Saturday, 25 June 2016

BaaS with Kinvey and Delphi 10.1 Berlin

In this article I will show you how to connect your desktop and mobile applications to a mobile backend as a service (mBaaS) with Delphi 10.1 Berlin. I normally use as a backend but as they announced that they will close their mBaaS service I will use Kinvey instead.
If you are interested in you can read my previous articles about creating your own self-hosted Parse server and deploying a Parse server to Heroku which achieves similar result to what I want to explain you today (basically having your data hosted anywhere in the cloud either using Kinvey as an mBaaS or Parse + Heroku as a PaaS).
 There are plenty of articles online about these topics and I just want to give you my input and how I dealt with some of the challenges I faced during development.

Join Kinvey and create your App environment
First step is to join Kinvey and create your application environment. Kinvey offers a Free plan for developers that it is ideal to test your applications. It includes the core mBaaS features and 1GB of data storage. Once you move your solution into production you can switch over one of the other plans available.
Once you are in the console management, press "New App" and enter the name of your backend:
Now you should see your enviromnent created:
Click on the Development label and the dashboard will be shown:
At this moment in time, you should know what data you are going to store. In this example I have created a simple collection that includes several fields for a sample application that I'm building and that the source code can be found here:
Here is my collection of values:
*Note that if you POST data to a non-existing collection, this will be created automatically.

Handling collections
Now it's time to start using the collection and querying/adding data via Http REST. For this task you will have to identify the required headers that are needed for your GET/POST requests. You can see one example here for Parse.

Kinvey follows a different approach than Parse in terms of security. Kinvey offers basic and session authentiation. Basic authentication uses the HTTP header "Authorization" with the components "Basic" and Base64Encode(AppId:MasterSecret). Session authentication sends a login request to collct an auth token from Kinvey backend and then this token is used in subsequent REST requests.

I will focus on Basic authentication as Session authentication is as simple but with more steps.

The first example is by using REST via IdHttp so you can see how GET/POST are handled manually and the second example is just by using the Kinvey provider component available with our Delphi 10.1 Berlin that will make our life easier.

Here it's my Win64 example that uses Kinvey BaaS:

Add action, adds data into the collection and reload just brings the data back from the cloud and displays it in a listview component.

Here is the code behind it:
Add item:
Load data:
As you can see, each method uses a POST/GET command to baas.kinvey url with some arguments, headers and options. I find this way really useful as you can clearly see what's going on and easily map what you could do via curl:

If you want to run this example successfully you'll need to include libeay32.dll and ssleay32.dll from OpenSSL.

You can test this app and its mobile companion app using the source code here.

Using Kinvey Provider component
Delphi 10.1 Berlin has a KinveyProvider component that we can use directly without having to worry about the request details. You'll see below that to do the same as the code sample above we will need just few lines of code:
The KinveyProvider needs the parameters:

  • AppKey
  • AppSecret
  • MasterSecret
Get those from the Kinvey dashboard and off you go.

Then connect the BackEndStorage component to the KinveyProvider component.

Now, here is the code to Add items to the collection and to load the collection via components:
Load Data:
Add Item:
As you can see now it's way simpler.

And here my android app up and running:
Now I have a Win64 app and an Android app that share the same back end using Kinvey BaaS.

And the data in Kinvey:

Although this article it's quite long I'm sure you will find it quite interesting if you still haven't played with these components and the cloud.

Note that this BackEnd service will cease to exist shortly (as the appkey is hardcoded in the android app and the source code is available).

Do not hesitate to contact me if you have any questions.

Monday, 6 June 2016

Invoke PowerShell remote command with parameters with spaces via TeamCity

One of the coolest things to do with TeamCity is to run some external applications via PowerShell. This will allow us to invoke remote commands without having to install an additional agent on the remote target and it will allow us to centralise those commands from our build agent environment.

The idea behind it is as follows:
I have a centralised Build Agent environment and I need to run a command line application en two additional machines. I don't want to install any TeamCity agent on those machines as these are just deployment machines and should be independent of the bulding process. I just need to remote deploy some binaries there via Powershell and then execute the application.
These two additional machines are in the same network and WinRM is configured in every instance with the correct permissions so TeamCity can run the commands without problems.
There are loads of guides over the internet regarding WinRM configuration. Here is the screenshot from my local configuration on my Win10 machine. I run the same on the TeamCity agent, a Win2012 machine:

I had to tweak first with the wifi connection as it was set to public by default and it needs to be private. Then just enable PSRemoting and add the trusteshosts as all (*). Then to test it out, run the Test-WSMan myRemoteMachine and you should see something similar to the image above.

In TeamCity, there are two additional steps, one to copy some binaries to a remote machine and the second one to run the binaries remotely. Both steps running powershell:

Here is the command for each step:

And the remote execution from Powershell:

Monday, 30 May 2016

Saturday, 28 May 2016

Getting dotCover to report in TeamCity via command line parameters

This is a series of articles about one of my favourite subjects: Continuous Integration and Continuous Delivery. In this article I will focus on the Development step that includes the build process, the packaging of artifacts, the testing and finally the reporting of code coverage. All this from TeamCity.

I will base this solution in one of my .net projects as the integration is really high and it is really easy to do and use. I faced some challenges when setting up NUnit 3.x and dotCover in TeamCity and this post tries to alleviate the pain with a deep explanation about the setting up and configuration.

In further articles I will delve into detail regarding the next items that are part of the continuous delivery pipeline.

One of the most important aspects of any solution is that if you want to get away from spaghetti code you need to have proper controls in place such as unit tests, integration tests, etc. This for me is a must-have in any project. If you can't answer the following question "What's your % of code coverage?" with something rather than 0, then you are in for trouble as you are probably maintaining something similar to spaghetti code. This doesn't relate to the ability you have for coding, this only relates to its maintainability and scalability.

I will use one of my projects from GitHub for this article:
This project contains a basic library with my MapReduce approach, a console application that runs the library and a unit test project that tries to cover as much code as possible.

Here is my TeamCity project for this github solution with the artifacts.
As you can see, the project gets automatically build via TeamCity and the configuration of the project is as follows:

1. VCS Root:

2. Build Step for Visual Studio:

3. Generation of Artifacts:

As you can see, the setting up of the build process is quite simple. Just create your project in teamcity, point your VCS Root to GitHub, create a build step for Visual Studio (pointing it to the .sln file) and add the location of the binaries to be picked up by TeamCity and generated as artifacts.

So far so good, right!?. Now we need to go one step forward. My project has a console app and a unit test project and I need to build both prior to run the unit test project. To achieve this I will have to piggyback on MsBuild.

Here is the structure of my project:
Now I need to build the projects CountingWordsConsole and MapReduce.Tests together prior to the running of the tests. Here is my msbuild file to build my solution:

And here is the configuration in TeamCity:
I got rid of the previous build step for Visual Studio and this time I'm creating an MsBuild step that will target all my project files.

You will also notice that in the MsBuild file there is a shared argument between TeamCity and MsBuild called ReleaseFolder. This property is set up in TeamCity with the folder location of where my projects will be built. This will help us later as to identify where are our binaries and how we pick those up from TeamCity as artifacts.
Notice that in the MsBuild file the notation of this property is via $(ReleaseFolder) whereas in TeamCity is %system.ReleaseFolder%.

Now that we have the project up and running via MsBuild, it's time to set up NUnit and dotCover.

Setting up NUnit and dotCover

1. Get the latest NUnit.
You can get the latest NUnit 3.2.1 from here. Download the .msi file and install the typical installation. This will leave the files in the following folder:

  • C:\Program Files (x86)\\nunit-console\
Add a new build step in TeamCity and configure it to run it for NUnit 3.x. As soon as you run the project you will get the following error:

This version of NUnit 3 is not a release version and is not compatible with TeamCity. Please update NUnit to a newer release version.

I even tried with NUnit 3.0 RC and NUnit 3.0 but the error never went away. How to fix this? via command line.

To make things a bit more exciting, I will configure directly dotCover as this one will run NUnit by default. dotCover comes automatically by default with TeamCity:
("C:\TeamCity\buildAgent\tools\dotCover") and you only need to configure your project with some configuration files to be able to run dotCover from the command line.

The other aspect to cover later on is how to publish the dotCover report in teamCity but I will get to it.

2. Using dotCover
Using dotCover is really simple, just call dotCover with the argument cover and the .xml config and that's it. Inside the configuration file, dotCover will call NUnit and report the tests back to TeamCity. Here is my configuration file:

Now configure the build step to use dotCover:
Once you run this step, you will see that TeamCity reports back this test automatically:
Now we are almost done. The last part is the tricky one and the answer to the title of this article "Getting dotCover to report in TeamCity via command line parameters". If you check the coverage.xml file, you will see that there is one report created called output.dcvr and now we need to tell TeamCity that the file is there to be picked up.

3. Using service messages.
The common way to report things back to TeamCity is via service messages. To do this, you just need to write this message in the console output:

##teamcity[importData type='dotNetCoverage' tool='dotcover' path='C:\MapReduce\MapReduce.Tests\output.dcvr']

So what I did was building a lightweight console application that just writes that command output:

Now place the executable in the root of your project so it can be called from TeamCity. Add a third build step in your project and use the following arguments:
Run the project in TeamCity and et voilĂ !:

Now you can see the coverage of my unit tests against my source code (>75%) and inspect the report further through TeamCity:

I can see that most of my classes are covered 100% so it gives me enough confidence to keep modifying the project knowing that if I break something the tests will tell me straight away.

I hope you find this useful as it's a quite a long and tedious post and I consider that you already know about TeamCity.

Monday, 23 May 2016

Deploying a PARSE server to Heroku

Heroku is a PaaS (Platform as a Service) that enabled developers to build and run applications entirely in the cloud. If you followed my previous post about PARSE server you will see that we are just one step ahead to move things from a self-hosted environment to the cloud. Heroku offers a free tier with 1 web and 1 worker (2 dynos - smart, lightweight containers) but they can't run 24/7 (must sleep 6 hours in a 24h period). For any additional dyno you'll have to pay $7/month. (there are also some considerations in terms of memory that can increase your final bill).

Deploy PARSE server to Heroku.
To deploy PARSE server to Heroku there are two alternatives. The first one which is the easy one where we just press the deploy button from the PARSE server example page and this would lead us to the Heroku page with the details we need to set up our system. To create a deploy button for your repo you need to follow the following tutorial.

The second one involves a bit more of configuration and I would definitely recommend you not to pursue this one. I spent one afternoon to correctly configure git and heroku to achive the same results as pushing a button.

Once you press the deploy button from PARSE server example, you'll be prompted with the following details:

Add you AppName and set the runtime selection. You will see that there is one additional addon added automatically in the app for a MongoDB database.

To finalise this step, the system will ask you to add your credit card details. There is no charge here as the deployment is for free and the MongoDB sandbox is also free, but this is one of the requirements.

Now the app is deployed and it will appear as active under Heroku:

It's time now to test the application. You can use curl, javascript or any other language to test the connectivity with Parse. In my case I will use Delphi as my preferred language and because I already have the libraries for it.

Here is my code:

As you can see this will call the remote instance of my Parse server and add a new item under Instances classes.

To see that everything has worked correctly. I can go to the remote mongoDB instance and check out the results:

And the records that have been inserted:

Now I can happily connect my devices to my remote Parse server and remove the old dependencies to

The second option to produce the same results involve using Heroku Toolbelt and mongoDB addon. For this, get the latest Heroku Toolbelt from here. I'm testing everything from a Win7 machine so I have downloaded the installer for windows. Then follow the steps from Heroku in terms of deploying the application through the command line via heroku and git. And you'll achieve the same results. Remember to configure your SSH key first before pushing anything through git.

In conclusion, using PaaS will change the future in terms of DevOps. Companies will rely more in cloud base platforms for their operations as the will require less worries in terms of load balancing, VPNs, clusterint, key rotation and some complex security policies. DevOps tools have matured a lot nowadays and with all this landscape constantly changing you can learn some valuable skills along the way.

There are also some other deployment solutions that I would like to try like Docker, Chef, Puppet, Ansible and Capistrano. Hopefull I will have the time to test them soon!.