Enforce Consistency through Application Infrastructure
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The document discusses the importance of consistency in application infrastructure, emphasizing how it can manage complexity and improve code quality. It introduces various design patterns and techniques, such as enforcing dependency injection, separation of concerns, and controlling data access through interfaces. The author argues that these practices allow developers to optimize their coding processes while maintaining structure and discipline in software development.
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public interface ILog
{
void Info(string message, params object[] args);
void Warn(string message, params object[] args);
void Error(string message, Exception ex);
}
Enforces Separation of Concerns
The application code only knows about ILog
Once I is defined we can develop screens and call
this interface to log traces or errors
The real implementation can be done later
If logging needs changes, we can modify the
interfaces at once in all places it is used
The implementation is in only one place, so one place to
change only
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Encapsulate Data Access Concerns
<<Interface>>
TDataModel
IRepository
+GetEntities<TDataModel>()
<<Interface>>
TDataModel
IUnitOfWork
+GetEntities<TDataModel>()
+SaveChanges()
Database
Repository UnitOfWork
<<Stereotype>>
<<DTO>>
Order
<<DTO>>
Person
[Service(typeof (IRepository))]
internal class EfRepository : IRepository, IDisposable
{
private readonly IDbContextFactory contextFactory;
private readonly IInterceptorsResolver interceptorsResolver;
private DbContext context;
private readonly IEnumerable<IEntityInterceptor> interceptors;
public EfRepository(IDbContextFactory contextFactory,
IInterceptorsResolver resolver)
{
this.contextFactory = contextFactory;
this.interceptorsResolver = interceptorsResolver;
this.interceptors =
resolver.GetGlobalInterceptors();
}
... iQuarcDataAccess
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Patterns for Read-Write data
public class OrdersController : Controller
{
...
[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult PlaceOrder(OrderRequestViewModel model)
{
...
using (IUnitOfWork uof = repository.CreateUnitOfWork())
{
SalesOrderHeader order = uof.GetEntities<SalesOrderHeader>()
.FirstOrDefault(o => o.CustomerID == c.ID && o.OrderDate.Month == DateTime.Now.Month);
if (order == null)
{
order = new SalesOrderHeader {Customer = c};
uof.Add(order);
}
AddRequestToOrder(model, order);
uof.SaveChanges();
}
...
}
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AppBoot Enforces Constructor Dependency Injection
<<Attribute>>
ServiceAttribute
+ ServiceAttribute()
+ServiceAttribute(Type contract)
+ ServiceAttribute(Type t, Lifetime lifetime)
Bootstrapper
+Bootstrapper(Assembly[] assemblies)
+Run()
public interface IPriceCalculator
{
int CalculateTaxes(Order o, Customer c);
int CalculateDiscount(Order o, Customer c);
}
[Service(typeof(IPriceCalculator), Lifetime.Instance)]
interal class PriceCalculator : IPriceCalculator
{
public int CalculateTaxes(Order o, Customer c)
{
return 10; // do actual calculation
}
public int CalculateDiscount(Order o, Customer c)
{
return 20; // do actual calculation
}
}
iQuarcAppBoot
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Software systems should separate the startup process, when the application objects are constructed and the
dependencies are “wired” together, from the runtime logic that takes over after startup
<<Interface>>
IModule
+ Initialize()
Application
+ Initialize()
*
+ Modules[]
AppModule1
+ Initialize()
AppModule2
+ Initialize()
Enforce Separation of Construction from Use
public static void Main(string[] args)
{
var assemblies = GetApplicationAssemblies().ToArray();
Bootstrapper bootstrapper = new Bootstrapper(assemblies);
bootstrapper.ConfigureWithUnity();
bootstrapper.AddRegistrationBehavior(new ServiceRegistrationBehavior());
bootstrapper.Run();
}
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Patters forCreating Services thatDepend Only onInterfaces
[Service(typeof (IOrderingService))]
public class OrderingService : IOrderingService
{
private readonly IRepository repository;
private readonly IPriceCalculator calculator;
private readonly IApprovalService orderApproval;
public OrderingService(IRepository repository, IPriceCalculator calculator, IApprovalService orderApproval)
{
this.repository = repository;
this.calculator = calculator;
this.orderApproval = orderApproval;
}
public SalesOrderInfo[] GetOrdersInfo(string customerName)
{
var orders = repository.GetEntities<SalesOrderHeader>()
...
return orders.ToArray();
}
public SalesOrderResult PlaceOrder(string customerName, OrderRequest request)
{
...
}
}
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Enforce Constructor DI to Prevent Circular Dependencies
[Service(typeof(IApprovalService))]
class ApprovalService : IApprovalService
{
private readonly IPriceCalculator priceCalculator;
public ApprovalService(IPriceCalculator priceCalculator)
{
this.priceCalculator = priceCalculator;
}
...
}
[Service(typeof (IPriceCalculator), Lifetime.Instance)]
public class PriceCalculator : IPriceCalculator
{
private readonly IApprovalService approvalService;
public PriceCalculator(IApprovalService approvalService)
{
this.approvalService = approvalService;
}
...
}
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Enforce Consistency through Application Infrastructure
- 1. https://onCodeDesign.com/DevTalks2018 Enforce Consistency through Application Infrastructure Florin Coroș .com www.iQuarc.com | www.InfiniSwiss.com | onCodeDesign.com [email protected] @florincoros
- 2. https://onCodeDesign.com/DevTalks2018 About me @florincoros Co-Founder & Partner Partner .com Co-Founder & Partner
- 3. https://onCodeDesign.com/DevTalks2018 Why Is Consistency the Key? 3
- 5. https://onCodeDesign.com/DevTalks2018 Different Solutions to the Same Problem 5
- 7. https://onCodeDesign.com/DevTalks2018 Cost of Change Wrong approach consistently repeated in all of the application screens vs Uniquely new approach in all of the application screens 7
- 8. https://onCodeDesign.com/DevTalks2018 Managing Complexity when projects do fail for reasons that are primarily technical, the reason is often uncontrolled complexity 8
- 9. https://onCodeDesign.com/DevTalks2018 Controlling the Complexity uniqueness consistency 9
- 10. https://onCodeDesign.com/DevTalks2018 Rules Are Easy to Ignore Quick and Dirty vs The only way to go fast, is to go well! 10
- 11. https://onCodeDesign.com/DevTalks2018 Quality through Discipline 11
- 12. https://onCodeDesign.com/DevTalks2018 Seniors May Be Overwhelmed with Review 12
- 13. https://onCodeDesign.com/DevTalks2018 Quality through Structure You enforce consistency with structure Create a structure that makes difficult to write bad code rather then code that follows the design You use assemblies and references among them to enforce rules Hide external frameworks to enforce the way they are used Enforce Constructor Dependency Injection and encourage Programming Against Interfaces 13
- 14. https://onCodeDesign.com/DevTalks2018 Assure Consistency in Using External Library by Hiding It Exception Wrappers Decorators <<Interface>> API Interfaces<<static class>> Log +LogError() +LogWarining() 14
- 15. https://onCodeDesign.com/DevTalks2018 public interface ILog { void Info(string message, params object[] args); void Warn(string message, params object[] args); void Error(string message, Exception ex); } Enforces Separation of Concerns The application code only knows about ILog Once I is defined we can develop screens and call this interface to log traces or errors The real implementation can be done later If logging needs changes, we can modify the interfaces at once in all places it is used The implementation is in only one place, so one place to change only 15
- 16. https://onCodeDesign.com/DevTalks2018 Encapsulate Data Access Concerns <<Interface>> TDataModel IRepository +GetEntities<TDataModel>() <<Interface>> TDataModel IUnitOfWork +GetEntities<TDataModel>() +SaveChanges() Database Repository UnitOfWork <<Stereotype>> <<DTO>> Order <<DTO>> Person [Service(typeof (IRepository))] internal class EfRepository : IRepository, IDisposable { private readonly IDbContextFactory contextFactory; private readonly IInterceptorsResolver interceptorsResolver; private DbContext context; private readonly IEnumerable<IEntityInterceptor> interceptors; public EfRepository(IDbContextFactory contextFactory, IInterceptorsResolver resolver) { this.contextFactory = contextFactory; this.interceptorsResolver = interceptorsResolver; this.interceptors = resolver.GetGlobalInterceptors(); } ... iQuarcDataAccess 16
- 17. https://onCodeDesign.com/DevTalks2018 public interface IRepository { IQueryable<TDbEntity> GetEntities<TDbEntity>() where TDbEntity : class; IUnitOfWork CreateUnitOfWork(); } public interface IUnitOfWork : IRepository, IDisposable { void SaveChanges(); void Add<T>(T entity) where T : class; void Delete<T>(T entity) where T : class; void BeginTransactionScope(SimplifiedIsolationLevel isolation); } Create Separated Patterns for Read-Only and Read-Write 17
- 18. https://onCodeDesign.com/DevTalks2018 Patterns for Read-Only data public class OrdersController : Controller { private readonly IRepository repository; public OrdersController(IRepository repository) { this.repository = repository; } public IActionResult Index(string customer) { var orders = repository.GetEntities<SalesOrderHeader>() .Where(soh => soh.Customer.Person.LastName == customer) .Select(soh => new OrdersListViewModel { CustomerName = customer, Number = soh.SalesOrderNumber, SalesPersonName = soh.SalesPerson, DueDate = soh.DueDate, }); return View(orders); } ... } 18
- 19. https://onCodeDesign.com/DevTalks2018 Patterns for Read-Write data public class OrdersController : Controller { ... [HttpPost] [ValidateAntiForgeryToken] public IActionResult PlaceOrder(OrderRequestViewModel model) { ... using (IUnitOfWork uof = repository.CreateUnitOfWork()) { SalesOrderHeader order = uof.GetEntities<SalesOrderHeader>() .FirstOrDefault(o => o.CustomerID == c.ID && o.OrderDate.Month == DateTime.Now.Month); if (order == null) { order = new SalesOrderHeader {Customer = c}; uof.Add(order); } AddRequestToOrder(model, order); uof.SaveChanges(); } ... } 19
- 20. https://onCodeDesign.com/DevTalks2018 Consistency Creates Optimizations Opportunities internal class EfRepository : IRepository, IDisposable { public IQueryable<T> GetEntities<T>() where T : class { return Context.Set<T>().AsNoTracking(); } public IUnitOfWork CreateUnitOfWork() { return new EfUnitOfWork(contextFactory, interceptorsResolver); } private sealed class EfUnitOfWork : IUnitOfWork { private DbContext context; private TransactionScope transactionScope; private readonly IDbContextFactory contextFactory; public EfUnitOfWork(IDbContextFactory contextFactory, IInterceptorsResolver resolver) { this.contextFactory = contextFactory; this.interceptorsResolver = interceptorsResolver; } } 20
- 21. https://onCodeDesign.com/DevTalks2018 Create Development Patters in how Data is Accessed 21
- 22. https://onCodeDesign.com/DevTalks2018 Enforce Separation of Data Access Concerns <<Interface>> TDataModel IRepository +GetEntities<TDataModel>() <<Interface>> TDataModel IUnitOfWork +GetEntities<TDataModel>() +SaveChanges() Database Repository UnitOfWork <<Stereotype>> <<DTO>> Order<<DTO>> Person 22
- 23. https://onCodeDesign.com/DevTalks2018 DIP to Enforce Separation of Data Access Concern <<Interface>> TDataModel IEntityInterceptor +OnLoad() +OnSaving() <<Interface>> TDataModel IDbContextFactory +CreateContext() Database <<DTO>> Customer<<DTO>> Order <<DTO>> Person DbContextFactoryUnitOfWork Repository 23
- 24. https://onCodeDesign.com/DevTalks2018 DIP to Move OnSave & OnLoad Logic out of Data Access <<Interface>> TDataModel IEntityInterceptor +OnLoad() +OnSaving() <<Interface>> TDataModel IDbContextFactory +CreateContext() DbContextFactoryUnitOfWork Repository 24
- 25. https://onCodeDesign.com/DevTalks2018 AppBoot: DI Abstractions & Type Descovery <<Attribute>> ServiceAttribute IModule <<Interface>> TDataModel IEntityInterceptor +OnLoad() +OnSaving() <<Interface>> TDataModel IRepository Database <<DTO>> Customer<<DTO>> Order<<DTO>> Person DbContextFactoryUnitOfWork Repository <<Interface>> TDataModel IUnitOfWork 25
- 26. https://onCodeDesign.com/DevTalks2018 AppBoot Enforces Constructor Dependency Injection <<Attribute>> ServiceAttribute + ServiceAttribute() +ServiceAttribute(Type contract) + ServiceAttribute(Type t, Lifetime lifetime) Bootstrapper +Bootstrapper(Assembly[] assemblies) +Run() public interface IPriceCalculator { int CalculateTaxes(Order o, Customer c); int CalculateDiscount(Order o, Customer c); } [Service(typeof(IPriceCalculator), Lifetime.Instance)] interal class PriceCalculator : IPriceCalculator { public int CalculateTaxes(Order o, Customer c) { return 10; // do actual calculation } public int CalculateDiscount(Order o, Customer c) { return 20; // do actual calculation } } iQuarcAppBoot 26
- 27. https://onCodeDesign.com/DevTalks2018 Software systems should separate the startup process, when the application objects are constructed and the dependencies are “wired” together, from the runtime logic that takes over after startup <<Interface>> IModule + Initialize() Application + Initialize() * + Modules[] AppModule1 + Initialize() AppModule2 + Initialize() Enforce Separation of Construction from Use public static void Main(string[] args) { var assemblies = GetApplicationAssemblies().ToArray(); Bootstrapper bootstrapper = new Bootstrapper(assemblies); bootstrapper.ConfigureWithUnity(); bootstrapper.AddRegistrationBehavior(new ServiceRegistrationBehavior()); bootstrapper.Run(); } 27
- 28. https://onCodeDesign.com/DevTalks2018 Patters forCreating Services thatDepend Only onInterfaces [Service(typeof (IOrderingService))] public class OrderingService : IOrderingService { private readonly IRepository repository; private readonly IPriceCalculator calculator; private readonly IApprovalService orderApproval; public OrderingService(IRepository repository, IPriceCalculator calculator, IApprovalService orderApproval) { this.repository = repository; this.calculator = calculator; this.orderApproval = orderApproval; } public SalesOrderInfo[] GetOrdersInfo(string customerName) { var orders = repository.GetEntities<SalesOrderHeader>() ... return orders.ToArray(); } public SalesOrderResult PlaceOrder(string customerName, OrderRequest request) { ... } } 28
- 29. https://onCodeDesign.com/DevTalks2018 Enforce Constructor DI to Prevent Circular Dependencies [Service(typeof(IApprovalService))] class ApprovalService : IApprovalService { private readonly IPriceCalculator priceCalculator; public ApprovalService(IPriceCalculator priceCalculator) { this.priceCalculator = priceCalculator; } ... } [Service(typeof (IPriceCalculator), Lifetime.Instance)] public class PriceCalculator : IPriceCalculator { private readonly IApprovalService approvalService; public PriceCalculator(IApprovalService approvalService) { this.approvalService = approvalService; } ... } 29
- 30. https://onCodeDesign.com/DevTalks2018 Design PatternslikeCompositionorChain of Responsibility30
- 31. https://onCodeDesign.com/DevTalks2018 Patters in How Dependencies are Created 31
- 32. https://onCodeDesign.com/DevTalks2018 iQuarc iQuarc Dependencies Management Design Patterns in Service Composition Enforce Consistency through Structure Enforce Separation of Concerns Patterns for Queries & Commands Interceptors for Queries & Commands Enforce Consistency through Application Infrastructure iQuarcCode-Design-Training onCodeDesign.comtraining 32
- 33. https://onCodeDesign.com/DevTalks2018 Florin Coroș Co-founder & Partner, iQuarc www.iquarc.com Co-founder & Partner, InfiniSwiss www.infiniswiss.com .com email: [email protected] blog: onCodeDesign.com tweet: @florincoros