External Systems¶
To obtain information from other systems OASIS uses “feeds”. These are small scripts which, when run, will communicate with other systems. For example, one might connect to a central LDAP server and retrieve enrolment information.
Working examples are included to cover several common cases, but you can add your own. If you name them local_SOMETHING, they will not be accidentally overwritten by future OASIS upgrades.
You can have different feeds connecting to different systems if you wish. There are currently two supported types of feed:
Group Feeds¶
Group Feed scripts tell OASIS how users are arranged into groups. For example: students enrolled in courses, or groups of tutors.
When run, the feed scripts should output a one line status code followed by a simple list of usernames, one per line:
OK
ccog001
fsmi324
jblo034
If the feed encounters an error, it should output a one line ERROR code, followed by a human readable error message, for example:
ERROR FATAL
This feed script was unable to contact
the LDAP server, please see the server
log for details.
OASIS will report these errors (if any) in the Server Administration feeds pages of the application.
The following status codes are meaningful to OASIS:
- OK
- The feed worked and the output can be used.
- ERROR TEMPORARY
- The error is temporary, OASIS can try again later.
- ERROR FATAL
- The error is serious, OASIS should deactivate the feed and not try it again until the systems administrator has investigated (and can manually reactivate the feed when it is fixed)
Look at the files in the OASIS deploy/feeds folder for some example scripts.
User Account Feeds¶
User Account feeds tell OASIS how to find details on users with non-OASIS accounts.
For example when “fjon032” logs in for the first time, OASIS may run the User Account Feed scripts and expect one of them to return the user’s full name, email address, and an optional ID. (The ID could be a student ID number or similar):
./user_feed_lookup fjon032
OK
fjon032,Freddie Jones,f.jones@example.com
./user_feed_lookup sdoo1
OK
sdoo1,Scooby Doo,s.doo@example.com,S10293754
It may periodically re-run these to pick up any changes to the user’s details.
The User Account Feed scripts can accept multiple usernames at a time. This allows them to be more efficient when, for example, retrieving information on a new large class with 500 students:
./script_fetch_students fjon032 dbla377 nrogers
OK
fjon032,Freddie Jones,f.jones@example.com
dbla377,NOTFOUND
nrogers,Norville Rogers,shaggy@example.com
In this example, the feed script could not find information about “dbla377”
If there is an error, it should output a one line status code, followed by a human readable error message, for example:
./script_fetch_students fjon032 dbla377 nrogers
ERROR TEMPORARY
Enrolment database is locked, please try later.
The status codes are the same as for Group Feeds.
No Feeds¶
It is entirely possible to run OASIS as a standalone system, without configuring any feeds. It will look after its own user accounts and groups. However, feeds allow you to integrate OASIS with other systems which may already look after accounts and groups for you.