Repairing the build and versioning–part 15

Now , after copy the plugins, the build is not working.

Thnking about the build events, I realize that to find same copy command on Linux and Windows is difficult – so Windows it is.

( and, BTW , In LInux the macro $(SolutionDir ) does not work use  repoRoot

https://docs.microsoft.com/en-us/visualstudio/msbuild/customize-your-build?view=vs-2019

https://github.com/Microsoft/msbuild/issues/2397

)

Switch windows-latest on https://help.github.com/en/actions/automating-your-workflow-with-github-actions/workflow-syntax-for-github-actions#jobsjob_idruns-on 

Now tests are failing – repairing the tests.

I realize that I cannot build just the csproj – the solution sln knows the order in which to build the projects- but the .csproj does not. So now building the sln and then publish

Now giving error in Github, but not on local. More, there was a not repeatable . I figured was because of the parallel builds so this is the final line

dotnet build –configuration Release InfoValutar/InfoValutar.sln /m:1

Now it works!

The only programming thing that I have done is to add versioning , https://github.com/microsoft/aspnet-api-versioning/wiki/How-to-Version-Your-Service . I do tend to say that the URL is a Unique Identifier – so I want the versioning be part of the URL.

As advised by https://github.com/microsoft/aspnet-api-versioning/wiki/Versioning-via-the-URL-Path

I added the pacakage Microsoft.AspNetCore.Mvc.Versioning and

services.AddApiVersioning();

and on the controller

[ApiVersion( “1.0” )]

[Route(“api/v{version:apiVersion}/[controller]/[action]”)]

and now I can access

api/v1.0/TodayRates/banks

And one hour passes...

(This is the result of 1 hour per day auto-challenge as a full cycle developer for an exchange rates application)
NrPost 
1Start
2Reading NBR from internet
3Source control and build
4Badge and test
5CI and action
6Artifacts and dotnet try
7Docker with .NET Try
8ECB
9Intermezzo - Various implementations for programmers
10Intermezzo - similar code - options
11Plugin implementation
12GUI for console
13WebAPI
14Plugin in .NET Core 3
15Build and Versioning
16Add swagger
17Docker - first part
18Docker - second part
19Docker - build Azure

Plugin copy and caching- part 14

I have had 2 problems to solve

  1. How to put the plugins for the console and web api ?
  2. How to cache the data  ? ( plugins / exchange rates)

 

The solution for the first problem should be easy for the programmer PC, and for the deploying the application ( console/ web api/ etc )There are several solutions :

  1. Each plugin knows where to copy the dll ( console/web api)
  2. The application ( console / webapi) knows a special place from which to copy the plugin definition

 

I tend to agree with both – but mostly with the second. So … the idea is as follows:

The plugin builds and copy the output to a special folder, named “plugins” ( what a surprise, righyt?)

The console /webapi copies the folder plugins under his directory

 

The only problem here is that we should ensure that plugins are build first, even if the application does NOT have reference to them.

For this, there is a special menu in VS for solution, namely “build order” – you go to this –and after to the second tab, project dependencies. For the console and web I select as dependency the two loading projects – InfoValutarNBR and InfoValutarECB. The changes are reflected into the sln file

I could have done this on just the InfoValutarLoadingLibs project – but maybe I can have another way to load the libraries ( not so much for the moment )

So now I begin to modify what happens

after build events for InfoValutarNBR and InfoValutarECB

xcopy “$(TargetDir)*.*” “$(SolutionDir)plugins\$(ProjectName)” /E /F /I /Y /R

and pre build events for InfoValutarDOS and InfoValutarWebAPI.

Now, there are several things to do:

  1. Add to .gitignore the plugins folder to not put into the source control( ok)
  2. Write some documentation about the process
  3. Think about linux/docker compiling – there is a xcopy there  ?

 

About the documentation –  I just did. More, I create a InfoValutarPluginStarter , in order for others to copy this project and make a new plugin.

Realized also that the WebAPI could be simpler

[HttpGet(“{bank}”)]
public IAsyncEnumerable<ExchangeRates> Rates([FromRoute] string bank)

And also that I should throw another exception if Bank is null or empty:

if(string.IsNullOrWhiteSpace(bank))
throw new ArgumentNullException($”{nameof(bank)} cannot be empty”);

 

For docker compiling – next time

And one hour passes...

(This is the result of 1 hour per day auto-challenge as a full cycle developer for an exchange rates application)
NrPost 
1Start
2Reading NBR from internet
3Source control and build
4Badge and test
5CI and action
6Artifacts and dotnet try
7Docker with .NET Try
8ECB
9Intermezzo - Various implementations for programmers
10Intermezzo - similar code - options
11Plugin implementation
12GUI for console
13WebAPI
14Plugin in .NET Core 3
15Build and Versioning
16Add swagger
17Docker - first part
18Docker - second part
19Docker - build Azure

Creating the WebAPI–part 13

I am now tired of continuously improving the console application – so now some work that others can see really.  Creating the WebAPI is simple as a project  – and I was amazed to see a WeatherForecast controller.

I need just to be able to see the today exchange rates via API . So created a TodayRates , modify the launchSettings.json in order to start with my controller.

I need the plugin that loads to be a global dependency. So I add as a Singletion in the services

services.AddSingleton< LoadExchangeProviders>(new LoadExchangeProviders(“plugins”));

and then I inject into the controller constructor ( I can do in the method also, but many methods needs the same dependency )

public TodayRates(ILogger<TodayRates> logger, LoadExchangeProviders prov)
{
_logger = logger;
_prov = prov;
}

 

Now I need a method to see what are the banks / plugins that are loaded . Linq to the rescue :

 

[HttpGet]
public IEnumerable<string> Banks()
{
return _prov
.LoadExchange()
.Select(it=>it.Bank)
.ToArray();
}

Now we should load the data from the provider to show actual rates

public async IAsyncEnumerable<ExchangeRates> Rates(string bank)
{
var provBank = _prov
.LoadExchange()
.FirstOrDefault(it => string.Equals(bank, it.Bank, StringComparison.InvariantCultureIgnoreCase));

switch (provBank)
{
case null:
yield return null;
break;
default:
{
await foreach (var data in provBank.GetActualRates())
{
yield return data;
}

break;
}
}

}

 

All good. There are  3 problems:

  1. How to put the plugins for the console and web api ?
  2. How to cache the data  ? ( plugins / exchange rates)
  3. Should we throw an exception when a bank does not exists, instead of returning null ?

 

Thinking of this code, I realized that I begin to put logic into controllers. So – let’s move from the controller to the business.

For example, now I have this:

[HttpGet]
public IEnumerable<string> Banks()
{
return _prov.Banks();
}

 

And this

[HttpGet]
public IAsyncEnumerable<ExchangeRates> Rates(string bank)
{
return _prov.Rates(bank);
}

So now I can change in the Business Layer without problems.

Looking at the Console Application vs  WebAPI, I realized that are different. The console is loading the whole data from the providers – the WebAPI is loading on demand.  We could do for the console the same behavior  – but the console is loading very fast all data.

For the answer at

Should we throw an exception when a bank does not exists, instead of returning null ?

– seems to be yes.

So instead of

case null:
yield return null;
I put

case null:
throw new ArgumentOutOfRangeException(nameof(bank),$”cannot find {bank}”);

 

For the 2 questions, the answer next time.

 

And one hour passes...

(This is the result of 1 hour per day auto-challenge as a full cycle developer for an exchange rates application)
NrPost 
1Start
2Reading NBR from internet
3Source control and build
4Badge and test
5CI and action
6Artifacts and dotnet try
7Docker with .NET Try
8ECB
9Intermezzo - Various implementations for programmers
10Intermezzo - similar code - options
11Plugin implementation
12GUI for console
13WebAPI
14Plugin in .NET Core 3
15Build and Versioning
16Add swagger
17Docker - first part
18Docker - second part
19Docker - build Azure

[ADCES] Today, 19:00, Akka.NET and SqlServer 2019

Today, 19:00, Akka.NET and SqlServer 2019
https://www.meetup.com/Bucharest-A-D-C-E-S-Meetup/events/265689067/

Presentation 1: Building Event-Driven Applications with Akka.NET
Presenter: Emilian Balanescu, https://www.linkedin.com/in/emilianbalanescu/
Description:

Akka.NET is an open-source toolkit that simplifies the construction of concurrent and distributed applications. In this presentation you’ll learn about the actor model and event-sourcing concepts that enables you to build highly concurrent, fault-tolerant and event-driven applications. We’ll start by describing what is an actor and then we’ll continue with some practical techniques for actors’ design, messaging patterns, organization of actors’ hierarchies and we’ll also have a look on how to implement event-sourcing with persistence actors and replicate events to materialize views of data. Finally, to demonstrate the practical application of those concepts we’ll review a money transfer demo application.

Presentation 2: What’s new in SqlServer 2019
Presenter: Bogdan Sahlean, https://stackoverflow.com/users/924077/bogdan-sahlean

Description: Bogdan will present:

Query Processing
Monitoring
In-Memory Database
Graph

https://www.meetup.com/Bucharest-A-D-C-E-S-Meetup/events/265689067/

Documentation and refactoring for plugins and wrong code coverage – part 12

I realized that will be no documentation for plugins – until I create one .

Figured also that each plugin should have a name  -to understand from where he grabs data – so some code involved code.

 

Asking when and if the plugins are copied to the application  – not found yet an answer…

 

Now the user can choose what bank he wants to see data ? We could do this for the console application –  and I think that is the moment to play with Icaza  Gui Terminal https://github.com/migueldeicaza/gui.cs  – Created buttons to display plugins (NBR and ECB ). Will not work if many plugins will come – but it is ok for the moment.

Discovered the window for code coverage – read https://github.com/tonerdo/coverlet/blob/master/Documentation/VSTestIntegration.md

Some error when writing the .runsettings file – discovered from command line ( GUI does not show)

Reading the docs , https://docs.microsoft.com/en-us/visualstudio/test/using-code-coverage-to-determine-how-much-code-is-being-tested?view=vs-2019#analyze-code-coverage , it says that is not available for community…

Back to square 1 after 1 hour- just made documentation.

And one hour passes...

(This is the result of 1 hour per day auto-challenge as a full cycle developer for an exchange rates application)
NrPost 
1Start
2Reading NBR from internet
3Source control and build
4Badge and test
5CI and action
6Artifacts and dotnet try
7Docker with .NET Try
8ECB
9Intermezzo - Various implementations for programmers
10Intermezzo - similar code - options
11Plugin implementation
12GUI for console
13WebAPI
14Plugin in .NET Core 3
15Build and Versioning
16Add swagger
17Docker - first part
18Docker - second part
19Docker - build Azure

Loading data from NBR / ECB as plugins–part 11

Modified project – instead of one project that have the NBR and ECB exchange rates,I have now 4
1. Common interfaces / classes

2 NBR loading( first plugin)

3 ECB loading ( second plugin)

4 plugin loading project

 

Going to .NET Standard 2.1 and trying to load the NuGet https://github.com/natemcmaster/DotNetCorePlugins/blob/master/docs/what-are-shared-types.md .

Does not load. Going back to .NET Core 2.0  – some result.

RTFM – not supported .NET Standard  https://github.com/natemcmaster/DotNetCorePlugins/issues/24

So created a .NET Standard dll and changed from

<TargetFramework>netstandard2.0</TargetFramework>

to

<TargetFramework>netcoreapp3.0</TargetFramework>

Copied the code from https://github.com/natemcmaster/DotNetCorePlugins/blob/master/samples/hello-world/HostApp/Program.cs .

Loaded 0 plugins.

Put plugins in plugins directory – again 0 plugins.

Read the code copied – I must create separate folders for each plugin – makes sense, because we can have plugin diamond dependency – see here https://github.com/natemcmaster/DotNetCorePlugins/blob/master/docs/what-are-shared-types.md

Put in separate folder – error in this line

// This assumes the implementation of IPlugin has a parameterless constructor
var plugin = Activator.CreateInstance(pluginType) as BankGetExchange;

 

Apparently , this code does NOT mean to have a parameterless contructor – even if seems from the code


public class GetNBRExchange: BankGetExchange
{
private readonly HttpClient httpClient;

public GetNBRExchange(HttpMessageHandler handler = null)
{
if (handler != null)
httpClient = new HttpClient(handler, disposeHandler: false);
else
httpClient = new HttpClient();
}

 

So small modification to preserve tests and default code:


public class GetNBRExchange: BankGetExchange
{
private readonly HttpClient httpClient;
public GetNBRExchange() : this(null)
{

}
public GetNBRExchange(HttpMessageHandler handler)
{
if (handler != null)
httpClient = new HttpClient(handler, disposeHandler: false);
else
httpClient = new HttpClient();
}

Now it works …

You can find modifications here

https://github.com/ignatandrei/InfoValutar/commit/0e4cf6b83bb5f4cbab71e9e8c96ae719771fcae1 – total 13 changed files….

And one hour passes...

(This is the result of 1 hour per day auto-challenge as a full cycle developer for an exchange rates application)
NrPost 
1Start
2Reading NBR from internet
3Source control and build
4Badge and test
5CI and action
6Artifacts and dotnet try
7Docker with .NET Try
8ECB
9Intermezzo - Various implementations for programmers
10Intermezzo - similar code - options
11Plugin implementation
12GUI for console
13WebAPI
14Plugin in .NET Core 3
15Build and Versioning
16Add swagger
17Docker - first part
18Docker - second part
19Docker - build Azure

Intermezzo–options for loading multiple providers of data – part 10

We have 2 national banks –  and we gather exchange rates from there. What if we want to add more banks  -or let other programmers to add their dll’s to our software to just display the exchange rates from other banks ?

 

Option 1: HardCode all the list


var l = new List<IExchangeRates[]>
{
new GetFirstBank()),
new GetSecondBank()),

};

Option 2: Reading from some config file the list of classes – letting DevOps to modify the config file

var l = new List<IExchangeRates[]>;

foreach(var line in File.ReadAllLines(“myListOfExchangeRates.txt”){

IExchangeRates r= Activator.CreateInstance(Type.GetType(line)) as IExchangeRates ;

l.Add ( r );

}

Option 3: Reflection – in the current assembly or in all assemblies to load the classes that implements the interface to load the data

var typeToFound = typeof(IExchangeRates);
Assembly a = Assembly.GetExecutingAssembly();
var types = a.GetTypes()
.Where(it=>it.IsPublic)
.Where(it => it.GetInterface(typeToFound.FullName)!=null)
.ToArray();
foreach(var t in types)
{
recognizes.Add(Activator.CreateInstance(t)as  IExchangeRates);
}

Option4 Load as plugins

use the library from  https://github.com/natemcmaster/DotNetCorePlugins/blob/master/samples/hello-world/HostApp/Program.cs  and there are 2 lines , basically:

var loader = new LoadExchangeProviders("plugins");
var exchange = loader.LoadExchangeProviders().ToArray();

And one hour passes...

(This is the result of 1 hour per day auto-challenge as a full cycle developer for an exchange rates application)
NrPost 
1Start
2Reading NBR from internet
3Source control and build
4Badge and test
5CI and action
6Artifacts and dotnet try
7Docker with .NET Try
8ECB
9Intermezzo - Various implementations for programmers
10Intermezzo - similar code - options
11Plugin implementation
12GUI for console
13WebAPI
14Plugin in .NET Core 3
15Build and Versioning
16Add swagger
17Docker - first part
18Docker - second part
19Docker - build Azure

Intermezzo–program based on experience–part 9

This post will be somewhat related to https://www.smart-jokes.org/programmer-evolution.html – but it makes total sense for me.

Let’s take what we achieved until now: We have 2 national banks –  and we gather exchange rates from there. What if we want to add more banks  -or let other programmers to add their dll’s to our software to just display the exchange rates from other banks ?

Let’s say now that the requirements are to to display the exchange rates for 2 national banks into a console program .  The manager says that later we may add other banks to load exchange rates . I will try to explain some differences how the code is created, depending on the experience.

Junior programmer: – all the code inside


int Main(){

// code for load and display the first bank exchange rates

// code for load and display the second bank exchange rates

}

Internship programmer: – create classes


//create  2 classes ( first bank, second bank ) and a Load method

int Main(){

var firstBank = new FirstBank();

var data = firstBank.Load();

DisplayData(data);

//same for second bank

}

Seasoned Programmer: – creates interfaces


//add to the 2 classes an interface , loading into a list, loading data for all the list, display

int Main(){

var l = new List<IExchangeRates[]>;
{
new GetFirstBank()),
new GetSecondBank()),

};

foreach(var rates in l){

var data= rates.Load();

DisplayData(data);

}

 

Until now, it is business as usual. But, from now on, there are many things that can be done , depending on programmer experience and will to do things ( until some error arrives and there is an official task for it) :

  1. How to handle errors ( Polly ? )
  2. How to load different libraries that contains our interface ( writing code that loads directly a list with all classes / DI / reflection / config files / plugin loader )
  3. Think about performance ( loading data in parallel / caching )
  4. Add Tests + code coverage
  5. CI / CD

( if I do miss something, please put on comments)

 

What is my point here ? Is that I expect any programmer to go very fast to the level of Seasoned Programmer. But , after that, the knowledge of each programmer is relevant about how he does the points above ( or, if he does not …)

And one hour passes...

(This is the result of 1 hour per day auto-challenge as a full cycle developer for an exchange rates application)
NrPost 
1Start
2Reading NBR from internet
3Source control and build
4Badge and test
5CI and action
6Artifacts and dotnet try
7Docker with .NET Try
8ECB
9Intermezzo - Various implementations for programmers
10Intermezzo - similar code - options
11Plugin implementation
12GUI for console
13WebAPI
14Plugin in .NET Core 3
15Build and Versioning
16Add swagger
17Docker - first part
18Docker - second part
19Docker - build Azure

Andrei Ignat weekly software news(mostly .NET)

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