feat: show a sensible error message if the address cannot be found (#46)

This handles ENOTFOUND errors and ensures that if the address is
unresolvable we fail-fast with a meaningful error.

README.md

@@ -75,8 +75,10 @@ The following error codes are returned:
 | Code | Meaning |
 |------|---------|
 | `0`  | The specified port on the host is accepting connections. |
-| `1`  | A timeout occured waiting for the port to open. |
-| `2`  | Un unknown error occured waiting for the port to open. The program cannot establish whether the port is open or not. |
+| `1`  | A timeout occurred waiting for the port to open. |
+| `2`  | An unknown error occurred waiting for the port to open. The program cannot establish whether the port is open or not. |
+| `3`  | The address cannot be found (e.g. no DNS entry, or unresolvable). |
+r
 
 # API
 

bin/wait-port.js

@@ -4,7 +4,8 @@ const debug = require('debug')('wait-port');
 const program = require('commander');
 const pkg = require('../package.json');
 const extractTarget = require('../lib/extract-target');
-const ValidationError = require('../lib/validation-error');
+const ValidationError = require('../lib/errors/validation-error');
+const ConnectionError = require('../lib/errors/connection-error');
 const waitPort = require('../lib/wait-port');
 
 program
@@ -38,8 +39,11 @@ program
       .catch((err) => {
         //  Show validation errors in red.
         if (err instanceof ValidationError) {
-          console.error(chalk.red(err.message));
+          console.error(`\n\n  ${chalk.red(err.message)}`);
           process.exit(2);
+        } else if (err instanceof ConnectionError) {
+          console.error(`\n\n  ${chalk.red(err.message)}`);
+          process.exit(4);
         } else {
           console.error(`Unknown error occurred waiting for ${target}: ${err}`);
           process.exit(3);

lib/errors/connection-error.js

@@ -0,0 +1,9 @@
+class ConnectionError extends Error {
+  constructor(message) {
+    super(message);
+    Error.captureStackTrace(this, this.constructor);
+    this.name = 'ConnectionError';
+  }
+}
+
+module.exports = ConnectionError;

lib/validation-error.js → lib/errors/validation-error.js

@@ -2,6 +2,7 @@ class ValidationError extends Error {
   constructor(message) {
     super(message);
     Error.captureStackTrace(this, this.constructor);
+    this.name = 'ValidationError';
   }
 }
 

lib/validate-parameters.js

@@ -1,5 +1,5 @@
 const outputFunctions = require('./output-functions');
-const ValidationError = require('./validation-error');
+const ValidationError = require('./errors/validation-error');
 
 function validateParameters(params) {
   //  Coerce the protocol.

lib/wait-port.js

@@ -2,6 +2,7 @@ const debug = require('debug')('wait-port');
 const net = require('net');
 const outputFunctions = require('./output-functions');
 const validateParameters = require('./validate-parameters');
+const ConnectionError = require('./errors/connection-error');
 
 function createConnectionWithTimeout({ host, port }, timeout, callback) {
   //  Variable to hold the timer we'll use to kill the socket if we don't
@@ -104,6 +105,12 @@ function tryConnect(options, timeout) {
             debug('Socket not open: ECONNRESET');
             socket.destroy();
             return resolve(false);
+          } else if (err.code === 'ENOTFOUND') {
+            //  This will occur if the address is not found, i.e. due to a dns
+            //  lookup fail (normally a problem if the domain is wrong).
+            debug('Socket cannot be opened: ENOTFOUND');
+            socket.destroy();
+            return reject(new ConnectionError(`The address '${options.host}' cannot be found`));
           }
 
           //  Trying to open the socket has resulted in an error we don't

lib/wait-port.spec.js

@@ -69,6 +69,20 @@ describe('wait-port', () => {
       });
   });
 
+  it('should error if the address is not found', () => {
+
+    //  Wait for a point on an address (I hope) does not exist.
+    return waitPort({ host: 'ireallyhopethatthisdomainnamedoesnotexist.com', port: 9021, timeout: 3000, output: 'silent' })
+      .then(() => {
+        assert.fail('The operation should throw, rather than completing.');
+      })
+      .catch((err) => {
+        assert.equal(err.name, 'ConnectionError', 'A ConnectionFailed error should be thrown');
+        assert(/.*address.*ireallyhopethatthisdomainnamedoesnotexist.com/.test(err.message));
+      });
+  });
+
+
   it('should successfully wait for a valid http response', () => {
     const server = http.createServer((req, res) => {
       res.writeHead(200);

package.json

@@ -12,7 +12,8 @@
   "man": "./man/wait-port.1",
   "scripts": {
     "lint": "eslint .",
-    "test": "DEBUG=wait-port nyc --report-dir 'artifacts/coverage' -x 'lib/**/*.spec.js' --reporter=html --reporter=text mocha --recursive -t 10000 'lib/**/*.spec.js' --reporter mocha-junit-reporter --reporter-options mochaFile=./artifacts/test-reports/test-results.xml",
+    "test": "DEBUG=wait-port nyc --report-dir 'artifacts/coverage' -x 'lib/**/*.spec.js' --reporter=html --reporter=text mocha --recursive -t 10000 'lib/**/*.spec.js'",
+    "test:ci": "DEBUG=wait-port nyc --report-dir 'artifacts/coverage' -x 'lib/**/*.spec.js' --reporter=html --reporter=text mocha --recursive -t 10000 'lib/**/*.spec.js' --reporter mocha-junit-reporter --reporter-options mochaFile=./artifacts/test-reports/test-results.xml",
     "test:watch": "DEBUG=wait-port mocha --watch --recursive -t 10000 'lib/**/*.spec.js'",
     "report-coverage": "nyc report --reporter=text-lcov > ./artifacts/coverage/coverage.lcov && codecov",
     "debug": "DEBUG=wait-port mocha --recursive --inspect --debug-brk 'lib/**/*.spec.js'"