Tech thursdays / GIT

Będzie Gitmam nadzieje...

Git / Why should I care?

http://www.google.com/trends/explore#cat=0-5-32&q=git%2C%20subversion%2C%20mercurial&cmpt=q



Git / What is Git ?

Git is an open source distributed version control system designed for speed and efficiency.

Initially designed and developed by Linus Torvalds for Linux kernel development.

Git / What's Linus likes ?

Git / Open Source



Git / Distributed



Git / Central vs Distributed

Computer A

checkout

file

Computer

checkout

file

Central VCS

version database

version 1

version 2

version 3

Git / Central vs Distributed

Computer A

version database

file

version 1

version 2

Computer A

version database

file

version 1

version 2Server Computer

version database

version 1

version 2

Git / Efficiency



Git / Efficiency

Not a shrink wrap product, so not quite what we are doing, however facebook have 700 developers, with new code pushed out daily

http://venturebeat.com/2012/08/03/facebook-code/

Our merging process seems to have slowed down, where merges are now held until the end of the iteration. We need to become more rapid and have user stories accepted earlier in the iteration cycle, with more regular and smaller merges taking place throughout the iteration.

Cheers,

XXX

Software Development Engineering Manager

Git / Efficiency

Git /Efficiency

$time to deliver (time to market) + additional costs (disk space,..)

=methodologies

version control systemopen-source projects

programming languages (functional/lambda = less code)modular architecture

continuous integrationtest automation

continuous deploymentmonitoring driven development

Git / Delta based storage

Commit 1 Commit 2 Commit 3 Commit 4 Commit 5

index.html

style.css

main.js

Δ1

Δ2

Δ3

Δ5

Δ7

Δ8

homt.html Δ6

Git / Direct Acyclic Graph Storage

Commit 1 Commit 2 Commit 3 Commit 4 Commit 5

entity 1

entity 2

entity 3

entity 4

entity 5

entity 6

entity 8

entity 9

entity 0

entity 7 entity 6

Git / Direct Acyclic Graph

Directed GraphArcs Connecting the nodes are directional.

Git / Direct Acyclic Graph

A->B->C->D->Ais a CYCLEAcyclic graphs have NO CYCLES

A

C

B

D

Git / Source control taxonomy

delta storage

local

centralized

distributed

rcs

cvs cvs perforce

darcs mercurial

dag storage

local

centralized

distributed

cp -r time machine

bitkeeper

git bazaar

Git / Meat

.gitconfig file

hooksindex

object databasereferences

Git / Object database

.gitconfig file

hooksindex


Git / Object database / Algorithm

new_content = type + ’ ‘ + content.size + \0+ content

sha = Digest::SHA1.hexdigest(new_content)“824aed035c0aa75d64c...”

compressed = zlib::deflate(new_content)

path = “.git/objects/82/4aed035c0aa75d64c...”

File.open(path, ‘w’) {|f| f.write(compressed)}

http://alblue.bandlem.com/2011/08/git-tip-of-week-objects.html



Git / Object database / GC

git gc.git/objects/82/4aed035c0aa75d64c....git/objects/1d/c9cbcb76cbb80fce1....git/objects/63/874f37013c1740acd....git/objects/04/fb8aee105e6e445e8...

.git/objects/45/b983be36b73c0788d....git/objects/f1/032eed02413a1145c...

.git/objects/pack/pack-999727..9f600.pack.git/objects/pack/pack-999727..9f600.idx

http://alblue.bandlem.com/2011/09/git-tip-of-week-objects-and-packfiles.html




blob tree

commit tag

FILE===============srutu tutu majtki z drutu

Git / Object database / Blob

blob [content size]\0

blob : a906cb

zlib::deflate




Git / Object database / Tree

./

blob : a874b7

blob : a906cb

tree : fe8971

blob : a0a60a

tree : 1a738d

index.html

js/

main.js

README

100644 blob a874b7 README100644 blob a906cb index.html040000 tree fe8971 js

Git / Object database / Tree

tree [content size]\0

tree : 1a738d

zlib::deflate

http://alblue.bandlem.com/2011/08/git-tip-of-week-trees.html



Git / Object database / Commit

commit

blob

blob

tree

blob

tree

tree

http://alblue.bandlem.com/2011/09/git-tip-of-week-commits.html

tree e1b3ecparent a11befauthor Marek Prochera

<[email protected]> 1205624433committer Marek Prochera

<[email protected]> 1205624433my second commit

Git / Object database / Commit

commit [content size]\0

commit : e1b3ec

zlib::deflate



Git / Object database / Tag

tag

tree

blob

commit

object 0576fatype committag v0.1tagger Marek Prochera

<[email protected]> 1205624655this is my v0.1 tag

Git / Object database / Tag

tag [content size]\0

tag : 0c819c

zlib::deflate

http://alblue.bandlem.com/2011/04/git-tip-of-week-tags.html




blob treeimmutable! fuck yea!

commit tag

Git / References

.gitconfig file

hooksindex


Referenceslightweight, movable pointers to a commit

stored in .git/refs/* as file

Git / References

HEAD

blob

commit

branch

tree

tagremote

Git / Object db + Refs / Use case

git checkout v.01

.git/refs/tags/v0.1 "0c819c"

tag: 0c819c

commit : a11bef

tree : 1a738d

README blob : a874b7

Git / References

commit historybranching and merging

remotes...

Git / Treeish

alternate ways to refer toobjects or ranges of objects

• full sha-1• partial sha-1

• branch or tag name• date spec

• ordinal spec• carrot parent

• tilde spec• tree pointer

• blob spec• ranges

Git / Treeish / Full sha-1

6e453f523fa1da50ecb04431101112b3611c6a4d

Git / Treeish / Partial sha-1

6e453f523fa1da50ecb04431101112b3611c6a4d6e453f523fa1da50

6e453

Git / Treeish / Branch, remote, tag

v1.0master

origin/kuciap

Git / Treeish / Ordinal Spec

master@{5}5th prior value of ‘master’

Git / Treeish / Tidle Spec

master~22nd generation grandparent of ‘master’

Git / Treeish / Tree Pointer

master^{tree}tree that ‘master’ points to

Git / Treeish / Blob spec

master:/path/to/fileblob of that file in ‘master’ commit

Git / Treeish / Ranges

ce0e4..e4272everything between two commits

Git / Index

.gitconfig file

hooksindex


Git / Index

working directory

repository

index

git add ...

git commit ...

http://alblue.bandlem.com/2011/10/git-tip-of-week-understanding-index.html



Git / Hooks

.gitconfig file

hooksindex


hooks = automation :)fuck yea!

Git / Hooks

Git / Config

.gitconfig file

hooksindex


config = config :)

Git / Config

Over 152 commands

42 porcelain

110 plumbing

Git / Git Playground

Git / ID

git config --global user.name “Marek Prochera”

git config --global user.email “[email protected]”

mpr:~ marek$ cat ~/.gitconfig [user]

name = Marek Procheraemail = [email protected]

Git / Clone

mpr:tmp marek$ git clone [email protected]:playframework/Play20.gitCloning into 'Play20'...

remote: Counting objects: 43846, done.remote: Compressing objects: 100% (17930/17930), done.

remote: Total 43846 (delta 22410), reused 40397 (delta 19382)Receiving objects: 100% (43846/43846), 57.74 MiB | 3.41 MiB/s, done.

Resolving deltas: 100% (22410/22410), done.

Git / and so on...

git init git add -A

git commit -a -m "Initial commit"git status

git loggit log --pretty=oneline

git log --pretty=format: %h %an %ar - %sgit diff (treeish1) (treeish2)

Git / and so on...

git branchgit show-branch

git checkout -b featuregit merge fature

git rebase

Git / Merge & rebase

develop

master

C 0 C 7

C 3

C 6

C 4 C 5

develop

master

C 0 C 6'C 3 C 4 C 5

Git / and so on...

mpr:test2 marek$ git remote add krogulec [email protected]:playframework/Play20.git

mpr:test2 marek$ git remote -vkrogulec [email protected]:playframework/Play20.git (fetch)krogulec [email protected]:playframework/Play20.git (push)

Git / and so on...

git remote show krogulecpush / pull krogulec master

pull = fetch + merge

no more scm document!

Git / Workflows

Git / Repo model / Shared

shared repository

dev 2dev 1

Git / Workflows

shared repository

dev 2dev 1

Git / Repo ... / dictator and lieutenants

blessed repository

dev 2

dev 1

lieutenants

dictator

lieutenants

Git / Repo ... / Integration manager

blessed repository

dev 2

dev 1

dev 1 public repo

integration manager

dev 2 public repo

Git / Git-Flow

Git / Git-Flow

http://nvie.com/posts/a-successful-git-branching-model/

https://github.com/nvie/gitflow

......git flow release

git flow release start <release> [<base>]git flow release finish <release>





Git / Repos

Provider Git Mercurial Free Priv Rep Premium

github

bitbucket

X

X !!!

X

X X

your own EC2 !!! !!!!!! !!!

http://www.wikivs.com/wiki/Git_vs_Mercurial#Hosting_Provider_Support



Git / Git as a SVN client

git as a client:do not mess in history !

sudo apt-get install git-svngit svn init svn://repo.path/trunk

git svn fetch -r HEAD

pull:git svn rebase

push:git svn dcommit

http://trac.parrot.org/parrot/wiki/git-svn-tutorial



Git / Tools/IDE support

Git / Tools/IDE support / Git alias

#make "com" alias for "commit"

git config alias.com commit

#make "co" alias for checkout

git config alias.co checkout

#make "br" alias for branch

git config alias.br branch

# When you want to see just the differences of one function in one file in two different commits

git config alias.funcdiff '!sh -c "git show \"\$1:\$3\" | sed -n \"/^[^ \t].*\$4(/,/^}/p\" > .tmp1 &&

git show \"\$2:\$3\" | sed -n \"/^[^ \t].*\$4(/,/^}/p\" > .tmp2 &&

git diff --no-index .tmp1 .tmp2"' -

Git / Tools/IDE support / bash

https://github.com/magicmonty/bash-git-prompt




Repository management (ssh keys, privileges ): gitosishttps://wiki.archlinux.org/index.php/Gitosis

Web based browsers:https://wiki.archlinux.org/index.php/Gitweb

Browser + code review:https://code.google.com/p/gerrit/

http://www.codebrag.com/

https://wiki.archlinux.org/index.php/Gitosis

https://wiki.archlinux.org/index.php/Gitosis

https://wiki.archlinux.org/index.php/Gitweb

https://wiki.archlinux.org/index.php/Gitweb

https://code.google.com/p/gerrit/

https://code.google.com/p/gerrit/



Git / Tools/IDE supportIntelliJ IDEA as always the best :)

egit in eclipse sucks

most of good GUI tools for git are dedicated for Mac OSX :/http://git-scm.com/downloads/guis

linuxgitk / gitg

(http://git.gnome.org/browse/gitg)

http://git-scm.com/downloads/guis

http://git-scm.com/downloads/guis


but if you like ponies ... you're lucky!

SourceTree @ Atlassianhttp://www.atlassian.com/software/sourcetree/overview

Git Bash!

http://www.atlassian.com/software/sourcetree/overview

http://www.atlassian.com/software/sourcetree/overview

Git / Git vs Hg

If you just give them a chance....

http://felipec.wordpress.com/2012/05/26/no-mercurial-branches-are-still-not-better-than-git-ones-response-to-jhws-more-on-mercurial-vs-git-with-graphs/




Git / Resources

https://www.google.com/search?q=git

http://alblue.bandlem.com/Tag/git/http://gitref.org/

ProGit (EN/PL) http://git-scm.com/

Git. Rozproszony system kontroli wersji (PL)http://helion.pl/ksiazki/git-rozproszony-system-kontroli-wersji-wlodzimierz-gajda,gitroz.htm

http://pcottle.github.io/learnGitBranching/



http://alblue.bandlem.com/Tag/git/

http://alblue.bandlem.com/Tag/git/

http://gitref.org/

http://gitref.org/

http://git-scm.com/

http://git-scm.com/

http://helion.pl/ksiazki/git-rozproszony-system-kontroli-wersji-wlodzimierz-gajda,gitroz.htm

http://helion.pl/ksiazki/git-rozproszony-system-kontroli-wersji-wlodzimierz-gajda,gitroz.htm



Git / This is the end

Thank you

Tech thursdays / GIT

Software

Transcript of Tech thursdays / GIT