Beginner's Guide to Creating Discourse Plugins Part 4: Git Setup

plugins

(Robin Ward) #1

Previous tutorials in this series:

Part 1: Creating a basic plugin
Part 2: Plugin outlets
Part 3: Custom Settings

Now that your plugin is getting more sophisticated, it’s time to get more sophisticated about how you develop it.

We suggest that you use git as version control for your plugin. We also recommend that you use github to share your plugin code with others.

Creating your Git Repo

Once you’ve created your Github account, visit this url to create a new repository. You can call it anything you want, but generally something that stars with discourse- is good. Make sure the repository is public. Here’s how my screen looked:

Creating your local working folder

At this point I create a local directory on my computer to hold the plugin. I usually put mine in ~/code but you can put it anywhere you like on your computer:

mkdir -p ~/code/discourse-plugin-test
cd ~/code/discourse-plugin-test

Now let’s follow the instructions from github to initialize the repo with a README:

echo "# discourse-plugin-test" >> README.md
git init
git add README.md
git commit -m "first commit"
git remote add origin git@github.com:eviltrout/discourse-plugin-test.git
git push -u origin master

Finally, create a plugin.rb file for your plugin as explained in part 1. For this example I just created a dummy one:

plugin.rb

# name: discourse-plugin-test
# about: Shows how to set up Git
# version: 0.0.1
# authors: Robin Ward

Creating a symlink

Because you followed our developer guide you should have a copy of discourse checked out on your computer somewhere. I checked mine out to ~/code/discourse but again you could have put it anywhere and this should still work if you adjust the following code accordingly:

cd ~/code/discourse/plugins
ln -s ~/code/discourse-plugin-test .

The above code created a symbolic link between your discourse code and your plugin folder. Restart your rails server and you should find your plugin is working!

The beauty of this setup is you can just check your plugin into github and not worry about the discourse codebase it lives inside. Your changes will be isolated to the plugin itself. If you need to edit discourse’s code you still can, but git will track the changes separately!

I recommend using one editor window for your plugin codebase and one for Discourse itself. It is easier when you think of them as two different things.


More in the series

Part 5: Admin Interfaces


Beginner’s Guide to Creating Discourse Plugins Part 6: Acceptance Tests
Beginner's Guide to Creating Discourse Plugins - Part 1
Allow reply-to individual instead of topic/forum (mailing list feature)
Rails Girls 2015 SoC Banter
#2
  • After many frustrating attempts, found out that apparently ln -s does not work in a Windows environment, or atleast not how it should.
  • ln -s essentially just copy-pasted the plugin folder into the discourse/plugins folder
  • Apparently, in Windows the way to create symbolic links is to use the mklink command in command prompt (run as administrator, and this command does not natively run in Windows PowerShell either).
  • Using the mklink command (with both arguments /d and /h), although the created symbolic link could be seen present in the directory, the plugin was not working with discourse (and also not showing in /admin/plugins).
  • I tried this multiple times with restarting the rails server, deleting the tmp folder, but to no avail.

@eviltrout, any idea what could I be doing wrong?


(Robin Ward) #3

I assume you are using Vagrant on windows? If you can’t get the symbolic links sent over, I think the only way you can do it is to copy the plugin into discourse/plugins manually and work from there. It should work as long as you are not making changes to the core discourse app at the same time, which confuses git.

When your plugin is ready, you’ll want to copy it to another directory to package it up for git.


#4

Yeah, OK this should be fine too.
Although the OCD side of me, much preferred the comparatively “cleaner” symbolic links method.

Anyway, Thanks.


(Marcus Baw) #5

@AhmadF.Cheema I had similar problems with the symlinking using Vagrant 1.9.8 on Linux, and a completely standard Discourse Vagrant development environment as per the docs.

The problem is simple when you look into it. From the scope of inside the Vagrant VM, the destination of the symlink is not a valid path. Try executing the command ls -al in the plugins directory inside your VM (in a standard install this is at /vagrant/plugins)

vagrant@discourse:/vagrant/plugins$ ls -al
total 36
drwxr-xr-x 1 vagrant vagrant 4096 Oct 22 09:08 ./
drwxr-xr-x 1 vagrant vagrant 4096 Oct 22 09:10 ../
drwxr-xr-x 1 vagrant vagrant 4096 Sep  7 19:51 discourse-details/
drwxrwxr-x 1 vagrant vagrant 4096 Oct 21 13:56 discourse-narrative-bot/
drwxr-xr-x 1 vagrant vagrant 4096 Oct 21 13:56 discourse-nginx-performance-report/
drwxr-xr-x 1 vagrant vagrant 4096 Sep  7 19:51 discourse-plugin-outlet-locations/
drwxrwxr-x 1 vagrant vagrant 4096 Oct 21 13:56 discourse-presence/
lrwxrwxrwx 1 vagrant vagrant   55 Oct 22 09:08 my-basic-plugin -> /home/marcus/code/discourse/my-basic-plugin
drwxr-xr-x 1 vagrant vagrant 4096 Oct 21 13:56 lazyYT/
drwxr-xr-x 1 vagrant vagrant 4096 Oct 21 13:56 poll/

As you can see, the path /home/marcus/code/discourse/my-basic-plugin cannot possibly be accessible from the VM because it doesn’t exist inside the VM!

The solution is to delete the externally created symlink and set up a separate shared folder in Vagrant, by adding a line to your Vagrantfile:

config.vm.synced_folder "/home/marcus/code/my-basic-plugin",  "/my-basic-plugin"

Then restart the Vagrant VM: vagrant halt && vagrant up so that this change is picked up

Now, when you enter your VM via SSH using vagrant ssh you can create a symlink inside the VM:

cd /vagrant/plugins
ln -s /my-basic-plugin .

Now you can develop in a neatly isolated local folder, and have the neat Git workflow that @eviltrout describes, and the symlinking happens inside the VM. Note that outside the VM, the symlink will be broken - but this shouldn’t matter for our purposes.


(Sam Saffron) #6

If you are developing on Linux using our docker based dev is way simpler


(Stephen Chung) #7

Windows symlinks are different from Unix symlinks, thus your confusion. Windows synlinks are very fussy, requiring particular versions of OS to support and sometimes applications must be written to be aware of this. In other words, the stars must line up perfectly for windows symlinks to work.

A hard link (/H) I dont think work with directories. Your /D makes a symlink on a directory, trumping your /H (which is used to create a hard link to a file, not a directory).

Confusing? Welcome to Windows.

There are four types of links in Windows:

  • MKLINK (no flags) – symbolic link to file
  • MKLINK /H – hard link to file
  • MKLINK /D – symbolic link to directory
  • MKLINK /J – junction (i.e. hard link) to directory

What you need is is a junction which is Windows-speak for hard link to a directory.

Do MKLINK /J to your plugins directory and the system will treat it as a subdirectory. In fact it won’t know otherwise. Beware, it is not common to have a Windows directory (folder in Windows-speak) to point to the same place as another directory, so you’ll get confused very easy and forget that both are the same things.

That’s why you’ll need to run the command in Administrator mode, otherwise Windows won’t let you create the directory junction.


(Marcus Baw) #8

Thanks for the info regarding Windows symlinks @schungx - it should be of help to the OP.

The workaround I described should work fine on any platform, since the symlinks happen inside the (Ubuntu) vagrant box

M


(Stephen Chung) #9

Yup, you’re right. If you can avoid it, avoid messing with Windows. Windows is very picky and may choose to die or go wrong at the most unfortunate moment…


(Cheng Zheng) #10

Work for me! 2018-4-29

1. I put discourse & my plugin in Desktop

instead of put 1c7-plugin under discourse/plugin

2. and put a “alias” into discourse/plugins folder

alias is a macOS concept,
it’s the same things as ln -s command

3. Discourse correctly load the plugin

(After reboot server with rails s)

4. Now they are separated, use git to manage code is much easier

Thanks!