feat: add the 'wait-for-dns' flag

Allows the user to wait even if the address cannot be resolved; useful
if you know you will have to wait for DNS records to be created. Closes #41

README.md

@@ -65,6 +65,7 @@ The following parameters are accepted:
 | `<target>` | Required. The target to test for. Can be just a port, a colon and port (as one would use with [httpie](https://httpie.org/) or host and port. Examples: `8080`, `:3000`, `127.0.0.1:443`. |
 | `--output, -o`  | Optional. Output style to use. Can be `dots` (default) or `silent` (no output). |
 | `--timeout, -t` | Optional. Timeout (in milliseconds). |
+| `--wait-for-dns` | Optional. Do not error if the response is `ENOTFOUND`, just keep on waiting (useful if you are waiting for a DNS record to also be created). |
 
 ### Error Codes
 
@@ -108,6 +109,7 @@ The CLI is a very shallow wrapper around this function. The `params` object take
 | `<target>`      | `port`        | Required. Port to wait for. |
 | `--output`      | `output`      | Optional. Defaults to `dots`. Output style to use. `silent` also accepted. |
 | `--timeout, -t` | `timeout` | Optional. Defaults to `0`. Timeout (in milliseconds). If `0`, then the operation will never timeout. |
+| `--wait-for-dns` | `waitForDns` | Optional. Defaults to `false`. |
 
 # Developer Guide
 

bin/wait-port.js

@@ -13,23 +13,27 @@ program
   .description('Wait for a target to accept connections, e.g: wait-port localhost:8080')
   .option('-t, --timeout [n]', 'Timeout', parseInt)
   .option('-o, --output [mode]', 'Output mode (silent, dots). Default is silent.')
+  .option('--wait-for-dns', 'Do not fail on ENOTFOUND, meaning you can wait for DNS record creation. Default is false.')
   .arguments('<target>')
   .action((target) => {
     //  Validate the parameters (extractTarget) will throw if target is invalid).
     const { protocol, host, port, path } = extractTarget(target);
     const timeout = program.timeout || 0;
     const output = program.output;
+    const waitForDns = program.waitForDns;
 
     debug(`Timeout: ${timeout}`);
     debug(`Target: ${target} => ${protocol}://${host}:${port}${path}`);
+    debug(`waitForDns: ${waitForDns}`);
 
     const params = {
       timeout,
       protocol,
       host,
       port,
       path,
-      output
+      output,
+      waitForDns,
     };
 
     waitPort(params)
@@ -59,6 +63,7 @@ program.on('--help', () => {
   console.log('    $ wait-port -t 10 :8080');
   console.log('    $ wait-port google.com:443');
   console.log('    $ wait-port http://localhost:5000/healthcheck');
+  console.log('    $ wait-port --wait-for-dns http://mynewdomain.com:80');
   console.log('');
 });
 

lib/validate-parameters.js

@@ -32,6 +32,10 @@ function validateParameters(params) {
   if (!Number.isInteger(timeout)) throw new ValidationError('\'timeout\' must be a number.');
   if (timeout < 0) throw new ValidationError('\'timeout\' must be greater or equal to 0.');
 
+  //  Validate and coerce the wait-for-dns parameter.
+  const waitForDns = params.waitForDns || false;
+  if (typeof waitForDns !== 'boolean') throw new ValidationError('\'wait-for-dns\' must be a boolean.');
+
   //  Coerce the output.
   const output = params.output || 'dots';
 
@@ -50,7 +54,8 @@ function validateParameters(params) {
     path,
     interval,
     timeout,
-    output
+    output,
+    waitForDns,
   };
 }
 

lib/validate-parameters.spec.js

@@ -8,7 +8,8 @@ describe('validateParameters', () => {
       port: 8080,
       interval: 2000,
       timeout: 0,
-      output: 'silent'
+      output: 'silent',
+      waitForDns: false,
     };
   };
 
@@ -126,4 +127,21 @@ describe('validateParameters', () => {
 
   });
 
+  it('should default the wait-for-dns flag to false', () => {
+
+    const params = validParams();
+    delete params.waitForDns;
+    const validatedParams = validateParameters(params);
+    assert.equal(validatedParams.waitForDns, false);
+
+  });
+
+  it('should throw if the wait-for-dns parameter is not a boolean', () => {
+
+    const params = validParams();
+    params.waitForDns = 'not-a-boolean';
+    assert.throws(() => validateParameters(params), /wait-for-dns.*boolean.*/);
+
+  });
+
 });