Introduce to Git and Jenkins

1. 1
Git & Jenkins Introduction

2. 2
Agenda
1. Git
1. Core concepts
2. Installation
3. Basic usage
2. Jenkins
1. What’s it? Why do we need it?
2. Terminologies
3. Jenkins architecture
3. Demo (integrate Jenkins with Git)

3. 3
1 What’s Git?
 The most commonly used version control
system (VCS) today.
 Distributed VCS, meaning your local copy of
code is a complete version control
repository.
 These fully-functional local repositories
make it is easy to work offline or remotely.

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1.1 Core concepts
 Repository
● Collection of files and their history organized in folders, branches, tags
● Is stored in a normal file system somewhere
● Can be on a local machine or a remote machine
● To work with GIT you will need a repo somewhere
● When creating a new one… it’s empty

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1.1 Core concepts (cont.)
 Index (Staging area)
● Snapshot of files in the workspace.
● You add to the index files you change / remove etc.
 Commit
● A snapshot of the workspace at some point
● Has unique revision number
● Knows the commit (commits) that it’s based on

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1.1 Core concepts (cont.)

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1.2 Installation
 Download installation at: https://git-scm.com/download
● Windows: Run installation file.
● Ubuntu:
sudo apt install git
● RedHat/CentOS:
sudo yum install git
 Verify installation:
git --version

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1.3 Basic usage - Configuration
 3 config files:
/etc/gitconfig -> all users, repositories (--system)
~/.gitconfig - > one user, all repositories (--global)
[repo]/.git/config -> specific to repository (default)
 Your identity – information for each commit:
git config --global user.name “An Nguyen”
git config –global user.email nthienan@tma.com.vn
 List all config values:
git config --list

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1.3 Basic usage - Configuration (cont.)
 Merge tool:
git config --global --add merge.tool kdiff3
git config --global --add mergetool.kdiff3.path "C:/Program Files/KDiff3/kdiff3.exe"
git config --global --add mergetool.kdiff3.trustExitCode false
 Diff tool:
git config --global --add diff.guitool kdiff3
git config --global --add difftool.kdiff3.path "C:/Program Files/KDiff3/kdiff3.exe"
git config --global --add difftool.kdiff3.trustExitCode false

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1.3 Basic usage - Create repository
 Initialized a repo:
git init
 Clone – creates a local repository by copying another (remote) repository
git clone <repo_url>
 Clone existing repo into directory
git clone <repo_url> <directory_name>

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1.3 Basic usage - Working with files
• Add changes to index (staging area):
git add <file_path>
git add –A
• Unstage files:
git reset HEAD <file_path>
• Reset all changes:
git reset --hard
• Discard unstaged changes in a file:
git checkout <file_path>
• Commit:
• git commit –m “message”
• git commit –am “message”

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1.3 Basic usage - View changes
 Show status of files:
git status
 Show unstage changes:
git diff
git difftool
 Show staged changes:
git diff --cached
git difftool --cached

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1.3 Basic usage - View history
 Show log:
git log [-n] [--pretty] [--graph]
-n <number_of_commit>: show n commit
--pretty=<format>: display format. See pretty format here
--graph: show history in diagram
Ex: git log -n 10 --pretty=short—graph
 There’re many GUI tools: SourceTree, GitHub Desktop, Git Extensions

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1.3 Basic usage - Branches
 Branch is a pointer to a commit
 A branch can point at other commits – it can move
 A branch is a way to organize working histories
 The default branch name in Git is master
 There is 2 types of branch: local and remote.
 Remote branches represent the state of a branch on the repository it is fetched
from
 You cannot checkout a remote branch. You create a local pointer to it

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1.3 Basic usage - Branches
 When doing a “commit” the current “branch” moves to point at the new
commit
C3 C2 C1bx
C3 C2 C1bx C4

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1.3 Basic usage - Branches
 Here is a branch
 Creating a new branch just adds another “pointer” to the same commit
C3 C2 C1bx
C3 C2 C1
bx
by

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1.3 Basic usage - Branches
 Other branches are not affected by a commit
C3 C2 C1
bx
by
C3 C2 C1
bx
by
C4

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1.3 Basic usage - Branches (cont.)
 List all local branches:
git branch
 List all remote branches:
git branch –r
 Create new branch:
git branch <branch_name>
 Switch branch:
git checkout <branh_name>
 Create new branch and switch to it:
git checkout -b <branch_name>
 Delete branch:
git branch –d <name>
Safe operation, prevents deleting branch
unmerged.
git branch –D <name> :
Force delete branch
 Rename branch
git branch –m <new_name>

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1.3 Basic usage - Merging
 Merge the specified branch into
the current branch
● git merge <branch_name>
 Merge the specified branch into
the current branch, but always
generate a merge commit:
● git merge --no-ff <branch_name>

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1.3 Basic usage - Resolving Conflicts
If the two branches you're trying to merge both changed the same part of the same
file => conflict => stop merge process
CONFLICT (content): Merge conflict in <file_paths>
Automatic merge failed; fix conflicts and then commit the result.
 Using merge tool to resolve conflicts:
git mergetool : open merge tool so that you can resolve the conflicts manually.
git commit : commit merge change and finish merge action.

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1.3 Basic usage - Remote
 Remotes are just symbolic
names
 You can have as many as you
like
 The default name is origin if
you’ve cloned
 Remote-tracking branches are
locally immutable
My Machine The Server
C1
master
C0
cloneC1
origin/master
C0
master

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1.3 Basic usage - Fetch
 Fetch – gets changes from a remote repository that you don’t already have.
 Fetch gets the changes to the local repository but does not touch the index or
workspace.
 After a fetch, usually a merge needs to take place
git fetch
git merge <remote>/<branch>

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1.3 Basic usage - Fetch (cont.)
My Machine
The Server
C1
C0
master
C2
C1
origin/master
C0
master
fetch
My Machine The Server
C1
C0
master
C2
C1
origin/master
C0
masterC2

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1.3 Basic usage - Pull
 Pull is just a shortcut command to do:
1. Fetch from a remote
2. Merge changes from “remote branch” into the “remote tracking branch”
 Sometimes the tool would also allow to “commit” merges for you right after the
pull (not part of pull, but a helper)
git pull

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1.3 Basic usage - Push
 Will take local objects (commits, tags) which are required to make a remote
branch complete – and send them.
 Will merge those local changes into the remote branch
 Will only do a “fast-forward” merge (other merge type, if required, will fail the
push)
 Push to existing branch
git push
 Push new branch
git push –u <remote> <branch>

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1.3 Basic usage - Push (cont.)
My Machine The Server
C1
C0
master
C2
C1
origin/master
C0
master
C2
C3
My Machine The Server
C1
C0
master
C2
C1
origin/master
C0
master
C2
C3 C3

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1.3 Basic usage - Push (cont.)
 If cannot do a fast-forward – will fail. Then, a fetch + merge (or pull) is required to
allow the push.
 Once remote changes merged locally again a fast forward is possible and the push
would work

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1.3 Basic usage - Push (cont.)
My Machine The Server
C1
C0
master
C2
C1
origin/master
C0
master
C2
C3 C4
push
My Machine The Server
C1
C0
master
C2
C1
origin/master
C0
master
C2
C3
C4
C4
C5

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1.3 Basic usage - Push (cont.)
My Machine The Server
C1
C0
master
C2
C1
origin/master
C0
master
C2
C3
C4
C4
C5
push
My Machine The Server
C1
origin/master
C0
master
C2
C3
C4
C5
C1
C0
master
C2
C3
C4
C5

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2.1 What’s Jenkins?
 Continuous integration server - detects changes
in Subversion, performs tasks, repeatedly (build,
test, deploy, package, etc.)
 An open source continuous integration tool
written in Java.
 It is a server-based system running in a servlet
container such as Apache Tomcat

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2.1 Why do we need?
 To integrate more frequently, detect errors quicker, improve quality and reduce
cost
 Co-ordinate the running of tasks as part of workflows.
 Compile, test and package, deploy, script, verify

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2.2 Terminology
 Job - a unit of work for a project
 View - user defined collection of jobs or a workflow
 Master - the central Jenkins master, does job scheduling
 Slave - executes one or more jobs within slots (executors)
 Workspace - the working area where a job is carried out

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2.3 Architecture

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2.3 Architecture (cont.)

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2.3 Jenkins Features
 Trigger a build
 Get source code from repository
 Automatically build and test
 Generate report & notify
 Deploy
 Distributed build

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2.3 Jenkins Plugins
 Build triggers
 Source code management
 Build tools
 Build wrappers
 Build notifiers
 Build reports
 Artifact uploaders
 UI plugins
 Authentication and user management

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2.3 Build Trigger
 Manually click build button
 Build periodically
 Poll SCM
 Build after other projects are built

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2.3 Security Management
 Security Realm
● LDAP
● Jenkins's own user database
 Authorization
● Anyone can do anything
● Logged-in users can do anything
● Matrix-based security
● Project-based Matrix Authorization Strategy

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2.3 Jenkins Pipeline

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2.3 Test Code Coverage
Ref: http://cobertura.sourceforge.net/sample/

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2.3 How does Jenkins fit into your work?

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3. Demo