feat: cache env value in-case network is not reachable (#10251)

pkg/env/web_env_test.go

@@ -0,0 +1,81 @@
+/*
+ * MinIO Cloud Storage, (C) 2020 MinIO, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package env
+
+import (
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"testing"
+
+	"github.com/gorilla/mux"
+)
+
+func GetenvHandler(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	if vars["namespace"] != "default" {
+		http.Error(w, "namespace not found", http.StatusNotFound)
+		return
+	}
+	if vars["name"] != "minio" {
+		http.Error(w, "tenant not found", http.StatusNotFound)
+		return
+	}
+	if vars["key"] != "MINIO_ARGS" {
+		http.Error(w, "key not found", http.StatusNotFound)
+		return
+	}
+	w.Write([]byte("http://127.0.0.{1..4}:9000/data{1...4}"))
+	w.(http.Flusher).Flush()
+}
+
+func startTestServer(t *testing.T) *httptest.Server {
+	router := mux.NewRouter().SkipClean(true).UseEncodedPath()
+	router.Methods(http.MethodGet).
+		Path("/webhook/v1/getenv/{namespace}/{name}").
+		HandlerFunc(GetenvHandler).Queries("key", "{key:.*}")
+
+	ts := httptest.NewServer(router)
+	t.Cleanup(func() {
+		ts.Close()
+	})
+
+	return ts
+}
+
+func TestWebEnv(t *testing.T) {
+	ts := startTestServer(t)
+
+	u, err := url.Parse(ts.URL)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	v, err := getEnvValueFromHTTP(
+		fmt.Sprintf("env://minio:minio123@%s/webhook/v1/getenv/default/minio",
+			u.Host),
+		"MINIO_ARGS")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if v != "http://127.0.0.{1..4}:9000/data{1...4}" {
+		t.Fatalf("Unexpected value %s", v)
+	}
+}