diff --git a/cmd/golangorg/app.prod.yaml b/cmd/golangorg/app.prod.yaml
index 9716567..732d4b2 100644
--- a/cmd/golangorg/app.prod.yaml
+++ b/cmd/golangorg/app.prod.yaml
@@ -3,10 +3,9 @@
 env: flex
 
 env_variables:
-  GOLANGORG_PROD: true
+  GOLANGORG_CHECK_COUNTRY: true
+  GOLANGORG_REQUIRE_DL_SECRET_KEY: true
   GOLANGORG_ENFORCE_HOSTS: true
-  GODOC_PROD: true                    # TODO: remove in the future
-  GODOC_ENFORCE_HOSTS: true           # TODO: remove in the future
   GOLANGORG_REDIS_ADDR: 10.0.0.4:6379 # instance "gophercache"
   GOLANGORG_ANALYTICS: UA-11222381-2
   DATASTORE_PROJECT_ID: golang-org
diff --git a/go.mod b/go.mod
index 7bac778..62d4bb6 100644
--- a/go.mod
+++ b/go.mod
@@ -6,11 +6,11 @@
 	github.com/googleapis/gax-go v2.0.0+incompatible // indirect
 	go.opencensus.io v0.19.0 // indirect
 	golang.org/x/crypto v0.0.0-20181025213731-e84da0312774
-	golang.org/x/net v0.0.0-20190206173232-65e2d4e15006
+	golang.org/x/net v0.0.0-20190213061140-3a22650c66bd
 	golang.org/x/oauth2 v0.0.0-20190115181402-5dab4167f31c // indirect
 	golang.org/x/sys v0.0.0-20190209173611-3b5209105503 // indirect
 	golang.org/x/text v0.3.1-0.20181227161524-e6919f6577db // indirect
-	golang.org/x/tools v0.0.0-20190219175448-49d818b07734
+	golang.org/x/tools v0.0.0-20190307163923-6a08e3108db3
 	google.golang.org/api v0.1.0 // indirect
 	google.golang.org/appengine v1.4.0
 	google.golang.org/genproto v0.0.0-20190123001331-8819c946db44 // indirect
diff --git a/go.sum b/go.sum
index 5a2300a..f5ca2a3 100644
--- a/go.sum
+++ b/go.sum
@@ -51,8 +51,8 @@
 golang.org/x/net v0.0.0-20181201002055-351d144fa1fc/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20181217023233-e147a9138326/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/net v0.0.0-20190108225652-1e06a53dbb7e/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
-golang.org/x/net v0.0.0-20190206173232-65e2d4e15006 h1:bfLnR+k0tq5Lqt6dflRLcZiz6UaXCMt3vhYJ1l4FQ80=
-golang.org/x/net v0.0.0-20190206173232-65e2d4e15006/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190213061140-3a22650c66bd h1:HuTn7WObtcDo9uEEU7rEqL0jYthdXAmZ6PP+meazmaU=
+golang.org/x/net v0.0.0-20190213061140-3a22650c66bd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
 golang.org/x/oauth2 v0.0.0-20180821212333-d2e6202438be/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
 golang.org/x/oauth2 v0.0.0-20181203162652-d668ce993890 h1:uESlIz09WIHT2I+pasSXcpLYqYK8wHcdCetU3VuMBJE=
 golang.org/x/oauth2 v0.0.0-20181203162652-d668ce993890/go.mod h1:N/0e6XlmueqKjAGxoOufVs8QHGRruUQn6yWY3a++T0U=
@@ -73,8 +73,8 @@
 golang.org/x/tools v0.0.0-20180828015842-6cd1fcedba52/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20181219222714-6e267b5cc78e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20190219175448-49d818b07734 h1:bNQjVDSQE5kjDZie/YsDogCCryxCd9ZJ+EC++Erg5SY=
-golang.org/x/tools v0.0.0-20190219175448-49d818b07734/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+golang.org/x/tools v0.0.0-20190307163923-6a08e3108db3 h1:2oZsfYnKfYzL4I57uYiRFsUf0bqlLkiuw8nnj3+voUA=
+golang.org/x/tools v0.0.0-20190307163923-6a08e3108db3/go.mod h1:25r3+/G6/xytQM8iWZKq3Hn0kr0rgFKPUNVEL/dr3z4=
 google.golang.org/api v0.0.0-20180910000450-7ca32eb868bf/go.mod h1:4mhQ8q/RsB7i+udVvVy5NUi08OU8ZlA0gRVgrF7VFY0=
 google.golang.org/api v0.0.0-20181220000619-583d854617af/go.mod h1:4mhQ8q/RsB7i+udVvVy5NUi08OU8ZlA0gRVgrF7VFY0=
 google.golang.org/api v0.1.0 h1:K6z2u68e86TPdSdefXdzvXgR1zEMa+459vBSfWYAZkI=
diff --git a/internal/dl/server.go b/internal/dl/server.go
index 4501491..342863f 100644
--- a/internal/dl/server.go
+++ b/internal/dl/server.go
@@ -252,7 +252,7 @@
 			// The code is left here for SDK use and in case a fresh
 			// deployment is ever needed.  "gophers rule" is not the
 			// real key.
-			if env.IsProd() {
+			if env.RequireDLSecretKey() {
 				panic("lost key from datastore")
 			}
 			theKey.Secret = "gophers rule"
diff --git a/internal/env/env.go b/internal/env/env.go
index 1803f6c..8fcf5a9 100644
--- a/internal/env/env.go
+++ b/internal/env/env.go
@@ -2,35 +2,54 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package env provides environment information for the godoc server running on
-// golang.org.
+// Package env provides environment information for the golangorg server
+// running on golang.org.
 package env
 
 import (
 	"log"
 	"os"
 	"strconv"
+
+	"golang.org/x/tools/godoc/golangorgenv"
 )
 
 var (
-	isProd       = boolEnv("GOLANGORG_PROD")
-	enforceHosts = boolEnv("GOLANGORG_ENFORCE_HOSTS")
+	requireDLSecretKey = boolEnv("GOLANGORG_REQUIRE_DL_SECRET_KEY")
 )
 
-// IsProd reports whether the server is running in its production configuration
-// on golang.org.
-func IsProd() bool {
-	return isProd
+// RequireDLSecretKey reports whether the download server secret key
+// is expected to already exist, and the download server should panic
+// on missing key instead of creating a new one.
+func RequireDLSecretKey() bool {
+	return requireDLSecretKey
+}
+
+// Use the golangorgenv package for common configuration, instead
+// of duplicating it. This reduces the risk of divergence between
+// the environment variables that this env package uses, and ones
+// that golangorgenv uses.
+//
+// TODO(dmitshur): When the golang.org/x/tools/playground package becomes unused,
+// and golang.org/x/tools/godoc is modified to accept configuration explicitly,
+// the golang.org/x/tools/godoc/golangorgenv package can be deleted.
+// At that time, its implementation can be inlined into this package, as needed.
+
+// CheckCountry reports whether country restrictions should be enforced.
+func CheckCountry() bool {
+	return golangorgenv.CheckCountry()
 }
 
 // EnforceHosts reports whether host filtering should be enforced.
 func EnforceHosts() bool {
-	return enforceHosts
+	return golangorgenv.EnforceHosts()
 }
 
 func boolEnv(key string) bool {
 	v := os.Getenv(key)
 	if v == "" {
+		// TODO(dmitshur): In the future, consider detecting if running in App Engine,
+		// and if so, making the environment variables mandatory rather than optional.
 		return false
 	}
 	b, err := strconv.ParseBool(v)
diff --git a/internal/proxy/proxy.go b/internal/proxy/proxy.go
index e465aab..cc740d6 100644
--- a/internal/proxy/proxy.go
+++ b/internal/proxy/proxy.go
@@ -152,17 +152,19 @@
 	io.Copy(w, resp.Body)
 }
 
+// googleCN reports whether request r is considered
+// to be served from golang.google.cn.
 func googleCN(r *http.Request) bool {
 	if r.FormValue("googlecn") != "" {
 		return true
 	}
-	if !env.IsProd() {
-		return false
-	}
 	if strings.HasSuffix(r.Host, ".cn") {
 		return true
 	}
-	switch r.Header.Get("X-AppEngine-Country") {
+	if !env.CheckCountry() {
+		return false
+	}
+	switch r.Header.Get("X-Appengine-Country") {
 	case "", "ZZ", "CN":
 		return true
 	}