GIT Workshop

What is Git

  • Open source project developed in 2005 by Linus Torvalds
  • Distributed Version Control System (VCS)

 

Linus Torvalds has quipped about the name “git“, which is British English slang for a stupid or unpleasant person: “I’m an egotistical b*****d, and I name all my projects after myself. First Linux, now git."

Why do you want to use Git ?

What do you want out of today ?

Title Text

What's good about Git

  • Performs well doing commen actions like branching, merging comparing history
  • Can use off line and push changes later
  • Easy to switch between branches
  • All changes are secured using SHA1 hashing so history can never be tampered with or accidentally changed
  • Becoming the standard VCS...

How Git works with files

  • Snapshots of each version (not deltas)
  • Checksum on each version (unique id)
  • Operations are additive
  • Operations are local
  • its OK to fail....

Command line interface (CLI)

  • You are completely in control of what you are doing
  • you completely understand what is happening
  • Easier to share what you are doing
  • Easier to get help online
  • It is easier to build actions into automation pipelines

 

GUIs exist: Atlassian source tree, Kraken, IDE (visual studio)

Our repository

https://bitbucket.org/peterkaras/global-aerospace

Simple html page we can explore feature of git. Explore the Bitbucket UI...

 

We are using Bitbucket to host our remote repo, but we could be use:

  • GitHub
  • Assembla
  • Peforce
  • Visual studio team services

They all provide very similar functionality

Distributed VCS

How we work

Slides - talk - discuss

Time for practice, work in groups around Laptops.

Questions, discussion...

We will practice commands as much as possible

Overview of content

  1. Basic commands
  2. Working with others
  3. Clean commits
  4. Gitflow
  5. Discussion...

1 Basic commands

git clone
git add
git commit
git push

Setting up user

Identifies you when you are pushing changes to a shared repository

$ git config --global user.name "John Doe"
$ git config --global user.email john@test.com
$ git

you are ready to go....

Getting Started

Creates a repository into a newly created directory: create .git folder

git clone https://bitbucket.org/peterkaras/global-aerospace.git
git init

Initialises a repository that you can later push to a shared repository

git status

Understanding local

Creates a repository into a newly created directory.

git clone git://sfdsfds
git remote -v

Lists remote repos

Setting up access

You can access by providing username and password each time

HTTPS
SSH

You can upload your public SSH key for easier long term access

Make a change

Add your new file to the staging area.

git add .
git status

Commits, creates a checkpoint with your change

git commit -m "my first change"
git status

What just happend

We organise our work into commits using the staging area

Internal view

Push changes

What happens when everyone pushes their changes at the same time ?

git push

2 Working with others

git branch
git fetch
git pull
git merge 
git push

Why do we need branches ?

Create a branch

Creates a new branch

git branch my-first-branch

Checkout the new branch

git checkout my-first-branch

Moves HEAD to point at your new branch

Make and commit a change

git status
git add .
git status
git commit -m "my change"
git status

Sharing your work

Shows you local and remote branches

git branch -a
git push -u origin my-first-branch

Stores your branch on the remote repository

Seeing other peoples work

Fetches the latest view of the shared repository

git fetch
git pull

fetch + merge into current branch.... see later

Merges

git checkout master
git pull 
git checkout mybranch
git merge master
git commit
git checkout master 
git merge another-branch
git commit

When are you sure you can merge to master ?

Why do we need to get latest versions from master ?

Conflicts

[1] All create a branch and make some changes and push...

[2] One person merge to master

[3] Everyone pull latest changes and merge master to their barnches

git checkout -b my-new-branch

Resolving conflicts

If you have questions, please
<<<<<<< HEAD
my text in the head 
=======
the text in branch-a
>>>>>>> branch-a

Git does a good job automerging, but sometimes you need to intervene manually to resolve conflicts

Collaborating with Pull requests

git push -u origin my-changes

Create a pull request and add each other as reviewers.

Why use pull requests ?

Branch management

How long do you think branches should stay open ?

 

Whats the disadvantage of having long lived branches ?

 

How does this relate to user stories (items of work) ?

3 Clean commits

git commit
git log
git stash
git rebase
git revert
git tag

Review logs in Bitbucket

How does the commit history look ?

Semantic commits

Makes commits meaningful

  • Include TFS / JIRA number

Can be

  • feature
  • fix
  • refactor
  • test
  • Doc
git commit -m "WAP-967 feature(postcode selection)"

Branch names

Self explanatory names

git checkout -b fb/GA-789/my-new-feature

Can use convention:

  • fb : feature branch
  • hf : hot fix

History

Keeping organised about commits means a clean history.

1 Story = 1 commit

git log
git rebase -i <commit number>

Allows you to clean up local history

Stash

Saves staged and working directory.

git stash
git stash apply

reapplies stashed changes

Tags

Creates a Tag V1.4

git tag -a v1.4 -m "my version 1.4"
git tag

lists tags

should you branch or tag ?

Delete a branch

#remote
git push -d <remote_name> <branch_name>

#local
git branch -d <branch_name>

Always delete merged branches

Unstaging / reverting

unstages local files

git reset HEAD .
git checkout .

replaces unstaged files with contents of HEAD. overwrites changes

Revert a change

Creates a new commit backing out those changes

git revert <commit>

1 Git flow

https://www.atlassian.com/git/tutorials/comparing-workflows/gitflow-workflow

Master / Develop branch

Feature branch

Release Branch

Hotfix branch

Complications

  • Large Stories / long lived feature branches
  • Multiple teams
  • Large product

If you use git flow and find yourself diverging from the simple model, you are probably compensating for organizational or infrastructure issues.

4 Questions / Discussion

Resources

git --help <command>

google git manual

google atlassian gitflow

google stackoverflow

The End

Optional Exercise

  • GA-01: Introduction text
  • GA-02: Submit button
  • GA-03: Copyright
  • GA-04: GDPR waiver
  • GA-05: Crazy background color
  • GA-06: Link to Global Aerospace website

Each take one of the following changes and create pull requests then merge to development.

GIT

By peterkaras

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