Storing Project Artifacts on Class Account

Storing Project Artifacts

Please read the following instructions carefully.

Quotas

The quota for all the students in the class is now 30 MB on the /home/scf-team partition, which is accessible on all SCF timesharing hosts and workstations. You will be writing your project artifacts to the cs577 directory on that partition, which is owned by cs577 and is only user-writable but is world-readable and world-searchable. Your quota on the /home/scf-team partition is separate from the one your home directory.

Team Directories

Accessing Your Team Directory

- There are sub-directories under /home/scf-team/cs577, one for each team. These subdirectories are owned by cs577. We already set them up such that access to a team directory is limited to only team members.
- Now, you should move and keep all the cs577 project-related artifacts on the newly allocated space
- Do not keep personal files on the class account, since it will be periodically inspected
- At the end of the semester, we will take ownership of all the files on that partition

- There are 21 directories name teamXa (X = 1,2...16,17,...,21).

You can access your team directory by doing:
% cd /home/scf-team/cs577/teamXa
or
% ~cs577/www/teamXa
(~cs577/www/teamXa is a symbolic link to the actual directory /home/scf-team/cs577/teamXa)

Team Permissions

All members (assuming that MX1, MX2, MX3, etc... are their usernames on the SCF hosts) of teamXa have been given rwx permission to the teamXa directory, using the setfacl command, executed by owner cs577:
setfacl -r -m user:MX1:rwx teamX
setfacl -r -m user:MX2:rwx teamX
setfacl -r -m user:MX3:rwx teamX
...
- So now, team members (MX1, MX2, MX3, etc...) can create sub-directories or files under the team directory (teamX)

Creating a sub-directory

Team member MX1 creates a sub-directory temp under teamX. The permissions would be:
drwx------ MX1 512 Oct. 17 temp

If team member MX1 wants team member MX2 and MX3 to have access to this directory, member MX1 has to give them permission (assuming rwx permission for MX2 and r-- permission for MX3):
setfacl -r -m user:MX2:rwx temp
setfacl -r -m user:MX3:r temp

then the access would look like (note the + sign):
drwx-------+ X1 512 Oct. 17 temp

Now if team member MX1 creates a file OCD.html in temp and team member MX2 creates a file SSRD.html in temp then team member MX1 needs to do:
setfacl -r -m user:MX2:rwx OCD.html
setfacl -r -m user:MX3:rwx OCD.html

and team member MX2 needs to do:
setfacl -r -m user:MX1:rwx SSRD.html
setfacl -r -m user:MX3:rwx SSRD.html

so that all three team members (MX1, MX2 and MX3) can now edit the file.

File Permissions

Note that all students in the class are in the same group. So, if you set the permissions to your files to rwx (for group) using (chmod), then any student in the class will have rwx access to your file.

For a file to be readable by the HTTP server (see below), you need to set the permissions to rwxr-xr-x. You can do that by running:
chmod 755 filename

You can find out more about the setfacl and getfacl commands by doing man setfacl or man getfacl (ACL stands for Access Control List). Also, you can find out more about the chmod command by doing man chmod

Troubleshooting File Permissions

If the Web server cannot access any file in the dirname directory and returns 'File Not found' error, even though it appears as if the permissions
are correctly set to rwxr-xr-x, you may have incorrectly specified permissions.

1. Look at the permissions of the directory dirname

getfacl dirname
# file: dirname
# owner: username1
# group: csci-577
user::rwx
user:username1:rwx         #effective:rwx
user:username2:rwx         #effective:rwx
user:username3:rwx         #effective:rwx
user:username4:rwx         #effective:rwx
group::---              #effective:---
mask:rwx
other:---

For the directory to be accessible by the web server, you need to have group::r-x

2. The solution is to execute (in the parent directory)
setfacl -r -m group:csci-577:r-x dirname

Note that the problem seems to happen whenever you create a directory, set the ACL, and then try to do the chmod. You may prevent the
problem from happening by:
1. Creating the directory (mkdir dirname)
2. Setting the permissions for the Web server (chmod 755 dirname)
3. Set the ACLs for the files in the directory to give specific rwx access to your team members,
e.g., setfacl -r -m user:username2:rwx dirname

Version Control

Now that team members can now have access to each other's document, make sure that you do not overwrite each other's changes to the various documents, which may lead to a lot of wasted time and effort. You can follow a simple configuration management scheme, make up your own or use any version control tool that you may have available (no support provided for any such tool)..

Simple Version Control

If you are still working on a document, and are not done with it yet, you can set read-only permission to your team members. Once you are done with your changes, and want to allow your team members to modify the document, you can give them read-write permissions to it.
When a document has read-write permissions, you might run into the problem of having two team members download their copy of the document, work on it independently, and then upload it back. Only the last one uploaded will be saved, thus one team member will overwrite the other's work. As a simple configuration management too, if you "check out" a document (e.g., OCD.html), and you are editing it, add some agreed-upon suffix to the filename (e.g., OCD-out.html). If your team members notice that the file has been renamed, it's probably because you are working on it. After you are done, upload it back, under its original name (OCD.html) and delete (OCDout.html) or rename it to keep the older version as a back-up in case you need to undo your changes (OCD.bak.html)

Directory Structure

Under your team directory, you have to set-up a directory structure as indicated in the guidelines. Failure to do so will result in severe penalties. Also remember NOT to delete anything you do for project (winwin, prototype, documents), since now you have enough space to store everything. Teams who do not keep project artifacts (for both the LCO and the LCA) will be penalized.
Make sure to use ONLY relative references so that your entire team directory structure can be moved to the archive without breaking any links. Some Web publishing tools tend to automatically generate absolute references instead of relative ones, unless you particularly pay attention to it.
i.e. use <ahref = "LCO/OCD/OCD.html"> instead of <ahref ="http://nunki.usc.edu:8082/teamXa/LCO/OCD/OCD.html">

Team Homepage

- As indicated in the guidelines, every team has to setup a team homepage.
- There is an HTTP server running on nunki.usc.edu at port 8082.
- The cs577 account administrators (currently the Teaching Assistants) are responsible for the administration of the web server. So, if you notice that the web server is down, please send email to the Teaching Assistants.