Merge pull request #493 from alphagov/load-backends-from-env-vars

Load backends from env vars

integration_tests/backend_helpers.go

@@ -1,6 +1,7 @@
 package integration
 
 import (
+	"net"
 	"net/http"
 	"net/http/httptest"
 	"strconv"
@@ -12,14 +13,39 @@ import (
 	"github.com/onsi/gomega/ghttp"
 )
 
-func startSimpleBackend(identifier string) *httptest.Server {
-	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+var backends = map[string]string{
+	"backend-1":   "127.0.0.1:6789",
+	"backend-2":   "127.0.0.1:6790",
+	"outer":       "127.0.0.1:6792",
+	"inner":       "127.0.0.1:6793",
+	"innerer":     "127.0.0.1:6794",
+	"root":        "127.0.0.1:6795",
+	"other":       "127.0.0.1:6796",
+	"fallthrough": "127.0.0.1:6797",
+	"down":        "127.0.0.1:6798",
+	"slow-1":      "127.0.0.1:6799",
+	"slow-2":      "127.0.0.1:6800",
+	"backend":     "127.0.0.1:6801",
+	"be":          "127.0.0.1:6802",
+	"not-running": "127.0.0.1:6803",
+	"with-path":   "127.0.0.1:6804",
+}
+
+func startSimpleBackend(identifier, host string) *httptest.Server {
+	l, err := net.Listen("tcp", host)
+	Expect(err).NotTo(HaveOccurred())
+
+	ts := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		_, err := w.Write([]byte(identifier))
 		Expect(err).NotTo(HaveOccurred())
 	}))
+	ts.Listener.Close()
+	ts.Listener = l
+	ts.Start()
+	return ts
 }
 
-func startTarpitBackend(delays ...time.Duration) *httptest.Server {
+func startTarpitBackend(host string, delays ...time.Duration) *httptest.Server {
 	responseDelay := 2 * time.Second
 	if len(delays) > 0 {
 		responseDelay = delays[0]
@@ -28,7 +54,11 @@ func startTarpitBackend(delays ...time.Duration) *httptest.Server {
 	if len(delays) > 1 {
 		bodyDelay = delays[1]
 	}
-	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+
+	l, err := net.Listen("tcp", host)
+	Expect(err).NotTo(HaveOccurred())
+
+	ts := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		body := "Tarpit\n"
 
 		if responseDelay > 0 {
@@ -44,24 +74,26 @@ func startTarpitBackend(delays ...time.Duration) *httptest.Server {
 		_, err := w.Write([]byte(body))
 		Expect(err).NotTo(HaveOccurred())
 	}))
+	ts.Listener.Close()
+	ts.Listener = l
+	ts.Start()
+	return ts
 }
 
-func startRecordingBackend() *ghttp.Server {
-	return startRecordingServer(false)
-}
-
-func startRecordingTLSBackend() *ghttp.Server {
-	return startRecordingServer(true)
-}
+func startRecordingBackend(tls bool, host string) *ghttp.Server {
+	l, err := net.Listen("tcp", host)
+	Expect(err).NotTo(HaveOccurred())
 
-func startRecordingServer(tls bool) (server *ghttp.Server) {
+	ts := ghttp.NewUnstartedServer()
+	ts.HTTPTestServer.Listener.Close()
+	ts.HTTPTestServer.Listener = l
 	if tls {
-		server = ghttp.NewTLSServer()
+		ts.HTTPTestServer.StartTLS()
 	} else {
-		server = ghttp.NewServer()
+		ts.Start()
 	}
 
-	server.AllowUnhandledRequests = true
-	server.UnhandledRequestStatusCode = http.StatusOK
-	return server
+	ts.AllowUnhandledRequests = true
+	ts.UnhandledRequestStatusCode = http.StatusOK
+	return ts
 }

integration_tests/integration_test.go

@@ -20,7 +20,14 @@ var _ = BeforeSuite(func() {
 	if err != nil {
 		Fail(err.Error())
 	}
-	err = startRouter(routerPort, apiPort, nil)
+
+	backendEnvVars := []string{}
+	for id, host := range backends {
+		envVar := "BACKEND_URL_" + id + "=http://" + host
+		backendEnvVars = append(backendEnvVars, envVar)
+	}
+
+	err = startRouter(routerPort, apiPort, backendEnvVars)
 	if err != nil {
 		Fail(err.Error())
 	}

integration_tests/performance_test.go

@@ -20,10 +20,8 @@ var _ = Describe("Performance", func() {
 		)
 
 		BeforeEach(func() {
-			backend1 = startSimpleBackend("backend 1")
-			backend2 = startSimpleBackend("backend 2")
-			addBackend("backend-1", backend1.URL)
-			addBackend("backend-2", backend2.URL)
+			backend1 = startSimpleBackend("backend 1", backends["backend-1"])
+			backend2 = startSimpleBackend("backend 2", backends["backend-2"])
 			addRoute("/one", NewBackendRoute("backend-1"))
 			addRoute("/two", NewBackendRoute("backend-2"))
 			reloadRoutes(apiPort)
@@ -58,10 +56,9 @@ var _ = Describe("Performance", func() {
 
 		Describe("with one slow backend hit separately", func() {
 			It("Router should not cause errors or much latency", func() {
-				slowBackend := startTarpitBackend(time.Second)
+				slowBackend := startTarpitBackend(backends["slow-1"], time.Second)
 				defer slowBackend.Close()
-				addBackend("backend-slow", slowBackend.URL)
-				addRoute("/slow", NewBackendRoute("backend-slow"))
+				addRoute("/slow", NewBackendRoute("slow-1"))
 				reloadRoutes(apiPort)
 
 				_, gen := generateLoad([]string{routerURL(routerPort, "/slow")}, 50)
@@ -73,8 +70,7 @@ var _ = Describe("Performance", func() {
 
 		Describe("with one downed backend hit separately", func() {
 			It("Router should not cause errors or much latency", func() {
-				addBackend("backend-down", "http://127.0.0.1:3162/")
-				addRoute("/down", NewBackendRoute("backend-down"))
+				addRoute("/down", NewBackendRoute("down"))
 				reloadRoutes(apiPort)
 
 				_, gen := generateLoad([]string{routerURL(routerPort, "/down")}, 50)
@@ -96,12 +92,10 @@ var _ = Describe("Performance", func() {
 		var backend2 *httptest.Server
 
 		BeforeEach(func() {
-			backend1 = startTarpitBackend(time.Second)
-			backend2 = startTarpitBackend(time.Second)
-			addBackend("backend-1", backend1.URL)
-			addBackend("backend-2", backend2.URL)
-			addRoute("/one", NewBackendRoute("backend-1"))
-			addRoute("/two", NewBackendRoute("backend-2"))
+			backend1 = startTarpitBackend(backends["slow-1"], time.Second)
+			backend2 = startTarpitBackend(backends["slow-2"], time.Second)
+			addRoute("/one", NewBackendRoute("slow-1"))
+			addRoute("/two", NewBackendRoute("slow-2"))
 			reloadRoutes(apiPort)
 		})
 		AfterEach(func() {

integration_tests/proxy_function_test.go

@@ -19,7 +19,6 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 
 	Describe("connecting to the backend", func() {
 		It("should return a 502 if the connection to the backend is refused", func() {
-			addBackend("not-running", "http://127.0.0.1:3164/")
 			addRoute("/not-running", NewBackendRoute("not-running"))
 			reloadRoutes(apiPort)
 
@@ -31,21 +30,20 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 
 			logDetails := lastRouterErrorLogEntry()
 			Expect(logDetails.Fields).To(Equal(map[string]interface{}{
-				"error":          "dial tcp 127.0.0.1:3164: connect: connection refused",
+				"error":          "dial tcp 127.0.0.1:6803: connect: connection refused",
 				"request":        "GET /not-running HTTP/1.1",
 				"request_method": "GET",
 				"status":         float64(502), // All numbers in JSON are floating point
-				"upstream_addr":  "127.0.0.1:3164",
+				"upstream_addr":  "127.0.0.1:6803",
 			}))
 			Expect(logDetails.Timestamp).To(BeTemporally("~", time.Now(), time.Second))
 		})
 
 		It("should log and return a 504 if the connection times out in the configured time", func() {
-			err := startRouter(3167, 3166, []string{"ROUTER_BACKEND_CONNECT_TIMEOUT=0.3s"})
+			err := startRouter(3167, 3166, []string{"ROUTER_BACKEND_CONNECT_TIMEOUT=0.3s", "BACKEND_URL_black-hole=http://240.0.0.0:1234/"})
 			Expect(err).NotTo(HaveOccurred())
 			defer stopRouter(3167)
 
-			addBackend("black-hole", "http://240.0.0.0:1234/")
 			addRoute("/should-time-out", NewBackendRoute("black-hole"))
 			reloadRoutes(3166)
 
@@ -74,14 +72,12 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 			var tarpit1, tarpit2 *httptest.Server
 
 			BeforeEach(func() {
-				err := startRouter(3167, 3166, []string{"ROUTER_BACKEND_HEADER_TIMEOUT=0.3s"})
+				err := startRouter(3167, 3166, []string{"ROUTER_BACKEND_HEADER_TIMEOUT=0.3s", "BACKEND_URL_slow-1=http://127.0.0.1:6256/", "BACKEND_URL_slow-2=http://127.0.0.1:6253/"})
 				Expect(err).NotTo(HaveOccurred())
-				tarpit1 = startTarpitBackend(time.Second)
-				tarpit2 = startTarpitBackend(100*time.Millisecond, 500*time.Millisecond)
-				addBackend("tarpit1", tarpit1.URL)
-				addBackend("tarpit2", tarpit2.URL)
-				addRoute("/tarpit1", NewBackendRoute("tarpit1"))
-				addRoute("/tarpit2", NewBackendRoute("tarpit2"))
+				tarpit1 = startTarpitBackend("127.0.0.1:6256", time.Second)
+				tarpit2 = startTarpitBackend("127.0.0.1:6253", 100*time.Millisecond, 500*time.Millisecond)
+				addRoute("/tarpit1", NewBackendRoute("slow-1"))
+				addRoute("/tarpit2", NewBackendRoute("slow-2"))
 				reloadRoutes(3166)
 			})
 
@@ -118,8 +114,7 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 
 	Describe("header handling", func() {
 		BeforeEach(func() {
-			recorder = startRecordingBackend()
-			addBackend("backend", recorder.URL())
+			recorder = startRecordingBackend(false, backends["backend"])
 			addRoute("/foo", NewBackendRoute("backend", "prefix"))
 			reloadRoutes(apiPort)
 		})
@@ -242,8 +237,7 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 
 	Describe("request verb, path, query and body handling", func() {
 		BeforeEach(func() {
-			recorder = startRecordingBackend()
-			addBackend("backend", recorder.URL())
+			recorder = startRecordingBackend(false, backends["backend"])
 			addRoute("/foo", NewBackendRoute("backend", "prefix"))
 			reloadRoutes(apiPort)
 		})
@@ -298,18 +292,20 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 
 	Describe("handling a backend with a non '/' path", func() {
 		BeforeEach(func() {
-			recorder = startRecordingBackend()
-			addBackend("backend", recorder.URL()+"/something")
-			addRoute("/foo/bar", NewBackendRoute("backend", "prefix"))
-			reloadRoutes(apiPort)
+			err := startRouter(3167, 3166, []string{"ROUTER_TLS_SKIP_VERIFY=1", "BACKEND_URL_with-path=http://127.0.0.1:6804/something"})
+			Expect(err).NotTo(HaveOccurred())
+			recorder = startRecordingBackend(false, backends["with-path"])
+			addRoute("/foo/bar", NewBackendRoute("with-path", "prefix"))
+			reloadRoutes(3166)
 		})
 
 		AfterEach(func() {
 			recorder.Close()
+			stopRouter(3167)
 		})
 
 		It("should merge the 2 paths", func() {
-			resp := routerRequest(routerPort, "/foo/bar")
+			resp := routerRequest(3167, "/foo/bar")
 			Expect(resp.StatusCode).To(Equal(200))
 
 			Expect(recorder.ReceivedRequests()).To(HaveLen(1))
@@ -318,7 +314,7 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 		})
 
 		It("should preserve the request query string", func() {
-			resp := routerRequest(routerPort, "/foo/bar?baz=qux")
+			resp := routerRequest(3167, "/foo/bar?baz=qux")
 			Expect(resp.StatusCode).To(Equal(200))
 
 			Expect(recorder.ReceivedRequests()).To(HaveLen(1))
@@ -329,8 +325,7 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 
 	Describe("handling HTTP/1.0 requests", func() {
 		BeforeEach(func() {
-			recorder = startRecordingBackend()
-			addBackend("backend", recorder.URL())
+			recorder = startRecordingBackend(false, backends["backend"])
 			addRoute("/foo", NewBackendRoute("backend", "prefix"))
 			reloadRoutes(apiPort)
 		})
@@ -362,10 +357,9 @@ var _ = Describe("Functioning as a reverse proxy", func() {
 
 	Describe("handling requests to a HTTPS backend", func() {
 		BeforeEach(func() {
-			err := startRouter(3167, 3166, []string{"ROUTER_TLS_SKIP_VERIFY=1"})
+			err := startRouter(3167, 3166, []string{"ROUTER_TLS_SKIP_VERIFY=1", "BACKEND_URL_backend=https://127.0.0.1:2486"})
 			Expect(err).NotTo(HaveOccurred())
-			recorder = startRecordingTLSBackend()
-			addBackend("backend", recorder.URL())
+			recorder = startRecordingBackend(true, "127.0.0.1:2486")
 			addRoute("/foo", NewBackendRoute("backend", "prefix"))
 			reloadRoutes(3166)
 		})

integration_tests/redirect_test.go

@@ -222,8 +222,7 @@ var _ = Describe("Redirection", func() {
 		var recorder *ghttp.Server
 
 		BeforeEach(func() {
-			recorder = startRecordingBackend()
-			addBackend("be", recorder.URL())
+			recorder = startRecordingBackend(false, backends["be"])
 			addRoute("/guidance/keeping-a-pet-pig-or-micropig", NewBackendRoute("be", "exact"))
 			addRoute("/GUIDANCE/keeping-a-pet-pig-or-micropig", NewBackendRoute("be", "exact"))
 			reloadRoutes(apiPort)

integration_tests/route_helpers.go

@@ -6,7 +6,6 @@ import (
 	"time"
 
 	"github.com/globalsign/mgo"
-	"github.com/globalsign/mgo/bson"
 
 	// revive:disable:dot-imports
 	. "github.com/onsi/ginkgo/v2"
@@ -91,11 +90,6 @@ func initRouteHelper() error {
 	return nil
 }
 
-func addBackend(id, url string) {
-	err := routerDB.C("backends").Insert(bson.M{"backend_id": id, "backend_url": url})
-	Expect(err).NotTo(HaveOccurred())
-}
-
 func addRoute(path string, route Route) {
 	route.IncomingPath = path
 

integration_tests/route_loading_test.go

@@ -1,7 +1,6 @@
 package integration
 
 import (
-	"fmt"
 	"net/http/httptest"
 
 	. "github.com/onsi/ginkgo/v2"
@@ -12,14 +11,11 @@ var _ = Describe("loading routes from the db", func() {
 	var (
 		backend1 *httptest.Server
 		backend2 *httptest.Server
-		backend3 *httptest.Server
 	)
 
 	BeforeEach(func() {
-		backend1 = startSimpleBackend("backend 1")
-		backend2 = startSimpleBackend("backend 2")
-		addBackend("backend-1", backend1.URL)
-		addBackend("backend-2", backend2.URL)
+		backend1 = startSimpleBackend("backend 1", backends["backend-1"])
+		backend2 = startSimpleBackend("backend 2", backends["backend-2"])
 	})
 	AfterEach(func() {
 		backend1.Close()
@@ -73,34 +69,4 @@ var _ = Describe("loading routes from the db", func() {
 			Expect(readBody(resp)).To(Equal("backend 1"))
 		})
 	})
-
-	Context("a backend an env var overriding the backend_url", func() {
-		BeforeEach(func() {
-			// This tests the behaviour of backend.ParseURL overriding the backend_url
-			// provided in the DB with the value of an env var
-			blackHole := "240.0.0.0/foo"
-			backend3 = startSimpleBackend("backend 3")
-			addBackend("backend-3", blackHole)
-
-			stopRouter(routerPort)
-			err := startRouter(routerPort, apiPort, []string{fmt.Sprintf("BACKEND_URL_backend-3=%s", backend3.URL)})
-			Expect(err).NotTo(HaveOccurred())
-
-			addRoute("/oof", NewBackendRoute("backend-3"))
-			reloadRoutes(apiPort)
-		})
-
-		AfterEach(func() {
-			stopRouter(routerPort)
-			err := startRouter(routerPort, apiPort, nil)
-			Expect(err).NotTo(HaveOccurred())
-			backend3.Close()
-		})
-
-		It("should send requests to the backend_url provided in the env var", func() {
-			resp := routerRequest(routerPort, "/oof")
-			Expect(resp.StatusCode).To(Equal(200))
-			Expect(readBody(resp)).To(Equal("backend 3"))
-		})
-	})
 })