Introduce changes from upstream

Author: Arvind Iyengar

.gitignore

@@ -3,4 +3,15 @@
 /bin
 /dist
 *.swp
-.idea
+.idea
+
+/.build/
+/.release/
+/.tarballs/
+/node_exporter*
+/prometheus*
+/data/
+/pushprox-client
+/pushprox-proxy
+
+/vendor

SECURITY.md

@@ -0,0 +1,6 @@
+# Reporting a security issue
+
+The Prometheus security policy, including how to report vulnerabilities, can be
+found here:
+
+https://prometheus.io/docs/operating/security/

cmd/client/main.go

@@ -21,7 +21,6 @@ import (
 	"crypto/x509"
 	"fmt"
 	"io/ioutil"
-	"math/rand"
 	"net"
 	"net/http"
 	"net/url"
@@ -31,7 +30,8 @@ import (
 
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 
-	"github.com/ShowMax/go-fqdn"
+	"github.com/Showmax/go-fqdn"
+	"github.com/cenkalti/backoff/v4"
 	"github.com/go-kit/kit/log"
 	"github.com/go-kit/kit/log/level"
 	"github.com/pkg/errors"
@@ -53,6 +53,9 @@ var (
 	insecureSkipVerify = kingpin.Flag("insecure-skip-verify", "Disable SSL security checks for client").Default("false").Bool()
 	useLocalhost       = kingpin.Flag("use-localhost", "Use 127.0.0.1 to scrape metrics instead of FQDN").Default("false").Bool()
 	allowPort          = kingpin.Flag("allow-port", "Restricts the proxy to only being allowed to scrape the given port").Default("*").String()
+
+	retryInitialWait = kingpin.Flag("proxy.retry.initial-wait", "Amount of time to wait after proxy failure").Default("1s").Duration()
+	retryMaxWait     = kingpin.Flag("proxy.retry.max-wait", "Maximum amount of time to wait between proxy poll retries").Default("5s").Duration()
 )
 
 var (
@@ -80,6 +83,15 @@ func init() {
 	prometheus.MustRegister(pushErrorCounter, pollErrorCounter, scrapeErrorCounter)
 }
 
+func newBackOffFromFlags() backoff.BackOff {
+	b := backoff.NewExponentialBackOff()
+	b.InitialInterval = *retryInitialWait
+	b.Multiplier = 1.5
+	b.MaxInterval = *retryMaxWait
+	b.MaxElapsedTime = time.Duration(0)
+	return b
+}
+
 // Coordinator for scrape requests and responses
 type Coordinator struct {
 	logger log.Logger
@@ -193,7 +205,7 @@ func (c *Coordinator) doPush(resp *http.Response, origRequest *http.Request, cli
 	return nil
 }
 
-func loop(c Coordinator, client *http.Client) error {
+func (c *Coordinator) doPoll(client *http.Client) error {
 	base, err := url.Parse(*proxyURL)
 	if err != nil {
 		level.Error(c.logger).Log("msg", "Error parsing url:", "err", err)
@@ -226,35 +238,18 @@ func loop(c Coordinator, client *http.Client) error {
 	return nil
 }
 
-// decorrelated Jitter increases the maximum jitter based on the last random value.
-type decorrelatedJitter struct {
-	duration time.Duration // sleep time
-	min      time.Duration // min sleep time
-	cap      time.Duration // max sleep time
-}
-
-func newJitter() decorrelatedJitter {
-	rand.Seed(time.Now().UnixNano())
-	return decorrelatedJitter{
-		min: 50 * time.Millisecond,
-		cap: 5 * time.Second,
+func (c *Coordinator) loop(bo backoff.BackOff, client *http.Client) {
+	op := func() error {
+		return c.doPoll(client)
 	}
-}
 
-func (d *decorrelatedJitter) calc() time.Duration {
-	change := rand.Float64() * float64(d.duration*time.Duration(3)-d.min)
-	d.duration = d.min + time.Duration(change)
-	if d.duration > d.cap {
-		d.duration = d.cap
-	}
-	if d.duration < d.min {
-		d.duration = d.min
+	for {
+		if err := backoff.RetryNotify(op, bo, func(err error, _ time.Duration) {
+			pollErrorCounter.Inc()
+		}); err != nil {
+			level.Error(c.logger).Log("err", err)
+		}
 	}
-	return d.duration
-}
-
-func (d *decorrelatedJitter) sleep() {
-	time.Sleep(d.calc())
 }
 
 func main() {
@@ -333,14 +328,7 @@ func main() {
 		TLSClientConfig:       tlsConfig,
 	}
 
-	jitter := newJitter()
 	client := &http.Client{Transport: transport}
-	for {
-		err := loop(coordinator, client)
-		if err != nil {
-			pollErrorCounter.Inc()
-			jitter.sleep()
-			continue
-		}
-	}
+
+	coordinator.loop(newBackOffFromFlags(), client)
 }

cmd/client/main_test.go

@@ -22,16 +22,6 @@ import (
 	"github.com/pkg/errors"
 )
 
-func TestJitter(t *testing.T) {
-	jitter := newJitter()
-	for i := 0; i < 100000; i++ {
-		duration := jitter.calc()
-		if !(jitter.min <= duration || duration <= jitter.cap) {
-			t.Fatal("invalid jitter value: ", duration)
-		}
-	}
-}
-
 type TestLogger struct{}
 
 func (tl *TestLogger) Log(vars ...interface{}) error {
@@ -76,7 +66,7 @@ func TestHandleErr(t *testing.T) {
 func TestLoop(t *testing.T) {
 	ts, c := prepareTest()
 	defer ts.Close()
-	if err := loop(c, ts.Client()); err != nil {
+	if err := c.doPoll(ts.Client()); err != nil {
 		t.Fatal(err)
 	}
 }

go.mod

@@ -3,12 +3,12 @@ module github.com/rancher/pushprox
 go 1.13
 
 require (
-	github.com/ShowMax/go-fqdn v0.0.0-20180501083314-6f60894d629f
-	github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d // indirect
+	github.com/Showmax/go-fqdn v1.0.0
+	github.com/cenkalti/backoff/v4 v4.1.0
 	github.com/go-kit/kit v0.10.0
-	github.com/google/uuid v1.1.1
+	github.com/google/uuid v1.2.0
 	github.com/pkg/errors v0.9.1
-	github.com/prometheus/client_golang v1.6.0
-	github.com/prometheus/common v0.10.0
+	github.com/prometheus/client_golang v1.10.0
+	github.com/prometheus/common v0.23.0
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 )