Commit directly to a bare repository

Question

Some Context

what this fits into

A collaboration focused web application that offers git hosting (as bare repos)

what we want to do

Allow users to add a set of files directly to their existing repositories.

My Question

Is there a tool or method to manually create a commit that only involves adding new files to a git repo?

We're able to do this now using temporary server-side sparse checkouts but we would like to optimize this process.

What do you mean "create a commit that only involves adding new files"? How is that any different than a normal commit? — Andrew Marshall, Mar 12 '12 at 15:53
It sounds like you want to have a web application where people can upload files, and those files, on the backend, get committed to a git repo? What language is the web site in? You would likely need to find a library to interact with git for whatever language you are using. — CodingWithSpike, Mar 12 '12 at 16:07
@rally25rs We are using a python wsgi app but we're not as concerned with what language or packages we need to use to do this. Any method can be triggered from the site as a subprocess. — rennat, Mar 12 '12 at 18:37
I'm also interested in this topic; I need it for phorkie, my git based pastebin tool. — cweiske, Apr 04 '12 at 09:52
This issue has been on my back burner while working out other parts of the platform but I will need to readdress it soon. If no module or library can be found I would like to start one as a lightweight open source project. For our platform making this a Python module makes sense but it would be beneficial to do it in a common format with multiple language bindings. If anyone is interested in contributing or leading this small project please let me know. — rennat, Apr 04 '12 at 17:46
I just want to say you're not mad, and I hope one of us finds the answer and puts it here for the next wanderers — Will, Dec 14 '12 at 07:22

score 12 · Accepted Answer · edited May 23 '17 at 12:16

The plumbing and porcelain page sort of have an example of this, but I'll try to simplify it.

It seems bare repos still have an index, which can be manipulated and made into a commit. It's probably also possible to create tree object from scratch, but I'm not aware of exactly how.

You probably have to lock the repository if there's a risk someone else might access it at the same time. I'll simply use lockfile from the procmail package here.

#!/bin/bash
cd myrepo.git

MY_BRANCH=master
MY_FILE_CONTENTS=$'Hello, world!\n'

# Note this is just a lock for this script. It's not honored by other tools.
lockfile -1 -r 10 lock || exit 1

PARENT_COMMIT="$(git show-ref -s "$MY_BRANCH")"

# Empty the index, not sure if this step is necessary
git read-tree --empty

# Load the current tree. A commit ref is fine, it'll figure it out.
git read-tree "${PARENT_COMMIT}"

# Create a blob object. Some systems have "shasum" instead of "sha1sum"
# Might want to check if it already exists. Left as an excercise. :)
BLOB_ID=$(printf "blob %d\0%s" $(echo -n "$MY_FILE_CONTENTS" | wc -c) "$MY_FILE_CONTENTS" | sha1sum | cut -d ' ' -f 1)
mkdir -p "objects/${BLOB_ID:0:2}"
printf "blob %d\0%s" $(echo -n "$MY_FILE_CONTENTS" | wc -c) "$MY_FILE_CONTENTS" | perl -MCompress::Zlib -e 'undef $/; print compress(<>)' > "objects/${BLOB_ID:0:2}/${BLOB_ID:2}"

# Now add it to the index.
git update-index --add --cacheinfo 100644 "$BLOB_ID" "myfile.txt"

# Create a tree from your new index
TREE_ID=$(git write-tree)

# Commit it.
NEW_COMMIT=$(echo "My commit message" | git commit-tree "$TREE_ID" -p "$PARENT_COMMIT")

# Update the branch
git update-ref "refs/heads/$MY_BRANCH" "$NEW_COMMIT" "$PARENT_COMMIT"

# Done
rm -f lock

It'd be nice if there were git commands to create blobs, but I didn't find one. The perl command was taken from another question.

As for how to create a tree/blob object from scratch, there seems to be a command called `git hash-object` that can do that for you, and it also adds it to the object store when passing it the `-w` flag. http://git-scm.com/docs/git-hash-object — Qqwy, Oct 24 '15 at 22:25

score 3 · Answer 2 · edited Mar 25 '14 at 02:12

3

The "Plumbing and Porcelain" chapter of Pro Git provides some insight into the internals of Git, which you could leverage into a way to create commits while bypassing some of the normal Git process.

edited Mar 25 '14 at 02:12

Chris Pitman

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answered Mar 14 '12 at 02:40

Amber

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Never fully resolved this but congrats on having the best answer! – rennat Jun 27 '12 at 16:37

score 2 · Answer 3 · answered May 10 '14 at 16:36

2

I created the sample for git add/rm files into bare repo using JGit. Check out https://github.com/junoyoon/git-online-commit-sample. In the test code you can know how to use JGit APIs for bare repo manipulation.

answered May 10 '14 at 16:36

JunHo Yoon

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