DDevelopment & Design

Gerrit notifications via Rocket.Chat

Case

Gerrit often sends a lot of emails, especially if you take part in many projects. For a while we felt that sometimes it’s hard to notice the most important ones, like reviewers’ and Sputnik‘s comments on our changes. We use Rocket.Chat for text communication inside the company and most of us are connected throughout the day, so we thought it might be useful to get chat message notification every time a comment is added on one’s changes.

Gerrit hooks

Gerrit has a built-in mechanism for running hooks – scripts that are called whenever a specific event occurs. The script must be named the same as the hook. We created a bash script named comment-added, which is run every time someone adds a comment. Gerrit provides it with a lot of useful parameters, like project name, comment author, score, change owner, etc. Full documentation can be found here. After parsing those parameters, we can send a message to change owner on Rocket.Chat.

Gerrit hooks script have to be placed in a certain location. To avoid manually updating the files there, we set up a repository for hook scripts. They are periodically pulled to the correct location which simplifies the process of making changes to the scripts.

Integration with Rocket.Chat

Rocket.Chat has a pretty versatile REST API that allows us to send messages by calling curl from the comment-added script. Full documentation for the API can be found here. Currently, the API is in beta version, but so far we haven’t had any issues with it.

We previously set up a user that sends Jenkins automatic messages to our team chat and we reuse this user here. Firstly, we have to log in by calling api/v1/login endpoint:

curl https://<Rocket.Chat server address>/api/v1/login -d "username=<username>&password=<password>"

In response, we get a JSON with the logged user’s id and authorization token:

{
  "status": "success",
  "data": {
    "authToken": "<authorization token>",
    "userId": "<user id>"
  }
}

Next, we send a direct message to user by their username (in our case, we can get the username from change owner’s email), calling api/v1/chat.postMessage endpoint. This sends a direct message to the user, even if there was no previous conversation between the users – no need to set up a room or open chat. Example:

curl -H "X-Auth-Token: <authorization token>" \
  -H "X-User-Id: <user id>" \
  -H "Content-Type: application/json" \
  -d "{\"channel\": \"@<recipient username>\", \"text\": \"<message>\"}" \
  https://<Rocket.Chat server address>/api/v1/chat.postMessage

Summary

We created a simple script to solve the issue of getting notified when we get comments on our changes. So far, the team seems pleased with how this works and finds it quite useful. We hope that it would be useful for you as well – full code can be found here.

— Previous article

Tired of exporting your OSGI metatype to client manually?

Next article —

Idiomatic Peeking with Java Stream API

You May Also Like
DDevelopment & Design

Phonegap / Cordova and cross domain ssl request problem on android.

In one app I have participated, there was a use case:
  • User fill up a form.
  • User submit the form.
  • System send data via https to server and show a response.
During development there wasn’t any problem, but when we were going to release production version then some unsuspected situation occurred. I prepare the production version accordingly with standard flow for Android environment:
  • ant release
  • align
  • signing
During conduct tests on that version, every time I try to submit the form, a connection error appear. In that situation, at the first you should check whitelist in cordova settings. Every URL you want to connect to, must be explicit type in: 
res/xml/cordova.xml
If whitelist looks fine, the error is most likely caused by inner implementation of Android System. The Android WebView does not allow by default self-signed SSL certs. When app is debug-signed the SSL error is ignored, but if app is release-signed connection to untrusted services is blocked.



Workaround


You have to remember that secure connection to service with self-signed certificate is risky and unrecommended. But if you know what you are doing there is some workaround of the security problem. Behavior of method 
CordovaWebViewClient.onReceivedSslError
must be changed.


Thus add new class extended CordovaWebViewClient and override ‘onReceivedSslError’. I strongly suggest to implement custom onReceiveSslError as secure as possible. I know that the problem occours when app try connect to example.domain.com and in spite of self signed certificate the domain is trusted, so only for that case the SslError is ignored. 

public class MyWebViewClient extends CordovaWebViewClient {

   private static final String TAG = MyWebViewClient.class.getName();
   private static final String AVAILABLE_SLL_CN 
                               = "example.domain.com";

   public MyWebViewClient(DroidGap ctx) {
       super(ctx);
   }

   @Override
   public void onReceivedSslError(WebView view, 
                                  SslErrorHandler handler, 
                                  android.net.http.SslError error) {

       String errorSourceCName = error.getCertificate().
                                  getIssuedTo().getCName();

       if( AVAILABLE_SLL_CN.equals(errorSourceCName) ) {
           Log.i(TAG, "Detect ssl connection error: " + 
                       error.toString() + 
                       „ so the error is ignored”);

           handler.proceed();
           return;
       }

       super.onReceivedSslError(view, handler, error);
   }
}
Next step is forcing yours app to  use custom implementation of WebViewClient. 

public class Start extends DroidGap
{
   private static final String TAG = Start.class.getName();

   @Override
   public void onCreate(Bundle savedInstanceState)
   {
       super.onCreate(savedInstanceState);
       super.setIntegerProperty("splashscreen", R.drawable.splash);
       super.init();

       MyWebViewClient myWebViewClient = new MyWebViewClient(this);
       myWebViewClient.setWebView(this.appView);

       this.appView.setWebViewClient(myWebViewClient);
       
       // yours code

   }
}
That is all ypu have to do if minSdk of yours app is greater or equals 8. In older version of Android there is no class 
android.net.http.SslError
So in class MyCordovaWebViewClient class there are errors because compliator doesn’t see SslError class. Fortunately Android is(was) open source, so it is easy to find source of the class. There is no inpediments to ‘upgrade’ app and just add the file to project. I suggest to keep original packages. Thus after all operations the source tree looks like:

Class SslError placed in source tree. 
 Now the app created in release mode can connect via https to services with self-signed SSl certificates.