What is CI?Azlam Abdulsalam

What is CI?

“Continuous Integration is a software development practice where members of a team integrate their work frequently, usually each person integrates at least daily - leading to multiple integrations per day. Each integration is verified by an automated build (including test) to detect integration errors as quickly as possible. Many teams find that this approach leads to significantly reduced integration problems and allows a team to develop cohesive software more rapidly”

-- Martin Fowler, May 2006

Main Keywords

CI is a practice

Integrate work of everyone

frequentlyat least once daily

automated buildinclude tests

Integrating Work of Everyone Quite Frequently!

Common Branch Strategies

Release Feature Branching

main

Feature 1

Feature 2

Time

C C C C C C

C C C C C

B B M M

B

M

C Commit

Branch

Merge

Release Feature Branching with Promiscuous Integration

main

Feature 1

Feature 2

Time

C C C C C C

C C C C C

B B M M

B

M

C Commit

Branch

Merge

Release For Customer A

MM

Release Feature Branching…

main

Feature 1

Feature 2

Time

C C C C C C

C C C C C

B B M M

B

M

C Commit

Branch

Merge

Release For Customer AM

Release For Customer BM

MM

Let’s add bit more complexity! – Fixes in Production

main

Feature 1

Feature 2

Time

C C C C C C

C C C C C

B B M M

B

M

C Commit

Branch

Merge

Release TaggingT

hotfix

M

M

M

C

T Tag

M

MM

That is why you had SCM Managers! –Something was not working… and minimal integration!

Integration Based Branching

integration

Time

B

M

C Commit

Branch

Merge

T Tag

B

main

B

Feature 1

M

C C C C

M

Feature 2

C

M

M C C

Feature 2

B

C C C C MFeature 3 C C

Feature 2

M

Feature 1

C

M

M

MT

Integration Branching is widely used and solves some of the cross merging issues… and very effective if feature is short lived.. Like agile!...

It’s not pure CI.. But currently most common implementation

Wait…There is one more method!

Trunk based development

main

Time

B

M

Branch

Merge

T Tag

C Commit

F1 : C F1 : C F2 : C F2 : C F1: C F3: C

Feature 1 Toggle

Feature 2 Toggle

Feature 3 Toggle

F2 : C

T

F1 : C F1 : CF3: C F3: C F3: C F1 : C

T

F3: C

T

Trunk Based Development

• Continuous Integration

• Adaptive scheduling

• Collaborative design

• Operational and Business Empowerment

• Not Easy• Feature Flags left to live can cause issues in production• Coding Complexity in managing runtime flags• There are frameworks to manage feature complexity

Automated Build

An Idea of the build process

• Pre processing

• Compiling Multiple Files

• Moving Files Around

• Packing Resources

• Creating Executables or Jar’s or DLLs

• Loading Schema into Databases

• ………….

An Idea of the build process

• Pre processing

• Compiling Multiple Files

• Moving Files Around

• Packing Resources

• Creating Executables or Jar’s or DLLs

• Loading Schema into Databases

• ………….

Can all this steps be automated???

Automating the build process

• One single command to generate a build….• For eg: gradlew assembleProdRelease <--- CSSM Mobility

• And How?• Using tools such as

• Java - Ant, Maven

• .NET -> Nant, MSBuild

• Unix -> Make

Automating the build process

• One single command to generate a build….• For eg: gradlew assembleProdRelease <--- CSSM Mobility

• And How?• Using tools such as

• Java Ant, Maven, Gradle

• .NET Nant, MSBuild

• Unix Make

Anyone should be able to bring in a virgin machine, check the sources out of the repository, issue a single command, and have a running system on their machine.

Good Build Tool should analyse what is to be built depending on the change

Make the build self testing!include tests

An Interesting Dilemma!

Some Pointers!

• Entire build process including testing has to be fast• No more than 15 minutes per commit

• But, it has to validate that bugs are not introduced as well

• Balance the needs of bug finding and speed so that a good commit build is stable enough for other people to work on.

• Some Ideas• Deployment Pipelines

• Unit Testing

• Smoke Testing

Thank You!