use config flag in place of environment variable

broker/fragment/store_gcs.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"io"
 	"net/url"
-	"os"
 	"strings"
 	"sync"
 	"time"
@@ -28,8 +27,6 @@ type GSStoreConfig struct {
 	RewriterConfig
 }
 
-var gcs_do_not_sign_urls = os.Getenv("GCS_DO_NOT_SIGN_URLS")
-
 type gcsBackend struct {
 	client           *storage.Client
 	signedURLOptions storage.SignedURLOptions
@@ -46,7 +43,7 @@ func (s *gcsBackend) SignGet(ep *url.URL, fragment pb.Fragment, d time.Duration)
 		return "", err
 	}
 
-	if gcs_do_not_sign_urls == "true" {
+	if SignedUrlsOff {
 		u := &url.URL{
 			Path: fmt.Sprintf("/%s/%s", cfg.bucket, cfg.rewritePath(cfg.prefix, fragment.ContentPath())),
 		}

broker/fragment/stores.go

@@ -21,6 +21,9 @@ import (
 // If true, fragments are not persisted, and stores are not listed for existing fragments.
 var DisableStores bool = false
 
+// Whether to return an unsigned URL when a signed URL is requested. Useful when clients do not require the signing.
+var SignedUrlsOff bool = false
+
 type backend interface {
 	Provider() string
 	SignGet(ep *url.URL, fragment pb.Fragment, d time.Duration) (string, error)

cmd/gazette/main.go

@@ -32,6 +32,7 @@ var Config = new(struct {
 		MinAppendRate  uint32        `long:"min-append-rate" env:"MIN_APPEND_RATE" default:"65536" description:"Min rate (in bytes-per-sec) at which a client may stream Append RPC content. RPCs unable to sustain this rate are aborted"`
 		DisableStores  bool          `long:"disable-stores" env:"DISABLE_STORES" description:"Disable use of any configured journal fragment stores. The broker will neither list or persist remote fragments, and all data is discarded on broker exit."`
 		WatchDelay     time.Duration `long:"watch-delay" env:"WATCH_DELAY" default:"30ms" description:"Delay applied to the application of watched Etcd events. Larger values amortize the processing of fast-changing Etcd keys."`
+		SignedUrlsOff  bool          `long:"signed-urls-off" env:"SIGNED_URLS_OFF" description:"When a signed URL is requested, return an unsigned URL instead. This is useful when clients do not require the signing."`
 	} `group:"Broker" namespace:"broker" env-namespace:"BROKER"`
 
 	Etcd struct {
@@ -71,6 +72,7 @@ func (cmdServe) Execute(args []string) error {
 	broker.MaxAppendRate = int64(Config.Broker.MaxAppendRate)
 	pb.MaxReplication = int32(Config.Broker.MaxReplication)
 	fragment.DisableStores = Config.Broker.DisableStores
+	fragment.SignedUrlsOff = Config.Broker.SignedUrlsOff
 
 	var (
 		lo   = pb.NewJournalClient(srv.GRPCLoopback)