Removing the org-mode source for the README.md file, and giving the README.md file that name
This commit is contained in:
parent
815191c736
commit
cd3e598051
2 changed files with 0 additions and 313 deletions
313
GitDeepDive.org
313
GitDeepDive.org
|
|
@ -1,313 +0,0 @@
|
|||
|
||||
#+OPTIONS: ^:{} toc:nil author:nil num:nil
|
||||
|
||||
* Git Deep Dive
|
||||
A Version 1 Technical Meetup talk covering the deep internals of git.
|
||||
|
||||
** Introduction
|
||||
This is the slide-deck and set-up scripts used to give the /Git Deep Dive/ technical meet-up talk on 2018-06-25 in Version 1, by Éibhear Ó hAnluain.
|
||||
|
||||
The pack comes with the following:
|
||||
- This document
|
||||
- The slide-deck, =GitDeepDive.pdf=
|
||||
- A script to set up a simple git repository for exploration purposes: =simple-setup.sh=
|
||||
- A script to set up the mimic of a development team and processes: =gitDemo.sh=
|
||||
- A script to set up another simple repository to run through the process for completely clearing a file out of a git database: =largeFile-setup.sh=.
|
||||
- A =.gitignore= file.
|
||||
|
||||
** Setup
|
||||
1) Run the script =simple-setup.sh=. This will create a git repository in =simpleRepo= and populate it with some commits. The commits in this repository will correspond to the diagrams in the slide-deck that relate to merging.
|
||||
2) Run the script =largeFile-setup.sh=. This will create another git repository in =largeFileRepo= and populate it with the same commits as in =simpleRepo=, and then puts in some more to create and manipulate a large binary file, and then to remove it. This will be used for the demonstration to remove a file completely from the repository.
|
||||
3) Run the script =gitDemo.sh=. This will replicate a previous git repository as a bare repo in =devTeamDemo/javaBootcampNoEclipse.git=, and then create a number of clones to represent the actions of a team lead and two developers, and mimic collaborative development among them. =gitDemo.sh= takes one optional parameter, =-s=, which will cause the progression to stop for 15 seconds following each "actor's" push in order to afford the opportunity to look at the git log.
|
||||
4) Use the =gpg= utility to generate a key-pair so that you can work through the commit- and tag-signing slide and sample commands. If you have access to =gpg2= and not =gpg=, you'll need to set the following =git config= to make sure it's picked up: =git config --global gpg.program gpg2=.
|
||||
5) Open the file =GitDeepDive.pdf=, and as you go through the slides, refer to the /Sample Commands/ section below for commands you can execute to get further insights.
|
||||
|
||||
** Sample commands
|
||||
|
||||
*** Slide: Configuration
|
||||
#+BEGIN_SRC shell
|
||||
# Go to where the GitDeepDive.pdf file is and set your BASE_DIR
|
||||
# environment variable.
|
||||
cd <where-you-have-this-repo-cloned-to>
|
||||
export BASE_DIR=$(pwd)
|
||||
# List your basic git config
|
||||
git config --list
|
||||
# Go into the simple repo location and look at the various config
|
||||
# contexts
|
||||
cd ${BASE_DIR}/simpleRepo
|
||||
git config --local --list
|
||||
git config --global --list
|
||||
git config --system --list
|
||||
# Set some settings
|
||||
git config --global user.name "<YourName>"
|
||||
git config --global user.email "<YourEmailAddress>"
|
||||
# Use a text editor to edit your config
|
||||
git config -e
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: fetch and merge, not pull
|
||||
#+BEGIN_SRC shell
|
||||
# Go into the clone belonging to one of the developers in the
|
||||
# development team demo area
|
||||
cd ${BASE_DIR}/devTeamDemo/javaBootcampNoEclipse.dev1
|
||||
# Update the clone, but don't merge anything
|
||||
git fetch --prune
|
||||
# Review the local and remote branches.
|
||||
git branch -va
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Merging approaches: fast-forward
|
||||
#+BEGIN_SRC shell
|
||||
cd ${BASE_DIR}/simpleRepo
|
||||
# Check out the master branch and review it's log
|
||||
git checkout master
|
||||
git log --decorate --graph --oneline --all
|
||||
# Merge in the Rel1 branch and review the new log.
|
||||
git merge Rel1
|
||||
git log --decorate --graph --oneline --all
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Merging approaches: merging strategies
|
||||
#+BEGIN_SRC shell
|
||||
cd ${BASE_DIR}/simpleRepo
|
||||
# Check out the master branch, merge the Rel2 branch and review the
|
||||
# new log.
|
||||
git checkout master
|
||||
# You'll be prompted for a commit message here.
|
||||
git merge Rel2
|
||||
git log --decorate --graph --oneline --all
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Merging approaches: Rebase
|
||||
#+BEGIN_SRC shell
|
||||
# Remove and refresh the simpleRepo
|
||||
${BASE_DIR}/simple-setup.sh
|
||||
cd ${BASE_DIR}/simpleRepo
|
||||
|
||||
# Check out master, review its log, merge Rel1 and review the log
|
||||
git checkout master
|
||||
git log --decorate --graph --oneline --all
|
||||
git merge Rel1
|
||||
git log --decorate --graph --oneline --all
|
||||
|
||||
# Check out Rel2
|
||||
git checkout Rel2
|
||||
# Rebase Rel2 onto the now-new master
|
||||
git rebase master
|
||||
# Review the log
|
||||
git log --decorate --graph --oneline --all
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: refs
|
||||
#+BEGIN_SRC shell
|
||||
# Remove and refresh the simpleRepo
|
||||
${BASE_DIR}/simple-setup.sh
|
||||
cd ${BASE_DIR}/simpleRepo
|
||||
|
||||
# Look at the contents of .git/refs/heads and one of the heads itself
|
||||
ls -l .git/refs/heads/
|
||||
cat .git/refs/heads/Rel2
|
||||
|
||||
# Tag a branch, look at the branch ref and the tag ref
|
||||
git tag Rel1.0 Rel1
|
||||
cat .git/refs/heads/Rel1
|
||||
cat .git/refs/tags/Rel1.0
|
||||
|
||||
# Look at the HEAD ref
|
||||
cat .git/HEAD
|
||||
|
||||
# Go to another clone and look at the refs for the origin remote
|
||||
cd ${BASE_DIR}/devTeamDemo/javaBootcampNoEclipse.dev1
|
||||
ls -l .git/refs/remotes/origin/
|
||||
# .git/packed-refs contains the refs that haven't been interacted with
|
||||
# yet.
|
||||
cat .git/packed-refs
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Annotated tags
|
||||
#+BEGIN_SRC shell
|
||||
cd ${BASE_DIR}/simpleRepo
|
||||
|
||||
# Look at a "lightweight" tag
|
||||
cat .git/refs/tags/Rel1.0
|
||||
# What type of object is it pointing to?
|
||||
git cat-file -t $(cat .git/refs/tags/Rel1.0)
|
||||
# What's in the object it's pointing to
|
||||
git cat-file -p $(cat .git/refs/tags/Rel1.0)
|
||||
|
||||
# Create an annotated tag and look at *it*
|
||||
git tag -a -m "Formal release of 1.0" Rel1.0.prod Rel1
|
||||
cat .git/refs/tags/Rel1.0.prod
|
||||
# What type of object is it pointing to?
|
||||
git cat-file -t $(cat .git/refs/tags/Rel1.0.prod)
|
||||
# What's in the object it's pointing to
|
||||
git cat-file -p $(cat .git/refs/tags/Rel1.0.prod)
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: blame
|
||||
#+BEGIN_SRC shell
|
||||
# Look at the lines of the file on master
|
||||
git checkout master
|
||||
git blame information.md
|
||||
# .. and on Rel1
|
||||
git checkout Rel1
|
||||
git blame information.md
|
||||
# And on master after Rel2 has been merged in.
|
||||
git merge Rel2
|
||||
git blame information.md
|
||||
# Slide
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Tag and commit signing
|
||||
#+BEGIN_SRC shell
|
||||
# Look at your secret keys
|
||||
gpg --list-secret-keys
|
||||
|
||||
# Check out master and make a change to information.md
|
||||
git checkout master
|
||||
cat <<EOF >> information.md
|
||||
An additional line for demonstrating commit-signing.
|
||||
|
||||
EOF
|
||||
|
||||
# Add and commit the change, signing the commit.
|
||||
git add information.md
|
||||
git commit -S<secretKeyID> -m "Update to information.md"
|
||||
|
||||
# Look at the commit object
|
||||
git cat-file -p master
|
||||
|
||||
# Create an annotated tag from the Rel2 branch, signing it.
|
||||
git tag -s -u <secretKeyID> -m "Release 2." Rel2.0 Rel2
|
||||
# Look at the tag object
|
||||
git cat-file -p Rel2.0
|
||||
|
||||
# Verify the signed tag and the signed commit.
|
||||
git tag -v Rel2.0
|
||||
git log --show-signature -1
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Git Objects -- blobs
|
||||
#+BEGIN_SRC shell
|
||||
# Generate the SHA1 of the contents of the ~/.bash_history file as
|
||||
# though git would
|
||||
cat ~/.bash_history | git hash-object --stdin
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Git Objects -- trees
|
||||
#+BEGIN_SRC shell
|
||||
cd ${BASE_DIR}/devTeamDemo/javaBootcampNoEclipse.dev1
|
||||
# Get the tree object for the latest version of the top-level of the
|
||||
# project
|
||||
git cat-file -p master | grep '^tree'
|
||||
# Look at the contents of that tree object:
|
||||
git cat-file -p $(git cat-file -p master | grep '^tree' | sed 's/^tree //')
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Git Objects -- commits
|
||||
#+BEGIN_SRC shell
|
||||
cd ${BASE_DIR}/simpleRepo
|
||||
git log --graph --all --decorate --oneline
|
||||
git cat-file -p HEAD
|
||||
git cat-file -p <anyOtherCommitId>
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Git Objects -- tags
|
||||
#+BEGIN_SRC shell
|
||||
# Find all the tag objects
|
||||
git cat-file --batch-check='%(objecttype) %(objectname) %(objectsize)' --batch-all-objects | grep tag
|
||||
git cat-file -p <anyOfTheTagObjects>
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: "Content Addressable Filesystem"
|
||||
#+BEGIN_SRC shell
|
||||
# Find all the objects, and select one that refers to a file
|
||||
git rev-list --all --objects
|
||||
# Look at the contents of the selected object
|
||||
git cat-file -p <selectedBlobObject>
|
||||
# Use git to get the SHA1 of the contents of that object
|
||||
git cat-file -p <selectedBlobObject> | git hash-object --stdin
|
||||
# The name of the file for that object is based on the SHA1.
|
||||
ls -l .git/objects/...
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: The reflog
|
||||
#+BEGIN_SRC shell
|
||||
# Look at the reflog, then clear it completely and look at it again.
|
||||
git reflog
|
||||
git reflog expire --expire=now --expire-unreachable=now --verbose --all
|
||||
git reflog
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: fsck and gc
|
||||
#+BEGIN_SRC shell
|
||||
git fsck
|
||||
git gc
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Useful commands
|
||||
#+BEGIN_SRC shell
|
||||
# Go into the repo where the large file had been created
|
||||
cd ${BASE_DIR}/largeFileRepo
|
||||
# List all the objects in increasing order of object size.
|
||||
git cat-file --batch-check='%(objecttype) %(objectname) %(objectsize)' --batch-all-objects | sed -n 's/^blob //p' | sort -n --key=2
|
||||
# Look for the file name associated with an object
|
||||
git rev-list --objects --all | grep <blobID>
|
||||
# Look for the commits that made changes to a specific file
|
||||
git log --follow -- "largeInformation.md"
|
||||
#+END_SRC
|
||||
|
||||
*** Slide: Permanently removing a file from your git db
|
||||
#+BEGIN_SRC shell
|
||||
|
||||
# Preserve information on the tags, as you may need this later.
|
||||
for tag in $(git tag)
|
||||
do
|
||||
echo "${tag},$(git log --format="%H,\"%cn\",\"%ci\",\"%s\"" ${tag} | head -1)"
|
||||
done | tee /tmp/tag_list.csv
|
||||
|
||||
# Create a local branch for all the remote branches. This does nothing
|
||||
# in this demo as there is no remote.
|
||||
for branch in $(git branch -r | grep -v HEAD | sed 's/\ \ origin\///')
|
||||
do
|
||||
git branch ${branch} origin/${branch}
|
||||
done
|
||||
|
||||
# Check out each branch and determine the amount of space it uses
|
||||
for branch in $(git branch | sed 's/^..//')
|
||||
do
|
||||
git checkout -q ${branch}
|
||||
du -sk . | sed "s/\./${branch}/"
|
||||
done | tee /tmp/branch_sizes.out
|
||||
|
||||
# Check out the Rel1 branch
|
||||
git checkout Rel1
|
||||
# Use git-filter-branch to remove the file from all the commits on the
|
||||
# branch
|
||||
git filter-branch --tree-filter 'rm -f largeInformation.md' --prune-empty HEAD
|
||||
# Update refs (will fail for some branches)
|
||||
git for-each-ref --format="%(refname)" refs/original/ | xargs -n 1 git update-ref -d
|
||||
|
||||
# Do the same for all the other branches
|
||||
for branch in Rel2 Rel3 Rel4 master
|
||||
do
|
||||
git checkout ${branch}
|
||||
git filter-branch --tree-filter 'rm -f largeInformation.md' --prune-empty HEAD
|
||||
git for-each-ref --format="%(refname)" refs/original/ | xargs -n 1 git update-ref -d
|
||||
done | tee /tmp/cleanup.out
|
||||
|
||||
# Clear out the reflog
|
||||
git reflog expire --expire-unreachable=now --all
|
||||
# Run the garbage collector on the repository
|
||||
git gc --prune=now
|
||||
# Run an FSCK on the repo
|
||||
git fsck --unreachable --no-reflogs
|
||||
|
||||
# Check out each branch again and determine the amount of space it
|
||||
# uses
|
||||
for branch in $(git branch | sed 's/^..//')
|
||||
do
|
||||
git checkout -q ${branch}
|
||||
du -sk . | sed "s/\./${branch}/"
|
||||
done | tee /tmp/branch_sizes_post_process.out
|
||||
#+END_SRC
|
||||
Loading…
Reference in a new issue