Are you happy with your code quality?

ARE YOU HAPPY WITH
YOUR CODE QUALITY?
Track Ruby/Rails, October 25th 2013.
Presentation by and
Vincent Pochet Romain Sempé

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VINCENT POCHET
Website:
Twitter:
Github:
vincent-pochet.eu
@vin100pochet
vincent-pochet

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ROMAIN SEMPÉ
Website:
Twitter:
Github:
sempe.me
@rsempe
rsempe

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CO-FOUNDERS OF
We provide our expertise in web technologies with Rails.
Located in Archamps, near Geneva.

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WHAT IS GOOD CODE?

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IT DEPENDS ON THE CONTEXT

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A good code is:
EFFICIENT
(The customer is happy)

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A good code is:
TESTED

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A good code is:
SIMPLE AND READABLE

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A good code is:
PERFORMANT AND SCALABLE

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A good code is:
SECURE

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A good code is:
FLEXIBLE AND REUSABLE

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A good code is:
NOT PERFECT

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OTHER MEASUREMENTS OF CODE QUALITY?

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HOW CAN I WRITE GOOD CODE?

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CREATE A POSITIVE WORK ENVIRONMENT

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TRUST IN WHAT YOU'RE DOING

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GET CLEAR SPECIFICATIONS

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COMMUNICATE WITH YOUR COWORKERS

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TEST DRIVEN DEVELOPMENT

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FOLLOW THE STYLE GUIDES
github.com/styleguide/ruby
guidelines.plataformatec.com.br/ruby.html

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BEST PRACTICES

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READ SOURCE CODE

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FOLLOW YOUR INTUITION

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WRITE ELOQUENT RUBY CODE
"Remember, good code is like a good joke: It
needs no explanation."

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FACTORIAL EXAMPLE

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FACTORIAL EXAMPLE (2)

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PROGRAMMING TRANSGRESSIONS
FIXME is a "fuck you" to your coworkers

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REFACTORING

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PAIR PROGRAMMING

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CODE REVIEWS

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HOW TO MEASURE MY CODE QUALITY?

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USE TOOLS!

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Measure:
LINE COUNT
$ r
a
k
e s
t
a
t
s
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
+
-
-
-
-
-
-
-
+
| N
a
m
e | L
i
n
e
s | L
O
C | C
l
a
s
s
e
s | M
e
t
h
o
d
s | M
/
C | L
O
C
/
M |
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
+
-
-
-
-
-
-
-
+
| C
o
n
t
r
o
l
l
e
r
s | 1
1
8
8 | 7
6
4 | 1
9 | 1
5
0 | 7 | 3 |
| H
e
l
p
e
r
s | 1
5
1 | 1
0
1 | 0 | 1
8 | 0 | 3 |
| M
o
d
e
l
s | 1
3
4
6 | 7
7
5 | 1
5 | 1
3
4 | 8 | 3 |
| L
i
b
r
a
r
i
e
s | 6
4 | 2
9 | 2 | 5 | 2 | 3 |
| I
n
t
e
g
r
a
t
i
o
n t
e
s
t
s | 0 | 0 | 0 | 0 | 0 | 0 |
| F
u
n
c
t
i
o
n
a
l t
e
s
t
s | 1
4
0
0 | 1
1
5
3 | 2
1 | 1
6
5 | 7 | 4 |
| U
n
i
t t
e
s
t
s | 1
5
8
1 | 1
2
4
1 | 4
3 | 1
7
6 | 4 | 5 |
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
+
-
-
-
-
-
-
-
+
| T
o
t
a
l | 5
7
3
0 | 4
0
6
3 | 1
0
0 | 6
4
8 | 6 | 4 |
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
+
-
-
-
-
-
-
-
+
C
o
d
e L
O
C
: 1
6
6
9 T
e
s
t L
O
C
: 2
3
9
4 C
o
d
e t
o T
e
s
t R
a
t
i
o
: 1
:
1
.
4

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Measure:
COMPLEXITY
Flog
Cyclomatic complexity
ABC metric

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Measure:
COMPLEXITY
FLOG
$ f
l
o
g a
p
p
/
m
o
d
e
l
s
1
1
8
2
.
2
: f
l
o
g t
o
t
a
l
7
.
8
: f
l
o
g
/
m
e
t
h
o
d a
v
e
r
a
g
e
4
1
.
6
: S
t
o
r
y
:
:
S
t
e
p
#
c
h
a
n
g
e
_
p
o
s
i
t
i
o
n a
p
p
/
m
o
d
e
l
s
/
s
t
o
r
y
/
s
t
e
p
.
r
b
:
1
3
3
2
7
.
7
: S
t
o
r
y
:
:
S
t
e
p
#
u
p
d
a
t
e
_
t
r
i
g
g
e
r
_
i
t
e
m
s
! a
p
p
/
m
o
d
e
l
s
/
s
t
o
r
y
/
s
t
e
p
.
r
b
:
8
3
2
5
.
8
: S
e
r
v
i
c
e
A
c
c
o
u
n
t
:
:
G
o
o
g
l
e
O
a
u
t
h
2
:
:
f
r
o
m
_
o
m
n
i
a
u
t
h a
p
p
/
m
o
d
e
l
s
/
s
e
r
v
i
c
e
_
a
c
c
o
u
n
t
/
g
o
o
g
l
e
_
o
a
u
2
5
.
8
: S
e
r
v
i
c
e
A
c
c
o
u
n
t
:
:
F
a
c
e
b
o
o
k
:
:
f
r
o
m
_
o
m
n
i
a
u
t
h a
p
p
/
m
o
d
e
l
s
/
s
e
r
v
i
c
e
_
a
c
c
o
u
n
t
/
f
a
c
e
b
o
o
k
.
r
b
:
2
0
2
2
.
3
: P
r
o
g
r
a
m
#
s
c
h
e
d
u
l
e
_
r
u
n a
p
p
/
m
o
d
e
l
s
/
p
r
o
g
r
a
m
.
r
b
:
1
0
9
2
1
.
4
: S
t
o
r
y
:
:
S
t
e
p
#
v
a
l
i
d
a
t
e
_
a
c
t
i
o
n a
p
p
/
m
o
d
e
l
s
/
s
t
o
r
y
/
s
t
e
p
.
r
b
:
2
3
2
2
1
.
4
: R
o
l
e
S
t
e
p
#
v
a
l
i
d
a
t
e
_
a
c
t
i
o
n a
p
p
/
m
o
d
e
l
s
/
r
o
l
e
_
s
t
e
p
.
r
b
:
6
4
1
7
.
6
: S
t
o
r
y
:
:
S
t
e
p
#
i
n
c
r
e
m
e
n
t
_
a
l
l
_
p
o
s
i
t
i
o
n
s a
p
p
/
m
o
d
e
l
s
/
s
t
o
r
y
/
s
t
e
p
.
r
b
:
1
7
8

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Measure:
DUPLICATION
KEEP IN MIND :
DRY principle is:
Every piece of knowledge must have a single,
unambiguous, authoritative representation
within a system.
And not:
Don’t type the same characters into the
keyboard multiple times.

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Measure:
DUPLICATION
FLAY
$ f
l
a
y a
p
p
/
m
o
d
e
l
s
T
o
t
a
l s
c
o
r
e (
l
o
w
e
r i
s b
e
t
t
e
r
) = 4
0
6
1
) I
D
E
N
T
I
C
A
L c
o
d
e f
o
u
n
d i
n :
d
e
f
s (
m
a
s
s
*
2 = 2
2
0
)
a
p
p
/
m
o
d
e
l
s
/
s
e
r
v
i
c
e
_
a
c
c
o
u
n
t
/
f
a
c
e
b
o
o
k
.
r
b
:
2
0
a
p
p
/
m
o
d
e
l
s
/
s
e
r
v
i
c
e
_
a
c
c
o
u
n
t
/
g
o
o
g
l
e
_
o
a
u
t
h
2
.
r
b
:
8
2
) S
i
m
i
l
a
r c
o
d
e f
o
u
n
d i
n :
d
e
f
n (
m
a
s
s = 7
0
)
a
p
p
/
m
o
d
e
l
s
/
r
o
l
e
_
s
t
e
p
.
r
b
:
6
4
a
p
p
/
m
o
d
e
l
s
/
s
t
o
r
y
/
s
t
e
p
.
r
b
:
2
3
2
3
) S
i
m
i
l
a
r c
o
d
e f
o
u
n
d i
n :
d
e
f
n (
m
a
s
s = 4
0
)
a
p
p
/
m
o
d
e
l
s
/
s
t
o
r
y
/
s
t
e
p
.
r
b
:
1
1
2
a
p
p
/
m
o
d
e
l
s
/
s
t
o
r
y
/
s
t
e
p
.
r
b
:
1
1
6

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Measure:
CHURN
The change of your source files over time
$ c
h
u
r
n
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
* P
r
o
j
e
c
t C
h
u
r
n
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
F
i
l
e
s
:
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
| f
i
l
e
_
p
a
t
h | t
i
m
e
s
_
c
h
a
n
g
e
d |
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
+
| c
o
n
f
i
g
/
l
o
c
a
l
e
s
/
e
n
.
y
m
l | 2
8
1 |
| d
b
/
s
t
r
u
c
t
u
r
e
.
s
q
l | 1
0
8 |
| a
p
p
/
v
i
e
w
s
/
p
l
a
y
e
r
/
s
h
o
w
.
h
t
m
l
.
e
r
b | 9
2 |
| a
p
p
/
v
i
e
w
s
/
s
t
o
r
i
e
s
/
s
h
o
w
.
h
t
m
l
.
e
r
b | 8
8 |
| G
e
m
f
i
l
e
.
l
o
c
k | 8
7 |

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Measure:
CHURN
Churn VS Complexity
Turbulence

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All metrics
METRIC FU
https://github.com/metricfu/metric_fu

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(For Ruby < 1.9)
:
Measure:
TEST COVERAGE
RCov
SimpleCov
$ C
O
V
E
R
A
G
E
=
t
r
u
e r
a
k
e t
e
s
t
# R
u
n
n
i
n
g t
e
s
t
s
:
F
i
n
i
s
h
e
d t
e
s
t
s i
n 1
4
.
5
5
6
9
4
3
s
, 1
1
.
8
8
4
4 t
e
s
t
s
/
s
, 2
4
.
7
9
9
2 a
s
s
e
r
t
i
o
n
s
/
s
.
1
7
3 t
e
s
t
s
, 3
6
1 a
s
s
e
r
t
i
o
n
s
, 0 f
a
i
l
u
r
e
s
, 0 e
r
r
o
r
s
, 0 s
k
i
p
s
r
u
b
y -
v
: r
u
b
y 2
.
0
.
0
p
2
4
7 (
2
0
1
3
-
0
6
-
2
7 r
e
v
i
s
i
o
n 4
1
6
7
4
)
1
0
7
1 / 1
1
8
7 L
O
C (
9
0
.
2
3
%
) c
o
v
e
r
e
d
.
R
u
n o
p
t
i
o
n
s
:
# R
u
n
n
i
n
g t
e
s
t
s
:
F
i
n
i
s
h
e
d t
e
s
t
s i
n 1
8
.
5
8
0
0
9
9
s
, 8
.
7
7
2
8 t
e
s
t
s
/
s
, 2
4
.
5
9
6
2 a
s
s
e
r
t
i
o
n
s
/
s
.
1
6
3 t
e
s
t
s
, 4
5
7 a
s
s
e
r
t
i
o
n
s
, 0 f
a
i
l
u
r
e
s
, 0 e
r
r
o
r
s
, 0 s
k
i
p
s
r
u
b
y -
v
: r
u
b
y 2
.
0
.
0
p
2
4
7 (
2
0
1
3
-
0
6
-
2
7 r
e
v
i
s
i
o
n 4
1
6
7
4
)
1
1
5
9 / 1
1
6
0 L
O
C (
9
9
.
9
1
%
) c
o
v
e
r
e
d
.

View Slide

Measure:
TEST COVERAGE
SIMPLECOV REPORT

View Slide

Measure:
TEST COVERAGE
SIMPLECOV REPORT DETAILS

View Slide

Security:
BRAKEMAN
http://brakemanscanner.org/

View Slide

View Slide

CI:
TRAVIS

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CI:
SEMAPHORE

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Coverage:
COVERALLS

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Project dependencies:
GEMNASIUM

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Perfomance:
NEW RELIC

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Code quality!
CODECLIMATE

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SOFTWARE != CODE

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"Good software meets the present objective at
an acceptable cost without incurring an
unacceptable amount of future risk"
Brandon Keepers - Github

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QUALITY VS VELOCITY

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MERCI ET BISOUS!

View Slide

Are you happy with your code quality?

Are you happy with your code quality?

Vincent Pochet

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