feat: allow to disable "end on process signal" handlers

Implements #280

Author: Cactusbone

README.md

@@ -161,6 +161,10 @@ A [bunyan logger](https://github.com/trentm/node-bunyan) instance. Created by de
 Sets the timeout (in ms) after that an idle connection is closed by the server  
 __Default:__ `0`
 
+#### `endOnProcessSignal`
+Whether to close ftp server and exit process on SIGTERM/SIGINT/SIGQUIT signals or not
+__Default:__ `true`
+
 ## CLI
 
 `ftp-srv` also comes with a builtin CLI.

src/index.js

@@ -24,7 +24,8 @@ class FtpServer extends EventEmitter {
       whitelist: [],
       greeting: null,
       tls: false,
-      timeout: 0
+      timeout: 0,
+      endOnProcessSignal: true,
     }, options);
 
     this._greeting = this.setupGreeting(this.options.greeting);
@@ -70,9 +71,11 @@ class FtpServer extends EventEmitter {
 
     const quit = _.debounce(this.quit.bind(this), 100);
 
-    process.on('SIGTERM', quit);
-    process.on('SIGINT', quit);
-    process.on('SIGQUIT', quit);
+    if (this.options.endOnProcessSignal) {
+      process.on('SIGTERM', quit);
+      process.on('SIGINT', quit);
+      process.on('SIGQUIT', quit);
+    }
   }
 
   get isTLS() {