add check to prevent IPv6 connection issue with localhost on MacOS (#79)

Co-authored-by: Mathias Kron <[email protected]>

Author: merowinger92

README.md

@@ -67,6 +67,7 @@ $ awslocal sns list-topics
 
 ## Change Log
 
+* 2.16.0: Add check to prevent IPv6 connection issue with `localhost` on MacOS
 * 2.15.0: Fix issue with undefined BUCKET_NAME_OUTPUT variable; add CI build and eslint config
 * 2.14.0: Add switches in patches to accommodate new esbuild packaging mechanism in CDK v2.14.0+
 * 1.65.7: Add switch that checks for asset existence before symlinking assets; fix parsing fetched template body for JSON/YAML formats; add missing dependency to "diff" package

bin/cdklocal

@@ -7,6 +7,7 @@ const path = require("path");
 const http = require("http");
 const https = require("https");
 const crypto = require("crypto");
+const net = require('net');
 
 // config constants
 
@@ -19,13 +20,36 @@ const LAMBDA_MOUNT_CODE = ["1", "true"].includes(process.env.LAMBDA_MOUNT_CODE);
 // UTIL FUNCTIONS
 //----------------
 
-const getLocalEndpoint = () => `http://${getLocalHost()}`;
+const getLocalEndpoint = async () => `http://${await getLocalHost()}`;
 
 const port = process.env.EDGE_PORT || DEFAULT_EDGE_PORT;
 
-const getLocalHost = () => {
-  const host = process.env.LOCALSTACK_HOSTNAME || DEFAULT_HOSTNAME;
-  return `${host}:${port}`;
+var resolvedHostname = undefined;
+
+const getLocalHost = async () => {
+  if (resolvedHostname) {
+    // early exit to not resolve again
+    return `${resolvedHostname}:${port}`;
+  }
+
+  var hostname = process.env.LOCALSTACK_HOSTNAME || DEFAULT_HOSTNAME;
+  // attempt to connect to the given host/port
+  const socket = new net.Socket();
+  try {
+    await socket.connect({ host: hostname, port });
+  } catch (e) {
+    if (hostname === "localhost") {
+      // fall back to using local IPv4 address - to fix IPv6 issue on MacOS
+      // see, https://github.com/localstack/serverless-localstack/issues/125
+      // and https://github.com/localstack/aws-cdk-local/issues/78
+      hostname = "127.0.0.1";
+    }
+  } finally {
+    socket.destroy();
+  }
+
+  resolvedHostname = hostname;
+  return `${hostname}:${port}`;
 };
 
 const useLocal = () => {
@@ -85,14 +109,14 @@ const importLib = function importLib (libPath) {
   }
 };
 
-const setSdkOptions = (options, setHttpOptions) => {
+const setSdkOptions = async (options, setHttpOptions) => {
   if (!useLocal(options)) {
     return;
   }
   if (setHttpOptions) {
     options = options.httpOptions = options.httpOptions || {};
   }
-  options.endpoint = getLocalEndpoint();
+  options.endpoint = await getLocalEndpoint();
   options.s3ForcePathStyle = true;
   options.accessKeyId = "test";
   options.secretAccessKey = "test";
@@ -101,10 +125,10 @@ const setSdkOptions = (options, setHttpOptions) => {
 const patchProviderCredentials = (provider) => {
   const origConstr = provider.SdkProvider.withAwsCliCompatibleDefaults;
   provider.SdkProvider.withAwsCliCompatibleDefaults = async (options = {}) => {
-    setSdkOptions(options, true);
+    await setSdkOptions(options, true);
     const result = await origConstr(options);
     result.sdkOptions = result.sdkOptions || {};
-    setSdkOptions(result.sdkOptions);
+    await setSdkOptions(result.sdkOptions);
     return result;
   };
 
@@ -118,18 +142,18 @@ const patchCdkToolkit = (CdkToolkit) => {
   const CdkToolkitClass = CdkToolkit.ToolkitInfo || CdkToolkit;
   getMethods(CdkToolkitClass.prototype).forEach((meth) => {
     const original = CdkToolkitClass.prototype[meth];
-    CdkToolkitClass.prototype[meth] = function methFunc (...args) {
-      setSdkOptions(this.props.sdkProvider.sdkOptions);
+    CdkToolkitClass.prototype[meth] = async function methFunc (...args) {
+      await setSdkOptions(this.props.sdkProvider.sdkOptions);
       return original.bind(this).apply(this, args);
     };
   });
 };
 
 const patchCurrentAccount = (SDK) => {
   const currentAccountOrig = SDK.prototype.currentAccount;
-  SDK.prototype.currentAccount = function currentAccount () {
+  SDK.prototype.currentAccount = async function currentAccount () {
     const {config} = this;
-    setSdkOptions(config);
+    await setSdkOptions(config);
     return currentAccountOrig.bind(this)();
   };
 
@@ -149,9 +173,9 @@ const patchToolkitInfo = (ToolkitInfo) => {
 
   const setBucketUrl = function setBucketUrl (object) {
     Object.defineProperty(object, "bucketUrl", {
-      get () {
+      async get () {
         const bucket = this.requireOutput(BUCKET_NAME_OUTPUT);
-        const domain = this.requireOutput(BUCKET_DOMAIN_NAME_OUTPUT) || getLocalHost();
+        const domain = this.requireOutput(BUCKET_DOMAIN_NAME_OUTPUT) || await getLocalHost();
         return `https://${domain.replace(`${bucket}.`, "")}:${port}/${bucket}`;
       }
     });

package.json

@@ -1,7 +1,7 @@
 {
   "name": "aws-cdk-local",
   "description": "CDK Toolkit for use with LocalStack",
-  "version": "2.15.0",
+  "version": "2.16.0",
   "bin": {
     "cdklocal": "bin/cdklocal"
   },