D瓜哥从去年开始,将所有的笔记都整合到了自建的 Wiki 中。整理分析,确实方便很多。
最近有两个部分,比较独立,自成系统。其中,有一个模块还考虑和其他小伙伴合作来搞。所以,就将这两部分抽取出来,独立成单独的项目来维护。但是,为方便查看和随时随地同步更新,正好可以使用 Git Submodule 特性。
另外,还有一种场景:开发的项目使用了第三方或者公司的基础库,使用同一个版本库肯定不合适,也不现实,这时就必须使用子模块来搞。
对 Git 不了解的,可以参考D瓜哥以前的文章:Git&Github社区化协作使用指南。下面,D瓜哥带领大家来学习一下 git submodule
的简单实用方法。
添加子模块
从新建一个项目,或者从远处服务器上克隆一个项目,作为“顶级项目”。这里,D瓜哥就从 Github 上新建一个项目,然后再克隆下来:
1 | ➜ /Users/diguage git clone git@github.com:diguage/parent.git |
3 | Cloning into 'parent' ... |
4 | remote: Counting objects: 5, done . |
5 | remote: Compressing objects: 100% (5/5), done . |
6 | remote: Total 5 (delta 0), reused 0 (delta 0), pack-reused 0 |
7 | Receiving objects: 100% (5/5), 4.59 KiB | 0 bytes/s, done . |
8 | Checking connectivity... done . |
进入刚克隆下来的项目,我们来添加子模块。这里的子模块就必须从远处服务器上克隆了。另外,子模块可以放在项目的任意目录下,并且可以根据自己的需要重命名。D瓜哥这里这是为了方便演示,所以就直接放在子目录了。进入顶级项目,我们先看一下版本库的状态:
1 | ➜ /Users/diguage cd parent |
3 | ➜ /Users/diguage/parent git:(master) git status |
6 | Your branch is up-to- date with 'origin/master' . |
7 | nothing to commit, working directory clean |
这里提示,项目中没有任何需要提交的东西。下面,我们开始添加子模块:
1 | ➜ /Users/diguage/parent git:(master) git submodule add git@github.com:diguage/child.git |
4 | remote: Counting objects: 5, done . |
5 | remote: Compressing objects: 100% (5/5), done . |
6 | remote: Total 5 (delta 0), reused 0 (delta 0), pack-reused 0 |
7 | Receiving objects: 100% (5/5), 4.63 KiB | 0 bytes/s, done . |
8 | Checking connectivity... done . |
这时,再看一下版本库的状态:
1 | ➜ /Users/diguage/parent git:(master) ✗ git status |
3 | Your branch is up-to- date with 'origin/master' . |
4 | Changes to be committed: |
5 | (use "git reset HEAD <file>..." to unstage) |
这时,我们看到,除了刚刚添加的 child
模块外,还多了一个 .gitmodules
文件。这个文件就是用于记录子模块的路径已经远程版本库地址的地方。这两个文件处于待提交的状态。下面把这个修改提交一下。
01 | ➜ /Users/diguage/parent git:(master) ✗ git commit -am "增加子模块" |
04 | 2 files changed, 4 insertions(+) |
05 | create mode 100644 .gitmodules |
06 | create mode 160000 child |
09 | ➜ /Users/diguage/parent git:(master) git push origin master |
11 | Counting objects: 3, done . |
12 | Delta compression using up to 8 threads. |
13 | Compressing objects: 100% (3/3), done . |
14 | Writing objects: 100% (3/3), 452 bytes | 0 bytes/s, done . |
15 | Total 3 (delta 0), reused 0 (delta 0) |
16 | To git@github.com:diguage/parent.git |
17 | e56cd5a..a05bfe0 master -> master |
这时,大家可以登录到 Github 或者其他的版本库服务器上看一下项目的状态。D瓜哥就不贴图了。
至此,添加子模块的工作已经完成。下面,我们来看一看如何更新。
更新子模块
当我们添加完子模块后,过段时间后,子模块有更新,这时候,我们就需要更新了。我们来看一下如何更新。
方式一
这个方式略微显得有的“笨拙”,但是大智若愚,大巧若拙,万变不离其宗。最笨的招数也许也是最实用的招数。扯了这么多,其实很简单,就是进入到每一个子模块,执行 git pull origin master
。
01 | ➜ /Users/diguage/parent git:(master) cd child |
03 | ➜ /Users/diguage/parent/child git:(master) git pull origin master |
05 | remote: Counting objects: 3, done . |
06 | remote: Compressing objects: 100% (3/3), done . |
07 | remote: Total 3 (delta 2), reused 0 (delta 0), pack-reused 0 |
08 | Unpacking objects: 100% (3/3), done . |
09 | From github.com:diguage/child |
10 | * branch master -> FETCH_HEAD |
11 | d4ec39a..1b855a4 master -> origin/master |
12 | Updating d4ec39a..1b855a4 |
15 | 1 file changed, 3 insertions(+) |
这时,我们再进入到顶级项目中,查看一下项目状态:
01 | ➜ /Users/diguage/parent/child git:(master) cd .. |
03 | ➜ /Users/diguage/parent git:(master) ✗ git status |
06 | Your branch is up-to- date with 'origin/master' . |
07 | Changes not staged for commit: |
08 | (use "git add <file>..." to update what will be committed) |
09 | (use "git checkout -- <file>..." to discard changes in working directory) |
11 | modified: child (new commits) |
13 | no changes added to commit (use "git add" and/or "git commit -a" ) |
这里可以看到明显的提示,在项目有一个新的提交。为什么会这样呢?其实,Git 在顶级项目中记录了一个子模块的提交日志的指针,用于保存子模块的提交日志所处的位置,以保证无论子模块是否有新的提交,在任何一个地方克隆下顶级项目时,各个子模块的记录是一致的。避免因为所引用的子模块不一致导致的潜在问题。如果我们更新了子模块,我们需要把这个最近的记录提交到版本库中,以方便和其他人协同。这也是刚刚添加完子模块后还要在顶级项目中提交一次的原因。
01 | ➜ /Users/diguage/parent git:(master) ✗ git commit -am "更新子模块" |
04 | 1 file changed, 1 insertion(+), 1 deletion(-) |
07 | ➜ /Users/diguage/parent git:(master) git push origin master |
09 | Counting objects: 2, done . |
10 | Delta compression using up to 8 threads. |
11 | Compressing objects: 100% (2/2), done . |
12 | Writing objects: 100% (2/2), 259 bytes | 0 bytes/s, done . |
13 | Total 2 (delta 1), reused 0 (delta 0) |
14 | To git@github.com:diguage/parent.git |
15 | a05bfe0..5ac4dbb master -> master |
这里D瓜哥再多说一句:进入子模块目录后,你就当做这是一个独立的项目,可以正常进行一个普通 Git 项目所执行的任何操作。更新完正常的修改、添加任务后,把所做的修改提交,然后推送到远处版本库上。然后,如果需要记得在顶级项目中,也做一次提交,修改一下顶级项目所引用的子模块的提交日志的“指针”。
克隆项目
当多人合作搞一个项目,或者需要同步公司电脑的代码到家里电脑上,就需要从远处版本库上克隆项目代码。这时,可以使用两种方式。
方式一
古语有云:由俭入奢易,由奢入俭难。所以,D瓜哥决定先从比较麻烦的方式入手。下面开始:
01 | ➜ /Users/diguage git clone git@github.com:diguage/parent.git |
03 | Cloning into 'parent' ... |
04 | remote: Counting objects: 10, done . |
05 | remote: Compressing objects: 100% (9/9), done . |
06 | remote: Total 10 (delta 2), reused 5 (delta 1), pack-reused 0 |
07 | Receiving objects: 100% (10/10), 5.11 KiB | 0 bytes/s, done . |
08 | Resolving deltas: 100% (2/2), done . |
09 | Checking connectivity... done . |
12 | ➜ /Users/diguage cd parent |
15 | ➜ /Users/diguage/parent git:(master) git submodule update --init --recursive |
17 | Submodule 'child' (git@github.com:diguage/child.git) registered for path 'child' |
18 | Cloning into 'child' ... |
19 | remote: Counting objects: 8, done . |
20 | remote: Compressing objects: 100% (8/8), done . |
21 | remote: Total 8 (delta 2), reused 0 (delta 0), pack-reused 0 |
22 | Receiving objects: 100% (8/8), 4.91 KiB | 0 bytes/s, done . |
23 | Resolving deltas: 100% (2/2), done . |
24 | Checking connectivity... done . |
25 | Submodule path 'child' : checked out '1b855a4987b44e7530dbd9904dee089fb31f3525' |
28 | ➜ /Users/diguage/parent git:(master) cd child |
31 | ➜ /Users/diguage/parent/child git:((1b855a4...)) git status |
33 | HEAD detached at 1b855a4 |
34 | nothing to commit, working directory clean |
37 | ➜ /Users/diguage/parent/child git:((1b855a4...)) git checkout master |
39 | Switched to branch 'master' |
40 | Your branch is up-to- date with 'origin/master' . |
这里需要大概四步,确实挺复杂。下面我们来看一看稍微简单一点的。
方式二
01 | ➜ /Users/diguage git clone --recursive git@github.com:diguage/parent.git |
03 | Cloning into 'parent' ... |
04 | remote: Counting objects: 10, done . |
05 | remote: Compressing objects: 100% (9/9), done . |
06 | remote: Total 10 (delta 2), reused 5 (delta 1), pack-reused 0 |
07 | Receiving objects: 100% (10/10), 5.11 KiB | 0 bytes/s, done . |
08 | Resolving deltas: 100% (2/2), done . |
09 | Checking connectivity... done . |
10 | Submodule 'child' (git@github.com:diguage/child.git) registered for path 'child' |
11 | Cloning into 'child' ... |
12 | remote: Counting objects: 8, done . |
13 | remote: Compressing objects: 100% (8/8), done . |
14 | remote: Total 8 (delta 2), reused 0 (delta 0), pack-reused 0 |
15 | Receiving objects: 100% (8/8), 4.91 KiB | 0 bytes/s, done . |
16 | Resolving deltas: 100% (2/2), done . |
17 | Checking connectivity... done . |
18 | Submodule path 'child' : checked out '1b855a4987b44e7530dbd9904dee089fb31f3525' |
21 | ➜ /Users/diguage cd parent/child |
24 | ➜ /Users/diguage/parent/child git:((1b855a4...)) git status |
26 | HEAD detached at 1b855a4 |
27 | nothing to commit, working directory clean |
30 | ➜ /Users/diguage/parent/child git:((1b855a4...)) git checkout master |
32 | Switched to branch 'master' |
33 | Your branch is up-to- date with 'origin/master' . |
这种方式确实比上面简单多了,少了一条命令。(别笑!严肃点,哥是认真的!)
删除子模块
也许未来有一天,我们项目成功了,公司上市了,可以不再引用别人的代码,自己早轮子了,那么我们就可以把子模块从版本库中删除。D瓜哥原以为很麻烦,今天为了写文章,特意试了一下,其实很简单。(我艹,哥是不是暴露了什么?!)如下:
01 | ➜ /Users/diguage/parent git:(master) git rm child |
06 | ➜ /Users/diguage/parent git:(master) ✗ git status |
09 | Your branch is up-to- date with 'origin/master' . |
10 | Changes to be committed: |
11 | (use "git reset HEAD <file>..." to unstage) |
17 | ➜ /Users/diguage/parent git:(master) ✗ git commit -am "删除子模块" |
20 | 2 files changed, 4 deletions(-) |
21 | delete mode 160000 child |
24 | ➜ /Users/diguage/parent git:(master) git push origin master |
26 | Counting objects: 3, done . |
27 | Delta compression using up to 8 threads. |
28 | Compressing objects: 100% (2/2), done . |
29 | Writing objects: 100% (3/3), 274 bytes | 0 bytes/s, done . |
30 | Total 3 (delta 1), reused 0 (delta 0) |
31 | To git@github.com:diguage/parent.git |
32 | 5ac4dbb..b0b088b master -> master |
直接一条命令就搞定了: git rm <SubModuleName>
。
参考资料