Add iac providers endpoint (#1307)

* Add GetProviderIacVersions function

* Add providers endpoint

* Fix set json resp Content-Type

* Update var name

* Add providers e2e test

* Add comments to iac providers

* Add IacProviders unit tests

Co-authored-by: Kyle Hasty <khasty@tenable.com>
Co-authored-by: Cesar Rodriguez <cesar@accurics.com>
Co-authored-by: Gaurav Gogia <16029099+gaurav-gogia@users.noreply.github.com>

pkg/http-server/helpers.go

@@ -23,8 +23,8 @@ import (
 
 // apiResponse creates an API response
 func apiResponse(w http.ResponseWriter, msg string, statusCode int) {
-	w.WriteHeader(statusCode)
 	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(statusCode)
 	fmt.Fprint(w, msg)
 }
 

pkg/http-server/iac-providers.go

@@ -0,0 +1,55 @@
+/*
+    Copyright (C) 2022 Tenable, 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 httpserver
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	iacProvider "github.com/tenable/terrascan/pkg/iac-providers"
+	"go.uber.org/zap"
+)
+
+// IacProvider contains response body for iac providers
+type IacProvider struct {
+	Type           string   `json:"type"`
+	Versions       []string `json:"versions"`
+	DefaultVersion string   `json:"defaultVersion"`
+}
+
+// iacProviders returns list of iac providers
+func (g *APIHandler) iacProviders(w http.ResponseWriter, r *http.Request) {
+	var providers = []IacProvider{}
+	for _, provider := range iacProvider.SupportedIacProviders() {
+		providers = append(providers, IacProvider{
+			Type:           string(provider),
+			Versions:       iacProvider.GetProviderIacVersions(provider),
+			DefaultVersion: iacProvider.GetDefaultIacVersion(provider),
+		})
+	}
+
+	response, err := json.MarshalIndent(providers, "", "  ")
+	if err != nil {
+		errMsg := fmt.Sprintf("failed to create JSON. error: '%v'", err)
+		zap.S().Error(errMsg)
+		apiErrorResponse(w, errMsg, http.StatusInternalServerError)
+		return
+	}
+
+	apiResponse(w, string(response), http.StatusOK)
+}

pkg/http-server/iac-providers_test.go

@@ -0,0 +1,41 @@
+package httpserver
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestIacProviders(t *testing.T) {
+
+	handler := NewAPIHandler()
+
+	t.Run("test providers api status", func(t *testing.T) {
+		var (
+			req, _ = http.NewRequest(http.MethodGet, "/v1/providers", nil)
+			resp   = httptest.NewRecorder()
+			want   = http.StatusOK
+		)
+		handler.iacProviders(resp, req)
+		got := resp.Result().StatusCode
+
+		if got != want {
+			t.Errorf("incorrect providers status code, got: '%v', want: '%v'", got, want)
+		}
+	})
+
+	t.Run("test providers api response structure", func(t *testing.T) {
+		var (
+			req, _ = http.NewRequest(http.MethodGet, "/v1/providers", nil)
+			resp   = httptest.NewRecorder()
+		)
+		handler.iacProviders(resp, req)
+
+		var data []IacProvider
+		err := json.NewDecoder(resp.Body).Decode(&data)
+		if err != nil {
+			t.Errorf("error parsing response body, error: '%v'", err.Error())
+		}
+	})
+}

pkg/http-server/routes.go

@@ -33,6 +33,7 @@ func (g *APIServer) Routes() []*Route {
 	h := NewAPIHandler()
 	routes := []*Route{
 		{verb: "GET", path: "/health", fn: h.Health},
+		{verb: "GET", path: versionedPath("/providers"), fn: h.iacProviders},
 		{verb: "POST", path: versionedPath("/{iac}/{iacVersion}/{cloud}/local/file/scan"), fn: h.scanFile},
 		{verb: "POST", path: versionedPath("/{iac}/{iacVersion}/{cloud}/remote/dir/scan"), fn: h.scanRemoteRepo},
 

pkg/iac-providers/providers.go

@@ -79,6 +79,17 @@ func SupportedIacVersions() []string {
 	return iacVersions
 }
 
+// GetProviderIacVersions returns list of Iac Provider versions for the given IaC type
+func GetProviderIacVersions(iacType string) []string {
+	var versions []string
+
+	for version := range supportedIacProviders[supportedIacType(iacType)] {
+		versions = append(versions, string(version))
+	}
+	sort.Strings(versions)
+	return versions
+}
+
 // GetDefaultIacVersion returns the default IaC version for the given IaC type
 func GetDefaultIacVersion(iacType string) string {
 	return string(defaultIacVersions[supportedIacType(iacType)])

test/e2e/server/server_test.go

@@ -107,13 +107,15 @@ var _ = Describe("Server", func() {
 				It("server should be accepting requests", func() {
 					// logs are written in StdErr
 					Eventually(session.Err, serverUtils.ServerCommandTimeout).Should(gbytes.Say("Route GET - /health"))
+					Eventually(session.Err, serverUtils.ServerCommandTimeout).Should(gbytes.Say("Route GET - /v1/providers"))
 					Eventually(session.Err, serverUtils.ServerCommandTimeout).Should(gbytes.Say("Route POST - /v1/{iac}/{iacVersion}/{cloud}/local/file/scan"))
 					Eventually(session.Err, serverUtils.ServerCommandTimeout).Should(gbytes.Say("Route POST - /v1/{iac}/{iacVersion}/{cloud}/remote/dir/scan"))
 					Eventually(session.Err, serverUtils.ServerCommandTimeout).Should(gbytes.Say("http server listening at port 9010"))
 				})
 
 				Context("request with no body on all handlers", func() {
 					healthCheckURL := fmt.Sprintf("%s:%d/health", host, defaultPort)
+					providersURL := fmt.Sprintf("%s:%d/v1/providers", host, defaultPort)
 					terraformV12LocalScanURL := fmt.Sprintf("%s:%d/v1/terraform/v12/all/local/file/scan", host, defaultPort)
 					terrformV12RemoteScanURL := fmt.Sprintf("%s:%d/v1/terraform/v12/aws/remote/dir/scan", host, defaultPort)
 
@@ -127,6 +129,16 @@ var _ = Describe("Server", func() {
 						})
 					})
 
+					When("GET request on providers is made", func() {
+						It("should get 200 OK response", func() {
+							r, err := serverUtils.MakeHTTPRequest(http.MethodGet, providersURL)
+							Expect(err).NotTo(HaveOccurred())
+							defer r.Body.Close()
+							Expect(r).NotTo(BeNil())
+							Expect(r.StatusCode).To(BeIdenticalTo(http.StatusOK))
+						})
+					})
+
 					When("GET request on file scan handler is made", func() {
 						It("should receive method not allowed response", func() {
 							r, err := serverUtils.MakeHTTPRequest(http.MethodGet, terraformV12LocalScanURL)
@@ -177,6 +189,16 @@ var _ = Describe("Server", func() {
 						})
 					})
 
+					When("POST request on providers", func() {
+						It("should receive method not allowed response", func() {
+							r, err := serverUtils.MakeHTTPRequest(http.MethodPost, providersURL)
+							Expect(err).NotTo(HaveOccurred())
+							defer r.Body.Close()
+							Expect(r).NotTo(BeNil())
+							Expect(r.StatusCode).To(BeIdenticalTo(http.StatusMethodNotAllowed))
+						})
+					})
+
 					Context("server is stopped", func() {
 						It("should gracefully exit", func() {
 							if utils.IsWindowsPlatform() {