Inside architecture

Inside ArchitectureWhat I meant to say at dotnetsheff 2016/08/02
Zeb MasonCopyright © 2016 by Zeb Mason

Agenda: Frivolity, Theory & Tools
Copyright © 2016 by Zeb Mason

The Colosseum

The Colosseum
RomeCopyright © 2016 by Zeb Mason

Roman Architecture?

Yes

Yes
and noCopyright © 2016 by Zeb Mason

Framework Architecture

Framework Architecture
Why?Copyright © 2016 by Zeb Mason

It’s full of holes!

The humble scarab beetle

Ancient Egyptians saw the god Ra rolling the
sun around the heavens

But is this how you feel when trying to get to
grips with your code?

Note that’s not a big ball of mud

Architects draw
Architecture
in Visio

Architects draw
Architecture Marketing
in Visio

Architecture Marketing

Markitecture

Markitecture
Box

Markitecture
Box
in a box

Markitecture
Box
in a box
in a box

Markitecture
Box
in a box
in a box
to keep
things tidy

Markitecture
Gradient fill
implies
vague
boundaries?

Leonhard Euler

The Seven Bridges of Königsberg

Graph Theory

Directed graphs
C
B D
A

Structure matrix
C
B D
A
A B C D
A
B 1
C 1 1
D

Sorted
C
B D
A
A B D C
A
B 1
D
C 1 1

Cycles don’t sort out
C
B D
A
A B D C E
A
B 1 1
D
C 1 1
E 1
E

Carl Friedrich Gauss

Triangular numbers
•Add 1 + 2 + 3 + … + N

Triangular numbers
•Add 1 + 2 + 3 + … + N
•Add N + N-1 + … + 1

Triangular numbers
•Add 1 + 2 + 3 + … + N
•Add N + N-1 + … + 1
•So N lots of N + 1

Triangular numbers
•Add 1 + 2 + 3 + … + N
•Add N + N-1 + … + 1
•Sum is
1
2
𝑁(𝑁 + 1)

Triangular numbers
•Add 1 + 2 + 3 + … + N
•Add N + N-1 + … + 1
•Sum is
1
2
𝑁(𝑁 + 1)
•Schoolboy maths!

Edges in a graph
•Undirected graph
•N nodes
•+1 node => +N edges
•i.e. triangular number
•Max 𝑁(𝑁 − 1)/2
edges
•Directed graph
•Double the sum
•Max 𝑁(𝑁 − 1) edges

Metrics
Cyclomatic number:
E + P – N
Cyclomatic complexity:
E + 2P – N
where
E is the number of edges
P is the number of parts

Metric invariance
Cyclomatic number:
E + P – N
= 2 + 1 – 3
= 0

Metric invariance
Cyclomatic number:
E + P – N
= 2 + 2 – 4
= 0

Metric invariance
Cyclomatic number:
E + P – N
= 3 + 1 – 4
= 0

Metric invariance
Cyclomatic number:
E + P – N
= 2 + 1 – 3
+ 1 + 1 – 2
= 0

Spot the difference
3 layer
architecture
3 tier
architecture
A
B
C
A
B
C

Spot the difference
3 layer
architecture
3 tier
architecture
A
B
C
A
B
C
using B

Spot the difference
3 layer
architecture
3 tier
architecture
A
B
C
A
B
C
using C
using B

Spot the difference
3 layer
architecture
3 tier
architecture
A
B
C
A
B
C
address of B
using C
using B

Spot the difference
3 layer
architecture
3 tier
architecture
A
B
C
A
B
C
address of B
address of Cusing C
using B

Find architecture patterns in code
• Dependency analysis
• e.g. Layered architecture
• Heap analysis
• e.g. Tiered architecture
• Change in heap
• e.g.

Find design patterns in code
• e.g. Factory method
• Heap analysis
• e.g.
• Change in heap
• e.g.

• Heap analysis
• e.g. Composite
• Change in heap
• e.g.

• Heap analysis
• e.g. Composite
• Change in heap
• e.g. State machine

Tools
•Ndepend
•Lattix
•structure101
•Visual Studio
•DeepEnds
•NsDepCop

Tools
•NDepend
•Lattix
•structure101
•Visual Studio
•DeepEnds
•NsDepCop

Visual Studio 2015
$2999 p.a.

Visual Studio 2015
$2999 p.a.
•Create digraphs in Enterprise
•Save as a DGML file
•Open in Community or Professional

Tools
•NDepend
•Lattix
•structure101
•Visual Studio
•DeepEnds
•NsDepCop
• Visual Studio extension
• Listed on Visual Studio gallery
• Input
• csproj files
• parsed by Roslyn
• .NET assemblies
• decompiled by Mono.Cecil
• vcxproj.filter files
• Output
• DGML file
• Structured by namespace or filter
• Nodes hyperlink to source code files
• HTML report
• Cyclomatic number
• Underlying dependencies

A DGML file - inside Mono.Cecil

Expand Mono.CompilerServices

Expand Mono.CompilerServices.SymbolWriter

A cycle is spotted

Why the cycle?

Concrete class inherits interface
namespace Mono.CompilerServices.SymbolWriter
{
public class CompileUnitEntry : ICompileUnit
{
}
}

Interface returns concrete class!
namespace Mono.CompilerServices.SymbolWriter
{
public class CompileUnitEntry : ICompileUnit
{
}
public interface ICompileUnit
{
CompileUnitEntry Entry {
get;
}
}
}

Underlying dependencies

Summary of metrics

The effect of time and refactoring

NsDepCop
• Some dependency analysis tools enforce design intent by rules
• i.e. one component cannot depend on another
• e.g. NsDepCop rules on namespace dependencies
• These rules can be run automatically
• e.g. NsDepCop is run by MSBuild
• Rule violations can be acted upon

The End
• Related articles on CodeProject
• As-Is Software Architecture
• Dive into Architecture with DeepEnds
• Source on GitHub
• zebmason/itdepends
• zebmason/netdepends
• Extension on Visual Studio gallery
• DeepEnds

Inside architecture

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