp.SwapBody(dst)
}
fasthttp.ReleaseRequest(req)
if err != nil {
fasthttp.ReleaseResponse(resp)
if err == fasthttp.ErrTimeout {
scrapesTimedout.Inc()
return dst, fmt.Errorf("error when scraping %q with timeout %s: %w", c.scrapeURL, c.hc.ReadTimeout, err)
}
if err == fasthttp.ErrBodyTooLarge {
return dst, fmt.Errorf("the response from %q exceeds -promscrape.maxScrapeSize=%d; "+
"either reduce the response size for the target or increase -promscrape.maxScrapeSize", c.scrapeURL, maxScrapeSize.N)
}
return dst, fmt.Errorf("error when scraping %q: %w", c.scrapeURL, err)
}
if ce := resp.Header.Peek("Content-Encoding"); string(ce) == "gzip" {
var err error
if swapResponseBodies {
zb := gunzipBufPool.Get()
zb.B, err = fasthttp.AppendGunzipBytes(zb.B[:0], dst)
dst = append(dst[:0], zb.B...)
gunzipBufPool.Put(zb)
} else {
dst, err = fasthttp.AppendGunzipBytes(dst, resp.Body())
}
if err != nil {
fasthttp.ReleaseResponse(resp)
scrapesGunzipFailed.Inc()
return dst, fmt.Errorf("cannot ungzip response from %q: %w", c.scrapeURL, err)
}
scrapesGunzipped.Inc()
} else if !swapResponseBodies {
dst = append(dst, resp.Body()...)
}
fasthttp.ReleaseResponse(resp)
if statusCode != fasthttp.StatusOK {
metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_scrapes_total{status_code="%d"}`, statusCode)).Inc()
return dst, fmt.Errorf("unexpected status code returned when scraping %q: %d; expecting %d; response body: %q",
c.scrapeURL, statusCode, fasthttp.StatusOK, dst)
}
scrapesOK.Inc()
return dst, nil
}
var gunzipBufPool bytesutil.ByteBufferPool
var (
scrapesTimedout = metrics.NewCounter(`vm_promscrape_scrapes_timed_out_total`)
scrapesOK = metrics.NewCounter(`vm_promscrape_scrapes_total{status_code="200"}`)
scrapesGunzipped = metrics.NewCounter(`vm_promscrape_scrapes_gunziped_total`)
scrapesGunzipFailed = metrics.NewCounter(`vm_promscrape_scrapes_gunzip_failed_total`)
scrapeRetries = metrics.NewCounter(`vm_promscrape_scrape_retries_total`)
)
func doRequestWithPossibleRetry(hc *fasthttp.HostClient, req *fasthttp.Request, resp *fasthttp.Response, deadline time.Time) error {
sleepTime := time.Second
for {
// Use DoDeadline instead of Do even if hc.ReadTimeout is already set in order to guarantee the given deadline
// across multiple retries.
err := hc.DoDeadline(req, resp, deadline)
if err == nil {
return nil
}
if err != fasthttp.ErrConnectionClosed && !strings.Contains(err.Error(), "broken pipe") {
return err
}
// Retry request if the server closes the keep-alive connection unless deadline exceeds.
maxSleepTime := time.Until(deadline)
if sleepTime > maxSleepTime {
return fmt.Errorf("the server closes all the connection attempts: %w", err)
}
sleepTime += sleepTime
if sleepTime > maxSleepTime {
sleepTime = maxSleepTime
}
time.Sleep(sleepTime)
scrapeRetries.Inc()
}
}
type streamReader struct {
r io.ReadCloser
cancel context.CancelFunc
bytesRead int64
}
func (sr *streamReader) Read(p []byte) (int, error) {
n, err := sr.r.Read(p)
sr.bytesRead += int64(n)
return n, err
}
func (sr *streamReader) MustClose() {
sr.cancel()
if err := sr.r.Close(); err != nil {
logger.Errorf("cannot close reader: %s", err)
}
}