如何同時用多個 git bare repository來管理你的專案並同步

無論是何原因，假設你想用多個repository來管理你的專案，
如何同時用多個 git bare repository來管理你的專案並同步呢？
一句話，
如果你需要多個 git repository （相同的git專案）, 那麼你需要用 --mirror 命令列去複製主 repository

例如:

狀況一：master repository --clone--> mirror repository，再由 mirror --create-->project
                project commit --sync back--> mirror --sync back--> master
建立主要 repository

$ mkdir main_repo

$ cd main_repo/

main_repo$ git init --bare

Initialized empty Git repository in /Users/user/temp/main_repo/

建立mirror repository from master(main) repository

$ git clone --mirror main_repo/ branch_repo

Cloning into bare repository 'branch_repo'...

warning: You appear to have cloned an empty repository.

done.

mirror --create--> developing project
從 mirror repository clone 到開發專案區
經編輯後上傳同步回 mirror

$ git clone branch_repo/ branch_working

Cloning into 'branch_working'...

warning: You appear to have cloned an empty repository.

done.

$ cd branch_working/

branch_working$ touch 1.txt

branch_working$ git add .

branch_working$ git commit -a -m "add 1.txt"

[master (root-commit) 7cf8070] add 1.txt

 1 file changed, 0 insertions(+), 0 deletions(-)

 create mode 100644 1.txt

上傳回 mirror

$ git push origin master

回 mirror 站看內容，有更新

$ cd ..

$ cd branch_repo/

branch_repo$ git log

commit 7cf80708eadc22df7844b9d1914b552d3b4cad64

此時若 mirror 要回傳 main , 只要 git push 回去即可

branch_repo$ git push 

Counting objects: 3, done.

Writing objects: 100% (3/3), 202 bytes | 0 bytes/s, done.

Total 3 (delta 0), reused 0 (delta 0)

---

狀況二：master --clone--> mirror --> project，假設mirror目前有問題，我們可以直接commit回master
                project commit --> add remote(master)  --push to master--> master


master --clone--> mirror --> project 請參考上方

在 working 的專案修改並 commit

branch_working$ touch 2.txt

branch_working$ git add .

branch_working$ git commit -a -m "add 2.txt"

[master 5678cfa] add 2.txt

 1 file changed, 0 insertions(+), 0 deletions(-)

 create mode 100644 2.txt

我們可以 add remote 建立 new remote，再回傳new remote

branch_working$ git remote add mybase /Users/user/temp/main_repo/ 

branch_working$ git push mybase master

Counting objects: 3, done.

Delta compression using up to 4 threads.

Compressing objects: 100% (2/2), done.

Writing objects: 100% (2/2), 229 bytes | 0 bytes/s, done.

Total 2 (delta 0), reused 0 (delta 0)

To /Users/user/temp/main_repo/

   7cf8070..5678cfa  master -> master

這時 master(main) repository 跟 project repository 已經同步。
那麼 mirror 要怎麼同步呢？
切到 mirror(branch_repo)，只要下 git fetch 即可

branch_repo$ git fetch

remote: Counting objects: 3, done.

remote: Compressing objects: 100% (2/2), done.

remote: Total 2 (delta 0), reused 0 (delta 0)

Unpacking objects: 100% (2/2), done.

From /Users/user/temp/main_repo

   7cf8070..5678cfa  master     -> master

branch_repo$ git log

commit 5678cfad38f70a8210f3d6a44dd4184cc9f15b22

Author: 

Date:   Mon Nov 24 19:05:18 2014 +0800

    add 2.txt

git log 出來看，2.txt 己 sync

從以上來看， mirror 及 main repository 可以很彈性的 sync