Add DefaultUpstreamFlushInterval to replace magic time.Second value

pkg/apis/options/legacy_options.go

@@ -27,7 +27,7 @@ func NewLegacyOptions() *LegacyOptions {
 		LegacyUpstreams: LegacyUpstreams{
 			PassHostHeader:  true,
 			ProxyWebSockets: true,
-			FlushInterval:   time.Duration(1) * time.Second,
+			FlushInterval:   DefaultUpstreamFlushInterval,
 		},
 
 		LegacyHeaders: LegacyHeaders{
@@ -62,7 +62,7 @@ type LegacyUpstreams struct {
 func legacyUpstreamsFlagSet() *pflag.FlagSet {
 	flagSet := pflag.NewFlagSet("upstreams", pflag.ExitOnError)
 
-	flagSet.Duration("flush-interval", time.Duration(1)*time.Second, "period between response flushing when streaming responses")
+	flagSet.Duration("flush-interval", DefaultUpstreamFlushInterval, "period between response flushing when streaming responses")
 	flagSet.Bool("pass-host-header", true, "pass the request Host Header to upstream")
 	flagSet.Bool("proxy-websockets", true, "enables WebSocket proxying")
 	flagSet.Bool("ssl-upstream-insecure-skip-verify", false, "skip validation of certificates presented when using HTTPS upstreams")

pkg/apis/options/upstreams.go

@@ -1,5 +1,12 @@
 package options
 
+import "time"
+
+const (
+	// DefaultUpstreamFlushInterval is the default value for the Upstream FlushInterval.
+	DefaultUpstreamFlushInterval = 1 * time.Second
+)
+
 // Upstreams is a collection of definitions for upstream servers.
 type Upstreams []Upstream
 

pkg/upstream/http.go

@@ -6,7 +6,6 @@ import (
 	"net/http/httputil"
 	"net/url"
 	"strings"
-	"time"
 
 	"github.com/mbland/hmacauth"
 	"github.com/oauth2-proxy/oauth2-proxy/v7/pkg/apis/options"
@@ -100,7 +99,7 @@ func newReverseProxy(target *url.URL, upstream options.Upstream, errorHandler Pr
 	if upstream.FlushInterval != nil {
 		proxy.FlushInterval = upstream.FlushInterval.Duration()
 	} else {
-		proxy.FlushInterval = 1 * time.Second
+		proxy.FlushInterval = options.DefaultUpstreamFlushInterval
 	}
 
 	// InsecureSkipVerify is a configurable option we allow

pkg/validation/upstreams.go

@@ -3,7 +3,6 @@ package validation
 import (
 	"fmt"
 	"net/url"
-	"time"
 
 	"github.com/oauth2-proxy/oauth2-proxy/v7/pkg/apis/options"
 )
@@ -70,7 +69,7 @@ func validateStaticUpstream(upstream options.Upstream) []string {
 	if upstream.InsecureSkipTLSVerify {
 		msgs = append(msgs, fmt.Sprintf("upstream %q has insecureSkipTLSVerify, but is a static upstream, this will have no effect.", upstream.ID))
 	}
-	if upstream.FlushInterval != nil && upstream.FlushInterval.Duration() != time.Second {
+	if upstream.FlushInterval != nil && upstream.FlushInterval.Duration() != options.DefaultUpstreamFlushInterval {
 		msgs = append(msgs, fmt.Sprintf("upstream %q has flushInterval, but is a static upstream, this will have no effect.", upstream.ID))
 	}
 	if upstream.PassHostHeader != nil {